Subject Re: [firebird-support] Re: Sort error No free space found in temporary...
Author Thomas Steinmaurer

> Thanks for the advise Thomas I will increase the value.
> After we changed TempCacheLimit to 567108864, we saw the problem once
> under heavy load - for a very sourt perio this time.

Increased TempCacheLimit value as a side-effect of serving more temp
stuff through RAM instead of spilling onto disk, thus somehow makes
sense to see the too many open files less frequent then.

> Is it correct
> understood that once TempCacheLimit was reached Firebird used /tmp/
> until the proccess reached the max open files?

Sounds reasonable, yes.

> Regarding TempBlockSize and TempCacheLimit do you or any other know of a
> way to monitor if the configured value is too low or the limit is about
> to be reached?

No, but I became a bit rusty regarding Firebird lately. :-)

> Since the server has plenty of RAM i was thinking about configuring
> TempCacheLimit to 2, 4 or 6 Gb, if this has no negative effect?

As you have mentioned that you are using SuperClassic, mind that
TempCacheLimit is maximum memory for temp stuff PER client connections
in this architecture, thus if configured too high with a high number of
concurrent connections, you may end up in exhausting host RAM, resulting
in swapping to disk if hitting boundaries.

> Likewise if there is no negative effect, is there anything to gain from
> increasing TempBlockSize from 2 megabytes to perhaps 4 or 6?

I doubt you will see a real difference.

Beside that, perhaps you are able to pin the SQL statement producing the
temp data load e.g. by using the Trace API.

With regards,
Thomas Steinmaurer

Professional Tools and Services for Firebird
FB TraceManager, IB LogManager, Database Health Check, Tuning etc.