Re: pl/pgsql functions outperforming sql ones?

2012/1/27 Carlo Stonebanks :
> 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