Subject Re: [firebird-support] Classic server vs. Super server
Author Daniel Rail

At December-11-09, 11:55 AM, Nico Callewaert wrote:

>> Page cache size is the only point of this list. Brain is required
>> because there are two places where it can be configured.
>> SY, SD.

> Thanks Dimitry for the quick reply. But of course this begs the next
> question : why 2 places or where ? I was thinking that every setting has to
> be entered where FB was installed ?
> Or is there a link to this information available (in case that was answered
> before already) ?

The default page cache size setting is in Firebird.conf. But, you can
also set it directly in the database, and this setting will be carried
over to any other server were this database will be copied to.

You set the database's(i.e.: employee.fdb) page cache to 10,000 pages,
because you are currently using SuperServer. But, later you decide to
use Classic instead, because you upgraded the motherboard and now want
to use all the cores of the CPU. Classic has a default page cache of
75 pages per client connection, but the database has a defined page
cache of 10,000 pages, so in this case Classic will be using a page
cache of 10,000 pages per client connection.

There's always something to be careful about when switching from
SuperServer to Classic of vice-versa. I prefer to define the page
cache size in Firebird.conf and not have one defined specifically in
the database for this particular reason.

Best regards,
Daniel Rail
Senior Software Developer
ACCRA Solutions Inc. (
ACCRA Med Software Inc. (