SGA_MAX_SIZE/MEMORY_MAX_TARGET Preallocated In 12.1.0.2 On AIX

(Doc ID 2329122.1)

Last updated on NOVEMBER 16, 2017

Applies to:

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

Symptoms

On AIX 7.1 platform, after upgrading from Oracle 11.2.0.4 to Oracle 12.1.0.2 noticed database uses much more Memory than before, right after startup.

It is noticed memory reserved/used for SGA is larger than SGA_TARGET. Specifically it is observed that up to SGA_MAX_SIZE is actually allocated out from the OS.

Testcase to illustrate the same:

 

Changes

 Upgrade to 12c

Cause

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