How to Match a Row Cache Object Child Latch to its Row Cache
Last updated on JUNE 06, 2018
Applies to:Oracle Database - Enterprise Edition - Version 18.104.22.168 and later
Information in this document applies to any platform.
- Starting with Oracle 9.2, the 'row cache objects' latch has multiple children.
- There are a number of row caches e.g. dc_objects, dc_users, dc_histograms etc.
- Each child latch covers a single row cache.
- In 22.214.171.124, each row cache is covered by 8 children latches.
In Database Performance investigations where 'latch free' waits on this type of latch consume significant database time, it is useful to be able to map each 'row cache objects' child latch to the row cache it covers. In this way, we can map the number of SLEEPS for a child latch (CHILD#) in V$LATCH_CHILDREN to a particular type of row cache.
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