… no need to create locks to prevent that from happening. 2- innodb_locks_unsafe_for_binlog = 1. Disables the gap locks except for foreign… locks can be different. In the following link there is a good source of information: http://dev.mysql.com/doc/refman/5.1/en/innodb-locks-set.html. Conclusion MySQL uses REPEATABLE READ as the default isolation level so it needs to lock the…
Post: MariaDB 5.3 is released as GA!
March 5, 2012 By 17 Comments
… plugin. MariaDB 5.3 isn’t the only exciting thing, however. MariaDB 5.3 is based on MySQL 5.1, but MariaDB 5.5 will be based on MySQL 5.5, so it will inherit… less lock contention, better diagnostics, improvements to partitioning, and the addition of multiple InnoDB buffer pools. Best of all, MariaDB 5.5 might…
Post: How FLUSH TABLES WITH READ LOCK works with Innodb Tables
March 23, 2012 By 20 Comments
…lock | 0 | 0 | 1 | | 10291 | root | localhost | dumptest | Query | 74 | Waiting for global read lock | insert into C values (“a”,1) | 0 | 0 | 1…
Comment: Avoiding auto-increment holes on InnoDB with INSERT IGNORE
March 11, 2012 By 7 Comments
… is traditional lock mode == > funcionality of auto_increment like before 5.1.22 # =1 is default value – consecutive lock mode # =2 is interleaved lock mode , i don’t investigate what it do innodb_autoinc_lock…
Comment: Innodb Performance Optimization Basics
March 28, 2012 By 69 Comments
… query output. The tables are in InnoDB with MySQL 5 and RHEL 5. Its a 32 bit machine with 12 Gb RAM…_buffer_size = 8M innodb_flush_log_at_trx_commit = 1 innodb_lock_wait_timeout = 50 A count command with approx 3 million… is taking too long and all my transactions are locked. select count(1),field1 from Table where REQUEST_TIME >= ’2012-03-26…
Post: Troubleshooting MySQL Memory Usage
March 21, 2012 By 3 Comments
… larger problems with MySQL 5.5 with addition of user variables,…| sum(data_length+index_length) | +——————————-+ | 126984 | +——————————-+ 1 row in set (0.98… 2623331) File system 294352 (82672 + 211680) Lock system 318875832 (318747272 + 128560) Recovery system …
Comment: Best kept MySQLDump Secret
March 29, 2012 By 11 Comments
I did the same test on windows2003 mysql 5.5.15 while mysqldump is going , alter table was BLOCKED! Eventually …(1) DEFAULT ” ) ENGINE=InnoDB DEFAULT CHARSET=utf8; /*!40101 SET character_set_client = @saved_cs_client */; — – Dumping data for table `z` — LOCK TABLES…
Post: MySQL 5.0, 5.1 and Innodb Plugin CPU Efficiency
December 3, 2008 By 15 Comments
… couple of weeks ago so MySQL 5.0.67, MySQL 5.1.29 and Innodb Plugin 1.0.1 were used which are not very… a bit better scalability. MySQL 5.1 plugin (compiled in) is further 3% slower compared to MySQL 5.1 with 2 cores and about… is hard to say anything about CPU efficiency. The RW-Lock patch is best in this case. It shows increased performance…
Post: Introducing percona-patches for 5.1
February 9, 2010 By 21 Comments
… up and sponsored the work to move the patches to 5.1. To refresh, the most interesting patches are: Performance patches for… threads – Adaptive checkpointing – Buffer pool mutex split – Reimplemented read-write locks Diagnostic patches. – We provide much more statistics in slow.log… results for tpce-like benchmark, where I compare MySQL-5.1.43 vs percona-5.1.43. The results made for TPCE configuration with…
Post: Percona Server 5.1.58-12.9
August 17, 2011 By 2 Comments
… to improve compatibility for those upgrading from MySQL 5.0 or 5.1 prior to version 5.1.24. A fix for a MySQL bug (#27877) introduced an incompatible change in collations in MySQL 5.1… the server to crash in some scenarios due to insufficient locking. Fixed by introducing a new mutex to protect from race…
