Scripts

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 …

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 …

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 …

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 …

dba_constraints: Query All Oracle Table Constraints Purpose A DDL export shows every constraint as text, and a design tool shows them as a diagram. Neither lets you filter, sort or count. DBA_CONSTRAINTS does. It holds one row per constraint, so a single query can list the constraints on one table, show which are …

List Tables That Are Using the Specified Table as a Foreign Key using dba_constraints Which tables point at SALES.CUSTOMER? You need the answer before you truncate it, drop it, reload it or change its primary key, because every child table with a foreign key to it will either block the change or be affected by it. …

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 …

Oracle Undo: Check Extent Status in DBA_UNDO_EXTENTS Purpose A report query runs for forty minutes on a busy system and ends with ORA-01555: snapshot too old. The query is correct. The undo it needed to build a consistent picture of the data was overwritten before the query finished. Somewhere between the size of the …

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, …

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 …