… (intersect). Below are two explains that I executed for the same SQL query with a couple of mins gap on the same mysql prod instance . The first SQL query executed in 0.03 secs whereas the second SQL query when using index…
Comment: How to find wrong indexing with glance view
August 23, 2008 By 27 Comments
…, looking_for, location; integer – age 3) All queries fall into X IN (…) AND Y IN …intersection of multiple accesses by indexes. When we talk about index_merge_intersection, we should understand that mysql… (City, Gender, Age, Available). So mysql can choose between two which is more selective. 3…
Post: Multiple column index vs multiple indexes
August 22, 2008 By 13 Comments
… Index Merge on Multiple Indexes vs Two Column Index efficiency. I mentioned in most cases when query can use both of the… remove the overhead of starting MySQL etc from equation I also measured execution of “SELECT 1″ query using same script and subtracted… is also worth to watchout a MySQL may decide not to do Index merge (either intersection or union) but instead do full…
Comment: Full text search for all MySQL Storage Engines
June 29, 2006 By 37 Comments
… about MySQL performance you’re right. There are two pieces which slow things down. First finding the rows which contain all keywords. Intersection of pretty large sets needs to be performed. Next problem is sorting – it is done by MySQL rather than… it looks like what you need. Also benchmark using real queries from your site might be very interesting 
