shared pool evictions

From: Noveljic Nenad <>
Date: Tue, 3 Mar 2020 14:52:26 +0000
Message-ID: <>

The SQL statements like the one below are getting evicted from the shared pool within a couple of minutes on a 18c database:

select /* nenad */ 1 from dual ;

The parameters are set as follows:

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
sga_target                           big integer 10G
shared_pool_size                     big integer 0

The size of the shared pool is ~1.6 GB:
select name,bytes/1024/1024/1024 gb from v$sgainfo ; NAME GB
Shared Pool Size 1.6875

There weren't any recent resize operations.

All statements are taking around 25% shared pool space in total: select ( sum(sharable_mem)+sum(persistent_mem)+sum(runtime_mem) )/1024/1024 mb   from v$sql ;

Since there are some statements residing a little bit longer in the shared pool, for which there aren't any open cursors, we can exclude "alter system flush shared_pool" being the source of the problem, I think.

Any ideas how to approach this systematically?



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Received on Tue Mar 03 2020 - 15:52:26 CET

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