Subject Re: [firebird-support] Issue with Database Ca che Size on FB 3.0
Author Alexey Kovyazin (ak)

Hi Fabian,

Firebird caches only actually used pages.

The small cache means that your application touches the small part of the database.

Alexey Kovyazin
PS It is difficult and wrong to give you any direct advice without all details in hands - it can lead to worse performance than with default parameters.

среда, 01 июня 2016г., 04:16 +03:00 от Fabian Ernesto Chocron fabianch@... [firebird-support]


Hi All

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. The setting we are playing with are:

On firebird.conf

FileSystemCacheThreshold = 0
FileSystemCacheSize = 17179869184 (this is 16 GB - the server has 32 GB

On databases.conf

MyTestDB = c:\Temp\MyDb.fdb
DefaultDbCachePages = 458752

Any ideas what could be wrong? Or what settings would give us maximum
RAM usage for the DB cache (we dont want file system cache meaning HDD
cache, we want to have the DB in RAM for the purpose of reading the DB)