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Understanding and Tuning Buffer Cache and DBWR (Doc ID 62172.1)

Last updated on SEPTEMBER 14, 2023

Applies to:

Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Gen 1 Exadata Cloud at Customer (Oracle Exadata Database Cloud Machine) - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Oracle Database Backup Service - Version N/A and later
Information in this document applies to any platform.

Purpose

 

This article describes what issues affect the performance of the buffer cache and DBWR (database writer) in Oracle releases 7.1 to 9.2 inclusive and onward. The notes here are particularly important if your system shows any of the following:

Latch contention for the 'cache buffers lru chain' or the "cache buffer chain" latch
Large "Average Write Queue" length
Lots of time spent waiting for "write complete waits"
Lots of time spent waiting for "free buffer waits" or "Buffer busy waits"

Scope

 

Details

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