… replace longish (25-30) indexed varchars with an additional bigint column …also would note there are some MySQL optimizer restrictions in how well… user_competition_entry user_id (INT), competition_id(INT); The table is only…index, also you only can have equality comparison as a search condition…
Post: Connecting orphaned .ibd files
May 13, 2011 By 19 Comments
…_LEN` int(10) unsigned default NULL, `CLUSTER_NAME` varchar(255) default NULL, `SPACE` int(… table actor it is equal to 15: mysql> select * from `INNODB_SYS_TABLES` where `…mysql>CREATE TABLE actor ( actor_id SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT, first_name VARCHAR(45) NOT NULL, last_name VARCHAR…
Post: Edge-case behavior of INSERT...ODKU
October 27, 2012 By 6 Comments
…situation: CREATE TABLE update_test ( id INT UNSIGNED NOT NULL AUTO_INCREMENT, username VARCHAR(20) NOT NULL, host_id … to be considered as being defined first. So, MySQL checks our INSERT, sees that the next auto-… LAST ROW, the one where the id is equal to the auto-increment max value, which is …
Post: Handling big result sets
June 26, 2006 By 13 Comments
… NULL, `f26` varchar(13) default NULL, `f27` varchar(39) default NULL, `f28` int(11) default NULL, `f29` float default NULL, `f30` int(11) default…_STORE_RESULT (used by default) is equal mysql_query, and with MYSQLI_USE_RESULT – is equal to mysql_unbuffered_query. Results: MYSQLI_STORE_RESULT…
Post: A case for MariaDB's Hash Joins
May 31, 2012 By Leave a Comment
…table If the size of the hash table equals the maximum in-memory size: Scan the …a look at the configuration used with different MySQL flavors. MySQL 5.5.24 Configuration innodb_file_…int(11) NOT NULL DEFAULT ’0′, `s_name` char(25) DEFAULT NULL, `s_address` varchar(40) DEFAULT NULL, `s_nationkey` int…
Post: Multi Column indexes vs Index Merge
September 19, 2009 By 31 Comments
…TABLE `idxtest` ( `i1` int(10) unsigned NOT NULL, `i2` int(10) unsigned NOT NULL, `val` varchar(40) DEFAULT NULL…of the columns has enumeration instead of equality index merge is not selected any more…. if we leave MySQL no choice but only to use combined index: mysql [localhost] {msandbox} (test) >…
