…running an analyze on a table with 11M rows I’ve seen cardinality range from 19 to over 19… mysql use index for group by? A: If you have Index on the column MySQL can avoid temporary table … for selecting using some date ranges? or between dates? or after a date? A: Date comparisons work very similar …
Post: Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5
March 21, 2012 By 10 Comments
…optimizer enhancement Multi Range Read (MRR). Its available in both MySQL 5.6 … it on TPC-H dataset (InnoDB tables) with a Scale Factor of 2 (InnoDB … ’1993-08-01′ and o_orderdate < date_add( ’1993-08-01′ ,interval ’3′…Using where; Rowid-ordered scan; Using temporary; Using filesort 1 SIMPLE customer …
Post: A case for MariaDB's Hash Joins
May 31, 2012 By Leave a Comment
…date DEFAULT NULL, `l_commitDATE` date DEFAULT NULL, `l_receiptDATE` date…MySQL 5.6. Test Case C – Join a small table with a large table with…00 | Using where; Using temporary; Using filesort | | 1…table orders resulting in sequential IO, while both MySQL 5.6 and MariaDB 5.5 prefer to do an index range…
Post: ORDER BY ... LIMIT Performance Optimization
September 1, 2006 By 100 Comments
…with constants) and so ORDER BY can be optimized even if it is done by second table: mysql…
