Re: syslog performance when logging big statements - Mailing list pgsql-performance

Στις Tuesday 08 July 2008 17:35:16 ο/η Tom Lane έγραψε:
> Achilleas Mantzios <achill@matrix.gatewaynet.com> writes:
> > In this case, the INSERT *needs* 20 minutes to return. This is because the logging through syslog seems to severely
slowthe system. 
> > If instead, i use stderr, even with logging_collector=on, the same statement needs 15 seconds to return.
>
> Hmm.  There's a function in elog.c that breaks log messages into chunks
> for syslog.  I don't think anyone's ever looked hard at its performance
> --- maybe there's an O(N^2) behavior?
>
>             regards, tom lane
>

Thanx,
i changed PG_SYSLOG_LIMIT in elog.c:1269 from 128 to 1048576
#ifndef PG_SYSLOG_LIMIT
/* #define PG_SYSLOG_LIMIT 128 */
#define PG_SYSLOG_LIMIT 1048576
#endif

and i got super fast stderr performance. :)

However, i noticed a certain amount of data in the log is lost.
Didnt dig much to the details tho.

--
Achilleas Mantzios