Trace from ORA-4031 can show 'miscellaneous' allocations to be much larger than expected
Last updated on MAY 07, 2012
Applies to:Oracle Server - Enterprise Edition - Version 220.127.116.11 to 10.1.0.5 [Release 8.1.7 to 10.1]
Information in this document applies to any platform.
This problem can occur on any platform.
With 18.104.22.168 and higher, the hidden parameter, _4031_dump_bitvec is set by default and a trace file is generated with occurances of the ORA-4031 error. The trace file will include a breakdown of memory structure allocations and this information can be misleading. For example, this information was from an ORA-4031 trace file recently sent in for review:
Memory Utilization of Subpool 1
Allocation Name Size
"free memory " 134830192
"miscellaneous " 1195164072 << quite large
"alert threshol " 3864
"evaluation con " 0
"PLS non-lib hp " 11240
"synonym source " 0
"KGLS heap " 856568
"KQR M SO " 32256
... additional allocations removed for space considerations in this note...
The memory structure 'miscellaneous' appears to be over 1GB in size, but this is not accurate and can lead one to believe they are seeing a bug in the dictionary views and/or trace files.
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