Search Results for: end state

MySQL Query Cache and prepared statements – support comming ?

Looking at post by Konstantin Osipov we should finally get Query Cache working with prepared statements in MySQL 5.1 The interesting thing Konstantin notes it just took few days to fix it – I believe MySQL Support Team alone spent much more times explaining customers why is it not done or troubleshooting cases with wrong […]

Extended EXPLAIN

One nice feature added for EXPLAIN statement in MySQL 4.1 is EXTENDED keyword which provides you with some helpful additional information on query optimization. It should be used together with SHOW WARNINGS to get information about how query looks after transformation as well as what other notes optimizer may wish to tell us. It is […]

Percona Server 5.6.24-72.2 is now available

Percona is glad to announce the release of Percona Server 5.6.24-72.2 on May 8, 2015. Download the latest version from the Percona web site or from the Percona Software Repositories. Based on MySQL 5.6.24, including all the bug fixes in it, Percona Server 5.6.24-72.2 is the current GA release in the Percona Server 5.6 series. Percona Server is open-source […]

Generated (Virtual) Columns in MySQL 5.7 (labs)

About 2 weeks ago Oracle published the MySQL 5.7.7-labs-json version which includes a very interesting feature called “Generated columns” (also know as Virtual or Computed columns). MariaDB has a similar feature as well: Virtual (Computed) Columns. The idea is very simple: if we store a column

in our table we may want to filter or group […]

Test your knowledge: Percona XtraDB Cluster (PXC) quiz

I often talk with people who are very interested in the features of Percona XtraDB Cluster (PXC) such as synchronous and parallel replication, multi-node writing and high availability. However some get confused when operating a real PXC cluster because they do not fully realize the implications of these features. So here is a fun way […]

Profiling MySQL queries from Performance Schema

When optimizing queries and investigating performance issues, MySQL comes with built in support for profiling queries aka SET profiling = 1; . This is already awesome and simple to use, but why the PERFORMANCE_SCHEMA alternative? Because profiling will be removed soon (already deprecated on MySQL 5.6 ad 5.7); the built-in profiling capability can only be enabled per session. This […]

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. Here, I would like to describe a small test case about how SELECT ..FOR UPDATE (with and without limit) behave […]