Subject Re: [firebird-support] max buffers on a database
Author Daniel Rail

At October 14, 2004, 12:50, JD FitzGerald wrote:

> I've been messing with the buffers setting on a database. I was under
> the impression that there was no maximum size, but I get 'bad parameters
> on attach or create database' when I try to specify a buffer greater
> than 65535 using gfix.
> Is there actually a limit or is there something wrong with my db?

Yes there's a limit and it's the one that you entered. But, at the
present time it's not recommended to have page buffers larger than
10,000, because there's a big chance of performance degradation beyond
10,000 page cache. And, have you checked how much RAM is available on
the system before even trying to increase the page buffers that high.
And, will there be only one database accessed on that system? Because
the page buffers are related to each database and not server wide.
And, with FB 1.5, Firebird uses some memory outside of the page cache
when it needs to do a SORT on a result set, if there's not enough
memory the SORT uses a physical file on disk.

> The page size is 4096 if that's relevant.

No, this is not relevant. With this page size and using the maximum
number of pages for one database would be approx. 256MB.

It has been talked about to make the memory manager more efficient
with larger page chache and I think it will be in place for FB 3.0.

Best regards,
Daniel Rail
Senior System Engineer
ACCRA Group Inc. (
ACCRA Med Software Inc. (