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Percona XtraDB Cluster 5.5.31-23.7.5 now available

Percona is glad to announce the release of Percona XtraDB Cluster 5.5.31-23.7.5 on June 25, 2013. Binaries are available from the downloads area or from our software repositories. New Features: Information about the wsrep sequence …

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InnoDB locks and deadlocks with or without index for different isolation level

Recently, I was working on one of the issue related to locks and deadlocks with InnoDB tables and I found very interesting details about how InnoDB locks and deadlocks works with or without index for different Isolation levels. …

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Looking deeper into InnoDB’s problem with many row versions

A few days ago I wrote about MySQL performance implications of InnoDB isolation modes and I touched briefly upon the bizarre performance regression I found with InnoDB handling a large amount of versions for a single …

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Q&A: Percona XtraDB Cluster as a MySQL HA solution for OpenStack

Thanks to all who attended my Nov. 12 webinar titled, “Percona XtraDB Cluster as a MySQL HA Solution for OpenStack.” I had several questions which I covered at the end and a few that I …

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How to deal with MySQL deadlocks

A deadlock in MySQL happens when two or more transactions mutually hold and request for locks, creating a cycle of dependencies. In a transaction system, deadlocks are a fact of life and not completely avoidable. …

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Do not trust vmstat IOwait numbers

I’ve been running a benchmark today on my old test box with conventional hard drives (no raid with BBU) and noticed something unusual in the CPU utilization statistics being reported. The benchmark was run like …

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OOM relation to vm.swappiness=0 in new kernel

I have recently been involved in diagnosing the reasons behind OOM invocation that would kill the MySQL server process. Of course these servers were primarily running MySQL. As such the MySQL server process was the …

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Innodb redo log archiving

Percona Server 5.6.11-60.3 introduces a new “log archiving” feature. Percona XtraBackup 2.1.5 supports “apply archived logs.” What does it mean and how it can be used? Percona products propose three kinds of incremental backups. The …

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Interactive Debugging of Transaction Conflicts with TokuDB

I am developing a concurrent application that uses TokuDB to store its database. Sometimes, one of my SQL statements returns with a ‘lock wait timeout exceeded’ error. How do I identify the cause of this …

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A TokuDB Stall Caused by Conflicting Transactions When Opening a Table

One of our customers reported that ‘create table select from’ statements stall for a period of time equal to the TokuDB lock timeout.  This indicated a lock conflict between multiple transactions.  In addition, other MySQL …

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