Zitat von azurIt <azu...@pobox.sk>: > Hi, > > i'm having some MySQL performance difficulties so i started to > search what can i do better. My table 'File' had these indexes > created: > CREATE INDEX file_jobid_idx on File (JobId); > CREATE INDEX file_jpf_idx on File (JobId, PathId, FilenameId); > > Which looks correct according to documentation: > http://www.bacula.org/en/dev-manual/main/main/Catalog_Maintenance.html > > BUT! The first index apperas to be unneeded as it's part of the > second index. According to MySQL documentation, 'any leftmost prefix > of the index can be used by the optimizer to find row': > http://dev.mysql.com/doc/refman/5.5/en/multiple-column-indexes.html > > I suggest to remove it. > > azur
Would also apply to PostgreSQL i guess: http://www.postgresql.org/docs/9.2/interactive/indexes-multicolumn.html Any comment why the additional single column index could be useful? Regards Andreas ------------------------------------------------------------------------------ Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with <2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031&iu=/4140/ostg.clktrk _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
