Subject ReTuning Firebird Server for Optimal performance
Author Victor Perez
I am running firebird 2.0 in a Windows 2003 R2 operating system server machine with two Intel Xeon 3.20 Ghz processors and 4 GB of RAM. I have two hard disks HD1: one partition C: 135 GB in a RAID 5  and HD2: one partition E: 68 MB in stand alone configuration.
The database is running under SUPERSERVER configuration. I have two databases in the system. SISTEMA.GDB (964 MB in size) installed in the C: partition of HD1 (the same as the Operating system) and SISTEMA2.GDB (1032 MB)  installed in the HD2  E: partition
My problem is that when the database is under high demand from processes (i..e. payroll processing,  end of the month sales/inventory reports, etc) and more number of users accessing (upto 30) the database, the system becomes very slow  and almost comes to a halt.
I have:
1. Installed a seconday disk (HD2) dedicate to SISTEMA2 database only and configure our applications so that the use this database the most. The idea was to have the main load in a HD which was not also using the Operating system
2. tried to play around with the firebird.conf file and changed the following settings to:
SortMemUpperLimit = 1582688000
DefaultDbCachePages = 409600
SortMemBlockSize = 134217728
Can anyone tell me what can I do to get the database running at optimum performance. I guess it will be worth noting that we have configure our application using a lot of begin and commit trans which locks tables, we have done this to assure completeness of the transactions.
I will appreciate help.

--- On Tue, 7/29/08, Milan Babuskov <milanb@...> wrote:

From: Milan Babuskov <milanb@...>
Subject: Re: [firebird-support] Tuning Firebird Server for Optimal Memory Usage
Date: Tuesday, July 29, 2008, 10:04 AM

Niben M Singh wrote:
> have 1GB memory in my PC with Linux kernel. I want to allocate like 400MB
> dedicated to my Firebird database. How can I modify firebird.conf (or
> operating system) to do so? Right now Firebird is not using much of RAM
> seems like.
> I am hoping with more caching in memory the performance will be better.

You can (as Anderson explained) but you probably don't want to. Linux
caches the filesystem very well - uses 99% RAM all the time to cache the
filesystem. So, if the machine has enough free RAM and is dedicated to
the database system, it most probably has the entire FB database file in
the filesystem cache, and fetching from there should not be
significantly slower than fetching from FB page cache.

Of course, you can play with it and see what happens. Just make sure you
don't give too much to Firebird and force rest of the system to swap to
disk as that would be really slow.

Milan Babuskov

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