On 06/26/14 22:52, Nikolay Samofatov wrote: > You know that it is used to store intermediate RecordBitmap's during index > retrieval operations. > This is very performance sensitive code, and this implementation outperformed > and used less memory > than older SBM-based implementation.
I remember an issue with RecordBitmap's when migrating from 1.5 to 2.0. On _dumb_ tests old SBM-based bitmap shows a bit better performance (I do not remember and do not have stored anywhere that numbers - it was too long ago). But due to much less memory consumption (tree with few records uses about 100-200 bytes vs. 10Kb for SBM) overall performance on really loaded systems will be almost always better for new implementation. Moreover, in some cases 1.5 might overflow 32-bit limit of RAM addressable while 2.0 worked OK - and that was due to new bitmap. But in some cases performance of BePlusTree-based bitmap was lower than old one. ------------------------------------------------------------------------------ Open source business process management suite built on Java and Eclipse Turn processes into business applications with Bonita BPM Community Edition Quickly connect people, data, and systems into organized workflows Winner of BOSSIE, CODIE, OW2 and Gartner awards http://p.sf.net/sfu/Bonitasoft Firebird-Devel mailing list, web interface at https://lists.sourceforge.net/lists/listinfo/firebird-devel
