Re: slow DSS large dataset query, help

Posted in 1999

Mark D. Stock — Mon, 13 Sep 1999 20:50:55 +0100 — source: Informix-list mailing list archive (1991-1998)

sjsyau@my-deja.com wrote: > > hash join is better than nested loop join? Not necessarily. But a hash join is better than a sequential scan for very large numbers of rows. If you are reading a large percentage of a table, then a sequential scan is cheaper than an index read, but a hash join is even quicker in certain instances. Just make sure you have lots of shared memory allocated to your virtual portion. Cheers, -- Mark. +----------------------------------------------------------+-----------+ | Mark D. Stock http://www.informix.com |//////// /| | mailto:mdstock@mydas.freeserve.co.uk |///// / //| | http://www.iiug.org +-----------------------------------+//// / ///| | |What year 2000 bug? year 2000 bug? |/// / ////| | |year 2000 bug? year 2000 bug? year |// / /////| | |2000 bug? year 2000 bug? year 1900 |/ ////////| +----------------------+-----------------------------------+-----------+