Re: PATCH: tracking temp files in pg_stat_database

2011/12/20 Tomas Vondra <tv@fuzzy.cz>:
> Hello everybody,
>
> this patch adds two counters to pg_stat_database to track temporary
> files - number of temp files and number of bytes. I see this as a useful
> feature, as temporary files often cause a lot of IO (because of low
> work_mem etc.). The log_temp_files is useful, but you have to parse the
> log and only temp files exceeding a size limit are logged so the actual
> amount of I/O is unknown.

Hey, cool, that was on my personal TODO list :-)


> The patch is rather simple:
>
> 1) two new fields in PgStat_StatDBEntry (n_temp_files, n_temp_bytes)
> 2) report/recv function in pgstat.c
> 3) FileClose modified to log stats for all temp files (see below)
> 4) two new fields added to pg_stat_database (temp_files, temp_bytes)

I haven't reviewed the code itself yet, but that seems like a
reasonable approach.


> I had to modify FileClose to call stat() on each temp file as this
> should log all temp files (not just when log_temp_file >= 0). But the
> impact of this change should be negligible, considering that the user is
> already using temp files.
>
> I haven't updated the docs yet - let's see if the patch is acceptable at
> all first.

Again, without having reviewed the code, this looks like a feature
we'd want, so please add some docs, and then submit it for the next
commitfest!

--
 Magnus Hagander
 Me: http://www.hagander.net/
 Work: http://www.redpill-linpro.com/