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Search Results for: e=t

What does the ‘Incorrect key file for table’ error mean?

What does it mean if MySQL returns the ‘Incorrect key file for table’ error for one of my queries? The answer is complicated and depends on which storage engine is returning the error. We have …

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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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Innotop: A real-time, advanced investigation tool for MySQL

GUI monitoring tools for MySQL are not always suitable for all our needs or situations. Most of them are designed to provide historical views into what happens to our database over time rather then real-time …

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Comparing MongoDB, MySQL, and TokuMX Data Layout

A lot is said about the differences in the data between MySQL and MongoDB. Things such as “MongoDB is document based”, “MySQL is relational”, “InnoDB has a clustering key”, etc.. Some may wonder how TokuDB, …

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How to fix your PRM cluster when upgrading to RHEL/CentOS 6.4

If you are using Percona Replication Manager (PRM) with RHEL/CentOS prior to 6.4, upgrading your distribution to 6.4 may break your cluster. In this post I will explain you how to fix your cluster in …

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Benchmarking Percona Server TokuDB vs InnoDB

After compiling Percona Server with TokuDB, of course I wanted to compare InnoDB performance vs TokuDB. I have a particular workload I’m interested in testing – it is an insert-intensive workload (which is TokuDB’s strong …

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How We Spent a Tuesday Fixing a MySQL Replication Bug

We found a simple XA transaction that crashes MySQL 5.5 replication. This simple transaction inserts a row into an InnoDB table and a TokuDB table. The bug was caused by a flaw in the logging …

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Find and remove duplicate indexes

Having duplicate keys in our schemas can hurt the performance of our database: They make the optimizer phase slower because MySQL needs to examine more query plans. The storage engine needs to maintain, calculate and …

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Announcing TokuDB v5.2: Improved Multi-Client Scaling and Faster Queries

TokuDB® v5.2, the latest version of Tokutek’s flagship storage engine for MySQL and MariaDB, is now available. This version offers performance enhancements over previous releases, especially for multi-client scale up and point queries, and extends …

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Bug#12704861

As Mark pointed out, there isn’t a lot of detail in the release notes about what could potentially be a very serious problem that is fixed in MySQL 5.1.60. I’ll repeat here the full documentation …

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