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* Slow C Function
@ 2006-05-09 21:57 Adam Palmblad <adam@terapeak.com>
0 siblings, 2 replies; 3+ messages in thread
From: Adam Palmblad @ 2006-05-09 21:57 UTC (permalink / raw)
To: pgsql-performance
Hi,
We've got a C function that we use here and we find that for every
connection, the first run of the function is much slower than any
subsequent runs. ( 50ms compared to 8ms)
Besides using connection pooling, are there any options to improve
performance?
By the way, we are using pg version 8.1.3.
-Adam
^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: Slow C Function
@ 2006-05-09 23:09 Joshua D. Drake <jd@commandprompt.com>
parent: Adam Palmblad <adam@terapeak.com>
1 sibling, 0 replies; 3+ messages in thread
From: Joshua D. Drake @ 2006-05-09 23:09 UTC (permalink / raw)
To: Adam Palmblad <adam@terapeak.com>; +Cc: pgsql-performance
Adam Palmblad wrote:
>
> Hi,
>
> We've got a C function that we use here and we find that for every
> connection, the first run of the function is much slower than any
> subsequent runs. ( 50ms compared to 8ms)
That is fairly standard because the data will be cached.
>
> Besides using connection pooling, are there any options to improve
> performance?
Not that I know of but then again I am not a C programer.
>
> By the way, we are using pg version 8.1.3.
>
> -Adam
>
>
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^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: Slow C Function
@ 2006-05-10 03:52 Tom Lane <tgl@sss.pgh.pa.us>
parent: Adam Palmblad <adam@terapeak.com>
1 sibling, 0 replies; 3+ messages in thread
From: Tom Lane @ 2006-05-10 03:52 UTC (permalink / raw)
To: Adam Palmblad <adam@terapeak.com>; +Cc: pgsql-performance
"Adam Palmblad" <adam@terapeak.com> writes:
> We've got a C function that we use here and we find that for every
> connection, the first run of the function is much slower than any
> subsequent runs. ( 50ms compared to 8ms)
Perhaps that represents the time needed to load the dynamic library
into the backend? If so, the "preload_libraries" parameter might
help you fix it. Or consider pooling connections. Or build a custom
executable with the function linked in permanently.
regards, tom lane
^ permalink raw reply [nested|flat] 3+ messages in thread
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2006-05-09 21:57 Slow C Function Adam Palmblad <adam@terapeak.com>
2006-05-09 23:09 ` Joshua D. Drake <jd@commandprompt.com>
2006-05-10 03:52 ` Tom Lane <tgl@sss.pgh.pa.us>
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