Re: reason for default PGSTAT_ACTIVITY_SIZE

Le 05/01/2010 18:02, frank joerdens a écrit :
> From my angle, it looks as if the default for PGSTAT_ACTIVITY_SIZE is
> too small, or rather that it ought to be configurable at least, so
> that longer current_query strings that are shown via
> pg_stat_get_backend_activity() in the system view pg_stat_activity
> aren't truncated.
>
> The use case is to watch pg_stat_activity when troubleshooting a
> busy/struggling live server which is building up a queue of long
> running queries, to be able to see which of your SQL is most
> problematic, and where it's coming from: We append a code reference as
> a comment to all SQL that is sent by the ORM (we use a python web
> application development framework, namely Django), in order to figure
> out where it originates, which is otherwise tricky with SQL that is
> generated by a translation layer - and this code reference is often
> cut off because the string is limited.
>
> Is there a good reason to set PGSTAT_ACTIVITY_SIZE at 256 and is my
> only option to recompile the server? Is there a practical
> limit/drawback to making the variable say 4 or 8 times the default?
>
> I am referring to this post here:
>
> http://archives.postgresql.org/pgsql-sql/2002-05/msg00087.php
>
> and this one:
>
> http://archives.postgresql.org/pgsql-novice/2004-02/msg00187.php
>
> according to which recompiling would be the only option, but that was
> a few years back so maybe it's a different story now.
>

On current releases, it has a higher value (1024 IIRC). And it's a
configuration parameter on 8.4.

--
Guillaume.
http://www.postgresqlfr.org
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