Re: [HACKERS] loading libraries on Postmaster startup

Tom Lane wrote:
> Joe Conway <mail@joeconway.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