… than multiple column indexes. This is in case you’re using OR between the columns. In this case the combined index is useless and MySQL has… combined index in this case. In case you’re using OR between columns – single column indexes are required for index merge to work and combined indexes can…
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 ways using multiple column index…Multiple Column index beats Index Merge in all cases when such index can be used. It is also worth to watchout a MySQL…
Post: Heikki Tuuri Innodb answers - Part I
October 26, 2007 By 17 Comments
…of Innodb scalability with multiple threads and multiple concurrent transactions ? HT: The…it would write at 100MBps vs 33MBps. Any plans to …by using couple of MySQL Servers on single node. You can make…index is required for fast lookups: it can be used if the columns are the first columns in an index…
Post: Why MySQL could be slow with large tables ?
June 9, 2006 By 139 Comments
…multiple drives do not really help a lot as we’re speaking about single… 30 millions of rows. “val” column in this table has 10000 …vs range scan by index: mysql> select count(pad) from large; +————+ | count(pad) | +————+ | 31457280 | +————+ 1 row in set (4 min 58.63 sec) mysql…
