I deleted comment from someone with name “mr unhappy”. The comment did … questions about XtraDB Cluster in our mailgroup http://groups.google.com/group/percona-discussion
Post: InnoDB's gap locks
March 27, 2012 By 14 Comments
… a SELECT. They only occur if you do UPDATE or DELETE or SELECT FOR UPDATE. InnoDB provides REPEATABLE READ for read… | | 25 | | 30 | +——+ Start a transaction and delete the record 25: transaction1 > START TRANSACTION; transaction1 > DELETE FROM t WHERE age=25; At this… there is a good source of information: http://dev.mysql.com/doc/refman/5.1/en/innodb-locks-set.html. Conclusion…
Comment: Moving Subtrees in Closure Table Hierarchies
April 18, 2012 By 7 Comments
… or the problem you have, which is how to delete one link without deleting all the ancestors’ links if there’s another… DAGs: “SQL Design Patterns” by Vadim Tropashko. http://www.amazon.com/SQL-Design-Patterns-Programming-In-Focus/dp/0977671542/
Comment: InnoDB's gap locks
April 6, 2012 By 14 Comments
…://dba.stackexchange.com/questions/15854/innodb-row-locking-how-to-implement/15864#15864. I haven’t tested it with INSERT/DELETEs, but…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
….commanual Com_create_udfblogpercona.commanual Com_create_userblogpercona.commanual Com_create_viewblogpercona.commanual Com_dealloc_sqlblogpercona.commanual Com_deleteblogpercona.commanual Com_delete_multiblogpercona.commanual Com_doblogpercona.commanual Com_drop_dbblogpercona.commanual Com_drop_eventblogpercona.commanual Com_drop_functionblogpercona.commanual Com_drop…
Comment: MySQL Server Memory Usage
September 1, 2006 By 18 Comments
…’ ‘Com_checksum’, ’0′ ‘Com_commit’, ’9558970′ ‘Com_create_db’, ’0′ ‘Com_create_function’, ’0′ ‘Com_create_index’, ’0′ ‘Com_create_table’, ’31′ ‘Com_dealloc_sql’, ’0′ ‘Com_delete‘, ’348788′ ‘Com_delete_multi’, ’1′ ‘Com…
Post: How to recover deleted rows from an InnoDB Tablespace
February 20, 2012 By 2 Comments
…_defs.h format in the following link: http://www.percona.com/docs/wiki/innodb-data-recovery-tool:mysql-data-recovery:generating… the salaries.recovery you can find lot of deleted rows, not only rows deleted accidentally. You should manually find the data you…); Query OK, 3 rows affected (0.01 sec) Records: 3 Deleted: 0 Skipped: 0 Warnings: 0 mysql (employees) > select * from salaries…
Post: STOP: DELETE IGNORE on Tables with Foreign Keys Can Break Replication
February 2, 2012 By 1 Comment
…) An expected behavior for DELETE IGNORE is that if the statement fails to delete all rows, none should be deleted at all, after… any existing constraints from t2 as we deleted them from above. master [localhost] {msandbox} (test) > DELETE IGNORE FROM t1 WHERE t1_c1… in this example will be considered STATEMENT (http://dev.mysql.com/doc/refman/5.1/en/binary-log-mixed.html) thus…
Post: MySQL Query Cache
July 27, 2006 By 69 Comments
… query_cache efficiency. First looking at number of your selects – Com_select and see how many of them are cached. Query Cache efficiency would be Qcache_hits/(Com_select+Qcache_hits). As you can see we have to… comes from modification statements which you can calculate by (Com_insert+Com_delete+Com_update+Com_replace)/Qcache_hits . These are some numbers you can…
Comment: MySQL Query Cache
July 20, 2011 By 69 Comments
… Qcache_hits/(Com_select+Qcache_hits)=984286623/(984286623+327790129)=0.75 , (Com_insert)/Qcache_hits = (2029732811)/984286623 = 2.0621,(Com_insert+Com_delete+Com_update+Com_replace…
