Re: shared pool waits

On 9/20/21 15:25, Pap wrote:

> Hi , We have a customer application in which we see high wait events
> like 'cursor:mutex ' and 'library cache lock' for a select query
> occasionally and thus a specific functionality impacted. This select
> query(which is part of a plsql procedure) is quick query which runs ~5
> million times/hr. But even though number of execution is same mostly
> throughout the day, it still went through these odd wait events making
> the per execution time went higher for around ~15 minutes duration
> causing slowness. And during this period, the ASH shows fro this
> query,  the value of column in_hard_parse as 'N' but in_parse as 'Y'
> and 'N' both. And we saw we were having stats gather running on that
> base object during same time. We have no_invalidate set as 'FALSE" as
> table stats preference, So wanted to understand from experts, can it
> be really because of 'parsing' issue and we should delete this
> no_invalidate preference so that it can inherit the default global
> preference i.e no_invalidate=>auto? The database version is 19C.

How about pinning the procedure in the SGA? That seems to be the purpose of DBMS_SHARED_POOL.KEEP procedure.

-- 
Mladen Gogala
Database Consultant
Tel: (347) 321-1217
https://dbwhisperer.wordpress.com

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