…’, mysql can use either indexes built on multiple columns or intersection of multiple accesses by indexes. When we talk about index_merge_intersection, we should understand that mysql…’s very not selective column. Should we avoid using it in indexes? Yes, if it’s an index based on this column only. No…’re smart enough and read mysql performance related articles then you’ll store all those fields as enums or tiny int with…
Post: Statistics of InnoDB tables and indexes available in xtrabackup
September 14, 2009 By 6 Comments
…NULL default CURRENT_TIMESTAMP, `kind` enum(‘link’,'img’) NOT NULL, …we run: xtrabackup –stats –tables=art.link* –datadir=/mnt/data/mysql/ which will show something like this: table: art/link_out104, index…index creation. With this feature, InnoDB creates indexes by sort, so page fill factor should…
Post: Using MMM to ALTER huge tables
March 27, 2008 By 11 Comments
… or change ENUM values. When it comes to changes that really require table to be rebuilt – adding/dropping columns or indexes, changing data type, converting data to different character set – MySQL master-master replication especially accompanied by…: start replication mysql> START SLAVE; On step #1 MMM should have stopped db1 => db2 replication so at this stage we start it to…
Post: Efficient Boolean value storage for Innodb Tables
April 23, 2008 By 6 Comments
…we use BIT(1), TINYINT or ENUM types but can we do better ? In fact we …length: 23068672 Max_data_length: 3096224743817215 Index_length: 1024 Data_free: 0 Auto…mysql> select count(*) from cbool where c1NULL; +———-+ | count(*) | +———-+ | 1048576 | +———-+ 1 row in set (0.22 sec) Should…
