Oracle Scripts

Enable a 10046 Trace for an Oracle Session

Fri, 10 Jul 2026 00:00:00 +0000

Enable a 10046 Trace for an Oracle Session

Purpose

A 10046 trace returns wait events only if the level includes them. Enabling the trace at level 1 and then wondering why the file shows no waits is the most common 10046 mistake in production diagnosis — the output has elapsed times and call counts, but none of the db file sequential read, latch: cache buffers chains, or enq: TX - row lock contention events that explain where those seconds actually went. Choosing the wrong level produces a trace file that answers a different question than the one being investigated.

Run a Consistent Export with expdp FLASHBACK_TIME

Fri, 10 Jul 2026 00:00:00 +0000

Run a Consistent Export with expdp FLASHBACK_TIME

Purpose

A Data Pump export that reads one table at 02:00 and the next at 02:15 is not a consistent snapshot — it is a photograph taken in pieces over time. For schemas where rows in one table reference rows in another, that time spread means the export can capture parent rows whose child records were not yet committed, or child records whose parents were deleted during the export window. The dump file looks intact until the import runs and foreign key constraints reveal the mismatch, or an ETL pipeline reports orphaned surrogate keys.

Monitor Data Pump Progress with V$SESSION_LONGOPS

Sun, 05 Jul 2026 00:00:00 +0000

Monitor Data Pump Progress with V$SESSION_LONGOPS

Purpose

Where the expdp and impdp log files record a status line per completed object — writing output at each table boundary, not while a large table is mid-transfer — V$SESSION_LONGOPS records progress while the operation is still running. That gap matters on a full-database export scheduled overnight or an import that has been running for six hours with no new log output. The log file will not tell you how far along the current table is. V$SESSION_LONGOPS will.

Insert Control Characters in vi with Ctrl-V for Oracle Prompts

Sat, 20 Jun 2026 00:00:00 +0000

Insert Control Characters in vi with Ctrl-V for Oracle Prompts

Purpose

A custom SQL*Plus prompt that prints the connected instance name in colour, or a login script that clears the screen before the banner, both need one thing the keyboard cannot type directly: a literal control character embedded in the file. Press Esc while editing and vi leaves insert mode. Press Enter and vi opens a new line instead of writing a carriage return into the buffer. The control codes a terminal escape sequence is built from are exactly the keys vi reserves for its own commands, so typing them does the wrong thing.

Check RESUMABLE_TIMEOUT and RESUMABLE Status in V$SESSION

Fri, 19 Jun 2026 00:00:00 +0000

Check RESUMABLE_TIMEOUT and RESUMABLE Status in V$SESSION

Purpose

V$SESSION carries two columns that tell you whether a session can survive running out of space: RESUMABLE and the resumable timeout that governs it. When resumable space allocation is enabled, a statement that hits a space error — a full tablespace, a maxed-out datafile, an exceeded user quota — does not fail immediately. Oracle suspends it, raises a RESUMABLE alert, and waits. If a DBA frees the space inside the timeout window, the statement wakes up and continues from where it stopped. If the window expires first, the statement fails with the original space error.

Monitor PGA Aggregate Target with V$PGASTAT in Oracle

Thu, 18 Jun 2026 00:00:00 +0000

Monitor PGA Aggregate Target with V$PGASTAT in Oracle

Purpose

Is PGA_AGGREGATE_TARGET set high enough for the work the instance actually does? V$PGASTAT answers that question. It is the instance-level statistics view for the Program Global Area — the private memory Oracle hands to each server process for sorting, hashing, and bitmap operations. Where a per-session PGA view tells you what one connection is using, V$PGASTAT rolls every process into one set of instance-wide numbers: the target you asked for, the bytes actually allocated, the high-water mark, and the cache hit percentage that says whether work-area operations are running in memory or spilling to temp.

Oracle Scheduler Job Monitoring with DBA_SCHEDULER_RUNNING_JOBS

Tue, 09 Jun 2026 00:00:00 +0000

Oracle Scheduler Job Monitoring with DBA_SCHEDULER_RUNNING_JOBS

Purpose

Which Oracle Scheduler jobs are executing at this instant, and how long has each been running? DBA_SCHEDULER_RUNNING_JOBS answers that directly. It lists only the jobs that are active right now — not the full job catalog, not the run history, just the live set. Joining it to DBA_SCHEDULER_JOBS adds the job's owner, program, and schedule, so a single query turns "is anything stuck?" into a concrete list of names, session IDs, and elapsed times.

Oracle DBMS_SCHEDULER: Create and Manage Jobs with PL/SQL

Mon, 08 Jun 2026 00:00:00 +0000

Oracle DBMS_SCHEDULER: Create and Manage Jobs with PL/SQL

Purpose

Automating a recurring task — a nightly statistics gather, a log purge, an end-of-month rollup — is a standard part of running an Oracle database. DBMS_SCHEDULER.CREATE_JOB is the procedure that registers that task with the database so it runs on a calendar schedule without an external cron entry. The job, its action, and its schedule all live inside the database, which means they are backed up, replicated to a standby, and visible in the data dictionary.

Query Wait Events by Session with Oracle V$SESSION_WAIT

Sun, 07 Jun 2026 00:00:00 +0000

Query Wait Events by Session with Oracle V$SESSION_WAIT

Purpose

V$SESSION_WAIT is the real-time view that shows what each Oracle session is waiting on this very second. For every session it exposes the wait event name, how long the session has been in that wait, and three event-specific parameters (P1, P2, P3) that pinpoint the resource — a file and block number, a lock type, a latch address. It is the view to reach for when the database "feels slow right now" and you need the current state, not a post-mortem from AWR.

Oracle Index Rebuild and Coalesce with ALTER INDEX

Sat, 06 Jun 2026 00:00:00 +0000

Oracle Index Rebuild and Coalesce with ALTER INDEX

Purpose

Over months of heavy delete and update activity, a B-tree index can accumulate empty and half-full leaf blocks. The index keeps working, but it grows wider than the data it points to, so range scans read more blocks than they need and the segment holds space that is no longer doing useful work. ALTER INDEX ... REBUILD and ALTER INDEX ... COALESCE are the two commands that address this — one rebuilds the index from scratch, the other merges adjacent sparse leaf blocks in place.

Search UNIX Man Pages for Oracle DBA Tools with man -k

Mon, 25 May 2026 00:00:00 +0000

Search UNIX Man Pages for Oracle DBA Tools with man -k

Purpose

Where Google answers most "how do I do X in UNIX" questions for a DBA today, man -k answers the narrower one — what tools the host actually has installed, and what each one does, without leaving the SSH session. Production Oracle hosts often run in change-controlled networks with no outbound HTTP, no browser, and a tight maintenance window; man -k and its synonym apropos are the offline discovery commands that close the gap between knowing a vague capability exists and finding the binary that delivers it.

Enable vi Command-Line Editing in ksh for Oracle DBA Shells

Sun, 24 May 2026 00:00:00 +0000

Enable vi Command-Line Editing in ksh for Oracle DBA Shells

Purpose

Recalling and editing the prior command without retyping it is the single most-used operation in a long DBA shift on an Oracle host. On the Korn shell (ksh) — the default login shell on AIX 7.x, Solaris 11, HP-UX 11i, and many older Oracle 11g/12c reference builds — that operation is gated behind one line in .profile: set -o vi. Without it, the up-arrow key prints a literal escape sequence and the only way to repeat a long RMAN BACKUP DATABASE PLUS ARCHIVELOG ... invocation is to type it again.

Disable vi Autoindent Before Pasting SQL Scripts on Oracle Hosts

Sat, 23 May 2026 00:00:00 +0000

Disable vi Autoindent Before Pasting SQL Scripts on Oracle Hosts

Purpose

Pasting a SQL script copied from email, a Confluence page, or a ticket comment into a vi buffer over SSH — and watching every line shift one indent right of the previous one — is the most common and most frustrating vi failure mode an Oracle DBA encounters. The script that ran fine when executed directly from the wiki snippet now fails on the host with SP2-0042: unknown command " INSERT" on every line. The cause is autoindent: vi assumed each new line should match the indentation of the previous one, and the terminal cannot distinguish a real keypress from a pasted character, so the indent compounds.

vi Editor Commands Reference for Oracle DBAs

Wed, 20 May 2026 00:00:00 +0000

vi Editor Commands Reference for Oracle DBAs

Every Oracle DBA on Unix or Linux ends up in vi whether they planned to or not. It opens by default when you crontab -e, it is what visudo drops you into, and it is the editor on most Oracle Linux and AIX hosts before anyone has installed nano or configured EDITOR. Knowing the core commands is not optional — it is the difference between a clean parameter change and a corrupted init.ora that brings down the instance.

Scan Every Oracle Alert and Trace Log for ORA- Errors with grep

Sun, 17 May 2026 00:00:00 +0000

Scan Every Oracle Alert and Trace Log for ORA- Errors with grep

Purpose

Every Oracle environment generates alert logs and process trace files recording instance events, errors, and diagnostics. When a support call comes in — "the database was slow last night, can you check the logs?" — the fastest first pass is a single grep across every log file in the diagnostic directory. This one-liner, drawn from the shutdownabort.com DBA Quick Guides (Andrew Barry, 2007–2013, preserved via the Wayback Machine), scans all alert logs under the Oracle diagnostic root and prints every line containing an ORA- error code.

Find the Biggest Files First When an Oracle Filesystem Fills Up

Sat, 16 May 2026 00:00:00 +0000

Find the Biggest Files First When an Oracle Filesystem Fills Up

Purpose

A full Oracle filesystem is a five-alarm incident. Whether it is the /u01/oradata mount holding datafiles, the Fast Recovery Area filling with archive logs, or the diag directory overflowing with trace files, the first question is always the same: which files are consuming the space? The two commands below — taken from the shutdownabort.com DBA Quick Guides (Andrew Barry, 2007–2013, preserved via the Wayback Machine) — are the DBA's first-response toolkit for answering that question within thirty seconds on any UNIX host without any Oracle database tools.

Recursive find and grep to Search Oracle Trace Files for Any String

Fri, 15 May 2026 00:00:00 +0000

Recursive find and grep to Search Oracle Trace Files for Any String

Purpose

Oracle's Automatic Diagnostic Repository (ADR) accumulates hundreds or thousands of trace files — one per background process event, one per incident, one per session that hits an error deep enough to dump. Finding the trace file that contains evidence of a specific error or a specific SQL statement requires searching the content of all of them, not just their names. The two-command pipeline below — from the shutdownabort.com DBA Quick Guides (Andrew Barry, 2007–2013, preserved via the Wayback Machine) — uses find to enumerate trace files and grep -l to identify which ones contain the target string.

Oracle Export Through a Named Pipe with mknod for Space-Constrained Hosts

Thu, 14 May 2026 00:00:00 +0000

Oracle Export Through a Named Pipe with mknod for Space-Constrained Hosts

Purpose

Oracle's original Export utility (exp) writes a binary dump file. On production hosts where disk space is tight — where staging a full-database dump and its compressed copy simultaneously would exhaust the filesystem — the classic workaround is a named pipe (FIFO). A named pipe looks like a file on the filesystem but has no storage: bytes written to one end are immediately readable from the other. By piping the Export directly through gzip or netcat, the dump never touches disk as an uncompressed file.

Unpacking Oracle Patch and Install Media with cpio

Wed, 13 May 2026 00:00:00 +0000

Unpacking Oracle Patch and Install Media with cpio

Purpose

Before Oracle began shipping all patches as .zip files, the standard delivery format for Oracle install media and large patch bundles was cpio — a tape archive format that predates tar and is still the underlying format used inside every RPM package. DBAs working with Oracle 8i, 9i, and early 10g installations, or with older patch archives from Oracle MetaLink, received media on tape or in .cpio files and used cpio -idmv to stage it for installation.

Diagnose Oracle Net and RAC Interconnect Routing with netstat -r

Tue, 12 May 2026 00:00:00 +0000

Diagnose Oracle Net and RAC Interconnect Routing with netstat -r

Purpose

Oracle Net connections and Oracle RAC private interconnect traffic both depend on correct IP routing. When an Oracle client cannot connect to the listener, when RAC Cache Fusion or heartbeat traffic is routing over the wrong interface, or when sqlnet.ora logs show unexpected source addresses, the OS routing table is the first place to look. netstat -r prints the kernel routing table — the same table that determines where every TCP packet on the Oracle server goes.

Find Oracle Archive Logs Older Than N Days with find -mtime

Sun, 03 May 2026 00:00:00 +0000

Find Oracle Archive Logs Older Than N Days with find -mtime

Purpose

Oracle databases in archivelog mode write a stream of .ARC (archived redo log) files to a destination directory. The directory fills up. When it fills up, the database hangs. The four find -mtime commands below let a DBA list, delete, compress, or move archive logs by age — the daily housekeeping that keeps the archive destination from filling.

Write Text Files from Oracle PLSQL with UTL_FILE Example

Sat, 02 May 2026 00:00:00 +0000

Write Text Files from Oracle PL/SQL with UTL_FILE Example

Purpose

UTL_FILE is the built-in Oracle PL/SQL package for reading and writing operating-system files from inside the database. The procedure below — taken straight from the shutdownabort.com DBA Quick Guides (Andrew Barry, 2007–2013, preserved via the Wayback Machine as the anchor source for this post) — opens a file in write mode, writes one line, and closes the handle. It is the smallest possible "hello world" for UTL_FILE and the right starting point for any DBA who needs to spool data to disk from PL/SQL.

Sample tnsnames.ora Dedicated Server Entry (with ASM)

Fri, 01 May 2026 00:00:00 +0000

Sample tnsnames.ora Dedicated Server Entry (with ASM)

Purpose

The tnsnames.ora file is the client-side address book for Oracle Net. Each entry maps a short alias (SCR9) to a full network address — protocol, host, port, and target service. Without a working tnsnames.ora entry, sqlplus, rman, and any application using OCI cannot reach the database.

The two entries below — taken straight from the shutdownabort.com DBA Quick Guides (Andrew Barry, 2007–2013, preserved via the Wayback Machine as the anchor source for this post) — are the smallest possible reference: one dedicated-server connection to a database service, and one connection to a non-default listener used by ASM.

Sample listener.ora with Static SID_LIST and Extproc

Thu, 30 Apr 2026 00:00:00 +0000

Sample listener.ora with Static SID_LIST and Extproc

Purpose

The listener.ora file is the server-side configuration for the Oracle Net listener — the process that accepts incoming client connections and hands them off to a database server process. The sample below — taken straight from the shutdownabort.com DBA Quick Guides (Andrew Barry, 2007–2013, preserved via the Wayback Machine as the anchor source for this post) — shows two fundamental patterns: a LISTENER block that names the network endpoints the listener listens on, and a SID_LIST_LISTENER block that statically registers two services: a regular database and the PLSExtProc agent for PL/SQL external procedures.

Delete the 500 Oldest Files in a Directory (Oracle DBA)

Wed, 29 Apr 2026 00:00:00 +0000

Delete the 500 Oldest Files in a Directory (Oracle DBA)

Purpose

Oracle's diagnostic destination (DIAGNOSTIC_DEST), audit file destination (AUDIT_FILE_DEST, also known as adump), and per-process trace directories collect thousands of small files over time. Inode counts, not bytes, are usually the limit that bites first — many filesystems cap directory entries or per-filesystem inodes well below the disk's byte capacity. The one-liner below — taken straight from the shutdownabort.com DBA Quick Guides (Andrew Barry, 2007–2013, preserved via the Wayback Machine as the anchor source for this post) — deletes the 500 oldest files in the current directory in one shot. It is the quickest way to free up enough headroom to keep the database running while a longer-term retention strategy is put in place.

List Files Opened by an Oracle Process with lsof -p

Tue, 28 Apr 2026 00:00:00 +0000

List Files Opened by an Oracle Process with lsof -p

Purpose

lsof (LiSt Open Files) is the UNIX tool for inspecting which processes have which files open. For an Oracle DBA it is the fastest answer to four common questions: which datafiles is this server process touching, which trace file is PMON writing into right now, why is df reporting more space used than du, and which library is the database currently mapped against. The one-liner below — taken straight from the shutdownabort.com DBA Quick Guides (Andrew Barry, 2007–2013, preserved via the Wayback Machine as the anchor source for this post) — is the smallest possible invocation: list every file held open by one process, identified by its PID.

Oracle CREATE DIRECTORY Command Explained

Sun, 12 Apr 2026 00:00:00 +0000

Oracle CREATE DIRECTORY Command Explained

The Oracle CREATE DIRECTORY command creates a directory object — a logical alias inside the Oracle database that points to a real folder on the server's file system. This is one of the most used setup steps for Oracle Data Pump exports and imports, UTL_FILE file operations, BFILEs, and external tables.

What Is an Oracle Directory Object?

A directory object does not create a real folder on the operating system. It only creates a pointer — or alias — inside Oracle that maps a name you choose to a physical path on the database server. This keeps your PL/SQL code and Data Pump jobs clean because you use the Oracle directory name instead of hard-coding full OS paths in your scripts.

Oracle Data Pump: Create the DATA_PUMP_DIR Directory

Sat, 11 Apr 2026 00:00:00 +0000

Oracle Data Pump: Create the DATA_PUMP_DIR Directory

Before you can run any Oracle Data Pump export (expdp) or import (impdp) job, Oracle needs to know where to write and read dump files and log files on the server. You do this by creating a directory object inside the database that points to a real folder on the operating system.

What This Script Does

This one-line SQL command creates a database directory object named DATA_PUMP_DIR that maps to the physical path /u01/ora_backup/datapump on the server. Once created, Oracle Data Pump jobs can use this directory to store export dump files and log files.

Oracle Data Pump Export Schema with expdp Command Guide

Fri, 10 Apr 2026 00:00:00 +0000

Oracle Data Pump Export Schema with expdp Command Guide

Oracle Data Pump's expdp utility lets you take a fast, flexible logical backup of any schema in your Oracle database. This post breaks down a simple schema-level export command, explains each parameter, and shows you how to run it safely.

What This Command Does

The command below exports all objects and data from the andy schema into a binary dump file stored in an Oracle directory object called my_dir.

Oracle expdp Schema Export Using Data Pump

Thu, 09 Apr 2026 00:00:00 +0000

Oracle expdp Schema Export Using Data Pump

Oracle Data Pump's expdp utility lets you export a full database schema — including tables, indexes, constraints, and data — into a portable dump file. This guide breaks down the single-line command that does exactly that for the andy schema.

Purpose of This Command

The goal of this command is to create a logical backup of a single Oracle database schema called andy. The export produces a binary dump file (andy.dp) saved to a pre-defined Oracle directory object (my_dir) on the server. This backup can later be imported into the same or a different Oracle database using impdp.

Oracle DBMS_FLASHBACK.ENABLE_AT_TIME: Session Flashback

Thu, 12 Mar 2026 00:00:00 +0000

Oracle DBMS_FLASHBACK Enable At Time: Session Flashback Guide

Oracle's DBMS_FLASHBACK.ENABLE_AT_TIME is a powerful procedure that lets you travel back in time within your database session — letting you query data exactly as it existed at a specific past moment, without needing a full database restore.

What This Code Does

This one-line call puts your entire Oracle session into "flashback mode," pointed at a specific past date and time. All SELECT queries you run after this call will return data as it was at that moment — not the current data. This is ideal for investigating accidental deletes, data corruption, or auditing historical states.

Oracle: Disable Flashback with DBMS_FLASHBACK.DISABLE

Wed, 11 Mar 2026 00:00:00 +0000

Overview

When working with Oracle Database, there are times when you need to look at data from the past — like rewinding a video to see what happened earlier. Oracle gives you a tool called Flashback to do this. But once you are done looking at past data, you must turn Flashback off. The command to do that is:

1EXEC DBMS_FLASHBACK.DISABLE;

This post explains what this command does, how it works, and when to use it.

Oracle Flashback Query: Copy Historical Data to a Table

Tue, 10 Mar 2026 00:00:00 +0000

Oracle Flashback Query: Copy Historical Data Into a New Table

Sometimes you need to go back in time and recover data the way it looked at a specific moment — without restoring the full database. Oracle makes this possible with Flashback Query, using the AS OF TIMESTAMP clause to read historical data directly from the undo tablespace. This post shows a clean, two-step pattern to create an empty copy of a table and then fill it with data from a past point in time.

Oracle exp: Export Database with FLASHBACK_TIME

Mon, 09 Mar 2026 00:00:00 +0000

Export an Oracle Database from a Point in Time Using FLASHBACK_TIME

The Oracle exp utility supports a FLASHBACK_TIME parameter that lets a database administrator export a full database with all data consistent to a single point in time. This is critical for large, active databases where export duration may span minutes or hours and data must not drift between tables.

Purpose

When you run a standard Oracle export on a live database, different tables may be captured at slightly different moments. This can produce an inconsistent dump file where related tables are out of sync. The FLASHBACK_TIME parameter solves this by anchoring all exported data to one specific timestamp — Oracle translates that timestamp into a System Change Number (SCN) and uses Flashback Query internally to read data as it was at that exact moment.

Oracle: Get Current SCN with DBMS_FLASHBACK

Sun, 08 Mar 2026 00:00:00 +0000

How to Find the Current SCN in Oracle Database Using DBMS_FLASHBACK

The System Change Number (SCN) is Oracle's internal logical clock. Every DBA needs to know how to read it. This post shows you the simplest SQL query to get the current SCN from any Oracle Database session, and explains exactly why it matters.

What Is an SCN?

The System Change Number (SCN) is a monotonically increasing integer that Oracle assigns to every committed transaction. It is the foundation of Oracle's consistency and recovery model. Think of it as Oracle's version of a timestamp — except it is more precise and more reliable than wall-clock time. Oracle uses the SCN for:

Oracle Fast Recovery Area: Set db_recovery_file_dest

Sat, 07 Mar 2026 00:00:00 +0000

Oracle Fast Recovery Area: Set DB Recovery File Dest and Size

The Oracle Fast Recovery Area (FRA) is a disk location where Oracle stores and manages files related to backup and recovery. Two dynamic initialization parameters — db_recovery_file_dest and db_recovery_file_dest_size — control its location and maximum size, and both can be changed without restarting the database.

The Code

1-- Set the database recovery directory and size
2-- These settings are dynamic
3
4ALTER SYSTEM SET db_recovery_file_dest='<path>' SCOPE=BOTH;
5/
6ALTER SYSTEM SET db_recovery_file_dest_size=<size> SCOPE=BOTH;
7/

1Replace `<path>` with a valid file system path, ASM disk group, or NFS mount point, and replace `<size>` with a value like `100G`, `2T`, or `500M`.

What This Code Does

These two commands configure the Oracle Fast Recovery Area at the system level while the database is running. The SCOPE=BOTH clause means the change takes effect immediately in the running instance and is saved to the server parameter file (SPFILE), so it persists across database restarts.

DB_FLASHBACK_RETENTION_TARGET: Set Oracle Flashback Window

Fri, 06 Mar 2026 00:00:00 +0000

Set Oracle Flashback Database Retention Target with ALTER SYSTEM

Oracle Flashback Database lets you rewind your entire database to a past point in time without a full restore. The command ALTER SYSTEM SET DB_FLASHBACK_RETENTION_TARGET controls how far back in time that rewind can go.

What This Command Does

The DB_FLASHBACK_RETENTION_TARGET parameter sets the upper limit, in minutes, on how far back you can flashback your database. Oracle uses this setting to decide how much flashback log data to keep inside the Fast Recovery Area (FRA). Think of it as a time window — anything older than the target may be cleaned up to free space.

Oracle Flashback: Enable with Shutdown, Mount, ALTER

Thu, 05 Mar 2026 00:00:00 +0000

How to Enable Oracle Database Flashback: Shutdown, Mount, and ALTER Commands

Oracle Flashback Database is one of the most powerful data protection tools available to a DBA. This guide walks you through the four commands needed to turn on Oracle Flashback — from a clean shutdown to opening the database in flashback mode.

What Is Oracle Flashback Database?

Oracle Flashback Database lets you rewind your entire database to a previous point in time — without a full restore. Think of it like an "undo" button for your whole database. Instead of restoring from backup tapes, Oracle reads special flashback logs stored in the Fast Recovery Area (FRA) and rolls the database back in minutes.

resumable_timeout and v$session: Monitor Oracle Resumable Jobs

Wed, 04 Mar 2026 00:00:00 +0000

Oracle Resumable Import Parameters: Monitor and Manage DBA_RESUMABLE

When you run a large Oracle Data Pump import (impdp), the job can fail mid-way if a tablespace runs out of space. Oracle's resumable import feature prevents this by suspending the job instead of failing it, giving you time to fix the problem and then letting the job continue automatically.

What Is a Resumable Import?

A resumable operation is a database operation that can be paused when it hits a correctable error — such as a full tablespace — and then automatically resumed once the problem is fixed. Instead of losing all progress and restarting from zero, you simply add space and the import picks up where it left off.

Oracle Full Export via Named Pipe and Gzip in KSH

Tue, 03 Mar 2026 00:00:00 +0000

Oracle Full Database Export Using a Named Pipe and Gzip Compression in KSH

Exporting a full Oracle database can produce very large dump files. This script solves that problem by streaming the export directly through a Linux named pipe into gzip, compressing the output on the fly — without ever writing an uncompressed file to disk.

What This Script Does

This KSH shell script performs a full Oracle database export (exp) and compresses the output simultaneously using gzip and a Linux named pipe (FIFO). It is designed to run as a background or nohup job on a Unix/Linux server where Oracle is installed.

Oracle exp/imp Parfile: Direct Path Schema Migration

Mon, 02 Mar 2026 00:00:00 +0000

Oracle exp/imp Parameter File: Direct Path User-to-User Data Migration

Using a parameter file (parfile) with Oracle's legacy exp and imp utilities is a clean, repeatable way to move schema data between users — especially when you need speed, control over what gets transferred, and a consistent log trail. This post breaks down a real-world Oracle export/import parameter file that uses OS authentication, direct path mode, and selective object filtering.

Oracle Export and Import via Gzip Named Pipe

Sun, 01 Mar 2026 00:00:00 +0000

Oracle Database Export and Import to Gzip Through a Named Pipe

When you need to export a large Oracle database but do not have enough disk space for a full uncompressed dump file, piping the export directly through gzip using a Unix named pipe is a proven technique. This method compresses data on the fly, producing a .dmp.gz file that is typically only 20% of the size of the original uncompressed dump.

Oracle RMAN Delete Obsolete Backups with Maintenance Channel

Tue, 17 Feb 2026 00:00:00 +0000

Oracle RMAN Delete Obsolete Backups with Maintenance Channel

Purpose

The Oracle RMAN (Recovery Manager) commands shown in this script help database administrators manage backup storage by automatically removing old, unnecessary backup files. These commands allocate a maintenance channel for disk operations and delete obsolete backups based on specific redundancy policies, freeing up valuable storage space while maintaining the required number of backup copies for database recovery.

Code

1ALLOCATE CHANNEL FOR MAINTENANCE DEVICE TYPE DISK;
2DELETE OBSOLETE REDUNDANCY = 4 device type disk;
3DELETE OBSOLETE REDUNDANCY = 2 device type disk;

Code Breakdown

Line 1: ALLOCATE CHANNEL FOR MAINTENANCE DEVICE TYPE DISK

1ALLOCATE CHANNEL FOR MAINTENANCE DEVICE TYPE DISK;

This command manually allocates a maintenance channel for disk-based operations. A maintenance channel is required before executing CHANGE, DELETE, or CROSSCHECK commands in RMAN. The maintenance channel tells RMAN which storage device (in this case, DISK) to use when managing backup files.

LIST BACKUPSET OF DATABASE: Oracle RMAN Command Guide

Mon, 16 Feb 2026 00:00:00 +0000

LIST BACKUPSET OF DATABASE: Oracle RMAN Command Guide

Purpose

The LIST BACKUPSET OF DATABASE command in Oracle Recovery Manager (RMAN) displays detailed information about all backup sets that contain database datafiles. This command helps database administrators verify backup existence, check backup status, find backup keys for restore operations, and audit backup history for compliance and recovery planning.

Command

1LIST BACKUPSET OF DATABASE;

Breakdown of Code

Command Structure

The command combines three key components to query the RMAN repository:

Oracle RMAN Delete Expired Backup: Repository Cleanup

Sun, 15 Feb 2026 00:00:00 +0000

Oracle RMAN Delete Expired Backup: Complete Guide to Repository Maintenance

The DELETE EXPIRED BACKUP command in Oracle RMAN (Recovery Manager) removes expired backup records from the RMAN repository after they have been identified as inaccessible during a crosscheck operation. This command is essential for maintaining an accurate and synchronized RMAN repository, especially when backup files have been deleted at the operating system level without using RMAN commands.

Purpose of Delete Expired Backup

The primary purpose of this command is to clean up the RMAN repository by removing metadata entries for backups that no longer exist physically on disk or tape. When someone accidentally deletes RMAN backup files using operating system utilities, the RMAN repository becomes out of sync with the actual backup files. The DELETE EXPIRED BACKUP command helps maintain repository accuracy by removing these orphaned records.

Oracle RMAN REPORT SCHEMA Command: Display Database Files

Sat, 14 Feb 2026 00:00:00 +0000

Oracle RMAN REPORT SCHEMA Command: Display Database Files

Purpose

The REPORT SCHEMA command is an essential Oracle RMAN (Recovery Manager) tool that displays comprehensive information about all database files in your Oracle database. This command provides database administrators with a quick view of the current database structure, including permanent datafiles, temporary files, tablespaces, and their associated details. Unlike SQL queries that target specific data dictionary views, REPORT SCHEMA retrieves information directly from the RMAN repository stored in the control file, making it a fast and reliable way to assess your database file structure before performing backup or recovery operations.

Oracle RMAN RESTORE DATABASE VALIDATE Backup Check

Fri, 13 Feb 2026 00:00:00 +0000

Oracle RMAN Restore Database Validate - Check Backup Integrity

The RESTORE DATABASE VALIDATE command is one of the most critical proactive health check operations in Oracle Recovery Manager (RMAN) that allows database administrators to verify backup integrity without performing an actual restore operation. This command checks whether backups are readable, accessible, and free from corruption, ensuring your database can be recovered when disaster strikes.

Purpose of RESTORE DATABASE VALIDATE

The main purpose of the RESTORE DATABASE VALIDATE command is to check for corrupt blocks, missing files, and determine whether a backup set can be successfully restored. RMAN scans backup pieces and validates that all necessary files exist and are not corrupted, providing confidence in your backup strategy without impacting production systems. By default, this command validates only datafile backups and does not check control files, archive logs, or server parameter files unless explicitly specified.

Oracle RMAN Delete Obsolete - Remove Unneeded Backups

Thu, 12 Feb 2026 00:00:00 +0000

Oracle RMAN Delete Obsolete - Remove Unneeded Backups

The DELETE OBSOLETE command in Oracle RMAN (Recovery Manager) is a powerful maintenance tool that automatically removes backup files that are no longer needed for database recovery. This command helps database administrators manage storage space by deleting backups that fall outside the configured retention policy.

Purpose

The primary purpose of the DELETE OBSOLETE command is to clean up old backups that are no longer required based on your retention policy. RMAN determines which backups are obsolete by comparing them against the configured retention policy, which can be based on either redundancy (number of backups to keep) or a recovery window (time period for point-in-time recovery). When backups become obsolete, they consume valuable storage space without providing additional recovery capabilities.

Oracle RMAN Report Obsolete Redundancy Command Guide

Wed, 11 Feb 2026 00:00:00 +0000

Oracle RMAN Report Obsolete Redundancy Command Guide

Purpose

The report obsolete redundancy = 2 command in Oracle Recovery Manager (RMAN) identifies database backups that are no longer necessary for recovery operations based on a redundancy-based retention policy. This command helps database administrators determine which backups can be safely deleted to free up storage space while maintaining a minimum of two backup copies for each database file.

Oracle RMAN Report Obsolete Command Guide

Tue, 10 Feb 2026 00:00:00 +0000

Oracle RMAN Report Obsolete Command

The REPORT OBSOLETE command in Oracle Recovery Manager (RMAN) helps database administrators identify backup files that are no longer required for recovery operations. This command compares existing backups against your configured retention policy and marks outdated backups as obsolete.

Code

1report obsolete;

Purpose

The REPORT OBSOLETE command serves a critical function in database backup management by identifying backups that can be safely removed The command does not delete any files automatically; it only marks files as obsolete based on your retention policy. This allows administrators to review which backups are no longer necessary before performing cleanup operations.

List Backup of Archivelog All: Oracle RMAN Command Guide

Mon, 09 Feb 2026 00:00:00 +0000

List Backup of Archivelog All: Oracle RMAN Command Guide

Purpose

The LIST BACKUP OF ARCHIVELOG ALL command in Oracle Recovery Manager (RMAN) displays all existing backups of archived redo log files stored in the RMAN repository. This command helps database administrators track and manage archived log backups, verify backup completion, and plan recovery operations. Archive log backups are essential for point-in-time recovery and maintaining database consistency during restore operations.

Oracle RMAN List Backup of Database Command

Sun, 08 Feb 2026 00:00:00 +0000

Oracle RMAN List Backup of Database Command

Purpose

The LIST BACKUP OF DATABASE command is an Oracle Recovery Manager (RMAN) utility that displays all existing database backups stored in the RMAN repository. This command helps database administrators verify backup availability, review backup history, and plan recovery operations by providing detailed information about all datafile backups for the target database.

Code

1list backup of database;

Breakdown of Code

The command consists of three main components that work together to query the RMAN repository:

Oracle RMAN List Backupset Command Guide

Sat, 07 Feb 2026 00:00:00 +0000

Oracle RMAN List Backupset Command Guide

Purpose

The list backupset; command in Oracle Recovery Manager (RMAN) displays detailed information about backup sets stored in the RMAN repository. This command helps database administrators view backup set metadata, including backup pieces, unique keys, completion times, and status information for recovery planning and backup verification.

Code

1list backupset;

Breakdown of the Command

The list backupset; command is a simple RMAN reporting command that requires no additional parameters. When executed at the RMAN prompt, it queries the RMAN metadata stored in either the control file or recovery catalog and displays all registered backup sets.

Oracle RMAN Crosscheck Archivelog - Fix RMAN-06059 Error

Fri, 06 Feb 2026 00:00:00 +0000

Oracle RMAN Crosscheck Archivelog - Fix RMAN-06059 Error

Purpose

The change archivelog all crosscheck command is an Oracle Recovery Manager (RMAN) utility that synchronizes the RMAN repository metadata with the physical reality of archived redo log files. This command specifically resolves the RMAN-06059 error, which occurs when RMAN expects an archived log file but cannot find it on disk or tape storage. The crosscheck operation validates whether archived logs registered in the RMAN repository still exist at their recorded locations and updates their status accordingly.

Delete Archive Log Older Than 5 Days in Oracle RMAN

Thu, 05 Feb 2026 00:00:00 +0000

Delete Archive Log Older Than 5 Days in Oracle RMAN

Purpose

The DELETE NOPROMPT ARCHIVELOG UNTIL TIME command removes old archive log files from your Oracle database to free up disk space and maintain storage efficiency. This RMAN (Recovery Manager) command automatically deletes archive logs that are older than a specified time period without requiring manual confirmation. Archive logs can quickly consume large amounts of disk space, making regular cleanup essential for database health and performance.

Oracle RMAN Database Restore and Recovery Guide

Wed, 04 Feb 2026 00:00:00 +0000

Oracle RMAN Database Restore and Recovery Guide

Purpose

This guide provides complete Oracle RMAN (Recovery Manager) scripts for restoring and recovering Oracle databases in different scenarios. These scripts help database administrators perform full database recovery, point-in-time recovery (PITR), and verify controlfile backup records using RMAN commands. The scripts use parallel channel allocation to optimize backup and restore operations by running multiple channels simultaneously.

Oracle RMAN Database Backup Commands Guide

Tue, 03 Feb 2026 00:00:00 +0000

Oracle RMAN Database Backup Commands Guide

Oracle Recovery Manager (RMAN) is the primary tool for backing up and recovering Oracle databases, offering automated backup operations with built-in compression, encryption, and validation capabilities. This guide covers essential RMAN backup commands for hot backups, cold backups, archivelog management, and channel allocation strategies.

Purpose of RMAN Backup Commands

RMAN provides database administrators with powerful backup capabilities that ensure data protection and enable point-in-time recovery. The commands in this guide demonstrate four critical backup scenarios: complete database backups with archivelogs, controlled channel allocation for custom backup paths, archivelog-only backups, and cold backups for offline database protection.

Oracle RMAN: Delete Backup Pieces with Manual Channel

Mon, 02 Feb 2026 00:00:00 +0000

How to Delete Oracle RMAN Backup Pieces Using Manual Channel Allocation

Purpose

The RMAN (Recovery Manager) delete backuppiece command removes specific backup pieces from Oracle database storage and updates the RMAN repository. This manual method allocates a maintenance channel to establish a direct connection between RMAN and the storage device (disk or tape), executes the deletion of a specific backup piece by its number, and then releases the channel. This approach gives database administrators precise control over which individual backup files to remove, making it useful for targeted cleanup operations when automated retention policies are not sufficient.

Oracle RMAN Resync Catalog Command Guide

Sun, 01 Feb 2026 00:00:00 +0000

Oracle RMAN Resync Catalog Command Guide

Purpose

The RESYNC CATALOG command synchronizes the metadata stored in your Oracle RMAN recovery catalog with the current information in the target database control file. This ensures that all backup, restore, and recovery operations use the most accurate and up-to-date database information. The command performs a full comparison between the recovery catalog and control file, updating any missing or changed records.

Oracle RMAN CROSSCHECK BACKUP Command Explained

Sat, 31 Jan 2026 00:00:00 +0000

Oracle RMAN Crosscheck Backup Command - Verify Backup Availability

Purpose

The CROSSCHECK BACKUP command is an essential Oracle RMAN (Recovery Manager) tool that verifies whether backup files recorded in the RMAN repository still physically exist on storage media. This command synchronizes the logical records in your RMAN repository with the actual physical reality of your backups on disk or tape. When backups are deleted outside of RMAN control or become unavailable due to hardware failures, the crosscheck command identifies these missing files and marks them as "EXPIRED". This process ensures your backup catalog remains accurate and prevents restore failures during critical recovery operations.

Oracle RMAN Reset Database After RESETLOGS Recovery

Fri, 09 Jan 2026 00:00:00 +0000

Oracle RMAN Reset Database After RESETLOGS Recovery

Purpose

The RESET DATABASE command in Oracle Recovery Manager (RMAN) notifies the recovery catalog that a new database incarnation has been created after opening the database with the RESETLOGS option. This command is essential for maintaining synchronization between the RMAN repository and the target database following incomplete recovery, point-in-time recovery, or recovery using a backup control file.

Oracle RMAN Unregister Database from Recovery Catalog

Thu, 08 Jan 2026 00:00:00 +0000

Oracle RMAN Unregister Database from Recovery Catalog

Purpose

Unregistering a database from an Oracle RMAN (Recovery Manager) recovery catalog removes all backup metadata and database information from the catalog repository. This process is essential when a database is decommissioned, no longer needs catalog-based backups, or when you need to clean up old database entries that are no longer accessible. The DBMS_RCVCAT package provides a direct SQL method to remove database registrations without requiring access to the target database.

How to Register an Oracle Database with RMAN Catalog

Wed, 07 Jan 2026 00:00:00 +0000

How to Register an Oracle Database with RMAN Catalog

Purpose

The RMAN register database command adds a target database to the recovery catalog so that Recovery Manager can track and maintain backup metadata. This allows RMAN to store backup information, recovery points, and database structure details in a central repository instead of relying only on the control file.

Prerequisites

Before registering a database with RMAN catalog, the target database must have a password file created. The password file enables remote authentication for SYSDBA or SYSBACKUP privileges, which RMAN requires to connect and manage backups. You can create a password file using the orapwd utility with the command orapwd file=orapw<SID> password=<password> entries=<number>

How to Create Oracle RMAN Recovery Catalog Step by Step

Tue, 06 Jan 2026 00:00:00 +0000

How to Create Oracle RMAN Recovery Catalog Step by Step

Purpose

The Oracle Recovery Manager (RMAN) recovery catalog is a dedicated database schema that stores metadata about backup and recovery operations for one or more target databases. This script demonstrates how to create a recovery catalog by establishing a separate tablespace, creating a catalog owner user, granting necessary privileges, and initializing the catalog schema. Using a recovery catalog provides better backup tracking, supports longer retention policies, and enables advanced RMAN features compared to using only the target database's control file.

Oracle Data Guard: V$ARCHIVE_DEST Log Destinations

Mon, 05 Jan 2026 00:00:00 +0000

Display Log Destinations Options for Oracle Data Guard Primary Database

Purpose

This SQL script displays detailed information about all configured archive log destinations on an Oracle Data Guard primary database. The query retrieves critical configuration parameters from the V$ARCHIVE_DEST view, allowing database administrators to monitor how redo logs are transmitted to standby databases and archived locally. This monitoring is essential for ensuring proper log shipping, identifying configuration issues, and maintaining high availability in Data Guard environments.

Oracle Data Guard Log Destinations Monitoring Script

Sun, 04 Jan 2026 00:00:00 +0000

Oracle Database Log Destinations Monitoring Script for Data Guard

Purpose

This Oracle SQL script monitors all log destinations in a Data Guard configuration from the primary database. The query provides real-time information about archive log destinations, their status, operational modes, and standby redo log activity. Database administrators use this script to verify that archive logs are being shipped correctly to standby databases and to identify any issues with log transmission.

Check Oracle Data Guard Standby Synchronization Status

Sat, 03 Jan 2026 00:00:00 +0000

How to Check Physical Standby Database Synchronization

Physical standby databases in Oracle Data Guard need regular monitoring to ensure they stay synchronized with the primary database. The most effective way to check synchronization status is by comparing the current sequence number on the primary database with the applied sequence number on the standby database.

Purpose

These SQL queries help database administrators quickly identify if a physical standby database is lagging behind the primary database. By comparing sequence numbers, you can determine the replication gap and take corrective action if the standby falls too far behind. This monitoring is essential for disaster recovery readiness and maintaining your Recovery Point Objective (RPO).

Oracle Logical Standby Apply Stop and Start Commands

Fri, 02 Jan 2026 00:00:00 +0000

Oracle Logical Standby Apply Stop and Start Commands

Purpose

The logical standby apply commands control the SQL Apply process in Oracle Data Guard logical standby databases. These commands allow database administrators to stop and start the application of redo log data from the primary database to the logical standby database, which is essential for maintenance tasks, troubleshooting, and configuration changes.

How to Check Oracle Database Role Using V$DATABASE View

Thu, 01 Jan 2026 00:00:00 +0000

How to Check Oracle Database Role Using V$DATABASE View

Purpose

The SQL query SELECT database_role FROM v$database is a fundamental Oracle Database command used to determine the current operational role of a database instance. This query is essential for Database Administrators (DBAs) working with Oracle Data Guard configurations, as it quickly identifies whether the database is functioning as a PRIMARY database, PHYSICAL STANDBY, LOGICAL STANDBY, or SNAPSHOT STANDBY.

Oracle Data Guard Standby Redo Log Query: Groups and Members

Thu, 01 Jan 2026 00:00:00 +0000

List All Standby Redo Logs in Oracle Data Guard

Purpose

A switchover attempted on a busy Friday afternoon reveals the gap: the standby has been synchronized for months, but no standby redo log group was sized to match the primary's 500 MB online redo logs. The configuration worked fine for the archived-log transport model, but enabling real-time apply requires SRL groups that were never created. The query below surfaces exactly this class of misconfiguration before it becomes a switchover incident.

Oracle Data Guard: Stop Broker with ALTER SYSTEM

Sat, 29 Nov 2025 00:00:00 +0000

How to Stop Oracle Data Guard Broker Using ALTER SYSTEM Command

Purpose

The command ALTER SYSTEM SET dg_broker_start=false stops the Oracle Data Guard broker by shutting down the Data Guard monitor (DMON) background process. This command is essential when you need to disable broker management temporarily for maintenance tasks, troubleshooting, or configuration changes. Setting this parameter to FALSE prevents the broker from automatically starting when the database instance restarts.

Oracle Enable FAL Tracing on Primary Database

Fri, 28 Nov 2025 00:00:00 +0000

Oracle Enable FAL Tracing on Primary Database

Purpose

Enabling FAL (Fetch Archive Log) tracing on the primary database helps database administrators monitor and troubleshoot archive log gap resolution between primary and standby databases in Oracle Data Guard environments. This command activates detailed trace logging for the FAL server process, which handles requests from standby databases when they detect missing archive logs. The trace output provides valuable diagnostic information for resolving synchronization issues and understanding redo transport behavior.

How to Disable and Enable Oracle Archive Log Destinations

Thu, 27 Nov 2025 00:00:00 +0000

How to Disable and Enable Oracle Archive Log Destinations

Purpose

The Oracle commands for disabling and enabling archive log destinations allow database administrators to control the availability of archive destinations without removing the configuration. These commands are commonly used in Oracle Data Guard environments to temporarily stop or resume redo log shipping to standby databases during maintenance operations, troubleshooting, or planned outages.

Check Missing Archive Logs in Oracle Data Guard

Wed, 26 Nov 2025 00:00:00 +0000

Check Missing Archive Logs in Oracle Data Guard Standby Database

Purpose

This SQL query helps database administrators identify missing archive logs on an Oracle Data Guard standby database. When archive logs fail to transfer from the primary to the standby database, it creates gaps that prevent proper synchronization. Running this query on the standby database reveals which log sequences are present locally but missing at the destination, allowing administrators to take corrective action before the gap becomes too large.

Oracle Data Guard: Fix FAL and Logfile Registration

Tue, 25 Nov 2025 00:00:00 +0000

Troubleshooting Oracle Data Guard FAL and Physical Logfile Registration Issues

Oracle Data Guard environments sometimes encounter issues when the Fetch Archive Log (FAL) process fails to automatically transfer missing archive logs to standby databases. When FAL reports that a log is already registered or cannot retrieve missing logs, database administrators need manual intervention to restore synchronization between primary and standby databases. This guide provides step-by-step commands to register physical logfiles and recover standby databases when automatic processes fail.

Register Missing Log File in Oracle Data Guard Database

Sun, 26 Oct 2025 00:00:00 +0000

Register Missing Log File in Oracle Database

The ALTER DATABASE REGISTER PHYSICAL LOGFILE command is used to manually register archived redo log files in an Oracle Data Guard environment, specifically for physical standby databases. This command becomes essential when automatic log registration fails or when gaps occur in the archive log sequence on standby databases.

Purpose

This SQL command serves a critical role in Oracle Data Guard configurations by allowing database administrators to manually register archived redo log files that were not automatically registered by the standby database. The primary purpose is to resolve gaps in the archive log sequence, ensuring that the standby database remains synchronized with the primary database and can successfully apply all redo data. When the automatic gap resolution mechanism fails or when logs are manually copied to the standby location, this command enables the control file to recognize and catalog these log files for recovery operations.

Cancel Oracle Data Guard Managed Recovery

Sat, 25 Oct 2025 00:00:00 +0000

How to Cancel Oracle Data Guard Managed Recovery

Overview

The ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL command stops the Managed Recovery Process (MRP) on an Oracle Data Guard physical standby database. This command is essential when you need to perform maintenance operations, open the database in read-only mode, or troubleshoot synchronization issues between primary and standby databases.

SQL Code

1-- Cancel managed recovery
2ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;

Purpose

The cancel managed recovery command serves several critical purposes in Oracle Data Guard environments:

Removing Standby Database Apply Delay in Oracle Data Guard

Fri, 24 Oct 2025 00:00:00 +0000

Removing Standby Database Apply Delay in Oracle Data Guard

Purpose

This script removes the apply delay from an Oracle Data Guard physical standby database. Apply delays are safety features that create a time lag between when redo data arrives at the standby database and when it is applied, protecting against corrupted or incorrect data from the primary database. These commands cancel any existing recovery process and restart it immediately without delay.

Oracle Data Guard Standby Database Startup Commands

Thu, 23 Oct 2025 00:00:00 +0000

Oracle Data Guard Standby Database Startup Commands

Oracle Data Guard standby database startup commands enable database administrators to initialize and maintain physical standby databases that provide disaster recovery and high availability for production systems. These three essential commands work together to bring a standby database online and synchronize it with the primary database through automated redo log application.

Purpose

The Oracle Data Guard startup sequence serves to establish and maintain a synchronized replica of the primary database at a remote location. These commands initialize the standby instance, mount the standby database, and activate the Managed Recovery Process (MRP) to continuously apply redo data from the primary database. This configuration enables organizations to protect against data loss, minimize downtime during disasters, and offload read-only workloads from production systems.

Oracle ASH Report: Generate with ashrpt.sql

Fri, 03 Oct 2025 00:00:00 +0000

Generate Active Session History ASH Report in Oracle Database

The Active Session History (ASH) report is a powerful diagnostic tool that helps database administrators analyze performance issues by capturing detailed snapshots of active database sessions every second. This report provides granular insights into what database sessions are doing at specific points in time, making it essential for troubleshooting performance problems.

Oracle Time Model Queries: v$sys_time_model Monitoring

Thu, 02 Oct 2025 00:00:00 +0000

Oracle Time Model Queries: System and Session Performance Monitoring

Purpose

Oracle time model queries provide database administrators with powerful tools to measure and analyze where time is spent within the database system. These queries use two essential dynamic performance views that track accumulated time for various database operations in microseconds. The primary purpose is to identify performance bottlenecks by examining how much time the database spends on different operations, helping administrators prioritize tuning efforts effectively. Time model statistics measure DB time, which represents the total time spent in database calls by foreground sessions and serves as an indicator of total instance workload. By analyzing these metrics, database professionals can determine whether the system is constrained by CPU resources or waiting for other operations to complete.

Oracle: Enable or Disable GATHER_STATS_JOB

Wed, 01 Oct 2025 00:00:00 +0000

Enable or Disable Oracle GATHER_STATS_JOB for Automatic Statistics Collection

The GATHER_STATS_JOB is a critical Oracle Database scheduled job that automatically collects optimizer statistics to ensure the database query optimizer generates efficient execution plans. This job is enabled by default when creating a new Oracle database and runs during predefined maintenance windows.

Purpose

The GATHER_STATS_JOB maintains optimal query performance by automatically gathering optimizer statistics for database objects that have missing or stale statistics. The job executes the internal procedure DBMS_STATS.GATHER_DATABASE_STATS_JOB_PROC, which prioritizes objects that most urgently need updated statistics. This ensures critical statistics are collected before the maintenance window closes.

How to Remove an Oracle AWR Baseline Using DROP_BASELINE

Tue, 30 Sep 2025 00:00:00 +0000

How to Remove an Oracle AWR Baseline Using DROP_BASELINE

Purpose

The DROP_BASELINE procedure removes a previously-defined AWR (Automatic Workload Repository) baseline from an Oracle database. This command is essential for database administrators who need to conserve storage space by deleting unused or outdated performance baselines while maintaining the flexibility to preserve or purge the underlying snapshot data.

Breakdown of Code

Query:

Oracle AWR Baseline with DBMS_WORKLOAD_REPOSITORY

Mon, 29 Sep 2025 00:00:00 +0000

Oracle AWR Create Baseline for Performance Monitoring DBMS_WORKLOAD_REPOSITORY.CREATE_BASELINE

What is Oracle AWR Create Baseline

The DBMS_WORKLOAD_REPOSITORY.CREATE_BASELINE procedure creates a baseline by preserving a specific range of AWR snapshots for future performance comparisons. A baseline protects performance data from automatic purging and allows database administrators to compare current performance against known good performance periods.

Purpose of Creating AWR Baselines

AWR baselines serve as reference points for database performance analysis by capturing system behavior during optimal or significant time periods. These preserved snapshots help identify performance degradation over time and provide a foundation for comparing different workload patterns. Baselines are excluded from automatic AWR purging processes and remain available indefinitely for analysis.

List All Oracle AWR Baselines Using DBA_HIST_BASELINE

Sun, 28 Sep 2025 00:00:00 +0000

List All Oracle AWR Baselines Using DBA_HIST_BASELINE

This SQL script retrieves all AWR baselines stored in an Oracle Database, displaying critical information about each baseline including its identifier, name, and associated snapshot range. AWR baselines preserve specific periods of database performance statistics that are excluded from automatic purging, allowing database administrators to compare current performance against historical optimal periods.

Purpose

The primary purpose of this query is to display all existing AWR baselines in the database system. Baselines are essential for performance diagnostics because they preserve typical runtime statistics in the AWR repository, enabling administrators to compare current database performance against established performance benchmarks. This script helps identify which time periods have been preserved for performance analysis and troubleshooting.

Oracle AWR Manual Snapshot: DBMS_WORKLOAD_REPOSITORY

Sat, 27 Sep 2025 00:00:00 +0000

How to Manually Take an AWR Snapshot in Oracle Database with dbms_workload_repository.create_snapshot

What is Oracle AWR Snapshot Creation?

Creating a manual AWR snapshot in Oracle Database allows database administrators to capture performance statistics at specific points in time, providing precise data for troubleshooting and performance analysis. The DBMS_WORKLOAD_REPOSITORY.CREATE_SNAPSHOT procedure creates an on-demand snapshot outside the automatic hourly collection schedule.

Purpose of Manual AWR Snapshots

Manual AWR snapshot creation serves critical purposes for Oracle database administrators and performance engineers. The primary purpose is to capture database performance metrics during specific time windows that require detailed analysis. Database administrators use manual snapshots when investigating performance issues that occur at irregular intervals or when testing changes before and after implementation. This allows for precise comparison of database behavior during shorter intervals than the default one-hour automatic snapshot period.

Oracle AWR: Change Retention Period to 14 Days

Fri, 26 Sep 2025 00:00:00 +0000

How to Change Oracle AWR Retention Period to 14 Days using dbms_workload_repository.modify_snapshot_settings

Purpose

The Oracle code changes the Automatic Workload Repository (AWR) retention period from the default 8 days to 14 days (two weeks). This allows database administrators to store performance snapshots for a longer period, enabling better historical analysis and trend identification across extended time frames.

Query and Code Breakdown

User Query: Change the retention period to two weeks (14 days)

Oracle AWR Snapshot Interval: modify_snapshot_settings

Thu, 25 Sep 2025 00:00:00 +0000

How to Change Oracle AWR Snapshot Interval to 30 Minutes using dbms_workload_repository.modify_snapshot_settings

Purpose

The Oracle Database Automatic Workload Repository (AWR) collects and stores performance statistics to help database administrators monitor and analyze database performance over time. The code modifies the snapshot collection interval from the default 60 minutes to 30 minutes, allowing for more frequent and detailed performance data capture. This adjustment provides better visibility into database behavior and helps identify short-lived performance issues that might be missed with longer intervals.

Oracle AWR Interval and Retention: DBA_HIST_WR_CONTROL

Wed, 24 Sep 2025 00:00:00 +0000

How to Check Oracle AWR Snapshot Interval and Retention Settings using table dba_hist_wr_control

Purpose

The Oracle Database Automatic Workload Repository (AWR) is a critical component for performance monitoring and database tuning that automatically collects and stores performance statistics at regular intervals. This SQL script allows database administrators to quickly view the current AWR snapshot interval (how often snapshots are taken) and retention period (how long snapshots are kept) by querying the DBA_HIST_WR_CONTROL view. Understanding these settings is essential for effective performance analysis, as they determine the granularity and historical depth of performance data available for troubleshooting and optimization tasks.

Oracle AWR Report Generation Using awrrpt.sql Script

Tue, 23 Sep 2025 00:00:00 +0000

Oracle AWR Report Generation Using awrrpt.sql Script

The awrrpt.sql script is a powerful Oracle tool that generates comprehensive performance reports from the Automatic Workload Repository (AWR), providing database administrators with detailed insights into database performance over specific time periods. This script is essential for troubleshooting performance issues, identifying bottlenecks, and optimizing Oracle database operations.

What is the Command

1@?/rdbms/admin/awrrpt.sql

This command executes the AWR report generation script located in the Oracle RDBMS admin directory. The question mark (?) is a SQL*Plus substitution variable that automatically represents the ORACLE_HOME directory path, eliminating the need to type the full path.

Oracle AWR Snapshots: Query dba_hist_snapshot

Mon, 22 Sep 2025 00:00:00 +0000

Understanding Oracle AWR Snapshot Display

The Oracle Automatic Workload Repository (AWR) is a performance diagnostic tool that collects, processes, and stores database statistics automatically. Displaying a list of available snapshots is essential for database administrators who need to generate AWR reports, analyze performance trends, and troubleshoot database issues. This script provides a quick and efficient way to view all available snapshots in the system with their snapshot IDs, levels, and start times.

Oracle Statspack: Automate Snapshots with spauto.sql

Sun, 07 Sep 2025 00:00:00 +0000

Oracle Statspack Automation: Scheduling Hourly Database Performance Snapshots

Oracle Statspack automation provides database administrators with continuous performance monitoring capabilities through scheduled snapshot collection. The spauto.sql script enables automated hourly snapshots that capture essential database performance metrics without manual intervention.

Purpose

The Oracle Statspack automation script serves as a critical tool for proactive database performance management. By implementing automated snapshots, database administrators can maintain consistent performance monitoring, identify trends, and troubleshoot issues using historical performance data.

Oracle: Uninstall Statspack Using the spdrop Script

Sat, 06 Sep 2025 00:00:00 +0000

How to Uninstall Oracle Statspack Using the spdrop Script - Complete Guide

Oracle Statspack uninstallation is accomplished using the @?/rdbms/admin/spdrop command, which completely removes the Statspack performance monitoring framework from your Oracle database. This command removes all associated objects including the PERFSTAT user, tables, procedures, and collected performance data.

Understanding the Query Breakdown

The user query "Uninstall statspack @?/rdbms/admin/spdrop" represents a common Oracle DBA task for removing the Statspack performance monitoring tool. The command structure breaks down into specific components that work together to cleanly remove all Statspack components from the database environment.

Oracle Statspack Installation Guide: spcreate Setup

Fri, 05 Sep 2025 00:00:00 +0000

Oracle Database Statspack Installation Guide - Complete Setup and Configuration

Oracle Statspack is a powerful database performance monitoring tool that collects and analyzes system statistics to help database administrators identify performance bottlenecks and optimize database operations.

Query Analysis and Code Breakdown

The original query involves installing Oracle Statspack with these essential steps:

Create a tablespace (minimum size 100MB) - This provides dedicated storage space for Statspack objects and data
Run @?/rdbms/admin/spcreate - This executes the main Statspack installation script that creates the PERFSTAT user and required database objects

Let's examine each component in detail.

Oracle Statspack: List Snapshots with stats$snapshot

Thu, 04 Sep 2025 00:00:00 +0000

How to List Oracle Statspack Snapshots with SQL Query

This Oracle Database query provides a simple way to view all Statspack snapshots stored in your database. Statspack is Oracle's built-in performance monitoring tool that captures database statistics at regular intervals, helping database administrators analyze system performance over time.

Purpose of the Code

The primary purpose of this SQL script is to retrieve and display a comprehensive list of all Statspack snapshots with their essential details. This information helps database administrators track when performance snapshots were taken and plan their performance analysis activities accordingly.

spreport.sql: Generate Oracle Statspack Performance Reports

Wed, 03 Sep 2025 00:00:00 +0000

Oracle Database Statspack spreport.sql Script: Complete Performance Tuning Guide

The Oracle Database @?/rdbms/admin/spreport.sql script is a comprehensive performance reporting tool that generates detailed Statspack reports for database analysis and optimization. This essential script provides database administrators with critical insights into instance-wide performance metrics, helping identify bottlenecks and optimization opportunities.

Overview and Purpose

Oracle Statspack is a performance diagnosis tool that uses SQL, PL/SQL, and SQL*Plus scripts to collect, automate, store, and view performance data. The spreport.sql script specifically generates detailed reports by comparing performance statistics between two snapshot points, similar to the older UTLBSTAT/UTLESTAT scripts but with enhanced flexibility.

Oracle Statspack sppurge: Snapshot Purge Script Guide

Tue, 02 Sep 2025 00:00:00 +0000

Oracle Database Statspack Snapshot Purge Script: Complete Guide to sppurge Administration

The Oracle Database @?/rdbms/admin/sppurge; command is a critical administrative script used to delete old Statspack snapshots and manage storage space in the PERFSTAT schema. This comprehensive guide explores the purpose, functionality, and best practices for using this essential database performance monitoring tool.

Purpose and Overview

The sppurge.sql script serves as Oracle's official method for purging unnecessary Statspack snapshot data from the PERFSTAT schema. Statspack is Oracle's performance monitoring and diagnosis tool that captures system statistics over time, allowing database administrators to analyze performance trends and identify bottlenecks. However, without proper maintenance, these snapshots can consume significant storage space, making the purge functionality essential for ongoing database administration.

Oracle Statspack Snapshot Levels: statspack.snap Guide

Mon, 01 Sep 2025 00:00:00 +0000

Oracle Statspack Snapshot Levels: Complete Guide to Database Performance Monitoring

Oracle Statspack snapshots are essential tools for database performance monitoring that capture system statistics at different granularity levels. Understanding how to properly execute snapshots and choose appropriate levels is crucial for effective Oracle database administration and performance tuning.

Purpose

Statspack snapshots serve as the foundation for Oracle database performance analysis by capturing point-in-time statistics. These snapshots enable DBAs to analyze system performance trends, identify bottlenecks, and make informed decisions about database optimization. The snapshot levels determine the depth and scope of data collection, allowing administrators to balance monitoring overhead with diagnostic detail.

How to Monitor Oracle Shared Pool Usage with V$SGASTAT

Fri, 22 Aug 2025 00:00:00 +0000

How to Monitor Oracle Shared Pool Usage with V$SGASTAT

Database Administrators (DBAs) frequently need to track memory allocation inside Oracle’s SGA (System Global Area), especially within the Shared Pool. Monitoring the shared pool helps identify memory fragmentation, excessive parsing, and potential memory-related performance issues.

One practical way to check shared pool usage is by querying the dynamic performance view V$SGASTAT.

Monitoring PGA Usage by Username in Oracle Database

Thu, 21 Aug 2025 00:00:00 +0000

Monitoring PGA Usage by Username in Oracle Database

Effective memory management is critical for Oracle Database administrators (DBAs) when diagnosing performance issues. Oracle uses the Program Global Area (PGA) for managing session memory, including operations like sorting, hashing, and storing session context. Monitoring this memory usage helps identify inefficient SQL workloads and users consuming disproportionate memory.

In this guide, we’ll break down a useful SQL script to check PGA usage by username in Oracle Database.

Oracle SGA Breakdown Script Using v$sgastat

Wed, 20 Aug 2025 00:00:00 +0000

Oracle Database SGA Breakdown Script for Performance Monitoring

Monitoring memory usage in an Oracle Database is one of the most important tasks for a DBA. The System Global Area (SGA) plays a crucial role in the performance of the database, as it stores data and control information used by Oracle processes.

In this post, we will explore an SQL script that provides a breakdown of SGA memory pools using the v$sgastat dynamic performance view. We'll go over its purpose, SQL breakdown, key points, and insights for DBAs.

Oracle SQL Execution Statistics Query with v$sqlarea

Sat, 09 Aug 2025 00:00:00 +0000

Oracle SQL Performance Analysis Query - Monitor SQL Execution Statistics

Purpose

This Oracle SQL query is designed to analyze the performance characteristics of a specific SQL statement by examining key execution metrics stored in the v$sqlarea dynamic performance view. Database administrators and performance analysts use this query to identify performance bottlenecks, resource consumption patterns, and optimization opportunities for SQL statements.

Oracle SQL Hash Lookup: Retrieve SQL Text from V$SQLAREA

Fri, 08 Aug 2025 00:00:00 +0000

Oracle SQL Hash Lookup Query - Retrieving SQL Text from V$SQLAREA

Purpose

This Oracle Database query is designed to retrieve the complete SQL statement text from the V$SQLAREA view using a specific hash value. This is particularly useful for database administrators and developers who need to identify and analyze SQL statements during performance tuning, troubleshooting, or monitoring activities.

The Code

1select sql_text
2from v$sqlarea
3where hash_value = '&hash'
4/

Code Breakdown

SELECT Statement Components

Column Selection:

Oracle Database: Find Query Hash Value Using V$SQLAREA

Thu, 07 Aug 2025 00:00:00 +0000

Oracle Database: Find Query Hash Value Using V$SQLAREA

Finding specific SQL queries in Oracle Database can be challenging when dealing with large systems running thousands of statements. This guide demonstrates how to efficiently locate query hash values using the V$SQLAREA system view by searching for unique text patterns within SQL statements.

Purpose

The primary purpose of this Oracle Database script is to:

Oracle EXPLAIN PLAN: SQL Performance Analysis Guide

Wed, 06 Aug 2025 00:00:00 +0000

Oracle Database EXPLAIN PLAN: Complete Guide to SQL Performance Analysis

EXPLAIN PLAN is one of Oracle Database's most powerful tools for analyzing SQL query performance and understanding how the Oracle optimizer executes your statements. This comprehensive guide covers everything you need to know about using EXPLAIN PLAN effectively for database performance tuning.

What is EXPLAIN PLAN?

EXPLAIN PLAN is an Oracle SQL statement that allows you to view the execution plan that the Oracle optimizer would use to execute a specific SQL statement without actually running the query. This makes it invaluable for performance analysis, as you can examine query costs, access methods, and join operations before committing resources to execution.

Oracle Autotrace Commands: SQL Execution Plan Analysis

Tue, 05 Aug 2025 00:00:00 +0000

Oracle Database Autotrace Commands: Complete Guide to SQL Execution Plan Analysis

Oracle Database's autotrace feature is a powerful built-in tool that enables database administrators and developers to analyze SQL statement performance by displaying execution plans and runtime statistics. This comprehensive guide covers all autotrace commands and their practical applications for database performance optimization.

What is Oracle Autotrace?

Oracle autotrace is a SQL*Plus feature that provides detailed information about how Oracle executes SQL statements. It reveals the execution path chosen by the Oracle optimizer and displays valuable performance metrics without requiring additional tools or complex setup procedures.

Oracle: Find Tables with Outdated Statistics via DBA_TABLES

Tue, 01 Jul 2025 00:00:00 +0000

Oracle Database Query: Find Tables with Outdated Statistics

Purpose

This Oracle Database query helps database administrators monitor the progress of table statistics collection by identifying tables that have analyze dates older than the current date. It's particularly useful when running large-scale ANALYZE operations and you need to track how many tables still require statistics updates.

This is useful if you are running an analyze and want to see how much is left to do

Show a Count of Analyzed Tables by Schema in Oracle Database

Mon, 30 Jun 2025 00:00:00 +0000

Show a Count of Analyzed Tables Broken Down by Schema in Oracle Database

Purpose:
This post explains how to use Oracle SQL to report the total number of tables and the number of analyzed tables for each schema in your Oracle Database. This is crucial for database administrators who want to monitor the health and performance of their database, ensure accurate statistics for the optimizer, and identify schemas where statistics may be outdated or missing.

Oracle PLAN_TABLE Setup and EXPLAIN PLAN Usage Guide

Sun, 29 Jun 2025 00:00:00 +0000

What is the Oracle PLAN_TABLE and how do you use it?

Oracle's PLAN_TABLE is a fundamental component for SQL performance analysis and query optimization. This comprehensive guide explores the setup, usage, and best practices for leveraging Oracle's execution plan functionality to optimize database performance.

SQL Code

1@?/rdbms/admin/utlxplan.sql

Understanding The Oracle PLAN_TABLE

The PLAN_TABLE serves as the default output repository for Oracle's EXPLAIN PLAN statement, storing detailed information about how the database optimizer intends to execute SQL queries.

Oracle ANALYZE Statement: Table and Index Statistics

Sun, 11 May 2025 00:00:00 +0000

Oracle ANALYZE Statement: Old-Style Table and Index Statistics Collection

The ANALYZE statement in Oracle Database is a legacy tool used to collect statistics on tables and indexes. These statistics help the database optimizer make decisions about the most efficient way to execute SQL queries. Although Oracle now recommends using the DBMS_STATS package for statistics gathering, understanding ANALYZE is essential for maintaining legacy systems or interpreting older scripts.

Purpose of the ANALYZE Statement

Collect statistics about tables, indexes, and clusters to help the optimizer generate efficient execution plans.

Export/Import Oracle Optimizer Statistics: Complete Guide

Tue, 29 Apr 2025 00:00:00 +0000

Oracle Optimizer Statistics Transfer Guide

This guide demonstrates how to migrate schema statistics between Oracle databases using DBMS_STATS procedures - crucial for maintaining consistent execution plans across environments.

Exporting and importing optimizer statistics in Oracle Database is essential for maintaining consistent query performance across different environments, such as migrating statistics from production to test systems. This process ensures that the Oracle optimizer has accurate data to generate optimal execution plans, minimizing the risk of performance degradation due to missing or stale statistics

Oracle DBMS_STATS: Delete Database Statistics

Thu, 16 Jan 2025 00:00:00 +0000

Oracle Database: Deleting Statistics with DBMS_STATS Package

The Oracle Database DBMS_STATS package provides powerful procedures for managing database statistics. This post explores the delete_stats procedures, which are crucial for maintaining accurate query optimization.

Understanding DBMS_STATS.DELETE_STATS Procedures

The DBMS_STATS package offers several procedures to delete statistics at different levels:

Database-wide: delete_database_stats
Schema-level: delete_schema_stats
Table-level: delete_table_stats
Index-level: delete_index_stats

Let's break down each procedure and its purpose:

Oracle DBMS_STATS.GATHER_SYSTEM_STATS for Query Tuning

Wed, 15 Jan 2025 00:00:00 +0000

Optimizing Oracle Database Performance with GATHER_SYSTEM_STATS

Oracle Database's DBMS_STATS package is a powerful tool for gathering and managing database statistics. This post focuses on the GATHER_SYSTEM_STATS procedure, which is crucial for optimizing query performance by collecting system-level statistics.

Understanding GATHER_SYSTEM_STATS

The GATHER_SYSTEM_STATS procedure collects system statistics that reflect the performance characteristics of your hardware. These statistics help the Oracle optimizer make more accurate cost estimates for query execution plans.Let's break down the code:

Oracle Statistics Gathering with DBMS_STATS Explained

Thu, 12 Dec 2024 00:00:00 +0000

Understanding Oracle Database Statistics Gathering: A Comprehensive Guide

Gathering database statistics is a crucial task in Oracle Database management, ensuring optimal performance for SQL queries and overall database operations. In this article, we will explore the purpose of gathering statistics, provide a breakdown of the relevant Oracle Database code, and highlight key insights for effective database management.

Sample SQL Command

 1Gather stats on the entire database...
 2
 3execute dbms_stats.gather_database_stats;
 4
 5Or...
 6
 7execute dbms_stats.gather_database_stats( -
 8estimate_percent => 1, -
 9method_opt => 'FOR ALL COLUMNS SIZE 1',-
10cascade => TRUE);

Purpose of Gathering Database Statistics

Database statistics provide essential information about the data stored within the database, including the number of rows, blocks, and data distribution. This information is used by the Oracle optimizer to create efficient execution plans for SQL queries, ultimately improving performance.

Oracle DBMS_STATS: Gather Schema and Table Statistics

Wed, 11 Dec 2024 00:00:00 +0000

Optimizing Performance with Oracle Database: Gathering Schema and Table Statistics

In database management, ensuring optimal performance is crucial for effective data handling and query execution. One of the foundational tasks for maintaining an Oracle Database system is gathering statistics, which helps the Oracle optimizer make informed decisions about the most efficient way to execute SQL statements. This article will explore how to gather stats for a single schema in Oracle Database using DBMS_STATS, breaking down the relevant code snippets, their purposes, and their implications for performance tuning.

Identifying Oracle Database Hot Blocks Using v$system_event

Tue, 01 Oct 2024 00:00:00 +0000

Identifying Oracle Database Hot Blocks using Oracle Table v$system_event: A Comprehensive Guide

Purpose

Understanding Hot Blocks

In an Oracle database, a "hot block" refers to a data block in the buffer cache that experiences a disproportionately high volume of concurrent requests. This contention can lead to significant performance bottlenecks, particularly latch contention on the 'cache buffers chains' latch, which can severely impact the overall database performance.

Analyzing Oracle 'Data Block' Waits with v$waitstat

Mon, 30 Sep 2024 00:00:00 +0000

Oracle "Data Block" Waits using Oracle table v$waitstat to identify disk Contention

Purpose

In Oracle databases, waiting for "data blocks" signifies contention for specific data blocks in memory. This contention can lead to performance bottlenecks and slowdowns. Understanding the root cause of these waits is crucial to effectively addressing these issues.

Unmasking the Culprits with v$waitstat

The v$waitstat view provides valuable insights into various wait events within the database instance. To get a comprehensive breakdown of "data block" waits, use the following query:

Oracle Buffer Busy Waits Analysis with v$session_wait

Sun, 29 Sep 2024 00:00:00 +0000

Unmasking Buffer Busy Waits in Oracle: A Deep Dive with v$session_wait

Purpose

"Buffer busy waits" are a common performance bottleneck in Oracle databases, occurring when multiple sessions try to access the same data block concurrently. Identifying the specific blocks and understanding the reasons behind these waits is crucial for effective troubleshooting and optimization. Pinpointing the Contention with v$session_wait The v$session_wait view provides real-time information about sessions waiting for specific events. To identify the file, block, and reason code associated with "buffer busy waits," use the following query:

Oracle v$statname and v$sysstat Performance Stats

Sat, 28 Sep 2024 00:00:00 +0000

Analyzing Oracle Performance Statistics with v$statname and v$sysstat

Purpose

Monitoring and understanding your Oracle database instance's performance is crucial for maintaining optimal efficiency. Oracle provides dynamic performance views, such as v$statname and v$sysstat, to access a wealth of performance statistics.

Unlocking Performance Insights

To gain a comprehensive overview of your instance's performance, use the following query:

Sample SQL Command

1select n.name
2, s.value
3from v$statname n
4, v$sysstat s
5where n.statistic# = s.statistic#
6order by n.class
7, n.name
8/

Code Breakdown

select n.name, s.value: This selects the statistic name and its corresponding value.
from v$statname n, v$sysstat s: This specifies the v$statname and v$sysstat views as the data sources.
where n.statistic# = s.statistic#: This joins the two views based on the statistic# column, linking each statistic value to its name.
order by n.class, n.name: This sorts the output first by the statistic class and then by the statistic name for organized presentation.

Key Points and Insights

v$statname: This view provides names and descriptions for all available statistics in the database instance.
v$sysstat: This view stores the actual values for various system statistics.
Statistic classes: Statistics are grouped into classes (e.g., user, redo, cache, OS) for easier interpretation.

Explanations

Performance monitoring: Regularly reviewing performance statistics helps identify potential bottlenecks, resource usage trends, and areas for optimization.
Dynamic performance views: These views offer real-time insights into the database instance's activity and performance.

Interpreting the Results

The query output presents a comprehensive list of performance statistics. Analyze these statistics to understand:

Oracle Segment Waits Analysis with v$segment_statistics

Wed, 25 Sep 2024 00:00:00 +0000

Demystifying Oracle Segment Waits: In-Depth Code Analysis and Insights Using Oracle Table v$segment_statistics

Purpose

In the realm of Oracle database performance tuning, understanding segment waits is crucial. Waits indicate areas where processes are contending for resources, potentially leading to bottlenecks. The code snippet we will explore helps pinpoint specific segments experiencing high waits, enabling targeted optimization.

Sample SQL Command

 1select object_name
 2, obj#
 3, statistic_name
 4, value
 5from v$segment_statistics
 6where owner like '&owner'
 7and statistic_name like '%waits%'
 8and value > 0
 9order by statistic_name
10, value desc
11/

Code Breakdown

This code extracts information about wait events associated with specific segments owned by a given user (specified using the &owner substitution variable). It identifies segments with non-zero wait counts and presents the results sorted by the type of wait and the number of waits.

Oracle Latch Contention Analysis with v$system_event

Tue, 24 Sep 2024 00:00:00 +0000

Oracle Performance Tuning: Analyzing Latch Contention with "Time Waited for Latches" using Using Oracle Tables v$system_event and v$sysstat

Purpose

In the world of Oracle database performance tuning, identifying and resolving latch contention is critical for maintaining a responsive system. Latches are low-level serialization mechanisms that protect shared data structures within the Oracle SGA (System Global Area). When multiple processes compete for the same latch, it can lead to delays and impact overall database performance.

Oracle Top 10 Hot Objects by Touch Count with x$bh

Fri, 20 Sep 2024 00:00:00 +0000

Top 10 Hottest Objects in Oracle by Touch Count using tables x$bh obj$ and user$

Purpose

This Oracle SQL query identifies the top 10 "hottest" objects within your database. In this context, "hot" refers to objects that have been accessed (or "touched") the most frequently. Understanding which objects are frequently used can help you:

Optimize performance: By identifying frequently accessed objects, you can consider strategies like indexing, data partitioning, or materializing views to improve query response times.
Capacity planning: Knowing your "hot" objects can assist in predicting storage and resource needs as your database grows.
Troubleshooting: High touch counts on certain objects could indicate areas of contention or bottlenecks within your database.

Sample SQL Command

 1col owner format a20 trunc
 2col object_name format a30
 3col touches format 9,999,999
 4select *
 5from (
 6 select count(*)
 7 , sum(tch) TOUCHES
 8 , u.name OWNER
 9 , o.name OBJECT_NAME
10 from x$bh x
11 , obj$ o
12 , user$ u
13 where x.obj = o.obj#
14 and o.owner# = u.user#
15 group by u.name, o.name
16 order by 2 desc
17 )
18where rownum < 11
19/

Code Breakdown

x$bh: This is a dynamic performance view that tracks buffer headers. The tch column within it indicates the touch count for a buffer.
obj$ and user$: These are static data dictionary views containing information about database objects and users, respectively.
The query joins these views to associate touch counts with the corresponding object and owner names.
group by: The results are grouped by OWNER and OBJECT_NAME to calculate the total touch count for each object.
order by 2 desc: The output is sorted in descending order based on the TOUCHES column, showing the most frequently accessed objects first.
rownum < 11: The query limits the output to the top 10 rows.

Explanations:

Oracle: Find Wait Events by Datafile with x$kcbfwait

Thu, 19 Sep 2024 00:00:00 +0000

Identify Waits by Datafile in Oracle using tables v$datafile and x$kcbfwait

Purpose

In Oracle databases, waiting events often indicate performance bottlenecks. This SQL query helps you pinpoint which datafiles are associated with the most wait events. By understanding where waits are occurring, you can take targeted action to improve performance.

Sample SQL Command

1col name format a60
2select name
3, count
4from x$kcbfwait
5, v$datafile
6where indx + 1 = file#
7order by 2
8/

Code Breakdown

Code Breakdown

Oracle Lock Conflicts with dba_lock and SQL*Plus Format

Fri, 06 Sep 2024 00:00:00 +0000

Oracle Database: Understanding Lock Conflicts with dba_lock and Column Formatting

Purpose

This Oracle SQL query is designed to investigate and understand lock conflicts within your database, particularly those causing performance bottlenecks. It leverages the dba_lock view to expose critical lock information in a human-readable format, thanks to explicit column formatting.

Sample SQL Command

 1column lock_type format a12
 2column mode_held format a10
 3column mode_requested format a10
 4column blocking_others format a20
 5column username format a10
 6SELECT session_id
 7, lock_type
 8, mode_held
 9, mode_requested
10, blocking_others
11, lock_id1
12FROM dba_lock l
13WHERE lock_type NOT IN ('Media Recovery', 'Redo Thread')
14/

Code Breakdown

column lock_type format a12
column mode_held format a10
column mode_requested format a10
column blocking_others format a20
column username format a10 [

These lines are not part of the core query. They are SQL*Plus (or similar client) commands that set the display width and format for specific columns, making the output more visually organized.

Identifying Locked Rows in Oracle Using v$session

Thu, 05 Sep 2024 00:00:00 +0000

Identifying Locked Rows in Oracle Database using tables v$session and dba_objects

Purpose

This Oracle query pinpoints the exact row a specific session is waiting on due to a lock. It first finds the locked object and row location, then constructs a ROWID to fetch and display the entire locked row from the table.

Sample SQL Command

 1/* Show which row is locked
 2
 3select do.object_name
 4, row_wait_obj#
 5, row_wait_file#
 6, row_wait_block#
 7, row_wait_row#
 8, dbms_rowid.rowid_create (1, ROW_WAIT_OBJ#, ROW_WAIT_FILE#,
 9 ROW_WAIT_BLOCK#, ROW_WAIT_ROW#)
10from v$session s
11, dba_objects do
12where sid=&sid
13and s.ROW_WAIT_OBJ# = do.OBJECT_ID
14/
15
16/* Then select the row with that rowid...
17
18select * from <table> where rowid=<rowid>;

Code Breakdown

Query 1:

Oracle Blocking Sessions Query with v$lock and v$session

Wed, 04 Sep 2024 00:00:00 +0000

Oracle Database: Uncover Blocking Sessions with a Powerful SQL Query using v$lock

Purpose

Identify and resolve performance bottlenecks in your Oracle database by detecting blocking sessions using this powerful SQL query. Gain insights into the query's mechanics and learn how to optimize your database for smoother operations

Sample SQL Command

1select 'SID ' || l1.sid ||' is blocking ' || l2.sid blocking
2from v$lock l1, v$lock l2
3where l1.block =1 and l2.request > 0
4and l1.id1=l2.id1
5and l1.id2=l2.id2
6/

Code Breakdown

This query leverages the v$lock dynamic performance view, which provides real-time information about locks held and requested by sessions within the database.

Identify Locked Objects in Oracle Database

Tue, 03 Sep 2024 00:00:00 +0000

Identify Locked Objects in Oracle Database using v$locked_object, dba_objects, v$lock and v$session

Purpose

A developer reports that an INSERT that should finish in seconds is still running after ten minutes. No error has come back to the application, no timeout has fired, and nothing is moving. In the vast majority of such cases the root cause is a database lock: a session with an uncommitted DML transaction is holding a row or table lock, and the waiting session cannot proceed until that lock is released. The four-view join below makes the diagnosis immediate.

Oracle Currently Executing SQL via v$sqlarea Monitoring

Mon, 02 Sep 2024 00:00:00 +0000

Oracle Database: Show Currently Executing SQL Statements

Purpose

This Oracle SQL query allows you to monitor and view the SQL statements that are actively running in your database. It provides insights into the current workload and helps identify resource-intensive or long-running queries that might impact performance.

Sample SQL Command

1select sql_text
2from v$sqlarea
3where users_executing > 0
4/

Code Breakdown

select sql_text: Selects the sql_text column, which contains the actual text of the SQL statement being executed.
from v$sqlarea: Queries the v$sqlarea dynamic performance view, which provides statistics about SQL statements currently in the shared SQL area.
where users_executing > 0: Filters the results to only include SQL statements that have at least one user actively executing them.
/: The forward slash at the end is required in SQL*Plus or similar command-line tools to execute the query.

Key Points:

Oracle User Table Constraints Query with dba_constraints

Sun, 01 Sep 2024 00:00:00 +0000

Oracle Database: Show All Table Constraints for a User using dba_constraints

Purpose

This Oracle SQL query is designed to retrieve a comprehensive list of all constraints associated with tables owned by a specific user in your Oracle database. Constraints are essential rules that ensure data integrity and consistency. This query offers a clear and organized view of these constraints, aiding in database management and troubleshooting.

Oracle: Find Parent Tables for Repair Using dba_constraints

Sat, 31 Aug 2024 00:00:00 +0000

Oracle Database: Identifying Parent Tables for Repair or Re-import using dba_constraints

Purpose

When working with Oracle databases, ensuring data integrity is paramount. Foreign key constraints play a crucial role in maintaining relationships between tables, but disabled constraints can signal potential issues that may require fixing or re-importing parent tables. This article dives into an SQL query designed to pinpoint such parent tables.

ORA-02298: Find Missing Foreign Key Values in Oracle

Fri, 30 Aug 2024 00:00:00 +0000

Oracle SQL: Finding Missing Foreign Key Values (ORA-02298)

Purpose

This Oracle SQL query is designed to help identify missing foreign key values within your database. This is particularly useful when troubleshooting the ORA-02298: cannot validate (constraint_name) - parent keys not found error, which indicates a foreign key constraint violation.

The query essentially generates a new SELECT statement that, when executed, will return the specific values in the child table's foreign key column that do not have corresponding values in the parent table's primary or unique key column.

Oracle Session Statistics with v$sesstat and v$statname

Thu, 29 Aug 2024 00:00:00 +0000

Oracle Database: Deep Dive into Session Statistics

Purpose

This Oracle SQL query is designed to retrieve a snapshot of active session statistics for a specific session within your Oracle database. Session statistics provide invaluable insights into the current activity and resource utilization of a particular database session. This information is invaluable for performance monitoring, troubleshooting and capacity planning.

Sample SQL Command

1select sn.name
2, st.value
3from v$sesstat st
4, v$statname sn
5where st.STATISTIC# = sn.STATISTIC#
6and st.VALUE > 0
7and st.SID = &SID
8order by value desc
9/

Code Breakdown

select sn.name, st.value: Selects two columns:

sn.name: Extracts the descriptive name of the statistic from the v$statname view.
st.value: Retrieves the current value of the statistic for the specified session from the v$sesstat view.

from v$sesstat st, v$statname sn: Joins two crucial data dictionary views:

v$sesstat: Contains statistics for each active session.
v$statname: Stores the names and descriptions of all available statistics.

where st.STATISTIC# = sn.STATISTIC#: Links the two views based on the STATISTIC# column, ensuring accurate mapping between statistic values and their names.
and st.VALUE > 0: Filters the results to only show statistics that have a non-zero value, focusing on active metrics.
and st.SID = &SID: Restricts the output to statistics for a specific session identified by its SID (Session ID). You'll be prompted to enter the SID when you execute this query.
order by value desc: Sorts the output in descending order based on the value column, presenting the most significant statistics first.
/: The forward slash is necessary in SQL*Plus or similar command-line tools to execute the query.

Key Points:

Oracle Resource-Intensive SQL Queries via v$sqlarea

Wed, 28 Aug 2024 00:00:00 +0000

Pinpoint Resource-Hungry SQL in Oracle: A Performance Optimization Deep Dive

Purpose

This Oracle SQL query is your go-to tool for identifying SQL statements that are putting a strain on your database resources. By analyzing execution statistics, it highlights queries that are consuming significant disk reads and buffer gets, providing crucial insights for performance tuning and optimization.

Sample SQL Command

 1select sql_text
 2, executions
 3, to_char((((disk_reads+buffer_gets)/executions) * 8192)/1048576, '9,999,999,990.00')
 4 as total_gets_per_exec_mb
 5, to_char((( disk_reads /executions) * 8192)/1048576, '9,999,999,990.00')
 6 as disk_reads_per_exec_mb
 7, to_char((( buffer_gets /executions) * 8192)/1048576, '9,999,999,990.00')
 8 as buffer_gets_per_exec_mb
 9, parsing_user_id
10from v$sqlarea
11where executions > 10
12order by 6 desc
13/

Code Breakdown

change 8192 to match block size: This initial comment serves as an important reminder to adjust the 8192 value in the subsequent calculations to match your database's actual block size.
select sql_text, executions: Selects the following columns:
- sql_text: Retrieves the actual text of the SQL statement.
- executions: Shows the number of times the statement has been executed.
to_char((((disk_reads+buffer_gets)/executions) * 8192)/1048576, '9,999,999,990.00') as total_gets_per_exec_mb: Calculates and formats the total data gets (disk reads + buffer gets) per execution in megabytes (MB).
to_char((( disk_reads /executions) * 8192)/1048576, '9,999,999,990.00') as disk_reads_per_exec_mb: Calculates and formats the disk reads per execution in MB.
to_char((( buffer_gets /executions) * 8192)/1048576, '9,999,999,990.00') as buffer_gets_per_exec_mb: Calculates and formats the buffer gets per execution in MB.
parsing_user_id: Shows the ID of the user who parsed the SQL statement.
from v$sqlarea: Queries the v$sqlarea dynamic performance view, which provides statistics about SQL statements currently in the shared SQL area.
where executions > 10: Filters out SQL statements that have been executed less than 10 times, focusing on queries with a significant impact.
order by 6 desc: Sorts the results in descending order based on the 6th column (total_gets_per_exec_mb), highlighting the most resource-intensive queries first.
/: The forward slash is required in SQL*Plus or similar command-line tools to execute the query.

Key Points:

Oracle File IO Performance with v$datafile and v$filestat

Tue, 27 Aug 2024 00:00:00 +0000

Oracle Database: Unlocking File I/O Insights for Performance Tuning

Purpose

This Oracle SQL query provides a crucial window into your database's file input/output (I/O) activity. It displays statistics like physical reads, writes, and associated timings for each data file, empowering you to identify I/O bottlenecks and optimize database performance.

Sample SQL Command

 1set lines 80 pages 999
 2col fname heading "File Name" format a60
 3col sizemb heading "Size(Mb)" format 99,999
 4col phyrds heading "Reads" format 999,999,999
 5col readtim heading "Time" format 99.999
 6col phywrts heading "Writes" format 9,999,999
 7col writetim heading "Time" format 99.999
 8select lower(name) fname
 9, (bytes / 1048576) sizemb
10, phyrds
11, readtim
12, phywrts
13, writetim
14from v$datafile df
15, v$filestat fs
16where df.file# = fs.file#
17order by 1
18/

Code Breakdown

Requires timed_statistics=true: The initial comment emphasizes the necessity of enabling the timed_statistics parameter for capturing time-related file I/O metrics.
set lines 80 pages 999: Configures output formatting for improved readability.
col fname heading "File Name" format a60: Defines a column alias (fname) with a specific heading and format for the file name.
Similar col commands define column aliases, headings, and formats for size, reads, read time, writes, and write time.
select lower(name) fname, (bytes / 1048576) sizemb, phyrds, readtim, phywrts, writetim: Selects the following columns:
- lower(name) fname: Retrieves the data file name in lowercase for consistency.
- (bytes / 1048576) sizemb: Calculates and displays the file size in megabytes (MB).
- phyrds: Shows the number of physical reads performed on the file.
- readtim: Displays the total time spent on physical reads (in seconds).
- phywrts: Shows the number of physical writes performed on the file.
- writetim: Displays the total time spent on physical writes (in seconds).
from v$datafile df, v$filestat fs: Joins two vital data dictionary views:
- v$datafile: Contains information about database data files.
- v$filestat: Provides I/O statistics for data files.
where df.file# = fs.file#: Links the two views based on the file# column, ensuring correct matching of file information and I/O statistics.
order by 1: Sorts the results alphabetically by the first column (fname), making it easier to locate specific files.
/: The forward slash is essential for executing the query in SQL*Plus or similar command-line tools.

Key Points:

Oracle In-Session SQL Tracing with DBMS_SYSTEM

Mon, 26 Aug 2024 00:00:00 +0000

Oracle Database: Real-Time SQL Tracing for In-depth Performance Insights

Purpose

This Oracle database technique empowers you to dynamically enable or disable SQL tracing for specific sessions. SQL tracing captures detailed information about SQL statements executed within a session, providing valuable insights into query performance, execution plans, and resource usage. This capability is indispensable for diagnosing performance bottlenecks, troubleshooting issues, and fine-tuning SQL statements.

Oracle SQL Tracing with Event 10046 Performance Tuning

Sun, 25 Aug 2024 00:00:00 +0000

Oracle Performance Tuning: Harness the Power of Event 10046 Tracing

Purpose

This Oracle Database technique allows you to enable extended SQL tracing using Event 10046. This produces highly detailed trace files capturing SQL statements, bind variables, wait events, and more, making it an indispensable tool for performance tuning and troubleshooting.

Sample SQL Command

1To switch it on:
2
3alter session set events '10046 trace name context forever, level 8';
4
5To switch it off:
6
7alter session set events '10046 trace name context off';

Code Breakdown

1. To Switch It On:

Oracle Storage: Analyze Rows per Block with SQL

Sat, 24 Aug 2024 00:00:00 +0000

Oracle Database: Understanding Rows per Block for Efficient Storage

Purpose

This Oracle SQL query helps you analyze the average, maximum, and minimum number of rows stored within each data block for a specific table. Understanding this metric is critical for optimizing storage efficiency, query performance, and overall database health.

Sample SQL Command

1select avg(row_count) avg
2, max(row_count) max
3, min(row_count) min
4from (
5 select count(*) row_count
6 from &table_name
7 group by substr(rowid, 1, 15)
8 )
9/

Code Breakdown

select avg(row_count) avg, max(row_count) max, min(row_count) min: Selects three calculated columns:

Oracle Buffer Cache Advisory: v$db_cache_advice Tuning

Fri, 23 Aug 2024 00:00:00 +0000

Oracle Database: Deciphering the Buffer Cache Advisory for Performance Gains

Purpose

This Oracle SQL query, coupled with the necessary system setting, unveils the Buffer Cache Advisory, a valuable tool for optimizing your database's buffer cache size. By estimating the potential reduction in physical reads at various cache sizes, it empowers you to make informed decisions about adjusting your buffer cache, ultimately improving query performance.

Oracle Disabled Foreign Key Constraints: dba_constraints

Sun, 04 Aug 2024 00:00:00 +0000

Identifying Disabled Foreign Key Constraints in Oracle Database using dba_constraints

Purpose

This SQL query is designed to identify and list all disabled foreign key constraints within an Oracle database. It provides information about the table and constraint name for each disabled foreign key.

Sample SQL Command

 1set lines 100 pages 999
 2col table format a60
 3col constraint_name format a30
 4select owner||'.'||table_name "table"
 5, constraint_name
 6from dba_constraints
 7where status = 'DISABLED'
 8and constraint_type = 'R'
 9and owner not in ('SYS','SYSTEM')
10order by 1,2
11/

Breakdown:

Oracle: Enable Disabled Foreign Key Constraints

Sat, 03 Aug 2024 00:00:00 +0000

Enabling Disabled Foreign Key Constraints in Oracle Database using dba_constraints

Purpose

This SQL query generates a list of SQL statements that can be executed to enable all disabled foreign key constraints in an Oracle database.

Sample SQL Command

1set lines 100 pages 999
2select 'alter table '||owner||'.'||table_name||' enable constraint
3'||constraint_name||';' "enable"
4from dba_constraints
5where status = 'DISABLED'
6and constraint_type = 'R'
7and owner not in ('SYS','SYSTEM')
8order by 1
9/

Understanding the Oracle SQL Code

Purpose: This SQL query generates a list of SQL statements that can be executed to enable all disabled foreign key constraints in an Oracle database.

dba_constraints: Query All Oracle Table Constraints

Wed, 19 Jun 2024 00:00:00 +0000

Show All Oracle Database Table Constraints using dba_constraints

This article delves into the world of Oracle Database constraints, empowering you to understand their types, statuses, and modification history. We'll dissect a powerful SQL query that retrieves this crucial information, making you a database management pro.

Sample SQL Command

 1col type format a10
 2col cons_name format a30
 3select decode(constraint_type,
 4 'C', 'Check',
 5 'O', 'R/O View',
 6 'P', 'Primary',
 7 'R', 'Foreign',
 8 'U', 'Unique',
 9 'V', 'Check view') type
10, constraint_name cons_name
11, status
12, last_change
13from dba_constraints
14where owner like '&owner'
15and table_name like '&table_name'
16order by 1
17/

Purpose:

Oracle: List Tables Using a Table as a Foreign Key

Tue, 18 Jun 2024 00:00:00 +0000

List Tables That Are Using the Specified Table as a Foreign Key using dba_constraints

Learn how to use an Oracle SQL query to identify tables referencing a specific table with foreign keys, understand database relationships, and ensure data integrity

Sample SQL Command

 1set lines 100 pages 999
 2select a.owner
 3, a.table_name
 4, a.constraint_name
 5from dba_constraints a
 6, dba_constraints b
 7where a.constraint_type = 'R'
 8and a.r_constraint_name = b.constraint_name
 9and a.r_owner = b.owner
10and b.owner = '&table_owner'
11and b.table_name = '&table_name'
12/

Same as above, but produces 'disable constraint' statements

 1set lines 100 pages 999
 2select a.owner
 3, a.table_name
 4, a.constraint_name
 5from dba_constraints a
 6, dba_constraints b
 7where a.constraint_type = 'R'
 8and a.r_constraint_name = b.constraint_name
 9and a.r_owner = b.owner
10and b.owner = '&table_owner'
11and b.table_name = '&table_name'
12/

Purpose:

Oracle Undo Retention Tuning: ALTER SYSTEM Guide

Sun, 12 May 2024 00:00:00 +0000

Optimizing Undo Retention in Oracle Databases

We will explain how to optimize the undo_retention parameter in Oracle databases using the SQL command ALTER SYSTEM SET undo_retention = 500 SCOPE = MEMORY;. Understanding this parameter is crucial for effective transaction management, rollback capabilities, and maintaining read consistency. Learn how to fine-tune it based on your workload, ensuring sufficient undo information is retained without negatively impacting performance.

Note: undo_retntion is in seconds.

Oracle Undo, A Deep Dive into DBA_UNDO_EXTENTS

Sat, 11 May 2024 00:00:00 +0000

Oracle Undo: A Deep Dive into DBA_UNDO_EXTENTS

Unlock the secrets of Oracle's undo mechanism with this in-depth guide to the DBA_UNDO_EXTENTS view. Learn how to analyze undo tablespace usage, interpret extent statuses (ACTIVE, UNEXPIRED, EXPIRED), and gain valuable insights for proactive database management. Avoid "snapshot too old" errors and ensure smooth transaction handling with this essential SQL query and expert tips.

Oracle Rollback Detection: Monitor Active Transactions

Fri, 10 May 2024 00:00:00 +0000

Real-Time Oracle Rollback Detection: Is Your Database Undoing Changes?

This SQL query monitors real-time rollbacks in Oracle databases. It identifies which sessions are actively undoing changes and tracks their progress by observing the used_ublk value (the number of undo blocks in use). When used_ublk reaches zero, the rollback is complete. Use this query to maintain data integrity, troubleshoot slowdowns, and proactively manage your Oracle database.

Notes: Is anything rolling back at the moment? Look for the used_ublk value decreasing. If it is, the session connected with it is rolling back. When it reaches zero, rollback is complete.

Oracle ALTER DATABASE DROP LOGFILE MEMBER Guide

Tue, 23 Apr 2024 00:00:00 +0000

Understanding ALTER DATABASE DROP LOGFILE MEMBER in Oracle Databases

Learn how to use ALTER DATABASE DROP LOGFILE MEMBER to remove redo log file members in Oracle databases. Get insights, explanations, and best practices.

Sample SQL Command

1alter database drop logfile member '<filename>';

Purpose of ALTER DATABASE DROP LOGFILE MEMBER

In Oracle databases, the ALTER DATABASE DROP LOGFILE MEMBER command is used to permanently remove individual redo log file members from a redo log group. Redo log files are essential for database recovery, as they store a record of all changes made to the database.

Oracle: Add Redo Log Members with ALTER DATABASE

Mon, 22 Apr 2024 00:00:00 +0000

Expand Your Oracle Database: Adding Redo Log File Members with ALTER DATABASE ADD LOGFILE MEMBER

Master the art of adding redo log file members in Oracle databases with ALTER DATABASE ADD LOGFILE MEMBER . Optimize performance, redundancy, and database management.

Sample SQL Command

1alter database add logfile member '<filename>' to group <group>;

Purpose: Enhancing Oracle Database Resilience with ALTER DATABASE ADD LOGFILE MEMBER

Calculating Redo Log File Sizes in Oracle Databases

Sun, 21 Apr 2024 00:00:00 +0000

Calculating Redo Log File Sizes in Oracle Databases

Maintaining optimal performance in your Oracle database often involves careful monitoring of various components. Redo log files, crucial for recovery, require attention to ensure they're sized appropriately. In this post, I'll share a code snippet to list redo log file members and their sizes, along with explanations and insights.

Sample SQL Command

1col member format a60
2col "Size MB" format 9,999,999
3select lf.member
4, ceil(lg.bytes / 1024 / 1024) "Size MB"
5from v$logfile lf
6, v$log lg
7where lg.group# = lf.group#
8order by 1
9/

Introduction Maintaining optimal performance in your Oracle database often involves careful monitoring of various components. Redo log files, crucial for recovery, require attention to ensure they're sized appropriately. In this post, I'll share a code snippet to list redo log file members and their sizes, along with explanations and insights.

Understanding Rollback Segments in Oracle Databases

Sat, 20 Apr 2024 00:00:00 +0000

Understanding Rollback Segments in Oracle Databases

Rollback segments are essential components of Oracle databases, providing a mechanism to reverse uncommitted transactions and maintain data consistency. This post presents a SQL query for inspecting rollback segments, as well as explanations and insights into their role.

Sample SQL Command

1select segment_name
2, status
3from dba_rollback_segs
4/

Purpose

This SQL code serves to:

Build OS Delete Commands for Oracle Database Files

Mon, 08 Apr 2024 00:00:00 +0000

Building Remove(rm) or Delete OS Commands for Oracle Database Files (Caution: Destructive)

Important Warning: Destructive Operation

The provided code snippet demonstrates how to construct operating system (OS) commands for all datafiles, temporary files, log files, and control files within an Oracle Database. However, it's crucial to understand that the constructed commands use thermcommand, which permanently deletes files. Running this code would result in the deletion of all these database files, leading to severe data loss and database failure.

Disable Autoextend for All Datafiles in Oracle Database

Sun, 07 Apr 2024 00:00:00 +0000

Disabling Autoextend for All Datafiles in Oracle Database

This guide explores a method to turn off autoextend for all datafiles within an Oracle Database. We'll delve into the provided SQL code, understand its purpose, and offer key considerations for implementation.

Turn autoextend off for all datafiles

Sample SQL Command

1select 'alter database datafile ''' || file_name || ''' autoextend off;'
2from dba_data_files
3/

Understanding Autoextend

Autoextend is a feature in Oracle Database that allows datafiles to automatically grow when they reach their designated size limit. While convenient, it can lead to uncontrolled storage consumption if left unchecked. Disabling autoextend gives you more granular control over datafile growth.

Move Oracle Database Datafiles and Log Files to New Disk

Sat, 06 Apr 2024 00:00:00 +0000

Moving Oracle Database Datafiles and Log Files to Another Disk

This guide addresses migrating Oracle Database datafiles and online redo log files from one disk location to another. We'll delve into the provided PL/SQL code, understand its functionality, and offer key considerations for implementation.

Move files between disks

Sample SQL Command

 1set trimspool on wrap off
 2set heading off
 3set verify off
 4set pages 1000 lines 100
 5
 6spool rename.sql
 7
 8select 'alter database rename file ''' ||
 9 name || ''' to ''' ||
10 replace(name || ''';', '/u01', '/u02')
11from v$datafile
12/
13
14select 'alter database rename file ''' ||
15 member || ''' to ''' ||
16 replace(member || ''';', '/u01', '/u02')
17from v$logfile
18/
19
20spool off

Understanding the Need for Relocation

Databases often require more storage space as data accumulates. Moving datafiles and log files to a dedicated disk with higher capacity or better performance can optimize database operations.

Find Oracle Control File Locations with v$controlfile

Fri, 05 Apr 2024 00:00:00 +0000

Viewing Control File Locations in Oracle Database

This guide explores a simple method to identify the locations of control files in your Oracle Database. We'll delve into the provided SQL code, understand its purpose, and offer insights into control files.

List controlfiles

Sample SQL Command

1select name
2from v$controlfile
3/

Understanding Control Files

Control files are essential, binary files in Oracle Database that store crucial metadata about the database's physical structure. This information includes:

Find Duplicate Filenames in Oracle Database

Thu, 04 Apr 2024 00:00:00 +0000

Find Duplicate Filenames in Oracle Database: Code Breakdown and Insights

This post dives into an Oracle Database code snippet that identifies duplicate filenames across your entire database. We'll break down the code, explain its purpose, and provide valuable insights for optimizing your database management.

Find duplicate filenames. Searches for files with the same name in all directories.

Sample SQL Command

1select count(substr(name, instr(name, '/', -1) + 1, 999)) "total"
2,count(distinct substr(name, instr(name, '/', -1) + 1, 999)) "distinct"
3from v$datafile
4/

Purpose:

Oracle: Identify Datafiles in Hot Backup Mode

Thu, 04 Apr 2024 00:00:00 +0000

Find Duplicate Filenames in Oracle Database: Code Breakdown and Insights

Find duplicate filenames. Searches for files with the same name in all directories.

Sample SQL Command

1select count(substr(name, instr(name, '/', -1) + 1, 999)) "total"
2,count(distinct substr(name, instr(name, '/', -1) + 1, 999)) "distinct"
3from v$datafile
4/

Purpose:

Oracle: List Datafiles, Tempfiles, and Logfiles with Sizes

Tue, 26 Mar 2024 00:00:00 +0000

Investigating Your Oracle Database Files: A Breakdown for Optimization

This blog post delves into an Oracle Database code snippet designed to provide valuable insights into your database's storage and activity. We'll dissect its purpose, explain each component, and reveal key points to optimize your database's health and performance.

Sample SQL Command

 1set lines 100 pages 999
 2col name format a50
 3select name, bytes
 4from (select name, bytes
 5 from v$datafile
 6 union all
 7 select name, bytes
 8 from v$tempfile
 9 union all
10 select lf.member "name", l.bytes
11 from v$logfile lf
12 , v$log l
13 where lf.group# = l.group#
14 union all
15 select name, 0
16 from v$controlfile) used
17, (select sum(bytes) as p
18 from dba_free_space) free
19/

Purpose:

Quick Oracle Database Datafile Health Check with SQL

Mon, 25 Mar 2024 00:00:00 +0000

Quick Oracle Database Datafile Health Check with SQL

This post explores a simple yet effective SQL query for a quick health check on your Oracle database's datafiles. We'll delve into the purpose, breakdown, key points, and insights gained from the query, providing valuable information for database administrators and anyone interested in maintaining optimal database health.

Sample SQL Command

1select distinct status from v$datafile
2/

Purpose:

Find Autoextensible Datafiles in Oracle Database

Sat, 23 Mar 2024 00:00:00 +0000

How to Find Autoextensible Datafiles in Oracle Database (SQL Included)

Are you managing an Oracle database and want to identify datafiles configured for automatic extension? This post will guide you through a simple SQL query to achieve that. We'll break down the code, explain its purpose, and offer valuable insights into autoextensible datafiles.

Sample SQL Command

1select file_name
2from dba_data_files
3where autoextensible = 'YES'
4/

Purpose:

Locate Your Oracle Database Datafile Directories with SQL

Fri, 22 Mar 2024 00:00:00 +0000

Locate Your Oracle Database Datafile Directories with SQL

This handy SQL query that helps you pinpoint the exact directories where your Oracle database stores its datafiles. Understanding datafile locations is crucial for database administrators and anyone involved in managing an Oracle database. We'll explore the purpose, breakdown, key points, and insights gained from the query, empowering you to effectively manage your database environment.

Quickly Identify Indexed Columns in Oracle Database Tables

Tue, 19 Mar 2024 00:00:00 +0000

Identify Indexed Columns in Oracle Database Tables

Optimizing queries in Oracle Database often involves understanding how indexes are used. This post will guide you through a powerful SQL code snippet that helps you efficiently identify the columns included in a specific index.

Sample SQL Command

1select column_name
2from dba_ind_columns
3where index_name = '&index'
4order by column_position
5/

Purpose: Unveiling the Secrets of Indexes

The provided code snippet serves a critical purpose for Oracle database administrators and developers. It allows you to query the dba_ind_columns data dictionary view and retrieve a list of columns that are part of a particular index. This information is essential for:

Oracle: Identify Large Indexes with SQL and DBA_SEGMENTS

Sun, 17 Mar 2024 00:00:00 +0000

Optimizing Your Oracle Database: A Guide to Identifying Large Indexes with SQL

Keeping your Oracle Database running smoothly requires constant monitoring and optimization. Indexes, a crucial component for efficient data retrieval, can sometimes grow excessively, impacting performance. This blog post dives into a powerful SQL query that helps you pinpoint large indexes associated with specific tables, empowering you to make informed decisions about database optimization.

Oracle PL/SQL: SHOW ERRORS and dba_errors Explained

Sat, 16 Mar 2024 00:00:00 +0000

Struggling with compilation errors and warnings in Oracle Database?

For those working with Oracle Database, ensuring code compiles smoothly is paramount. Compilation errors can derail stored procedures, functions, packages, and triggers, leading to unexpected behavior. This guide equips you with the knowledge to effectively identify and understand compilation errors and warnings using theSHOW ERRORSstatement anddba_errorsview in Oracle Database.

Understanding Compilation Errors and Warnings

Compilation translates human-readable code (like PL/SQL) into instructions the database can execute. During this process, the compiler scans for syntax errors (incorrect grammar), semantic errors (logical inconsistencies), and potential issues that might affect code execution.

dba_segments: Find Oracle Table Storage Usage by User

Fri, 15 Mar 2024 00:00:00 +0000

Uncovering Table Storage Usage in Oracle Database: A Guide with `dba_segments`

For Oracle Database administrators (DBAs) and developers, managing storage efficiently is critical. Keeping track of table sizes helps identify potential space hogs and optimize resource allocation. This guide delves into a powerful SQL query that leverages the dba_segments view to effectively list all tables owned by a user, sorted by their size in megabytes (MB).

Oracle DBMS_METADATA.GET_DDL: Extract Object DDL

Thu, 07 Mar 2024 00:00:00 +0000

Unveiling the Mystery: Extracting Object DDL in Oracle Database (9i onwards)

Ever faced the situation where you needed the Data Definition Language (DDL) script for an existing table, view, or other database object in your Oracle database (version 9i or later)? This can be crucial for various tasks, such as replicating schema structures, documenting changes, or troubleshooting issues. Fear not, for Oracle provides a powerful built-in function, DBMS_METADATA.GET_DDL , that empowers you to retrieve the DDL script for virtually any database object. This article delves into the purpose, breakdown, and key points of the provided Oracle code snippet, offering insights and explanations to equip you with the knowledge to effectively extract object DDLs in your Oracle environment.

Find Tables Containing a Specific Column in Oracle Database

Wed, 06 Mar 2024 00:00:00 +0000

Use a SQL Query To Find Tables Containing a Specific Column in Oracle Database

Introduction

Managing a complex Oracle database often involves navigating a labyrinth of tables and columns. Identifying specific data points within these tables can be crucial for various tasks. Knowing which tables contain a particular column is essential for tasks like:

Data Relationship Analysis: Understanding how data flows between tables requires knowledge of shared columns.
Modifying Database Structures: Altering existing tables or adding new columns necessitates knowing where the relevant data resides.
Ensuring Data Integrity: Maintaining data consistency often involves verifying the presence and validity of specific columns across tables.

This article explores an efficient SQL query that helps you locate all tables containing a designated column name in your Oracle database. We'll delve into the code breakdown, key points, and insights to empower you with this valuable technique.

Unveiling the Mystery Oracle for Object Size Analysis

Wed, 28 Feb 2024 00:00:00 +0000

Unveiling the Mystery: Demystifying an Oracle SQL Code Snippet for Object Size Analysis

In the ever-evolving realm of database management, efficient resource utilization is paramount. Oracle, a widely recognized database management system, offers powerful tools to help optimize storage and performance. This blog post delves into a specific Oracle SQL code snippet, empowering you to understand its purpose, function, and key insights it reveals.

Oracle DBA_OBJECTS: List All Objects Owned by a User

Tue, 27 Feb 2024 00:00:00 +0000

Unveiling Your Database Toolkit: Exploring Objects Owned by a User in Oracle

In the intricate world of database management, understanding the landscape of objects is crucial for efficient operation. This blog post empowers you to leverage a specific Oracle Database SQL code snippet to list all objects owned by a particular user. This knowledge equips you to navigate user privileges, manage object dependencies, and gain valuable insights into your database's structure.

Query The Oracle Database Procedure Source Code

Mon, 26 Feb 2024 00:00:00 +0000

Unveiling the Mystery: Demystifying an Oracle Database Procedure

In the realm of relational databases, procedures serve as powerful tools for encapsulating complex sets of instructions and improving code reusability. They act as building blocks, streamlining development and maintenance. Today, we'll delve into the intricacies of an Oracle Database procedure, providing a breakdown and explanation of the following code below:

Sample SQL Command

1select text
2from dba_source
3where owner = 'BILL'
4and name = 'FILE_TEST'
5and type = 'PACKAGE BODY'
6order by line
7/

Purpose:

Search Objects in Oracle Database

Sun, 25 Feb 2024 00:00:00 +0000

How to Search for Objects in Oracle Database

This post explains how to search for objects (tables, views, sequences, etc.) in an Oracle database using SQL.

Sample SQL Command

 1set pages 999
 2col owner format a15
 3col object_name format a40
 4col object_type format a20
 5select owner
 6, object_name
 7, object_type
 8from dba_objects
 9where lower(object_name) like lower('%&object%')
10order by owner, object_type, object_name
11/

Sample Oracle Output

 1OWNER OBJECT_NAME OBJECT_TYPE
 2--------------- ---------------------------------------- -----------------
 3ORDSYS flashType172_T TYPE
 4PUBLIC DBMS_FLASHBACK SYNONYM
 5PUBLIC FLASHBACK_TRANSACTION_QUERY SYNONYM
 6PUBLIC GV$FLASHBACK_DATABASE_LOG SYNONYM
 7PUBLIC GV$FLASHBACK_DATABASE_LOGFILE SYNONYM
 8PUBLIC GV$FLASHBACK_DATABASE_STAT SYNONYM
 9PUBLIC V$FLASHBACK_DATABASE_LOG SYNONYM
10PUBLIC V$FLASHBACK_DATABASE_LOGFILE SYNONYM
11PUBLIC V$FLASHBACK_DATABASE_STAT SYNONYM
12PUBLIC V$FLASH_RECOVERY_AREA_USAGE SYNONYM
13SYS DBMS_FLASHBACK PACKAGE
14SYS DBMS_FLASHBACK PACKAGE BODY
15SYS FLASHBACKTBLIST TYPE
16SYS FLASHBACK_TRANSACTION_QUERY VIEW
17SYS GV_$FLASHBACK_DATABASE_LOG VIEW
18SYS GV_$FLASHBACK_DATABASE_LOGFILE VIEW
19SYS GV_$FLASHBACK_DATABASE_STAT VIEW
20SYS V_$FLASHBACK_DATABASE_LOG VIEW
21SYS V_$FLASHBACK_DATABASE_LOGFILE VIEW
22SYS V_$FLASHBACK_DATABASE_STAT VIEW
23SYS V_$FLASH_RECOVERY_AREA_USAGE VIEW
24
2521 rows selected.

Purpose:

Identify and Fix Invalid Objects in Oracle Database

Sat, 24 Feb 2024 00:00:00 +0000

How to Identify and Fix Invalid Objects in A Oracle Database

Below we explain how to identify and fix invalid objects in your Oracle database using SQL. This improves the database health and performance.

Sample SQL Command

1set lines 200 pages 999
2col "obj" format a40
3select owner || '.' || object_name "obj",
4object_type
5from dba_objects
6where status = 'INVALID'
7/

Sample Oracle Output

 1OBJ OBJECT_TYPE
 2---------------------------------------- --------------------
 3WEBUSER.CHECK PACKAGE BODY
 4WEBUSER.MAILER PACKAGE
 5WEBUSER.APP_FUNCS PACKAGE BODY
 6PUBLIC.DBA_HIST_FILESTATXS SYNONYM
 7PUBLIC.DBA_HIST_SQLSTAT SYNONYM
 8PUBLIC.DBA_HIST_SQLBIND SYNONYM
 9PUBLIC.DBA_HIST_TABLESPACE_STAT SYNONYM
10PUBLIC.DBA_HIST_SERVICE_STAT SYNONYM
11PUBLIC.DBA_HIST_SERVICE_WAIT_CLASS SYNONYM

Purpose:

Oracle Recompile Invalid Objects with utlrp.sql

Fri, 23 Feb 2024 00:00:00 +0000

Instructions On How To Re-compile Invalid Objects in Oracle Database: A Comprehensive Guide

Sample SQL Command

1@?/rdbms/admin/utlrp.sql

Purpose

Ensuring the smooth operation of your Oracle database requires maintaining the validity of its objects. These objects, including tables, procedures, functions, and packages, can become invalid due to various reasons like schema changes, database upgrades, or compilation errors. Invalid objects hinder database performance and can lead to unexpected behavior or errors when accessed.

Creating a Temporary Tablespace in Oracle Database

Thu, 15 Feb 2024 00:00:00 +0000

Creating a Temporary Tablespace in Oracle Database

This guide explains an Oracle Database SQL code snippet for creating a temporary tablespace named temp, its purpose, key points, and insights.

Sample SQL Command

1create temporary tablespace temp
2tempfile '<file_name>' size 500M
3/

Create a Temporary Tablespace named temp. Here's a breakdown

Purpose:

To establish a dedicated space for storing temporary data used within the current database session. This improves performance and simplifies cleanup as temporary objects are automatically removed upon session termination.

Breakdown:

Understanding User Quotas in Oracle Database

Wed, 14 Feb 2024 00:00:00 +0000

How to Query User Quotas in Oracle Database

The code below retrieves and displays information about user quotas on all tablespaces excluding the temporary tablespace (TEMP) on a Oracle database.

Sample SQL Command

1col quota format a10
2select username
3tablespace_name
4decode(max_bytes, -1, 'unlimited', ceil(max_bytes / 1024 / 1024) || 'M' ) "QUOTA"
5from dba_ts_quotas
6here tablespace_name not in ('TEMP')

Sample Oracle Output

 1USERNAME TABLESPACE_NAME QUOTA
 2-------------------- ---------------------------------------- ----------
 3LARRY LARRY 50M
 4ODM_REPOSITORY ODM unlimited
 5PERFSTAT TOOLS 500M
 6CABBOY USERS unlimited
 7ORA_IT ORAIT unlimited
 8
 998 rows selected.
10SQL>

Purpose

Understanding Tablespace Usage in Oracle Database

Tue, 13 Feb 2024 00:00:00 +0000

Description of Oracle Database SQL code for Tablespace Usage

This code provides a comprehensive overview of tablespace usage in your Oracle database. Here's a breakdown of its purpose, components, and key points:

Sample SQL Command

 1set pages 999
 2col tablespace_name format a40
 3col "size MB" format 999,999,999
 4col "free MB" format 99,999,999
 5col "% Used" format 999
 6select tsu.tablespace_name, ceil(tsu.used_mb) "size MB"
 7, decode(ceil(tsf.free_mb), NULL,0,ceil(tsf.free_mb)) "free MB"
 8, decode(100 - ceil(tsf.free_mb/tsu.used_mb*100), NULL, 100,
 9 100 - ceil(tsf.free_mb/tsu.used_mb*100)) "% used"
10from (select tablespace_name, sum(bytes)/1024/1024 used_mb
11 from dba_data_files group by tablespace_name union all
12 select tablespace_name || ' **TEMP**'
13 , sum(bytes)/1024/1024 used_mb
14 from dba_temp_files group by tablespace_name) tsu
15, (select tablespace_name, sum(bytes)/1024/1024 free_mb
16 from dba_free_space group by tablespace_name) tsf
17where tsu.tablespace_name = tsf.tablespace_name (+)
18order by 4
19/

Sample Oracle Output

 1TABLESPACE_NAME size MB free MB % used
 2---------------------------------------- ------------ ----------- ------
 3USERS_VIT 25 25 0
 4INDX 5 5 1
 5PERFSTAT 5 5 1
 6USERS 25 25 3
 7UNDOTBS2 2,000 1,886 5
 8APP_USER_DATA 10 10 6
 9ODM 10 10 6
10TOOLS 600 509 15
11DRSYS 20 15 25
12WEB_DATA 100 72 28
13CAP_DATA 3,500 2,316 33
14CAP_INDEXES 4,500 2,705 39
15SYSAUX 350 132 62
16XDB 60 13 79
17SYSTEM 650 84 87
18ANDY 10 2 88
19TEMP **TEMP** 1,050 0 100
20TEMP_VIT **TEMP** 25 0 100
21
2218 rows selected.
23SQL>

Purpose:

Exploring Datafiles within Oracle Tablespaces

Mon, 12 Feb 2024 00:00:00 +0000

Description of Oracle Database SQL code for Showing Tablespace Files

This code displays information about the datafiles composing a specific tablespace in your Oracle database. Here's a breakdown of its purpose, components, and key points:

Show thea data files that comprise a tablespace

Sample SQL Command

1col file_name format a70
2select file_name
3, ceil(bytes / 1024 / 1024) "size MB"
4from dba_data_files
5where tablespace_name like '&TSNAME'
6/

Sample Oracle Output

 1set lines 100
 2col file_name format a70
 3select file_name
 4, ceil(bytes / 1024 / 10SQL> SQL> 2 24) "size MB"
 5from dba_data_files
 6where tablespace_name like '&TSNAME'
 7/ 3 4 5
 8Enter value for tsname: SYSAUX
 9old 4: where tablespace_name like '&TSNAME'
10new 4: where tablespace_name like 'SYSAUX'
11
12FILE_NAME size MB
13------------------------------------------------------- ----------
14/opt/oracle/oradata/FREE/sysaux01.dbf 730
15
16SQL>

Purpose:

Oracle crsctl query css votedisk Command Explained

Sun, 11 Feb 2024 00:00:00 +0000

Understanding crsctl query css votedisk Command in Oracle Clusterware

This page explains the crsctl query css votedisk command, its purpose, breakdown, and key points, offering insights and explanations for Oracle Clusterware management.

Sample Oracle Command

1crsctl query css votedisk

Description of Oracle Database SQL code:`crsctl query css votedisk`

This code is not actually SQL syntax, but rather a command from thecrsctlutility used to manage Oracle Clusterware. However, it interacts with the cluster registry which relies on an underlying database, so I can still offer insights and explanations.

Oracle Clusterware ocrcheck: Verify OCR Health

Sat, 10 Feb 2024 00:00:00 +0000

Overview Of ocrcheck Command

The ocrcheck command is a valuable tool for managing the Oracle Cluster Registry (OCR) within Oracle Clusterware

Retrive OCR (Oracle Cluster Registry) information

Sample SQL Command

1ocrcheck

Purpose:

ocrcheck is a command-line utility used to verify the health and consistency of the Oracle Cluster Registry (OCR). This registry stores crucial configuration information for all resources managed by Oracle Clusterware, including cluster membership, voting disks, and resources like databases and applications.

Oracle srvctl disable database: Prevent Auto Startup

Fri, 09 Feb 2024 00:00:00 +0000

Preventing a Database Startup at Boot Time: `srvctl disable database`

This command, commonly used in Oracle environments, instructs Oracle Clusterware to prevent a specific database from automatically starting when the operating system boots. Understanding its purpose, breakdown, and key points can help you manage your database effectively.

Sample SQL Command

1srvctl disable database -d <database name>

Preventing a Database Startup at Boot Time: `srvctl disable database`

Oracle oifcfg getif: Identify Cluster Interconnect Subnet

Thu, 08 Feb 2024 00:00:00 +0000

Understanding oifcfg getif for Oracle Cluster Interconnect Subnet Change

The Oracle Clustware command oifcfg getif is a crucial utility for managing Oracle Clusterware and its private interconnect subnet. Below is breakdown of its purpose, usage, and key points:

Change the private interconnect subnet. First find the interface which is in use as the interconnect - run as root from the crs home

Sample SQL Command

1oifcfg getif

Purpose:

Oracle Clusterware: Modify Interconnect Subnet with oifcfg

Wed, 07 Feb 2024 00:00:00 +0000

Understanding `oifcfg` for Changing Oracle Cluster Interconnect Subnet

The oifcfg Oracle Clusterware commands presented involve modifying the Oracle Clusterware private interconnect subnet.What follows is a breakdown of their purpose, usage, and key points:

Make a note of the interface name (eth1 in the following example), then aun the following:

Sample SQL Command

1oifcfg delif -global eth1
2
3oifcfg setif -global eth1/<your new subnet>:cluster_interconnect

Command Overview

While not directly an Oracle Database SQL command, the oifcfg commands presented involve modifying the Oracle Clusterware private interconnect subnet. Here's a breakdown of their purpose, usage, and key points:

Oracle Tablespaces Needing More Space: SQL Script

Tue, 06 Feb 2024 00:00:00 +0000

Description of Oracle Database SQL code for Identifying Tablespaces Needing Space

This code helps identify tablespaces requiring additional space to maintain an 80% utilization threshold in your Oracle database. Below is a breakdown of its purpose, components, and key points:

Sample SQL Command

 1set pages 999 lines 100
 2col "Tablespace" for a50
 3col "Size MB" for 999999999
 4col "%Used" for 999
 5col "Add (80%)" for 999999
 6select tsu.tablespace_name "Tablespace"
 7, ceil(tsu.used_mb) "Size MB"
 8, 100 - floor(tsf.free_mb/tsu.used_mb*100) "%Used"
 9, ceil((tsu.used_mb - tsf.free_mb) / .8) - tsu.used_mb "Add (80%)"
10from (select tablespace_name, sum(bytes)/1024/1024 used_mb
11 from dba_data_files group by tablespace_name) tsu
12, (select ts.tablespace_name
13 , nvl(sum(bytes)/1024/1024, 0) free_mb
14 from dba_tablespaces ts, dba_free_space fs
15 where ts.tablespace_name = fs.tablespace_name (+)
16 group by ts.tablespace_name) tsf
17where tsu.tablespace_name = tsf.tablespace_name (+)
18and 100 - floor(tsf.free_mb/tsu.used_mb*100) >= 80
19order by 3,4
20/

Sample Oracle Output

 1SQL> set pages 999 lines 100
 2col "Tablespace" for a50
 3col "Size MB" for 999999999
 4col "%Used" fSQL> SQL> SQL> or 999
 5col "Add (80%)" for 999999
 6select tsu.tablespace_name "Tablespace"
 7, ceil(tsu.used_mb) "Size MB"
 8, 100 - floor(tsf.free_mb/tsu.used_mb*100) "%Used"
 9, ceil((tsu.used_mb - tsf.free_mb) / .8) - tsu.used_mb "Add (80%)"
10from (select tablespace_name, sum(bytes)/1024/1024 used_mb
11 from dba_data_files group by tablespace_name) tsu
12, (select ts.tablespace_name
13 , nvl(sum(bytes)/1024/1024, 0) free_mb
14 from dba_tablespaces ts, dba_free_space fs
15 where ts.tablespace_name = fs.SQL> SQL> 2 3 4 5 6 7 8 9 10 tablespace_name (+)
16 group by ts.tablespace_name) tsf
17where tsu.tablespace 11 12 _name = tsf.tablespace_name (+)
18and 100 - floor(tsf.free_mb/tsu.used_mb*100) >= 80
19order by 3,4
20/
21 13 14 15
22Tablespace Size MB %Used Add (80%)
23-------------------------------------------------- ---------- ----- ---------
24SYSAUX 730 95 130
25SYSTEM 1070 100 260
26
27SQL>

Purpose:

Listing Objects in an Oracle Tablespace

Mon, 05 Feb 2024 00:00:00 +0000

SQL lists all objects within a specific tablespace in an Oracle database

A detailed explanation of Oracle Database SQL code used to list objects within a tablespace, including purpose, breakdown, key points, and insights.

Sample SQL Command

 1set pages 999
 2col owner format a15
 3col segment_name format a40
 4col segment_type format a20
 5select owner
 6, segment_name
 7, segment_type
 8from dba_segments
 9where lower(tablespace_name) like lower('%&tablespace%')
10order by owner, segment_name
11/

Sample Oracle Output

 1OWNER SEGMENT_NAME SEGMENT_TYPE
 2--------------- ---------------------------------------- --------------------
 3LARRY BIN$Q+k4qsgBLNngRAAQg5ZRWg==$0 INDEX
 4LARRY BIN$Q+k4qsgCLNngRAAQg5ZRWg==$0 TABLE
 5LARRY BIN$Q+k4qsgELNngRAAQg5ZRWg==$0 INDEX
 6LARRY BIN$Q+k4qsgFLNngRAAQg5ZRWg==$0 TABLE
 7LARRY BOX TABLE
 8LARRY BOX_PK INDEX
 9LARRY CD TABLE
10LARRY CD_PK INDEX
11LARRY LOCATION TABLE
12LARRY LOCATION_PK INDEX
13LARRY LOTS_OF_ROWS TABLE
14LARRY POO TABLE
15LARRY SERVERS TABLE
16LARRY SYS_C0023466 INDEX
17LARRY SYS_C0023467 INDEX
18LARRY SYS_C0027234 INDEX
19LARRY TEST_TABLE TABLE
20LARRY TRACK TABLE
21LARRY TRACK_PK INDEX
22
2319 rows selected.

Purpose:

Identifying User Tablespaces and Space Usage in Oracle

Sun, 04 Feb 2024 00:00:00 +0000

Query to Display All Tablespaces Used by A Specified User and The Total Space Occupied (rounded to MB)

Sample SQL Command

1select tablespace_name
2, ceil(sum(bytes) / 1024 / 1024) "MB"
3from dba_extents
4where owner like '&user_id'
5group by tablespace_name
6order by tablespace_name
7/

Sample Oracle Output

1TABLESPACE_NAME MB
2---------------------------------------- ----------
3LARRY_DATA 9
4LARRY_INDEX 15
5
62 rows selected.

Purpose:

To identify and report the tablespaces where a user owns objects and the approximate amount of storage they consume.

Breakdown:

Setting a Default Temporary Tablespace in Oracle Database

Sat, 03 Feb 2024 00:00:00 +0000

Alters The Default Temporary Tablespace for the Entire Database to "temp"

Sample SQL Command

1alter database default temporary tablespace temp
2/

Purpose:

To specify the preferred location where temporary data should be stored for all user sessions within the database. This provides centralized management and potentially performance benefits by consolidating temporary data storage.

Breakdown:

alter database: Initiates the modification of database-level settings.
default temporary tablespace temp: Sets the new default temporary tablespace name to "temp."

Key Points:

Oracle Segments Nearing Max Extents via dba_segments

Fri, 02 Feb 2024 00:00:00 +0000

Identify Oracle Database Segments Nearing Their Maximum Extent Limit

This guide explains an Oracle Database SQL code snippet that identifies segments approaching their maximum extent limit, its purpose, key points, and insights

Sample SQL Command

 1col segment_name format a40
 2select owner
 3, segment_type
 4, segment_name
 5, max_extents - extents as "spare"
 6, max_extents
 7from dba_segments
 8where owner not in ('SYS','SYSTEM')
 9and (max_extents - extents) < 10
10order by 4
11/

Purpose:

Adjusting Segment Growth with MAXEXTENTS in Oracle Database

Thu, 01 Feb 2024 00:00:00 +0000

Alters The MAXEXTENTS Parameter For A Specific Database Segment

Sample SQL Command

1alter <segment_type> <segment_name> storage(maxextents 150);
2/

Purpose:

To define the maximum number of extents the segment can occupy, controlling its potential growth and space allocation behavior.

Breakdown:

alter <segment_type> <segment_name>: This clause initiates the alteration process, specifying the type (e.g.,TABLE,INDEX) and name of the segment.
storage(maxextents 150): This subclause defines the new maxextents value to 150. You can replace this with your desired number of extents.

Key Points:

Monitoring Temporary Tablespace Usage in Oracle Database

Wed, 31 Jan 2024 00:00:00 +0000

Lists the Contents of the Temporary Tablespace(s), Including Details About Each Temporary Object and Its Associated Session

Sample SQL Command

 1set pages 999 lines 100
 2col username format a15
 3col mb format 999,999
 4select su.username
 5, ses.sid
 6, ses.serial#
 7, su.tablespace
 8, ceil((su.blocks * dt.block_size) / 1048576) MB
 9from v$sort_usage su
10, dba_tablespaces dt
11, v$session ses
12where su.tablespace = dt.tablespace_name
13and su.session_addr = ses.saddr
14/

Sample Oracle Output

1USERNAME SID SERIAL# TABLESPACE MB
2--------------- ---------- ---------- ------------------------------- --------
3REP_USER 117 1243 TEMP 25
4APP_DATA_OWNER 81 32 TEMP 231
5
62 rows selected.

Purpose:

Oracle Clusterware: Modify VIP Address and Network Interface

Sun, 28 Jan 2024 00:00:00 +0000

Modifying VIP Address, Subnet Mask, or Interface in Oracle Clusterware

Learn how to change the Virtual IP (VIP) address, subnet mask, or network interface for clustered nodes in an Oracle environment. This step-by-step guide includes commands, explanations, and key points to ensure a smooth and successful configuration update.

Change the VIP address, subnetmask or interface

1srvctl stop nodeapps -n <node1>
2srvctl stop nodeapps -n <node2>
3srvctl modify nodeapps -n <node1> -A <ip_address>/<net mask>/<interface>
4srvctl modify nodeapps -n <node2> -A <ip_address>/<net mask>/<interface>
5srvctl start nodeapps -n <node1>
6srvctl start nodeapps -n <node2>

Description of the Oracle Database SQL code

Purpose:

Oracle srvctl config nodeapps Command in Clusterware

Sat, 27 Jan 2024 00:00:00 +0000

Understanding the srvctl config nodeapps Command in Oracle Clusterware

Check the VIP config

1srvctl config nodeapps -n <node> -a -g -s -l

Sample Oracle Output

1
2no rows selected
3SQL>

Description of the Oracle Database SQL code

Purpose:

The srvctl config nodeapps -n <node> -a -g -s -l command is not directly related to Oracle Database SQL but rather serves as a crucial tool in Oracle Clusterware environments to effectively manage node applications and their associated Virtual IPs (VIPs). It retrieves detailed information about node applications on a specific node, including attributes, groups, startup mode, and network listeners, enabling you to:

Starting and Stopping Oracle Database Instances with SRVCTL

Fri, 26 Jan 2024 00:00:00 +0000

Start and stops a specific Oracle Database instance with the Server Control Utility (SRVCTL)

SQL Code

Start Database (Specific Node or Instance)

1srvctl start instance -d <database name> -i <instance name>

Stop Database (Specific Node or Instance)

1srvctl stop instance -d <database name> -i <instance name>

Sample Oracle Output

1
2no rows selected
3SQL>

Description of the Oracle Database SQL code

Purpose:

Oracle srvctl Start and Stop Database in Clusterware

Thu, 25 Jan 2024 00:00:00 +0000

Demystifying Database Start/Stop in Oracle Clusterware with srvctl

SQL Code

Start Database (All Nodes)

1srvctl start database -d <database name>

Stop Database (All Nodes)

1srvctl stop database -d <database name>

Demystifying Database Start/Stop in Oracle Clusterware with srvctl

These commands, srvctl start database and srvctl stop database, empower you to control the state of entire databases within your Oracle Clusterware environment. Let's delve into their purpose, breakdown, and key points:

Oracle Clusterware: srvctl start asm and srvctl stop asm

Mon, 22 Jan 2024 00:00:00 +0000

Demystifying Start/Stop ASM with srvctl in Oracle Database

These commands, specifically srvctl start asm and srvctl stop asm, play a crucial role in managing the Oracle Automatic Storage Management (ASM) instance within your Oracle Clusterware environment. Let's dive into their purpose, breakdown, and key points.

SQL Code

Start ASM

1srvctl start asm -n <node name>

Stop ASM

1srvctl stop asm -n <node name>

Description of the Oracle Database SQL code

Purpose:

Oracle Clusterware: Manage Node Apps with srvctl

Fri, 19 Jan 2024 00:00:00 +0000

Controlling Node Level Applications in Oracle Clusterware with srvctl

Master the srvctl start nodeapps and srvctl stop nodeapps commands to effectively manage node-level applications within your Oracle Clusterware environment. Gain insights into their purpose, breakdown, key points, and practical considerations

SQL Code

Start Nodeapps

1srvctl start nodeapps -n <node name>

Stop Nodeapps

1srvctl stop nodeapps -n <node name>

Description of the Oracle Commands

Purpose:

Managing Oracle Clusterware CRS

Tue, 16 Jan 2024 00:00:00 +0000

Essential commands for starting, stopping, checking, and monitoring CRS services

Note: Start/stop need to be run as root from the CRS home

SQL Code

Start CRS

1crsctl start crs

Stop CRS

1crsctl stop crs

Check CRS's status

1crsctl check crs

See the status of the various services

1crs_stat -t

Sample Oracle Output

1
2no rows selected
3SQL>

Description of the Oracle Database SQL code

Purpose:

Checking All Disks in Diskgroup Data

Mon, 15 Jan 2024 00:00:00 +0000

This SQL code instructs Oracle to perform a thorough check of all disks within the diskgroup named data1

Check the internal consistency of a diskgroup

SQL Code

1alter diskgroup data1 check all
2/

Sample Oracle Output

1no rows selected
2SQL>

Description of the Oracle Database SQL code

Purpose:

To initiate a comprehensive check of all disks within the diskgroup named data1 in an Oracle Database environment.
To proactively identify and address potential disk-related issues that could impact data integrity and availability.

Breakdown:

Oracle ASM Disk Balancing: Monitor with v$asm_operation

Sun, 14 Jan 2024 00:00:00 +0000

Monitoring ASM Operations in Oracle Database, Using the`v$asm_operation`View

SQL Code

1select *
2from v$asm_operation
3/

Mount/dismount disk groups

1alter diskgroup all mount
2/

1alter diskgroup data1 mount
2/

1alter diskgroup all dismount
2/

1alter diskgroup data1 dismount
2/

Description of the Oracle Database SQL code

Here's a description of the Oracle Database SQL code related to ASM operations and diskgroup management:

Oracle ASM: Drop a Disk Group with DROP DISKGROUP

Fri, 12 Jan 2024 00:00:00 +0000

Removing a Disk Group Permanently in Oracle Database, The `drop diskgroup` Command

SQL Code

1drop diskgroup '<name>'
2/

Description of the Oracle Database SQL code

Purpose:

The primary purpose of this SQL code is to permanently remove an entire disk group, identified by its name, from the Oracle database environment.
This action effectively eliminates the disk group and all associated data, freeing up the underlying physical storage resources.

Breakdown:

Oracle ASM: Add a Disk to an Existing Disk Group

Wed, 10 Jan 2024 00:00:00 +0000

Expanding Storage Capacity in Oracle Database, Adding a Disk to Diskgroup Data1

SQL Code

Note: Wildcards can be used for raw device names (eg. raw*

1alter diskgroup data1
2add disk '/dev/raw/raw4'
3/

Sample Oracle Output

1no rows selected
2SQL>

Description of the Oracle Database SQL code

Purpose:

The primary purpose of this SQL code is to expand the storage capacity of an existing disk group named "data1" within an Oracle database environment.
It achieves this by adding a new physical disk, identified as '/dev/raw/raw4', to the existing disk group.

Breakdown:

Oracle ASM: Create a Disk Group with External Redundancy

Mon, 08 Jan 2024 00:00:00 +0000

Creating an ASM Disk Group with External Redundancy in Oracle

SQL Code

1create diskgroup data1
2external redundancy
3disk '/dev/raw/raw1'
4/

Or with multiple raw partitions

SQL Code

1create diskgroup data1
2external redundancy
3disk '/dev/raw/raw1'
4/

Or with multiple fail groups...

SQL Code

1create diskgroup data3
2normal redundancy
3failgroup controller1 disk '/dev/raw/raw4'
4failgroup controller2 disk '/dev/raw/raw6'
5/

Sample Oracle Output

1no rows selected
2SQL>

Purpose:

Querying ASM Disk Information in Oracle

Sun, 07 Jan 2024 00:00:00 +0000

Querying ASM Disk Information in Oracle

SQL Code

1select name
2, group_number
3, disk_number
4, total_mb
5, free_mb
6from v$asm_disk
7order by group_number
8/

Sample Oracle Output

1no rows selected
2SQL>

Purpose:

Retrieves and displays key information about Automatic Storage Management (ASM) disks within the database.
Provides insights into disk configuration, capacity, and available space.
Facilitates storage management, monitoring, and capacity planning.

Breakdown:

Visualizing Disk Groups in Oracle ASM with SQL

Sat, 06 Jan 2024 00:00:00 +0000

Visualizing Disk Groups in Oracle ASM with SQL

Note: A group number of zero his indicates that a disk is available but hasn't yet been assigned to a disk group.

SQL Code

 1set lines 100
 2col name format a10
 3col path format a30
 4select name
 5, group_number
 6, disk_number
 7, mount_status
 8, state
 9, path
10from v$asm_disk
11order by group_number
12/

Purpose:

Checking Cluster Health with crsctl check cssd

Fri, 05 Jan 2024 00:00:00 +0000

Checking Cluster Health with crsctl check cssd

SQL Command

1crsctl check cssd

Purpose:

To verify the status and health of the Cluster Synchronization Services (CSS) daemon (cssd), a crucial component of Oracle Clusterware.
It's typically used in Oracle Real Application Clusters (RAC) and Oracle Automatic Storage Management (ASM) environments to ensure cluster integrity and coordination.

Breakdown:

crsctl: The command-line utility for managing Oracle Clusterware resources.
check: Initiates a health check on a specific resource.
cssd: The target resource, the Cluster Synchronization Services daemon.

Key Points:

dba_role_privs: List Oracle Roles Granted to a User

Thu, 04 Jan 2024 00:00:00 +0000

Retrieving User Role Privileges in Oracle using the view dba_role_privs

This page examines an Oracle SQL code snippet that fetches granted roles and their associated admin options for a specified user.

SQL Code

1select grantee
2, granted_role
3, admin_option
4from dba_role_privs
5where grantee like upper('&username')
6/

Purpose:

This code retrieves the roles granted to a specific user, indicating whether each role has the admin option enabled. This information is crucial for understanding user privileges and authorizations within the database.

Breakdown:

dba_roles PASSWORD_REQUIRED: Query Oracle Role Definitions

Thu, 04 Jan 2024 00:00:00 +0000

Find an Oracle role using the view dba_roles

This page explores an Oracle SQL code snippet that retrieves information about database roles based on user-provided search criteria.

SQL Code

1select *
2from dba_roles
3where role like '&role'
4/

Purpose:

This code retrieves information about a specific database role, based on a partial or complete role name provided by the user.

Breakdown:

Oracle Table Privileges Granted to a Role via role_tab_privs

Thu, 04 Jan 2024 00:00:00 +0000

Oracle Table Privileges Granted to a Role via role_tab_privs

Purpose

ROLE_TAB_PRIVS holds the complete inventory of object privileges Oracle has packaged into each named role — every table, view, and sequence grant, the precise privilege type, whether the right covers the entire object or is scoped to a single column, and whether the role can pass the grant further down the privilege chain. It is the correct starting point when you need to answer the question that surfaces in every access review: what table-level access does this role actually allow?

Assessing Database Storage Utilization in Oracle Database

Sun, 31 Dec 2023 00:00:00 +0000

How large is the Oracle Database?

Gain a comprehensive overview of database size, free space, and used space to proactively manage storage resources and plan for future growth.

SQL Code

 1col "Database Size" format a20
 2col "Free space" format a20
 3col "Used space" format a20
 4select round(sum(used.bytes) / 1024 / 1024 / 1024 ) || ' GB' "Database Size"
 5 ,round(sum(used.bytes) / 1024 / 1024 / 1024 ) -
 6 round(free.p / 1024 / 1024 / 1024) || ' GB' "Used space"
 7 ,round(free.p / 1024 / 1024 / 1024) || ' GB' "Free space"
 8from (select bytes
 9 from v$datafile
10 union all
11 select bytes
12 from v$tempfile
13 union all
14 select bytes
15 from v$log) used
16 ,(select sum(bytes) as p
17 from dba_free_space) free
18group by free.p

Sample Oracle Output

 11 col "Database Size" format a20
 22 col "Free space" format a20
 33 col "Used space" format a20
 44select round(sum(used.bytes) / 1024 / 1024 / 1024 ) || ' GB' "Database Size"
 55 , round(sum(used.bytes) / 1024 / 1024 / 1024 ) -
 66 round(free.p / 1024 / 1024 / 1024) || ' GB' "Used space"
 77 , round(free.p / 1024 / 1024 / 1024) || ' GB' "Free space"
 88 from (select bytes
 99 from v$datafile
1010 union all
1111 select bytes
1212 from v$tempfile
1313 union all
1414 select bytes
1515 from v$log) used
1616, (select sum(bytes) as p
1717 from dba_free_space) free
1818 group by free.p
19/
20
21Database Size Used space Free space
22-------------------- -------------------- --------------------
23564 GB 493 GB 71 GB
24
25SQL>

Purpose:

How to Block a User in Oracle Database (ACCOUNT LOCK)

Sun, 31 Dec 2023 00:00:00 +0000

Lock or Unlock an Oracle User in the Database

A brief guide on locking user accounts using the alter user <username> account lock; command, including its purpose, key points, and best practices.

Lock User

SQL Code

1alter user <username> account lock;
2/

Unlock User

SQL Code

1alter user <username> account unlock;
2/

Purpose:

To lock a specific user account in the Oracle database, preventing any further login attempts using that account.

Breakdown:

Oracle Active SQL: Monitor Sessions with v$session

Sun, 31 Dec 2023 00:00:00 +0000

Show all Active SQL for Sessions using v$session and v$sqlarea

Gain real-time insights into currently active user sessions and the SQL statements they are executing to troubleshoot performance issues and optimize resources

SQL Code

 1set feedback off
 2set serveroutput on size 9999
 3column username format a20
 4column sql_text format a55 word_wrapped
 5begin
 6 for x in
 7 (select username||'('||sid||','||serial#||') ospid = '|| process ||
 8 ' program = ' || program username,
 9 to_char(LOGON_TIME,' Day HH24:MI') logon_time,
10 to_char(sysdate,' Day HH24:MI') current_time,
11 sql_address,
12 sql_hash_value
13 from v$session
14 where status = 'ACTIVE'
15 and rawtohex(sql_address) <> '00'
16 and username is not null ) loop
17 for y in (select sql_text
18 from v$sqlarea
19 where address = x.sql_address ) loop
20 if ( y.sql_text not like '%listener.get_cmd%' and
21 y.sql_text not like '%RAWTOHEX(SQL_ADDRESS)%' ) then
22 dbms_output.put_line( '--------------------' );
23 dbms_output.put_line( x.username );
24 dbms_output.put_line( x.logon_time || ' ' || x.current_time || ' SQL#=' || x.sql_hash_value);
25 dbms_output.put_line( substr( y.sql_text, 1, 250 ) );
26 end if;
27 end loop;
28 end loop;
29end;

Sample Oracle Output

1no rows selected
2SQL>

Purpose:

Oracle dba_users: List All User Account Information

Sun, 31 Dec 2023 00:00:00 +0000

List all the Oracle Users Account Information for the Oracle Database using dba_users

A detailed overview of user accounts in the Oracle database, including their status, creation date, tablespaces, and more

SQL Code

 1set pages 999 lines 100
 2col username format a20
 3col status format a8
 4col tablespace format a20
 5col temp_ts format a20
 6select username
 7, account_status status
 8, created
 9, default_tablespace tablespace
10, temporary_tablespace temp_ts
11from dba_users
12order by username
13/

Purpose:

Tracking Completed Long Operations in Oracle Database

Sun, 31 Dec 2023 00:00:00 +0000

Display Oracle v$session_longops sessions

Gain visibility into recently completed long-running operations for monitoring performance and resource usage

SQL Code

 1set lines 100 pages 999
 2col username format a15
 3col message format a40
 4col remaining format 9999
 5select username
 6, to_char(start_time, 'hh24:mi:ss dd/mm/yy') started
 7, time_remaining remaining
 8, message
 9from v$session_longops
10where time_remaining = 0
11order by time_remaining desc

Sample Oracle Output

1no rows selected
2SQL>

Purpose:

Unveiling Language and Locale Settings in Oracle Database

Sun, 31 Dec 2023 00:00:00 +0000

Display the Oracle database chararter set information

Explore language and locale configurations that shape data interpretation and presentation for globalized applications and accurate data handling.

SQL Code

1select * from nls_database_parameters
2/

Sample Oracle Output

11
22SQL>

Purpose:

To retrieve and display all current National Language Support (NLS) database parameters. These parameters govern how Oracle handles language, territory, character sets, and other locale-specific settings, ensuring accurate data representation and processing for diverse user groups and applications.

Breakdown:

Monitoring Opened Cursors by User Session in Oracle Database

Fri, 29 Dec 2023 00:00:00 +0000

List all open oracle cursors by user or username

Track open cursor usage across user sessions to identify potential resource constraints or inefficiencies in database access patterns

SQL Code

 1set pages 999 lines 300
 2col username format a40
 3select sess.username as username
 4, sess.sid as sid
 5, sess.serial# as serial
 6, stat.value cursors
 7from v$sesstat stat
 8, v$statname sn
 9, v$session sess
10where sess.username is not null
11and sess.sid = stat.sid
12and stat.statistic# = sn.statistic#
13and sn.name = 'opened cursors current'
14order by value

Sample Oracle Output

 1USERNAME SID SERIAL# CURSORS
 2--------------- ---------- ---------- ----------
 3SYS 143 10 1
 4WEBUSER 132 33364 3
 5WEBUSER 116 18996 3
 6WEBUSER 118 23832 3
 7WEBUSER 120 423 3
 8ORA_TIV 126 37072 3
 9WEBUSER 127 4392 3
10WEBUSER 124 20787 4
11SYS 131 34710 5
12CNUSERMAN 145 19887 5
13CNUSERMAN 129 8407 5
14CNUSERMAN 144 17898 5
15CNUSERMAN 141 3881 5
16ORA_TIV 139 5349 8
17ORA_TIV 115 6676 9
18
1915 rows selected.
20SQL>USERNAME SID SERIAL# CURSORS
21--------------- ---------- ---------- ----------
22SYS 143 10 1
23WEBUSER 132 33364 3
24WEBUSER 116 18996 3
25WEBUSER 118 23832 3
26WEBUSER 120 423 3
27ORA_TIV 126 37072 3
28WEBUSER 127 4392 3
29WEBUSER 124 20787 4
30SYS 131 34710 5
31CNUSERMAN 145 19887 5
32CNUSERMAN 129 8407 5
33CNUSERMAN 144 17898 5
34CNUSERMAN 141 3881 5
35ORA_TIV 139 5349 8
36ORA_TIV 115 6676 9
37
3815 rows selected.
39SQL>

Purpose:

Oracle Modified Init Parameters Query with v$parameter

Fri, 29 Dec 2023 00:00:00 +0000

Show latent parameter changes

Analyzing Modified Oracle Database Parameters for Insights and Optimization Uncover configuration customizations, potential performance bottlenecks, and security considerations by examining modified initialization parameters in Oracle Database.

SQL Code

1select name
2, value
3from v$parameter
4where ismodified != 'FALSE'
5/

Sample Oracle Output

1no rows selected
2SQL>

Purpose:

To identify and display all Oracle database initialization parameters that have been modified from their default values, either during the current instance or in previous instances. This provides insights into the database's configuration, potential customizations, and areas that might require attention for optimization or troubleshooting.

Breakdown:

Resetting an Oracle Database Parameter to Its Default Value

Fri, 29 Dec 2023 00:00:00 +0000

Reset or unset a Oracle parameter in the spfile

Setting a parameter to = ' ' often isn't enough. Do this instead. The sid='*' bit is always necessary, even in non-RAC databases.

SQL Code

1alter system reset <parameter> scope=spfile sid='*'
2/

Sample Oracle Output

1no rows selected
2SQL>

Purpose:

To reset a specified database initialization parameter to its default value, ensuring the change takes effect across all instances in a Real Application Clusters (RAC) environment upon the next database startup. This aids in troubleshooting, optimizing performance, or addressing configuration issues.

Breakdown:

v$parameter: Show Non-Default Oracle Init Parameters

Fri, 29 Dec 2023 00:00:00 +0000

Show non-default parameters in the table v$parameter

SQL Code

 1set pages 999 lines 100
 2col name format a30
 3col value format a50
 4select name
 5, value
 6from v$parameter
 7where isdefault = 'FALSE'
 8and value is not null
 9order by name
10/

Sample Oracle Output

1no rows selected
2SQL>

Purpose:

Monitoring User-Specific SQL Activity in Oracle Database

Sat, 09 Dec 2023 00:00:00 +0000

Display the users current Session SQL

SQL Code

1Select sql_text
2from v$sqlarea
3where (address, hash_value) in
4(select sql_address, sql_hash_value
5 from v$session
6 where username like '&username')
7/

Sample Oracle Output

1Enter value for username: sys
2old 6: where username like '&username')
3new 6: where username like 'sys')
4
5no rows selected
6SQL>

Purpose:

To retrieve and display the SQL text of all SQL statements currently being executed by a specific user within the Oracle database, providing insights into their activities, potential performance issues, and opportunities for optimization. This aids in troubleshooting, performance tuning, and security auditing.

Breakdown:

v$session v$process: Map Oracle Sessions to OS PIDs

Sat, 09 Dec 2023 00:00:00 +0000

Display Session status associated with the specified os process id

SQL Code

 1select s.username
 2, s.sid
 3, s.serial#
 4, p.spid
 5, last_call_et
 6, status
 7from V$SESSION s
 8, V$PROCESS p
 9where s.PADDR = p.ADDR
10and p.spid='&pid'
11/

Sample Oracle Output

1Enter value for pid: 9999
2old 10: and p.spid='&pid'
3new 10: and p.spid='9999'
4
5no rows selected
6SQL>

Purpose:

Oracle Feature Usage with dba_feature_usage_statistics

Sat, 02 Dec 2023 00:00:00 +0000

Show all the Oracle database used or installed Oracle features using dba_feature_usage_statistics

Discover which database features have been actively used, providing insights for license management, optimization, and future planning.

Show all the Oracle database installed features for an instance

SQL Code

1select name
2, detected_usages
3from dba_feature_usage_statistics
4where detected_usages > 0
5/

Sample Oracle Output

11
22SQL>

Purpose:

To identify and display database features that have been actively used within a specified period, providing insights into feature adoption, usage patterns, and potential areas for optimization or license management.

Breakdown:

Oracle Map Sessions to OS Processes via v$session

Sat, 02 Dec 2023 00:00:00 +0000

Select Oracle user info including os pid

SQL Code

 1col "SID/SERIAL" format a10
 2col username format a20
 3col osuser format a15
 4col program format a50
 5select s.sid || ',' || s.serial# "SID/SERIAL"
 6, s.username
 7, s.osuser
 8, p.spid "OS PID"
 9, s.program
10from v$session s
11, v$process p
12Where s.paddr = p.addr
13order by to_number(p.spid)
14/

Sample Oracle Output

 1SID/SERIAL USERNAME OSUSER OS PID PROGRAM
 2---------- -------------------- --------------- ------------------------ --------------------------------------------------
 31,51318 oracle 1751 oracle@localhost.localdomain (PMON)
 4238,32433 oracle 1756 oracle@localhost.localdomain (CLMN)
 52,46817 oracle 1762 oracle@localhost.localdomain (PSP0)
 6239,38809 oracle 1768 oracle@localhost.localdomain (VKTM)
 73,60083 oracle 1775 oracle@localhost.localdomain (GEN0)
 8240,38968 oracle 1780 oracle@localhost.localdomain (MMAN)
 9242,5837 oracle 1789 oracle@localhost.localdomain (GEN2)
105,43292 oracle 1791 oracle@localhost.localdomain (VOSD)
11241,6809 oracle 1793 oracle@localhost.localdomain (DIAG)
1215,1554 SYS oracle 1798 oracle@localhost.localdomain (OFSD)
13249,54000 oracle 1798 oracle@localhost.localdomain (SCMN)
146,34531 oracle 1802 oracle@localhost.localdomain (DBRM)
15243,12974 oracle 1806 oracle@localhost.localdomain (VKRM)
167,13091 oracle 1812 oracle@localhost.localdomain (SVCB)
17244,5064 oracle 1816 oracle@localhost.localdomain (PMAN)
188,25470 oracle 1818 oracle@localhost.localdomain (DIA0)
19245,44799 oracle 1822 oracle@localhost.localdomain (DIA1)
209,52018 oracle 1824 oracle@localhost.localdomain (LMHB)
21247,23362 oracle 1830 oracle@localhost.localdomain (DBW0)
2210,26928 oracle 1833 oracle@localhost.localdomain (LGWR)
23246,14445 oracle 1835 oracle@localhost.localdomain (CKPT)
2412,54188 oracle 1839 oracle@localhost.localdomain (SMON)
25248,5389 oracle 1844 oracle@localhost.localdomain (SMCO)
2611,14458 oracle 1850 oracle@localhost.localdomain (RECO)
27250,4512 oracle 1859 oracle@localhost.localdomain (LREG)
2813,26195 oracle 1865 oracle@localhost.localdomain (PXMN)
2914,57678 oracle 1877 oracle@localhost.localdomain (MMON)
30252,34776 oracle 1880 oracle@localhost.localdomain (MMNL)
31254,26559 oracle 1899 oracle@localhost.localdomain (BG00)
3218,30813 oracle 1899 oracle@localhost.localdomain (BG00)
33251,1313 oracle 1899 oracle@localhost.localdomain (SCMN)
34253,36102 oracle 1899 oracle@localhost.localdomain (BG00)
3519,6764 oracle 1899 oracle@localhost.localdomain (BG00)
3624,36119 oracle 1899 oracle@localhost.localdomain (BG00)
37255,24331 oracle 1913 oracle@localhost.localdomain (BG01)
3820,48416 oracle 1913 oracle@localhost.localdomain (SCMN)
39257,12867 oracle 1913 oracle@localhost.localdomain (BG01)
4021,35536 oracle 1913 oracle@localhost.localdomain (BG01)
41256,34711 oracle 1913 oracle@localhost.localdomain (BG01)
42259,47947 oracle 1924 oracle@localhost.localdomain (BG02)
4323,697 oracle 1924 oracle@localhost.localdomain (BG02)
44258,29095 oracle 1924 oracle@localhost.localdomain (SCMN)
4522,11344 oracle 1924 oracle@localhost.localdomain (BG02)
46260,46618 oracle 1936 oracle@localhost.localdomain (GCW0)
47261,9692 oracle 1950 oracle@localhost.localdomain (TMON)
4826,24917 oracle 1953 oracle@localhost.localdomain (RCBG)
494,45620 oracle 2116 oracle@localhost.localdomain (TT00)
50263,14430 oracle 2119 oracle@localhost.localdomain (TT01)
5132,28875 oracle 2826 oracle@localhost.localdomain (AQPC)
52265,47138 oracle 3157 oracle@localhost.localdomain (QM02)
5335,53257 oracle 3170 oracle@localhost.localdomain (Q003)
5446,26591 oracle 3809 oracle@localhost.localdomain (CL00)
5547,56309 oracle 3882 oracle@localhost.localdomain (Q004)
5649,18860 oracle 3891 oracle@localhost.localdomain (CJQ0)
57286,58632 ORDS_PUBLIC_USER oracle 4175 Oracle REST Data Services
5853,20873 ORDS_PUBLIC_USER oracle 4179 Oracle REST Data Services
5916,14520 oracle 8232 oracle@localhost.localdomain (GCR0)
6025,35234 oracle 8235 oracle@localhost.localdomain (W000)
61271,17974 oracle 8241 oracle@localhost.localdomain (GCR1)
6243,13620 oracle 8267 oracle@localhost.localdomain (M001)
6338,45731 oracle 8273 oracle@localhost.localdomain (M003)
64276,28467 oracle 8276 oracle@localhost.localdomain (M004)
6541,61869 oracle 8304 oracle@localhost.localdomain (GCR2)
66273,42070 oracle 8313 oracle@localhost.localdomain (W001)
6754,58456 SYS oracle 8510 sqlplus@localhost.localdomain (TNS V1-V3)
6842,36219 oracle 8907 oracle@localhost.localdomain (M005)
69237,9496 SYS oracle 9666 oracle@localhost.localdomain (J000)
7052,29429 oracle 9685 oracle@localhost.localdomain (J001)
71272,7991 oracle 9786 oracle@localhost.localdomain (J002)
72284,27835 oracle 10371 oracle@localhost.localdomain (M002)
73
7470 rows selected.
75SQL>

Purpose:

Identifying Idle User Sessions in Oracle Database

Fri, 01 Dec 2023 00:00:00 +0000

Oracle sessions sorted by logon time

Track idle time for user sessions to uncover potential resource leaks, optimize database performance, and maintain security best practices.

SQL Code

1et lines 100 pages 999
2select username
3, floor(last_call_et / 60) "Minutes"
4, status
5from v$session
6where username is not null
7order by last_call_et
8/

Sample Oracle Output

 1USERNAME OSUSER ID STATUS LOGIN_TIME LAST_CALL_ET
 2-------------------- --------------- --------------- -------- -------------- ------------
 3SYS oracle 54,58456 ACTIVE 20:09 10/12/23 0
 4SYS oracle 52,61761 ACTIVE 21:37 10/12/23 100
 5SYS oracle 15,1554 ACTIVE 23:34 09/12/23 79495
 6ORDS_PUBLIC_USER oracle 286,58632 INACTIVE 23:36 09/12/23 79361
 7ORDS_PUBLIC_USER oracle 53,20873 INACTIVE 23:36 09/12/23 79360
 8
 95 rows selected.
10SQL>

Purpose:

Tracking Idle Time for User Sessions in Oracle Database

Fri, 01 Dec 2023 00:00:00 +0000

Display all Oracle users by the time since last user activity

Identify idle user sessions and their inactive duration for resource optimization, performance tuning, and security best practices.

SQL Code

1set lines 100 pages 999
2select username
3, floor(last_call_et / 60) "Minutes"
4, status
5from v$session
6where username is not null
7order by last_call_et
8/

Sample Oracle Output

 1USERNAME Minutes STATUS
 2-------------------- ---------- --------
 3SYS 0 ACTIVE
 4SYS 1 ACTIVE
 5ORDS_PUBLIC_USER 1305 INACTIVE
 6ORDS_PUBLIC_USER 1305 INACTIVE
 7SYS 1307 ACTIVE
 8
 95 rows selected.
10SQL>

Purpose:

Check if Java is Installed in Oracle Database

Wed, 29 Nov 2023 00:00:00 +0000

Identify if Java is installed in the Oralce database using all_objects

Gain visibility into the quantity of Java objects owned by the SYS user, aiding in understanding database usage and potential security considerations.

This will return 9000'ish if it is...

SQL Code

1select count(*)
2from all_objects
3where object_type like '%JAVA%'
4and owner = 'SYS'
5/

Sample Oracle Output

11
22SQL>

Purpose:

Oracle Top 10 Largest Segments Query with dba_segments

Wed, 29 Nov 2023 00:00:00 +0000

Show the ten largest oracle objects in the database using dba_segments

Pinpoint the segments occupying the most storage space within the database to optimize storage usage, address potential bottlenecks, and enhance performance.

SQL Code

 1col owner format a15
 2col segment_name format a30
 3col segment_type format a15
 4col mb format 999,999,999
 5select owner
 6, segment_name
 7, segment_type
 8, mb
 9from (
10 select owner
11 , segment_name
12 , segment_type
13 , bytes / 1024 / 1024 "MB"
14 from dba_segments
15 order by bytes desc
16 )
17where rownum < 11
18/

Sample Oracle Output

 1OWNER SEGMENT_NAME SEGMENT_TYPE MB
 2--------------- ------------------------------ --------------- ------------
 3MYAPP TRANS_LOG TABLE 7,880
 4MYAPP DESCRIPTION INDEX 6,028
 5MYAPP EVT_LOG TABLE 4,984
 6ARCHIVE EVT_LOG TABLE 3,080
 7MYAPP ATTRIBUTES TABLE 2,312
 8MYAPP UNIQUE_EVT INDEX 2,129
 9MYAPP EVT_HOSTNAME INDEX 1,409
10MYAPP SOURCE INDEX 1,407
11
128 rows selected.

Purpose:

Oracle DBA SQL Scripts and Database Commands

Thu, 23 Nov 2023 00:00:00 +0000

Oracle SQL Scripts and Database Commands 23c 21c 19c 18c 12c 11g 10g 9i 8i

We are in the process of building a list of simple scripts used every day by DBA and others. If you have your own scripts you reuse in a text file on you workstation please send it to us.

To look at other scripts see the Oracle Scripts Tag

Thanks for coming by!!

Security Grants

1grant select on PERSON_TABLE to public with grant option;
2
3select * from dba_tab_privs where TABLE_NAME = 'PERSON_TABLE';
4
5select * from dba_role_privs where granted_role = 'PORTMAN_TABLE';

Resizing A Data File

1alter database datafile '/u04/oradata/wpk/temp01.dbf' resize 500m;

Show All Product Information

1select * from product_component_version;

Show Row Counts For All Tables That Have ANALYZE On

1select owner table_name, num_rows from dba_tables where num_rows > 0;

Select All Users Active In The System

1select sid, serial#,user#, Username, machine, program, server, status, command, type from v$session order by username;

Show What A Current User Is Doing

1select sid, serial#, status, server from v$session where username = 'BROWNBH';

Create Count For All Tables

1select 'Select count(*) from ' ||owner|| '.' ||table_name|| ';' from dba_all_tables order by owner, table_name;

Show All Indexes

1select owner, index_name, table_type, tablespace_name from dba_indexes where  owner <>'SYSTEM' and owner <> 'DBSNMP' and owner <> 'ORDSYS' and owner <> 'OUTLN' and owner <> 'SYS' and owner <> 'SYSTEM' order by owner, index_name, tablespace_name;

Show All Tables

1select owner, table_name, table_type, tablespace_name from dba_all_tables where owner <>'SYSTEM' and owner <> 'DBSNMP' and owner <> 'ORDSYS' and owner <> 'OUTLN' and owner <> 'SYS' and owner <> 'SYSTEM' order by owner, table_name, tablespace_name;

Show Space Used

1select Tablespace_Name, /*Tablespace name*/ Owner, /*Owner of the segment*/ Segment_Name, /*Name of the segment*/ Segment_Type, /*Type of segment (ex. TABLE, INDEX)*/ Extents, /*Number of extents in the segment*/ Blocks, /*Number of db blocks in the segment*/ Bytes /*Number of bytes in the segment*/ from DBA_SEGMENTS where owner <>'SYSTEM' and owner <> 'DBSNMP' and owner <> 'ORDSYS' and owner <> 'OUTLN' and owner <> 'SYS' and owner <> 'SYSTEM';

Sum Space By Owner

1select owner, sum(blocks) Totalblocks, sum(bytes)TotalBytes from DBA_SEGMENTS group by owner;

Sum Space by Tablespace

1select tablespace_name, sum(blocks) Totalblocks, sum(bytes)TotalBytes from DBA_SEGMENTS  group by tablespace_name;

Show Reads And Writes By File Name In Oracle DB

1select v$datafile.name "File Name", v$filestat.phyrds "Reads", v$filestat.phywrts "Writes" from v$filestat,v$datafile where v$filestat.file# = v$datafile.file#;

Show Versions Of Software

1select * from V$VERSION;

Identify Segments That Are Getting Close To Their Max-Extent Values

1select owner,tablespace_name,segment_name,bytes,extents,max_extents from dba_segments where extents*2 > max_extents;

Identifies Segments That Are Getting Close To Running Out Of Contiguous Free Space

1select owner, s.tablespace_name, segment_name, s.bytes, next_extent, max(f.bytes) largest from dba_segments s, dba_free_space f where s.tablespace_name = f.tablespace_name(+) group by owner, s.tablespace_name, segment_name, s.bytes, next_extent having next_extent*2 >max(f.bytes);

Displays Archived Redo Log Information

1select * from v$database;

Display Count Historical Archived Log Information From The Control File

1select count(*) from v$archived_log;
2
3select min(completion_time) from v$archived_log;

Shows Current Archive Destinations

1select * from v$archive_dest;

Backups Of Archived Logs

1select count(*) from v$backup_redolog;

Display All Online Redo Log Groups For The database

1select * from v$log;

Show All Datafiles For Tablespace And Oracle Stuff

1select * from dba_data_files order by tablespace_name, file_name;

Monitoring Active and Idle User Sessions in Oracle Database

Wed, 15 Nov 2023 00:00:00 +0000

Show all the Oracle users connected to the database

SQL Code

 1set lines 100 pages 999
 2col ID format a15
 3col USERNAME format a20
 4select username
 5, sid || ',' || serial# "ID"
 6, status
 7, last_call_et "Last Activity"
 8from v$session
 9where username is not null
10order by status desc
11, last_call_et desc
12/

Sample Oracle Output

 1USERNAME ID STATUS Last Activity
 2-------------------- --------------- -------- -------------
 3ORDS_PUBLIC_USER 286,58632 INACTIVE 1709
 4ORDS_PUBLIC_USER 52,56550 INACTIVE 1708
 5ORDS_PUBLIC_USER 53,20873 INACTIVE 1708
 6SYS 15,1554 ACTIVE 1843
 7SYS 237,34880 ACTIVE 81
 8SYS 36,39003 ACTIVE 0
 9
106 rows selected.

Purpose:

Oracle Schema Space Usage with dba_segments and dba_objects

Tue, 14 Nov 2023 00:00:00 +0000

Shows the distribution of objects and data across all schemas using dba-segments & dba_objects

Gain insights into object distribution across database users and their corresponding storage usage for data management, capacity planning, and optimization.

Which schemas are taking up all of the space?

SQL Code

 1set pages 999
 2col "size MB" format 999,999,999
 3col "Objects" format 999,999,999
 4select obj.owner "Owner"
 5, obj_cnt "Objects"
 6, decode(seg_size, NULL, 0, seg_size) "size MB"
 7from (select owner, count(*) obj_cnt from dba_objects group by owner) obj
 8, (select owner, ceil(sum(bytes)/1024/1024) seg_size
 9 from dba_segments group by owner) seg
10where obj.owner = seg.owner(+)
11order by 3 desc ,2 desc, 1
12/

Sample Oracle Output

 1Owner Objects size MB
 2------------------------------ ------------ ------------
 3ANDY 219 46,323
 4SYS 22,923 706
 5SYSMAN 1,341 49
 6XDB 680 49
 7MDSYS 896 33
 8SYSTEM 454 23
 9OLAPSYS 720 16
10WMSYS 242 7
11CTXSYS 339 5
12EXFSYS 281 4
13DBSNMP 46 2
14ORDSYS 1,720 1
15DMSYS 189 1
16OUTLN 8 1
17SCOTT 6 1
18TSMSYS 3 1
19PUBLIC 19,990 0
20ORDPLUGINS 10 0
21
2218 rows selected.
23
24SQL>

Purpose:

Determining Oracle Database Startup Time using v$instance

Mon, 13 Nov 2023 00:00:00 +0000

Oracle Startup Time

Discover the precise moment when the database was last initialized, providing insights for troubleshooting, performance analysis using v$instance

Identify the Oralce Startup Time using SQL Script

SQL Code

1select to_char(startup_time, 'HH24:MI DD-MON-YY') "Startup time"
2from v$instance
3/

Sample Oracle Output

1 1 select to_char(startup_time, 'HH24:MI DD-MON-YY') "Startup time"
2 2* from v$instance
3SQL> /
4
5Startup time
6---------------
702:55 17-MAY-23

Purpose: