Do any of you know?
- From: <Christopher.Taylor2@xxxxxxxxxxxx>
- To: <jonathan@xxxxxxxxxxxxxxxxxx>, <mwf@xxxxxxxx>, <niall.litchfield@xxxxxxxxx>, <oratune@xxxxxxxxx>, <breitliw@xxxxxxxxxxxxx>
- Date: Fri, 12 Oct 2012 09:43:07 -0500
When gathering SYSTEM stats, do those stats take a while to affect the query
plans once they are collected? (a "while" being some "x" amount of time - I
thought they would be immediate)
Last night I had executed:
dbms_stats.gather_system_stats(gathering_mode=>'NOWORKLOAD');
Once that completed I kicked off:
dbms_stats.gather_system_stats(gathering_mode=>'INTERVAL', interval=>1440);
This morning I stopped that interval gathering and ran my queries.
It "appears" that the system stats change didn't immediately affect my queries
but is now affecting my queries.
I could see that happening if I was getting a cached plan versus a new plan but
my test script is "supposed" to flush the plan out using:
dbms_pool.purge.
I guess I need to verify that the purge is actually working...
Chris
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