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Top 5 Database and/or Instance Performance Issues in RAC Environment (Doc ID 1373500.1)

Last updated on OCTOBER 30, 2022

Applies to:

Oracle Database - Enterprise Edition - Version to [Release 10.1 to 12.1]
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
Information in this document applies to any platform.


The purpose of this document is to provide a summary of  top database and/or instance performance issues and the possible solutions in a RAC environment.

Please note that Issue #3 (High Waits on Mutexes) and Issue #5 (High CPU and Memory Consumption) are generic database issues and not RAC-specific. However, they have been included in this document because they are one of the TOP issues, and can occur locally on an instance in a RAC environment.




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In this Document
 Issue #1: High counts of lost blocks(gc lost blocks, gc current/cr lost blocks)
 Issue #2: High log file sync waits
 Issue #3: High Waits on Mutex
 Issue #4: High gc buffer busy, enq: TX -row lock contention, enq: TX - index contention, enq: TX - ITL allocate entry waits
 Issue #5: High CPU and memory consumption

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