ORA-4031 After Upgrade To 11.2.0.3 With Leak in 'KTC latch subh' Subheaps (Doc ID 1398984.1)

Last updated on NOVEMBER 28, 2016

Applies to:

Oracle Database - Enterprise Edition - Version 11.2.0.1 to 11.2.0.3 [Release 11.2]
Information in this document applies to any platform.

Symptoms

This issue was observed in 11.2.0.3 shortly after upgrading to 11.2.0.3.

The symptoms are:

  1. ORA-4031 errors after the database has been running for some time.
  2. The ORA-4031 can show messages for Shared Pool, Streams Pool, or any other pool in the SGA, but most commonly for the Shared Pool.
  3. The heapdump will show the largest memory area is 'KTC latch subh'.
  4. Even without a ORA-4031, heapdumps taken at intervals will show this subheap continually growing in size.

 

Example from multiple heap dumps:
 At 2011-11-28 18:33:27, 'KTC latch subh' size was 425320296 bytes.
 At 2011-11-29 11:52:20, 'KTC latch subh' size was 438683272 bytes.
 At 2011-11-29 11:57:29, 'KTC latch subh' size was 458469272 bytes.
 At 2011-12-02 16:16:02, 'KTC latch subh' size was 630790264 bytes.
 At 2011-12-05 21:00:14, 'KTC latch subh' size was 1040848080 bytes.

Cause

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