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 laterOracle 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.
Symptoms
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 |
Changes
Cause
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In this Document
| Symptoms |
| Changes |
| Cause |
| Solution |
| References |