Search Results for: using where query

Using per-query variable statements in Percona Server

Percona Server has implemented per-query variable statement support in version 5.6.14-62.0. This feature provides the ability to set variable values only for a certain query, after execution of which the previous values will be restored. Per-query variable values can be set up with the following command:

Example: If we want to increase the sort_buffer_size […]

How to generate per-database traffic statistics using mk-query-digest

We often encounter customers who have partitioned their applications among a number of databases within the same instance of MySQL (think application service providers who have a separate database per customer organization … or wordpress-mu type of apps). For example, take the following single MySQL instance with multiple (identical) databases:

The future of MySQL quality assurance: Introducing pquery

Being a QA Engineer, how would you feel if you had access to a framework which can generate 80+ crashes – a mix of hitting developer introduced assertions (situations that should not happen), and serious unforeseen binary crashes – for the world’s most popular open source database software – each and ever hour? What if you could […]

Using Percona Cloud Tools to solve real-world MySQL problems

For months when speaking with customers I have been positioning Percona Cloud Tools (PCT) as a valuable tool for the DBA/Developer/SysAdmin but only recently have I truly been able to harness the data and make a technical recommendation to a customer that I feel would have been very difficult to accomplish otherwise. Let me provide […]

How a set of queries can be killed in MySQL using Percona Toolkit’s pt-kill

You might have encountered situations where you had to kill some specific select queries that were running for long periods and choking the database. This post will go into more detail with an example of report query offloading. Report query (select) offloading to a slave server is a common practice to reduce the workload of the […]

How to avoid hash collisions when using MySQL’s CRC32 function

Percona Toolkit’s  pt-table-checksum performs an online replication consistency check by executing checksum queries on the master, which produces different results on replicas that are inconsistent with the master – and the tool pt-table-sync synchronizes data efficiently between MySQL tables. The tools by default use the CRC32. Other good choices include MD5 and SHA1. If you have installed the FNV_64 user-defined function, pt-table-sync will […]

How to scale big data applications using MySQL sharding frameworks

This Wednesday I’ll be discussing two common types of big data: machine-generated data and user-generated content. These types of big data are amenable to sharding, a commonly used technique for spreading data over more than one database server. I’ll be discussing this in-depth during a live webinar at 10 a.m. Pacific time on Sept. 24. […]

Using sysbench 0.5 for performing MySQL benchmarks

Given the recent excitement & interest around OpenStack I wanted to make sure I was ready to conduct appropriate evaluations of system performance.  I generally turn to sysbench since it comes with a variety of different tests (accessed via –test= option interface), including: fileio – File I/O test cpu – CPU performance test memory – […]

Advanced MySQL Query Tuning (Aug. 6) and MySQL 5.6 Performance Schema (Aug. 13) webinars

I will be presenting two webinars in August: Aug 6, 10 a.m. PDT: Advanced Query Tuning in MySQL 5.6 and Beyond Aug 13, 10 a.m. PDT:  Using Performance Schema to Monitor and Troubleshoot MySQL 5.6 This Wednesday’s webinar on advanced MySQL query tuning will be focused on tuning the “usual suspects”: queries with “Group By”, “Order […]