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Thousands of active sessions waiting on latch free in relation to 'transaction branch allocation' (Doc ID 2018260.1)

Last updated on FEBRUARY 22, 2019

Applies to:

Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata 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
Oracle Database Cloud Exadata Service - Version N/A and later
Information in this document applies to any platform.


Experiencing contention for "transaction branch allocation" latch with a large fraction of the requests from location kpupuc.

A large number of active sessions are waiting for latch free as per the AWR report which shows 

Event Waits Time(s) Avg wait (ms)  % DB time Wait Class
latch free 1,237,131 128,011 103 31.44 Other 

Most of latch waits are for "transaction branch allocation" i.e. 121,162 seconds 

Latch Name Get Requests Pct Get Miss  Avg Slps /Miss Wait Time (s) NoWait Requests
transaction branch allocation 112,307,430 15.11 0.07 121162 0

AWR report shows the highest number of waits/sleeps are occurring in function ksupuc followed by functions ktcsbr and ktcbba as per the following section

Latch Name Where NoWait Misses  Sleeps Waiter Sleeps
transaction branch allocation ksupuc 0 811,508 891,320
transaction branch allocation ktcsbr 0 128,862 82,780
transaction branch allocation ktcbba 0 84,239 143,093




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