Improving Database I/O A number of performance indicators can suggest a need to improve Oracle disk I/O. A major aim of configuring an Oracle server is to ensure that disk I/O does not become a bot...
The redo logs store all transactions which alter the database, all committed updates, adds, deletes of tables, structures or data. If archiving is disabled, only data in the current off-line and on-li...
DB file waits Wait conditions starting with the phrase DB FILE (for example, db file parallel write, db file scattered read, db file sequential read, and db file single write) all occur when an Ora...
Buffer busy waits Buffer busy waits occur when a session cannot access a needed block because it is in use by another session. The two most common causes are: insufficient free lists for a table...
Like tables and indexes, rollback segments may run out of space during processing and need to request additional extents. Dynamic extension can have a serious impact on performance, particularly on th...
Oracle is an Object-Relational Database Management System, or, ORDBMS for short. A traditional RDBMS (Oracle Version 7 and below) stores data in tables called relations. These relations are two dimens...
This section discusses the following Net8 configurations: Dedicated server Multi-threaded server (MTS) Oracle Internet Directory Oracle Names Connection Manager As you read these sections, bear...
There are several ways to look at what's happening in a multi-threaded server environment. Using operating-system commands, you may be able to see a list of the dispatcher and shared server processes ...
As their name implies, locally managed tablespaces do not manage their free and used extents by the data dictionary but are instead managed at the local tablespace level. This local management is acco...
Shared pool latch contention can occur when the shared pool is sized too large to be effectively managed. Starting with Oracle version 8.1.6, Oracle implemented improved shared pool management archite...
SGA refers to a Shared Global Area. As the term global implies, this area is accessible to all Oracle processes and users. Each instance will have its own SGA. Oracle processes and users must share la...
Oracle9i has renamed the multi-threaded server (MTS) to shared server. The shared-server architecture increases the scalability of applications and the number of clients that can be simultaneously con...
