On 4 June 2018 at 06:08, Pavel Stehule <pavel.stehule@gmail.com> wrote:
> 4. optimization expression without necessity to create snapshots -
> experiments
>
> @4 There are lot of not database expressions in PLpgSQL - like var1 := var1
> + var2 or var1 := var1 + konst. Own calculation needs about 1% of time of
> total expression evaluation time. Almost all time get preparing plan cache,
> preparing snapshot, .. For this case, when no database object is used, we
> don't need use this infrastructure. I would to measure performance impact,
> and testing if these optimizations are interesting or not.
Sounds good. I think this would need to be restricted by operator and
datatype, since in general you won't know if the datatype functions
need a snapshot or not. Immutable functions for the operators ought to
do it, but I think that might not be enough.
--
Simon Riggs http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services