Oracle database internals by Riyaj

Discussions about Oracle performance tuning, RAC, Oracle internal & E-business suite.

Posts Tagged ‘_shared_pool_reserved_min_alloc’

A stroll through shared pool heaps

Posted by Riyaj Shamsudeen on January 15, 2009

Last week, we were discussing about increasing shared_pool_reserved_size to combat a performance issue(bug) in a conference call. I thought, it was a common knowledge that shared_pool reserved area is part of a shared_pool and surprisingly it is not-so-common.

In this blog, we will discuss about shared_pool and shared_pool reserved area internals. First, we will discuss about details specific to release 9i and then discuss changes in later releases 10g/11g.

oradebug command

We will use oradebug command to dump the heap with level 2. Level 2 is to dump shared_pool heap in to a trace file.

 oradebug setmypid
 oradebug dump heapdump 2

Above command generates a trace file and we will walk through the trace file and review various areas closely.

Parameters

In this test instance, we have a bigger SGA. Shared_pool (6GB) and shared_pool_reserved_size values are printed below.


SQL> show parameter shared_pool
shared_pool_reserved_size            big integer 629145600
shared_pool_size                     big integer 6442450944

Trace file analysis
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Posted in Oracle database internals, Performance tuning | Tagged: , , , , , , , , | 8 Comments »

 
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