Are you using InnoDB tables on MySQL version 5.1.22 or newer? If so, you probably have gaps in your auto-increment columns. A simple INSERT IGNORE query creates gaps for every ignored insert, but this is undocumented behaviour. This documentation bug is already submitted. Firstly, we will start with a simple question. Why do we have […]
Search Results for: innodb mutex
It is no secret that bugs related to multithreading–deadlocks, data races, starvations etc–have a big impact on application’s stability and are at the same time hard to find due to their nondeterministic nature. Any tool that makes finding such bugs easier, preferably before anybody is aware of their existence, is very welcome.
It’s Friday again (so soon!) and time for our TGIF contest, to give away a free ticket to Percona Live London. Before we do that, though, just what in the world does this output from SHOW INNODB STATUS mean?
Mutex spin waits 5870888, rounds 19812448, OS waits 375285
To understand this text, you have to understand how InnoDB handles mutexes. It tries a […]
Even though multiple fixes have been implemented in Percona Server and MySQL 5.5, there are still workloads in which case mutex (or rw-lock) contention is a performance limiting factor, helped by ever growing number of cores available in the systems. It is interesting though the contention may manifest itself in the different form from the […]
InnoDB compression is getting some traction, and I see quite contradictory opinions. Someone has successful deployments in productions, and someone says that compression in current implementation is useless. To get some initial impression about performance I decided to run some sysbench with multi-tables benchmarks. I actually was preparing to do complex research, but even first […]
I again work with the system which needs high insertion rate for data which generally fits in memory. Last time I worked with similar system it used MyISAM and the system was built using multiple tables. Using multiple key caches was the good solution at that time and we could get over 200K of inserts/sec. […]
I recently did a quick analysis of the distribution of writes to InnoDB’s log files. On a high-traffic commodity MySQL server running Percona XtraDB for a gaming workload (mostly inserts to the “moves” table), I used strace to gather statistics about how the log file writes are distributed in terms of write size. InnoDB writes […]
Running many benchmarks on fast storage (FusionIO, SSDs) and multi-cores CPUs system I constantly face two contention problems. So I suspect it’s going to be next biggest issues to make InnoDB scaling on high-end system. This is also reason why in benchmarks I posted previously CPU usage is only about 50%, leaving other 50% in […]
To continue fun with FusionIO cards, I wanted to check how MySQL / InnoDB performs here. For benchmark I took MySQL 5.1.42 with built-in InnoDB, InnoDB-plugin 1.0.6, and XtraDB 1.0.6-9 ( InnoDB with Percona patches). As benchmark engine I used tpcc-mysql with 1000 warehouses ( which gives around 90GB of data + indexes) on my […]
It is rather typical for systems to start as MyISAM but as system growths to move to Innodb. The reason of the move could be just desire for better data consistency guaranty or being bitten repairing multiple GB MyISAM table few times, though Table Locks is probably the most important issue – with modern multi […]