Hello Vlad, >> currently investigating nbackup reliability/bugs. CORE-2648 is marked as >> fixed in 2.1.4 and CORE-3521, which is currently open, seems to like >> similar (forced writes vs. flushing to disc). >> >> How do they differ? > > CORE-2648 set FW mode for delta file in the same value as of main > database file. > > CORE-3521 flushed delta file buffers when main database files buffers > are flushed. > > This is different things. FW mode defines how OS file cache will handle > writes. > When FW is OFF then file system free to accumulate writes in file cache and do > actual writes when OS think it is necessary\feasible. When FW is ON then file > system still cached data pages but not delayed physical writes to disk. > > Flushing is different thing. It instructs OS to write all dirty cached > buffers of given file > immediately. Firebird calls flush every time some transaction is finished and > on disconnect > (look also at MaxUnflushedWrites and MaxUnflushedWriteTime settings at > firebird.conf). > Note, when FW is ON then OS shouldn't have dirty buffers and Firebird do not > flushed its files. > > So, before CORE-2648 was fixed, delta file was always opened in FW=OFF > mode > despite of database settings.
So, if the server crashes, we have a problem here? Or does writing the delta file also take both config options mentioned above into account? Before CORE-3521 was fixed delta file contents was not > flushed to disk when transactions finished. So, without a fix for CORE-3521, cached dirty pages aren't written to disk while nbackup is running at all? Do both issues relate to corrupting the database in any way? Thanks for your feedback! > Hope it is clear, > Vlad > > PS CORE-3521 is not marked as fixed because it is not backported into 2.1.5 > still. Ok. Thanks. Regards, Thomas ------------------------------------------------------------------------------ AppSumo Presents a FREE Video for the SourceForge Community by Eric Ries, the creator of the Lean Startup Methodology on "Lean Startup Secrets Revealed." This video shows you how to validate your ideas, optimize your ideas and identify your business strategy. http://p.sf.net/sfu/appsumosfdev2dev Firebird-Devel mailing list, web interface at https://lists.sourceforge.net/lists/listinfo/firebird-devel
