At $WORK we were running a MySQL setup that required an unusually large number of concurrent connections. Most of them were idle. Only a few dozen connections were running queries. The total number of connections was around twelve thousand and was growing slowly. When the total number of connections reached close to 12,200, things started to break. New clients could no longer connect to the database. The error in the MySQL log was: ...
http://www.xaprb.com/blog/2011/01/29/how-innodb-performs-a-checkpoint/
http://www.xaprb.com/blog/2011/01/29/how-innodb-performs-a-checkpoint/ An article about MySQL InnoDB checkpoint-ing mechanism written by Perconna folks. Read comments as well, several PostgreSQL core committers have participated in the discussion. “InnoDB’s checkpoint algorithm is not well documented. It is too complex to explain in even a long blog post, because to understand checkpoints, you need to understand a lot of other things that InnoDB does. I hope that explaining how InnoDB does checkpoints in high-level terms, with simplifications, will be helpful. A lot of the simplifications are because I do not want to explain the complexities of how the simple rules can be tweaked for optimization purposes, while not violating the ACID guarantees they enforce.” ...
http://www.mysqlperformanceblog.com/2011/02/03/how-innodb-handles-redo-logging/
http://www.mysqlperformanceblog.com/2011/02/03/how-innodb-handles-redo-logging/ How MySQL InnoDB implements transaction log, aka REDO (Oracle), aka WAL (PostgreSQL)
http://www.mysqlperformanceblog.com/2011/04/04/innodb-flushing-theory-and-solutions/ blog posts that describes how MySQL InnoDB flushes data to disk (also see bgwriter, checkpoint_* parameters in PostgreSQL)
http://vbtechsupport.com/606/ Sysbench-based benchmark comparing OLTP workloads for different builds and forks of MySQL on 64-core intel machine (Quad Intel Xeon L7555 ) . Only one definitive result is that MySQL cannot scale beyond 8 or 16 cores, or in some cases beyond just 2 cores (booo! ). In all cases performance went down when more than 24 cores were used .
http://www.insight-it.ru/masshtabiruemost/arkhitektura-vkontakte/ [ENG] http://translate.google.com/translate?u=http%3A%2F%2Fwww.insight-it.ru%2Fmasshtabiruemost%2Farkhitektura-vkontakte%2F&sl;=ru&tl;=en&hl;=&ie;=UTF-8 some info about internals of vkontakte.ru - russian facebook clone, most popular social network in Russia, #34 in top100 websites according to alexa (btw, Flickr.com is #35).
http://rhaas.blogspot.com/2010/11/mysql-vs-postgresql-part-1-table.html An article from a well-known PostgreSQL developer comparing MySQL InnoDB and PostgreSQL table structures
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