Comments on: Merge Tables Gotcha http://www.mysqlperformanceblog.com/2007/05/09/merge-tables-gotcha/ Everything about MySQL Performance Sat, 21 Nov 2009 05:23:57 -0800 http://wordpress.org/?v=2.8.4 hourly 1 By: Tim Little http://www.mysqlperformanceblog.com/2007/05/09/merge-tables-gotcha/comment-page-1/#comment-645825 Tim Little Thu, 03 Sep 2009 02:58:19 +0000 http://www.mysqlperformanceblog.com/2007/05/09/merge-tables-gotcha/#comment-645825 Arie, I realize that it's been a year, but here's my idea (something similar happened to me) : Check to see that all five tables have the same indexes as well as the same types for all columns. For us, what clinched it was when we made the merge on tables T1 + T2 + T3 + T4 + T5 failed then we removed one table at a time, then constructed the merge table with two tables at a time and checked the cardinalities. Arie, I realize that it’s been a year, but here’s my idea (something similar happened to me) :
Check to see that all five tables have the same indexes as well as the same types for all columns.

For us, what clinched it was when we made the merge on tables T1 + T2 + T3 + T4 + T5 failed then we removed one table at a time, then constructed the merge table with two tables at a time and checked the cardinalities.

]]> By: Arie http://www.mysqlperformanceblog.com/2007/05/09/merge-tables-gotcha/comment-page-1/#comment-257814 Arie Wed, 26 Mar 2008 22:46:10 +0000 http://www.mysqlperformanceblog.com/2007/05/09/merge-tables-gotcha/#comment-257814 i have a strange problem with merge table. i create 5 tables from the same create statement and merge table on them. indexes cardinality equals none. when i alter the merge table and leave only any 4 tables (in the union) index cardinality becomes a number. i have a strange problem with merge table. i create 5 tables from the same create statement and merge table on them.
indexes cardinality equals none. when i alter the merge table and leave only any 4 tables (in the union) index cardinality becomes a number.

]]> By: peter http://www.mysqlperformanceblog.com/2007/05/09/merge-tables-gotcha/comment-page-1/#comment-124788 peter Mon, 14 May 2007 22:09:28 +0000 http://www.mysqlperformanceblog.com/2007/05/09/merge-tables-gotcha/#comment-124788 Thanks Sergei Fixed. Thanks Sergei Fixed.

]]> By: Sergei Golubchik http://www.mysqlperformanceblog.com/2007/05/09/merge-tables-gotcha/comment-page-1/#comment-121758 Sergei Golubchik Thu, 10 May 2007 16:10:10 +0000 http://www.mysqlperformanceblog.com/2007/05/09/merge-tables-gotcha/#comment-121758 typos: "merge table over merge tables" and "underlying merge tables". typos: “merge table over merge tables” and “underlying merge tables”.

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