Hello.
> Why is it that adding an index before or after the addition of data >makes a difference on SELECT performance? Check whether the problem still exists if you run ANALYZE table after inserts in case you have already created indexes. FORCE_INDEX in the SELECT clause should help as well. Have a look here: http://dev.mysql.com/doc/refman/5.0/en/how-to-avoid-table-scan.html Allan Miller wrote: > In MySQL 4.1.11, if you create two temporary tables with non-unique indices > as part of the CREATE TEMPORARY TABLE statement, then > insert several hundred (or thousand) rows, a subsequent SELECT using a JOIN > between the two tables is substantially slower than if > you create the indices after inserting the rows into the temporary tables. > When I run a SHOW INDEX for these tables, the only > difference is the Cardinality field, where it is NULL if the index was > created prior to any inserts and is a number if the index was > created after the inserts. > > Why is it that adding an index before or after the addition of data makes a > difference on SELECT performance? > > Allan Miller > > > > -- For technical support contracts, goto https://order.mysql.com/?ref=ensita This email is sponsored by Ensita.NET http://www.ensita.net/ __ ___ ___ ____ __ / |/ /_ __/ __/ __ \/ / Gleb Paharenko / /|_/ / // /\ \/ /_/ / /__ [EMAIL PROTECTED] /_/ /_/\_, /___/\___\_\___/ MySQL AB / Ensita.NET <___/ www.mysql.com -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
