… isolation level READ COMMITTED, then InnoDB normally does not lock the ‘gaps’, and it does not lock rows whose latest committed version does… with all pages in buffer pool it well may be faster to do 1 write than flush 10 non sequential pages… you have a battery-backed disk controller cache, then the commit returns in less than 100 microseconds. And if you do…
Post: New SpecJAppServer results at MySQL and Sun.
November 12, 2008 By Leave a Comment
… settings: transaction-isolation = READ-COMMITTED – this is indeed good setting for many workloads so unless you have repeatable reads requirement consider using this… have smaller sort buffer because allocating it will likely be faster. query_cache_size = 0M – query cache disabled. Not a big…
Post: Innodb performance gotcha w Larger queries.
August 28, 2009 By 7 Comments
… row statements. So with single statement MyISAM was about 10% faster, which is quite expected but with 1000 rows in the…
Post: Innodb Performance Optimization Basics
November 1, 2007 By 70 Comments
… are tiny but often faster than bigger ones. RAID10 works well for data storage and for read-mostly cases when you still… case increase it a bit. innodb_flush_log_at_trx_commit=2 If you’re not concern about ACID and can… application can run in READ-COMMITED isolation mode – if it does – set it to be default as transaction-isolation=READ-COMMITTED. This option has…
Post: MySQL Users Conference - Innodb
May 9, 2007 By 6 Comments
… it currently does which can be multiple orders of magnitude faster for large tables. There is fair number of questions about… to build them physically sorted so they should be much faster for IO Bound Index scans and large range scans. We… which limit concurrency in many cases can be removed for READ-COMMITED isolation mode which will start offering more performance benefits in…
Post: Percona XtraDB Cluster Feature 2: Multi-Master replication
January 19, 2012 By 16 Comments
… of writes. That is the write is either committed on all nodes or not committed at all. Let me draw some diagram… locally on the node, and only on COMMIT there is special handling. When you issue COMMIT, your transaction has to pass certification… master may apply event faster than a slave. And if you do read from the slave, you may read data, that has not…
Comment: Falcon Storage Engine Design Review
January 12, 2007 By 19 Comments
… up the index with records? A denser index is a faster index. Clustered indexes are a vestige from the small, expensive… thing to add, assuming that the performance is acceptable. Only committed changes go to the disk There’s no reason that… written to the serial log before commit. All that is necessary is the bookkeeping to read the record from the log (if…
Post: How Does Semisynchronous MySQL Replication Work?
January 19, 2012 By 23 Comments
… you commit a transaction, the commit does not complete until all replicas have also committed successfully. In MySQL’s semi-synchronous replication, the commit… you seen the bumper sticker that says “don’t drive faster than your Guardian Angel can fly?” That is the effect… you to read the relevant section of the MySQL manual. But read carefully, for example, the following sentences: When a commit returns successfully…
Post: How InnoDB handles REDO logging
February 3, 2011 By 18 Comments
… start recovery from the last checkpoint.InnoDB achieves this by reading the LSN of the page and compares that to the… must guarantee the logging action happens before the transaction is committed, this is known as write-ahead-logging. This essentially means… apply page changes at commit, therefore what would be a random write is translated into a much faster sequential write. The background…
Post: MySQL Limitations Part 1: Single-Threaded Replication
October 20, 2010 By 16 Comments
… trying to modify, so it can do it faster. This rarely works. I’m not criticizing anyone…The worker thread would run up until the COMMIT, but not actually commit, and then report back to the… threads that have forgotten where they should be reading in multiple binlogs?). Regardless of the solution, it…
