Utilizing SQL tuning features Each release of Oracle introduces new and improved SQL performance features. In particular the cost-based optimizer contains improvements in each release—many of whic...
Relieving latch contention Operations that affect the contents of the SGA require that a process acquire a latch. A latch is similar to a lock, but instead of preventing two sessions from concurren...
Redo log configuration When a transaction is committed, a physical write to the redo log file must occur. The write must complete before the commit call returns control to the user. Hence, redo log...
Optimizing archiving Archived logs are copies of online redo logs. They can be used to recover a database to point of failure or to another point in time after a backup has been restored. Archive l...
Log file wait events Just as Oracle sessions must wait for database file I/O, they must also wait for log file I/O. Such waits occur whenever a COMMIT statement causes a write to the redo log. The ...
Naming Conventions A naming convention is used when Oracle creates managed database datafiles. The following table shows the naming conventions fo the database datafiles. (Note that these may differ f...
A tablespace is the primary level of logical storage in an Oracle database. All "hard" database objects such as tables, indexes, sequences, and clusters reside in tablespaces. An Oracle database can ...
Improving database writer performance Free buffer or write complete waits can indicate that the database writer process (DBWR) process is experiencing a disk I/O bottleneck. The DBWR is the only pr...
Fragmentation in a tablespace is thought to be a performance killer. This has been proven to be a myth. Fragmentation by itself does not cause performance problems in a multi-user Oracle database. Wha...
Disks for redo devices When a transaction is committed, the redo log entry in the redo log buffer must be written to disk. The characteristics of the redo log writes are very different from that of...
This topic documents the initialization parameters used to configure the multi-threaded server (MTS). Only the currently recommended parameters are described here. Parameters that were made obsolete w...
The DBMS_JOB package is actually an API into an Oracle subsystem known as the job queue. The Oracle job queue allows for the scheduling and execution of PL/SQL routines (jobs) at predefined times and/...
