21.04.2012 19:13, Dimitry Sibiryakov wrote: > Theoretically: if used, may it be more effective than quick sort for grouping > the same > key values?
If you speak *only* about grouping, then I believe you should compare hash aggregate vs sort aggregate as different data access methods, not hash table vs quick sort in the existing sorting implementation. And yes, hashing (as a complete replacement algorithm) can be much faster if the grouping keys are badly selective. Dmitry ------------------------------------------------------------------------------ For Developers, A Lot Can Happen In A Second. Boundary is the first to Know...and Tell You. Monitor Your Applications in Ultra-Fine Resolution. Try it FREE! http://p.sf.net/sfu/Boundary-d2dvs2 Firebird-Devel mailing list, web interface at https://lists.sourceforge.net/lists/listinfo/firebird-devel
