…bet that MySQL is up and running. That said, there are plenty of other MySQL and OS-level …MySQL world, except maybe MyISAM files on top of a clustered filesystem with an external lock manager. You might say that MySQL…with –skip-grant-tables and insert a few rows into an InnoDB table, but trying to …
Post: MySQL and the SSB - Part 2 - MyISAM vs InnoDB low concurrency
May 22, 2013 By Leave a Comment
… when a larger number of rows must be joined together (Q4.1,… caching of data at the filesystem level. The InnoDB indexes were built …mysql56/data basedir=/usr/local/mysql socket=/var/lib/mysql/mysql.sock user=justin innodb_…innodb_buffer_pool_instances=16 metadata_locks_hash_instances=32 table_open_…
Post: Innodb Table Locks
July 31, 2012 By 4 Comments
… having locking issues with Innodb chances are it is row level locks or auto increment table level lock (mostly with MySQL 5.0 and older MySQL versions). MySQL level locks are entirely different story. Explicitly locking tables on MySQL level will…
Post: InnoDB's gap locks
March 27, 2012 By 15 Comments
One of the most important features of InnoDB is the row level locking. This feature provides better concurrency under heavy write load but… a consistent Statement based replication. To accomplish that, row level locking databases also acquire gap locks. What is a Phantom Read A Phantom Read… 72C, ACTIVE 755 sec 4 lock struct(s), heap size 1248, 3 row lock(s), undo log entries 1 MySQL thread id 3, OS…
Post: Modeling MySQL Capacity by Measuring Resource Consumptions
March 8, 2011 By 1 Comment
… as well as inevitable application specific scalability restrictions, such as row level locks. There is also a load aspect – “random arrivals” tell us… ? You can take a look at procfs for MySQL process: root@ubuntu:/var/log/mysql# cat /proc/19018/stat 19018 (mysqld) S… separately through number of IOPS) but it also can be row level locks, etc. The ratio between Wait Time and CPU time is…
Post: Percona Server on the Raspberry Pi: Your own MySQL Database Server for Under $80
February 25, 2013 By 10 Comments
… mysqld Connect using the mysql client: [root@alarmpi ~]# /usr/bin/mysql Welcome to the MySQL monitor. Commands end with ; or \g. [...] mysql> SHOW ENGINES… transactions, row-level locking, and foreign keys | YES | YES | YES | [...] mysql> SELECT “Hello World!” AS “Success!” \G *************************** 1. row *************************** Success!: Hello World! 1 row in set…
Post: Scaling problems still exist in MySQL 5.5 and Percona Server 5.5
May 20, 2011 By 11 Comments
…_event_wait_low,sync_array_wait_event,rw_lock_s_lock_spin,pfs_rw_lock_s_lock_fu nc,btr_search_build_page_hash…_search_to_nth_level,btr_p cur_open_with_no_init_func,row_sel_get_clust_rec_for_mysql,row_search_for_mysql,ha_innobase…_search_to_nth_level,btr_p cur_open_with_no_init_func,row_sel_get_clust_rec_for_mysql,row_search_for_mysql,ha_innobase…
Post: SELECT LOCK IN SHARE MODE and FOR UPDATE
August 6, 2006 By 51 Comments
…: mysql> commit; Query OK, 0 rows affected (0.01 sec) SESSION2: mysql> select * from tst; Empty set (0.00 sec) mysql> select * from tst lock… peices missing in Locking implementation of Innodb are: Lock table Innodb can lock tables but it will still need to set row level locks which is…
Post: How much memory Innodb locks really take ?
July 13, 2006 By 11 Comments
…to lock 1638400 rows, making it less than 3 bits per locked row; Now lets see how much exclusinve locks take: mysql> begin; Query OK, 0 rows…locked row. In practice this means memory consumption by row level locks should not be the problem even for rather large databases – even billion of locked rows…
Post: Table locks in SHOW INNODB STATUS
June 8, 2010 By 1 Comment
… id 1141287232 2 lock struct(s), heap size 368 MySQL thread id 8, query id 164 localhost root TABLE LOCK table `test/t1… table lock on test/t1 table and many people tend to think Innodb in fact in some circumstances would abandon its row level locking and use table locks instead. I’ve seen various theories ranging from lock escalation to using table locks in special…
