--- In [email protected], "ramix001" <ramix001@...> wrote: > > > > > > > --- In [email protected], "karolbieniaszewski" <liviuslivius@> > wrote: > > > > > > > > --- In [email protected], "ramix001" <ramix001@> wrote: > > > > > > I'm trying to get more performance out of my Firebird server. A way to do > > > that is to increase amount of RAM Firebird will use. I'm looking for a > > > reliable method to do that. > > > > > > I started by increasing the DefaultDbCachePages value in firebird.conf to > > > 8192 in Super-Server installations and to 1024 in > > > Classic/SuperClassic-Server installations. But there wasn't a noticeable > > > performance increase. Then I started to increase the DefaultDbCachePages > > > to higher values using this formula: > > > For Super-Server: > > > (Physical RAM in KB / default page size in KB) * 0.04 (4% of total RAM). > > > For Classic/SuperClassic-Server: > > > (Physical RAM in KB / default page size in KB) * 0.005 (0.5% of total > > > RAM). > > > I use this formula only on Windows machines. On Linux this would be > > > counterproductive (I have read). All the databases I use have the default > > > page size of 4 KB and they have no specified cache size (Page Buffers set > > > to 0) only DefaultDbCachePages setting in firebird.conf is being used. > > > > > > With this formula setting in some Firebird SuperServer installations the > > > server process crashes after the fifth simultaneous database connection > > > with the error "Allocated nnnnn page buffers of xxxxx requested". So this > > > formula isn't quite correct. > > > > > > Please tell me: > > > - Does increasing then DefaultDbCachePages really help increasing the > > > server performance? > > > - If it does, are there more things I have to consider to make this > > > formula work properly, e.g. database size, maximum/minimum values, > > > usability with different Firebird versions starting with 1.5? > > > - What functions do settings like FileSystemCacheSize and > > > FileSystemCacheThreshold have in this context? > > > > > > > > > Thanks and best regards > > > > > > Rami B. > > > > > > > > > Hi. > > > > Your formula is wrong > > you must calculated it in this way > > > > ((Free physical RAM in KB without FB started)*0.8 / default page size in KB > > ) / count of running databases > > > > eg. you have 8GB RAM but only free is 4GB RAM and 16KB page size and 7 > > databases > > > > 4 * 1024 * 1024 * 0.8 = 3355443,2 > > > > 3355443,2 / 16 = 209715,2 > > 209715,2 / 7 = 29 959 Pages only for DefaultDbCachePages for SuperServer - > > for classic you mast modify formula and add whole conections count in place > > where count of running databases are > > > > Karol Bieniaszewski > > > > Hi Karol, > > Thanks for sharing. Where does the 0.8 comes from? >
This is free memory for other process and windows if from some reason must be consumed and is experimental value - i never have problem with this this settings (never swap to disk) and as someone say below - this formula is ok only for SuperServer but i only work with it never with classic ;-) Karol Bieniaszewski
