Bug 20370037 - Shared Pool from KGLH0 constantly growing causing ORA-04031 and Latch contention (Doc ID 2119923.1)

Last updated on NOVEMBER 14, 2016

Applies to:

Oracle Database - Enterprise Edition - Version 12.1.0.2 and later
Information in this document applies to any platform.

Symptoms

Outage due to latch contention issue on "latch: shared pool" (19%) and "latch: row cache objects" (12%),
AND  shared pool from KGLH0 is constantly growing, and it's now 22 times larger than normal and still growing,
and getting hundreds of ORA-04031 errors related to  KGLH0 growth;

Databases (12.1.0.2) are running out of memory and crashing because the KGLH0 process is consuming all the memory.

These problems with shared pool growth from KGLH0 did not start until after upgrading to 12.1.

Issue is occurring most of day and system seems sluggish and is affecting their ability to complete
other application tasks;

Shared Pool Size under Cache Sizes increased .5 GB in AWR for just this one 60 minute period
and continues to increase every day.

KGLH0 is memory allocated for child cursors, and for some reason, Oracle is not reusing child cursors
and is creating more instead.

Adding memory is only a temporary stop-gap solution to address the symptoms,
while Oracle just fills all available free memory again and reaches 100% memory utilization due to shared pool growth from KGLH0.

Changes

 Upgrade to 12.1.

Cause

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