Solaris 10 memory management conflicts with Automatic PGA Memory Management (Doc ID 460424.1)

Last updated on JANUARY 24, 2011

Applies to:

Oracle Server - Enterprise Edition - Version: 9.0.1.0 to 11.2.0.2 - Release: 9.0.1 to 11.2
Oracle Solaris on SPARC (64-bit)
Oracle Solaris on x86-64 (64-bit)
Solaris Operating System (SPARC) (64-bit)Solaris Operating System (x86-64)
Solaris Operating System (SPARC 64-bit)

Symptoms

There is an interoperability issue between Solaris 10's memory management and
Oracle's Automatic PGA Memory Management in a Solaris 10 environment with a large
number of CPUs. The issue causes CPU spikes happening at random intervals and
increases system cpu time. The database server is unacceptably slow.

DTrace output profiling cpu usage during these times shows Oracle processes to be 
performing mmap(2) to /dev/zero to acquire memory. This operation can be quite expensive 
on a machine with a number of cpus, as each time an mmap(2) is done by a process it 
results in cross calls (xcalls) to all cpus on which this process has run.

Changes

Upgrade to Solaris 10

Cause

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