IF: Undo Related Wait Event - Latch: undo global data (Doc ID 1951702.1)

Last updated on JULY 21, 2017

Applies to:

Oracle Database - Enterprise Edition - Version 9.2.0.1 and later
Information in this document applies to any platform.
***Checked for relevance on 21-Jul-2017***

Symptoms

AWR report shows event latch: undo global data as the top wait event

Eg:

  

Top 5 Timed Foreground Events

Event Waits Time(s) Avg wait (ms) % DB time Wait Class
latch: undo global data 72,119,056 865,904 12 47.88 Other  <<<
DB CPU 753,239 41.65
db file sequential read 57,249,544 118,554 2 6.55 User I/O
wait list latch free 1,767,054 17,961 10 0.99 Other
SQL*Net message from dblink 1,916,501 14,427 8 0.80 Network

  

Cause

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