On 23-7-2015 21:07, conversar@... [firebird-support] wrote:

> Hi there, we have a 7 GB Firebird 2.5 database, running on FB Classic
> 2.5.2 64 bits on a Windows Server. This is a 64 bits Windows server with
> 24 CPU cores and 32 GB of RAM.
>
> When the client connection count surpasses 200, the database starts
> "freezing", I.E., opening a connection with IBExpert can take up to 5
> minutes, and you can see the "Loading Views...", "Loading Tables..."
> etc. events happening in slow motion in the IBExpert window.

What is the value of DefaultDbCachePages, FileSystemCacheThreshold, and
FileSystemCacheSize in firebird.conf

What is the output of gstat -h and fb_lock_print for your database at
the time of the problem? Does the firebird.log have anything interesting
around this time?

Is CPU utilization high or low, is the server swapping (running out of
physical memory)?

> We instruct the users to close client apps and when the connection count
> drops to 150 or so, the database "breathes in" and the performance goes
> back to normal.

What is the output of gstat -h and fb_lock_print after normal
performance has been restored?

> Is there a limit of client connections for Firebird?

No for classic except when you reach OS limits (memory, threads,
processes, etc) (there is a limit of 1024 for SuperServer and
SuperClassic in 2.5.3 and earlier, 2048 since 2.5.4)

>
> Right now we are puzzled, any pointers / recommendations are much
> appreciate d.

Consider upgrading to 2.5.4; a lot of bugs have been fixed since 2.5.2
(including security problems). I don't know whether it will actually fix
your problem though.

Mark
--
Mark Rotteveel