Hi, Trying to figure out the best settings for my database and app usage. Firebird 3.0.4 SuperServer on virtualized Windows Server 2016 with 40 Gbyte RAM and fast SSD disks (separate disks for OS and DB). Database almost 200 Gbyte. Page size 16k.
We can assume that no other heavy work is running on the server. The app itself uses a few Gbyte RAM. I have set in databases.conf: DefaultDbCachePages = 1310720 FileSystemCacheThreshold = 640K And in firebird.conf: FileSystemCacheSize = 50% TempCacheLimit = 4G MaxUnflushedWrites = 100 MaxUnflushedWriteTime = 60 All other settings (except some security ones) are set to default. 1. Would you recommend any changes to these settings, and why? 2. I see that the firebird.exe process has commit size about 2.2 Gbyte, which seems small considering the DefaultDbCachePages = 1310720 setting. Shouldn't this result in a page cache of 20 Gbyte? 3. I did change the DefaultDbCachePages setting without restarting the superserver process, but I did make sure all connections to the database in questions were closed. Does this setting take effect only when the server process is restarted? 4. It's not clear to me how the FileSystemCacheThreshold setting actually works. I have read the release notes for FB 2.5 as well as the comments inside firebird.conf and a couple of support list messages. But I still find it a bit muddy... I can see that the database file is cached, using RAMMap.exe. It reports "Standby" as "28733844 K" for that file. It seems that the file system cache works and keeps large parts of the database file in the cache, but I do realize that the batch will for the most part need to read "new" data. The important thing ought to be to keep the indexes in cache. Right? Reason/background: The use case is a batch operation that will do mostly (only?) reads and will read large parts of the database. The batch does its job in "chunks", and I can see that after a while the time to process each chunk goes up from about half a minute to about a full minute, or even worse. Restarting the app makes it go back to about half a minute per chunk, but just stopping the batch operation (without restarting the app) doesn't seem to help. I will investigate this more, of course. It's possible that the app has some garbage piling up that might slow things down. Mvh, Kjell Kjell Rilbe Telefon: 0733-44 24 64 Marknadsinformation i Sverige AB Sundbybergs Torg 1 H 7 tr 172 67 Sundbyberg, Sweden www.marknadsinformation.se <http://www.marknadsinformation.se/> 08-514 905 90 Företagskontakt.se <http://www.f%C3%B6retagskontakt.se/> Personkontakt.se <http://www.personkontakt.se/> DI Gasell 2018DI Gasell 2019 [Non-text portions of this message have been removed]
