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Content Server Manual / Version 2204

Table Of Contents Optimization Options

In order to optimize your ORACLE database, you should consider the following hints:

  • Use an I/O subsystem with write caches.

  • Five hard disks are recommended for database operation: one each for redo logs, rollback, index, data, and archive logs.

  • Striping increases performance further. Hard disks could be mirrored in pairs, and striping could be defined across the mirror pairs.

  • RAID 5 should be avoided for performance reasons.

  • Larger redo logs might be necessary (for example 500MB). The aim is to rotate the logs less than once every three minutes. Larger redo logs increase recovery time.

  • Large redo log buffers (such as 10 MB) are recommended.

  • The tables Blobdata and PK_Blobdata should have larger than default values of init_trans, for example, 10 or 20 (depending on the number of concurrently active database connections, which is also configurable). The parameter init_trans determines how many processes can write to a single block in parallel. Large "waits for data block" in the statspack report indicate an init_trans problem. Increasing init_trans by 1 requires about 25 additional bytes per block for management information.

  • To check if init_trans is too small, this command shows the waiting database jobs: select sid, sql_text from v$session s, v$sqltext t where s.sql_hash_value=t.hash_value and s.sid in (select sid from v$session_wait where event = 'enqueue') order by sid,piece;

  • Be sure to update the database optimizer statistics on a regular basis

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