Subject Re: Issue with Database Cache Size on FB 3.0
Author Dmitry Yemanov
01.06.2016 04:16, Fabian Ernesto Chocron wrote:
> We are having trouble setting up the database cache size on FB 3.0
> running on Windows 2008 R2 64 bits with 32 GB ram.
> The problem we have is we cannot get the server to allocate the ram for
> the cache as we intend. With FB 2.54 we had the DB cache set very high,
> close to 1 GB per database, all running in RAM memory. With FB 3.0 we
> read it can allocate much more RAM to the cache, but it appears the
> server is allocating very small amount of Ram when the first user
> connects to the DB, and as we connect more users to the DB the ram
> consumption increases slowly.

What memory counters do you look at? Virtual (reserved) memory usage
should grow high with the first connect, physical (committed) memory
usage should grow together with your load, while pages are being read
from disk.

> On firebird.conf
> FileSystemCacheThreshold = 0
> FileSystemCacheSize = 17179869184 (this is 16 GB - the server has 32 GB
> ram.)

These changes conflict with each other. You disable filesystem cache
with the first line and still want to use 16GB with the second line.

> On databases.conf
> MyTestDB = c:\Temp\MyDb.fdb
> {
> DefaultDbCachePages = 458752
> }

First of all, I'd suggest to reset FileSystemCacheSize back to zero and
set FileSystemCacheThreshold to something higher than 458752 pages (e.g.
500000). Then re-test your memory usage and only then start tweaking the
filesystem cache.

BTW, don't you occasionally have page cache override at the database
level? What is gstat -h output?