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TOI wsrep_RSU_method in PXC 5.6.24 and up

 | July 6, 2015 |  Posted In: MySQL, Percona XtraDB Cluster

I noticed that in the latest release of Percona XtraDB Cluster (PXC), the behavior of wsrep_OSU_method changed somewhat.  Prior to this release, the variable was GLOBAL only, meaning to use it you would:

This had the (possibly negative) side-effect that ALL DDL’s issued on this node would be affected by the setting while in […]

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Playing with Percona XtraDB Cluster in Docker

 | June 30, 2015 |  Posted In: Docker, High-availability, MySQL, Percona XtraDB Cluster, Quality Assurance, XtraDB Cluster

Like any good, thus lazy, engineer I don’t like to start things manually. Creating directories, configuration files, specify paths, ports via command line is too boring. I wrote already how I survive in case when I need to start MySQL server (here). There is also the MySQL Sandbox which can be used for the same […]

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Update on the InnoDB double-write buffer and EXT4 transactions

 | June 17, 2015 |  Posted In: Benchmarks, Hardware and Storage, InnoDB, MySQL

IMPORTANT: DON’T TRY THIS IN PRODUCTION. As demonstrated by Marko (see comments), it may corrupt your data. In a post, written a few months ago, I found that using EXT4 transactions with the “data=journal” mount option, improves the write performance significantly, by 55%, without putting data at risk. Many people commented on the post mentioning […]

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Speed up GROUP BY queries with subselects in MySQL

 | June 15, 2015 |  Posted In: MySQL

We usually try to avoid subselects because sometimes they force the use of a temporary table and limits the use of indexes. But, when is good to use a subselect? This example was tested over table a (1310723 rows), b, c and d ( 5 rows each) and with MySQL version 5.5 and 5.6. Let’s […]

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Percona XtraDB Cluster: Quorum and Availability of the cluster

 | June 12, 2015 |  Posted In: MySQL

Percona XtraDB Cluster (PXC) has become a popular option to provide high availability for MySQL servers. However many people are still having a hard time understanding what will happen to the cluster when one or several nodes leave the cluster (gracefully or ungracefully). This is what we will clarify in this post. Nodes leaving gracefully […]

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