On 4/25/2012 5:05 PM, Stephen Russell wrote: > On Wed, Apr 25, 2012 at 3:06 PM, MB Software Solutions, LLC > <[email protected]> wrote: >> On 4/25/2012 10:01 AM, Ted Roche wrote: >>> Quantify, please: "I load 50 million rows of data and run a query that >>> should return 10 records and it takes 15 minutes." Or "I expect 25 >>> million rows" in which case it should take 15 minutes! Or "It takes 7 >>> seconds and I want it to take 5" -- these are different questions. > >> Yes, and I thought I read you and the MySQL manual online earlier >> (http://dev.mysql.com/doc/refman/5.1/en/index-merge-optimization.html) >> to say that MySQL needs that compound index of the 3 fields to best >> optimize this query?!? I thought that MySQL couldn't use all 3 separate >> single-field indexes and as such I wouldn't gain as much optimization. ??? > ------------------------------- > > You will get an index scan instead of an index seek. Both of those > are much better than a table scan!
Yeah, I avoid table scans like the plague. -- Mike Babcock, MCP MB Software Solutions, LLC President, Chief Software Architect http://mbsoftwaresolutions.com http://fabmate.com http://twitter.com/mbabcock16 _______________________________________________ Post Messages to: [email protected] Subscription Maintenance: http://leafe.com/mailman/listinfo/profox OT-free version of this list: http://leafe.com/mailman/listinfo/profoxtech Searchable Archive: http://leafe.com/archives/search/profox This message: http://leafe.com/archives/byMID/profox/[email protected] ** All postings, unless explicitly stated otherwise, are the opinions of the author, and do not constitute legal or medical advice. This statement is added to the messages for those lawyers who are too stupid to see the obvious.
