| From: | Christoph Moench-Tegeder <cmt(at)burggraben(dot)net> |
|---|---|
| To: | Ron <ronljohnsonjr(at)gmail(dot)com> |
| Cc: | pgsql-general list <pgsql-general(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: Example code Re: Singleton SELECT inside cursor loop |
| Date: | 2022-10-01 12:21:15 |
| Message-ID: | Yzgwu2MHvqlfkdwH@elch.exwg.net |
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| Lists: | pgsql-general |
## Ron (ronljohnsonjr(at)gmail(dot)com):
> Note how quickly it runs the first five times, but takes 780x longer the
> sixth time I run it. Exiting psql and entering again causes the same
> slowness the sixth time it's run.
Tanks at the sixth time? That rings a bell: "The current rule for this
is that the first five executions are done with custom plans[...]" from
https://www.postgresql.org/docs/12/sql-prepare.html
And your functions create prepared statements under the hood:
https://www.postgresql.org/docs/12/plpgsql-implementation.html#PLPGSQL-PLAN-CACHING
I guess you should visit
https://www.postgresql.org/docs/12/runtime-config-query.html#GUC-PLAN-CACHE_MODE
and try if plan_cache_mode = force_custom_plan helps here.
Regards,
Christoph
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