…Read-only transactions, while a great optimization in itself, applies only to the following kinds of transactions: MySQL transactions started with START TRANSACTION READ ONLY MySQL transactions…
Post: trx descriptors: MySQL performance improvements in Percona Server 5.5.30-30.2
April 12, 2013 By 3 Comments
Post: Differences between READ-COMMITTED and REPEATABLE-READ transaction isolation levels
August 28, 2012 By 3 Comments
… differences between the READ COMMITTED and REPEATABLE READ transaction isolation levels. There are a few differences between READ-COMMITTED and REPEATABLE-READ, and they…READ COMMITTED: —TRANSACTION 1EAB06, ACTIVE 11 sec 631 lock struct(s), heap size 96696, 1 row lock(s), undo log entries 1 MySQL…
Post: READ-COMMITED vs REPETABLE-READ in tpcc-like load
February 11, 2010 By 6 Comments
…read committed for InnoDB . Serge in his post explains why READ COMMITED is better for TPCC load, so why don’t we take tpcc-mysql…transaction” in READ-COMMITED mode, and 0 Deadlocks in REPEATABLE-READ mode. I understand that 60 deadlocks for total 2704687 transactions…
Post: New SpecJAppServer results at MySQL and Sun.
November 12, 2008 By Leave a Comment
… most interesting: MySQL 5.0 Tuning in /etc/my.cnf (included in FDA) [mysqld] sql-mode = IGNORE_SPACE transaction-isolation = READ-COMMITTED max_allowed_packet…. Other important settings: transaction-isolation = READ-COMMITTED – this is indeed good setting for many workloads so unless you have repeatable reads requirement consider using this…
Post: Using Flexviews - part two, change data capture
March 25, 2011 By 26 Comments
… that triggers can not, under normal conditions, detect the commit order of transactions. This above all makes triggers an unacceptable CDC method….cnf log_slave_updates=1, if this is a MySQL slave transaction_isolation=READ-COMMITTED You can get FlexCDC directly out of the Flexviews SVN…
Post: Shard-Query EC2 images available
May 11, 2011 By 2 Comments
…=’Contains all avaialble data from 1988 to 2010′; mysql> use ontime1; Database changed mysql> show table status like ‘ontime_fact’G *************************** 1…=barracuda innodb-file-per-table innodb-flush-log-at-trx-commit=1 innodb-flush-method=O_DIRECT innodb-ibuf-active-contract…-cache-size=32 thread-stack=256K tmp-table-size=64M transaction-isolation=READ-COMMITTED user=mysql wait-timeout=86400 To be continued You can now…
Post: Implications of Metadata Locking Changes in MySQL 5.5
February 1, 2013 By 9 Comments
… you can see how isolation is broken because the SELECT was not repeatable although transaction isolation level of REPEATABLE-READ was used. This behavior… waiting for the transaction to commit. For the reasons described above the implementation of Metadata Locking was changed, starting MySQL 5.5.3…
Post: Innodb undo segment size and transaction isolation
January 12, 2011 By 3 Comments
…read only transactions as well. This is how long transaction looks: —TRANSACTION 17402D749, ACTIVE 15867 sec, process no 19349, OS thread id 1630148928 MySQL… setting isolation mode to READ-COMMITTED can be good idea if your application supports it. Note you can set isolation mode on transaction …
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
…MySQL…commit…transaction_alloc_block_sizeblogpercona.commanual transaction_isolationblogpercona.commanual transaction…
Post: Innodb Performance Optimization Basics
November 1, 2007 By 75 Comments
… your application can run in READ-COMMITED isolation mode – if it does – set it to be default as transaction-isolation=READ-COMMITTED. This option has some performance benefits, especially in locking in 5.0 and even more to come with MySQL 5…
