… remove double buffering. In distant future, I would like to have the memlock also. PZ: memlock already works – it is global MySQL… of MySQL process. Q20: We’ve migrated to using INNODB so that it operates 100% out of memory. This way every write…: I do not think so. Sergei Golubchik serialized the MySQL binlog write and the InnoDB log flush with a mutex in 5…
Post: How does MySQL Replication really work?
January 9, 2013 By 9 Comments
… it. So, I decided to write one now. Of course, there are many aspects of MySQL replication, but my main focus will… the MySQL manual here. Put simply, the events can be one of two types: Statement based – in which case these are write… will be the SQL thread, still it makes sense to double check. You can do that by comparing the replication status…
Post: When would you use SAN with MySQL ?
March 9, 2009 By 18 Comments
… in particular hurts log writes which are very latency critical. Now what is about MySQL/Innodb specifics ? First, in MySQL if you’re looking for durable transactions the log write latency is triple important… split in two (ie for recovery purposes). Sure it needs double the storage but you get 2 copies of data too…
Post: Aligning IO on a hard disk RAID – the Theory
June 9, 2011 By 18 Comments
…, it’s guaranteed to be slower both for reading and writing. So, how do we avoid misalignment? Well, we must ensure… (at a certain level) so when writing a file, file system decides how to distribute writes properly so they make the best…, with RAID5 – N-1 (single parity), with RAID6 – N-2 (double parity). You want to know that when setting parameters for…
Post: MySQL Query Cache
July 27, 2006 By 70 Comments
… “Query Cache” which is quite helpful for MySQL Performance optimization tasks but there are number… query cache effectiveness – if you have high write application such as forums, query cache efficiency… I’ve seen query cache offering about double performance for simple queries with select done…
Post: MySQL 5.5.8 - in search of stability
January 3, 2011 By 11 Comments
…_files_in_group = 2 innodb_read_io_threads = 16 innodb_write_io_threads = 16 innodb_purge_threads=1 innodb_adaptive_flushing… activity actually adds significant I/O activity. Basically, it doubles the amount of writes 
, as you see from its name. So, let… NOTPM. The throughput is about 1.33x better than in “MySQL compatible mode”, though it requires 10500MB for checkpoint age; that…
Post: UDF -vs- MySQL Stored Function
September 6, 2010 By 8 Comments
… it to sphinx – MySQL did not have a function to do the thing so I thought I’ll write MySQL Stored Function and… some text”, and (2) same two varchar columns needed some double characters changed to single one so “Picasso” becomes “Picaso”, “Wesselmann… did not necessarily have to write a function, I could have written it as an SQL statement: mysql> select REPLACE( REPLACE( REPLACE…
Post: Percona's Commitments to MySQL Users
November 5, 2010 By 10 Comments
… the last few years. This era is over. MySQL has never progressed so rapidly towards better features, … such as these can be filled with corporate double-speak. Let there be no doubt: Percona is… our customers are in business to make money. We write software that contributes to our business goals, and…
Post: MySQL Replication vs DRBD Battles
April 28, 2008 By 12 Comments
… comparing here – it is mainly DRBD to MySQL Replication based techniques (lets leave MySQL Cluster and Continnuent alone for a while as… CPU cycles on double caching. Even in this case DRBD slave node can’t be called hot because write load often does… transaction loss and automated fail over. Whenever you’re using MySQL Cluster, DRBD or MySQL Replication you have to have some compromises.
Post: MySQL Users Conference - Innodb
May 9, 2007 By 6 Comments
…might look like it is too late to write about stuff happened at Users Conference but I’m just… increasingly important as their number per CPU just keeps doubling. It is also rather interesting how is sort file … out where already which may come in MySQL 5.2 or even MySQL 5.1. I surely would like to …
