…fixed #1128906 (Alexey Bychko). The method of generating md5 digest over tuples in a table with…applying would fail in case mixed CHAR and VARCHAR columns would be used in foreign key … hanging. Bug fixed #1130888 (Seppo Jaakola). If MySQL replication threads were started before running wsrep …
Comment: InnoDB, InnoDB-plugin vs XtraDB on fast storage
January 23, 2013 By 13 Comments
…varchar(100) DEFAULT NULL ) ENGINE=InnoDB DEFAULT CHARSET=latin1 In this case, percona server takes more time than MySQL…
Post: Using CHAR keys for joins, how much is the overhead ?
June 18, 2007 By 18 Comments
… expected as MyISAM uses key compression for varchar columns so random key lookups become significantly …was expected this to shorten some internal buffers MySQL has to allocate for key comparison as… for most character based keys – uuid, sha1/md5 based etc. Latin1 encoding indeed gave significant…
Post: To SQL_CALC_FOUND_ROWS or not to SQL_CALC_FOUND_ROWS?
August 28, 2007 By 57 Comments
…` int(10) NOT NULL, `c` int(10) NOT NULL, `d` varchar(32) NOT NULL, PRIMARY KEY (`a`), KEY `bc` (`b`,`c… with following script (which creates 10M records): mysql_connect(“127.0.0.1″, “root”); mysql_select_db(“test”); for ($i = 0; $i…++) { $b = $i % 1000; mysql_query(“INSERT INTO count_test SET b=$b, c=ROUND(RAND()*10), d=MD5($i)”); } First of all…
Post: How much memory Innodb locks really take ?
July 13, 2006 By 11 Comments
… auto_increment, `j` varchar(255) default NULL, PRIMARY KEY (`i`), KEY `j` (`j`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 mysql> show table status…, however we can see locking overhead is not that large: mysql> select count(i) from sample; +———-+ | count(i) | +———-+ | 1638400 | +———-+ 1 row… (column j was populated by md5(rand()) values) : mysql> begin; Query OK, 0 rows affected (0.00 sec) mysql> select count(*) from sample…
Post: Idea: Couple of more string types
April 18, 2008 By 12 Comments
MySQL has a lot of string data types – CHAR, VARCHAR, BLOB, TEXT, ENUM and bunch of variants such as VARBINARY … able to store hex strings, such as those returned as MD5() and SHA1() efficiently. With little modification it could work for…. Though this is likely to require more significant changes in MySQL so I would not expect to happen quickly. The basic…
Post: Long PRIMARY KEY for Innodb tables
October 3, 2006 By 8 Comments
… stored in the database: CREATE TABLE `imagecache` ( `url` varchar(255) character set latin1 NOT NULL default ”, `thumb_… – checking/repairing large MyISAM tables in case of MySQL/System crash is painful and great to be … case as if I would decide to use md5(url) or something similar as a key – it…
