On 2014.05.10. 9:52, Dimitry Sibiryakov wrote: > 10.05.2014 9:03, Molnár Attila wrote: >> *VARIANT data type in PSQL* >> - gain : a little memory and/or CPU overhead but much cleaner code. >> Also >> rdb$get/set_context value colud be variant. > Welcome to the hell of unpredictable type conversion. > >> *Optimization II. >> * - temporal indexing of materialization : e.g. when ORDER/GROUP BY has >> no index then >> currently the whole resultset is materialized, and the sorting moves the >> whole row each >> time. Instead of this it should create a temporal index on the order/group >> columns then >> fetching on the temporal index. In this way much less writes needed. This >> shold be applied >> after a treshold : common sense sais after index size/row size rate is >> smaller than 0.5. > Uncommon sense says that random IO can be much more than two times slower.
OK, this just means smaller treshold rate. But with this some case you can gain HUGE performance boost (especially when the resultset can't fit into memory and have to write to disk) > ------------------------------------------------------------------------------ Is your legacy SCM system holding you back? Join Perforce May 7 to find out: • 3 signs your SCM is hindering your productivity • Requirements for releasing software faster • Expert tips and advice for migrating your SCM now http://p.sf.net/sfu/perforce Firebird-Devel mailing list, web interface at https://lists.sourceforge.net/lists/listinfo/firebird-devel
