Re: pl/pgsql functions outperforming sql ones? - Mailing list pgsql-performance

From Pavel Stehule
Subject Re: pl/pgsql functions outperforming sql ones?
Date
Msg-id CAFj8pRCceGDEp1sxvMoe0oaio6P=O2nJPfs9MWgu4-+zCTdrVg@mail.gmail.com
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In response to Re: pl/pgsql functions outperforming sql ones?  ("Carlo Stonebanks" <stonec.register@sympatico.ca>)
Responses Re: pl/pgsql functions outperforming sql ones?
Re: pl/pgsql functions outperforming sql ones?
List pgsql-performance
2012/1/27 Carlo Stonebanks <stonec.register@sympatico.ca>:
> Yes, I did test it  - i.e. I ran the functions on their own as I had always
> noticed a minor difference between EXPLAIN ANALYZE results and direct query
> calls.
>
> Interesting, so sql functions DON'T cache plans? Will plan-caching be of any
> benefit to SQL that makes no reference to any tables? The SQL is emulating
> the straight non-set-oriented procedural logic of the original plpgsql.
>

It is not necessary usually - simple SQL functions are merged to outer
query - there are e few cases where this optimization cannot be
processed and then there are performance lost.

For example this optimization is not possible (sometimes) when some
parameter is volatile

Regards

Pavel Stehule

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