Re: [HACKERS] loading libraries on Postmaster startup

Tom Lane wrote:
> Joe Conway <mail(at)joeconway(dot)com> writes:
>
>>In my testing with PL/R, it reduces the first call to a PL/R function
>>(after connecting) from almost 2 seconds, down to about 8 ms.
>
> Hm, pretty significant. Can you measure any per-fork cost (ie, the loss
> incurred by children that don't use PL/R)? Is there any measurable
> benefit for our other PLs (plperl etc)?

Here's what I got:

10000 connect/disconnect in tight loop
----------------------------------------------------------
condition time top
----------------------------------------------------------
with no preload 87 seconds ~10% CPU, ~2.2 MB
with plr preload 133 seconds ~10% CPU, ~13 MB
with plperl preload 92 seconds ~10% CPU, ~3.2 MB
with pltcl preload 88 seconds ~10% CPU, ~2.3 MB
with plpython preload 93 seconds ~10% CPU, ~2.3 MB

1000 connect/"select some_simple_func()"/disconnect in tight loop
------------------------------------------------------------------
condition time top
------------------------------------------------------------------
plr-func without preload 739 seconds ~60% CPU, ~13 MB
plr-func with preload 26 seconds ~10% CPU, ~13 MB
plperl-func without preload 46 seconds ~4% CPU, ~3.2 MB
plperl-func with preload 33 seconds ~3% CPU, ~3.2 MB
pltcl-func without preload 22 seconds ~5% CPU, ~2.3 MB
pltcl-func with preload 17 seconds ~4% CPU, ~2.3 MB
plpython-func without preload 33 seconds ~4% CPU, ~2.3 MB
plpython-func with preload 31 seconds ~4% CPU, ~2.3 MB

Joe