--- 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
