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Probability perspective on MySQL Group replication and Galera Cluster

Comparing Oracle MySQL Group Replication and Galera Cluster through a probability perpective seems quite interesting.

At commit time both use a group certification process that requires network round trips. The required time for these network roundtrips is what will mainly determined the cost of a transaction. Let us try to compute an estimate of the [...]

MaxScale, ProxySQL and MySQL Proxy

At FOSDEM 2014 ProxySQL and MaxScale were both presented. Both are proxy that can help build sophisticated MariaDB/MySQL architectures. But currently what is the most used proxy with MySQL? It is HAproxy. HAproxy is a level 4 proxy that has no knowledge of the MySQL protocol. Being low level makes it very fast but it [...]

InfiniDB column store moves to open source ! Congrats !

Like TokuDB, InfiniDB is now a fully open source server product. In the past infiniDB was “almost open source”. The open source version was an old release with no access to the advance functions like MPP multi-server execution. This is no more the case. With InfiniDB 4 the open source version is the latest release [...]

A new kid in the MySQL sharding world

MySQL Connect 2013 has been a great edition. There was of course a lot of nice announcements of improvements in the the core MySQL server technology. One of the major announcement that received a lot of buzz was MySQL Fabric. MySQL Fabric is an infrastructure component aimed at simplifying construction of a highly available, sharded, [...]

Why do we need InnoDB per table IO statistics ?

InnoDB plugin offers an adaptative compression that is very interesting for performance.
This compression works at a table level. Like most optimization techniques it is not black or white.
You have to decide depending on IO patterns / CPU usage / Memory usage / disks constraints what tables are good candidates for compression.
I was trying to define a methodology to help decide which tables to compress to reach performance gains.
I thought I could use MySQL “show status” command or information_schema tables. Unfortunately MySQL does not offer any per tables IO statistics.

InnoDB : Why not use the same isolation level as ORACLE ?

By default InnoDB uses REPEATABLE READ as its isolation level. So this is the isolation level used with innoDB by almost all MySQL users.

The default isolation level of Oracle is READ COMMITTED. READ COMMITTED is the mode widely used by Oracle users. This mode incurs less penalty on the server scalability by allowing to [...]