DBA

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 …

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 …

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 …

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, …

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 …

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 …

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 …

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 …

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 …

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 …