Measuring Max Replication Throughput on Percona XtraDB Cluster with wsrep_desync
Checking throughput with async MySQL replicationReplication throughput is the measure of just how fast the slaves can apply replication (at least by my definition). In MySQL async replication this is...
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Using the new spatial functions in MySQL 5.6 for geo-enabled applications
Geo-enabled (or location enabled) applications are very common nowadays and many of them use MySQL. The common tasks for such applications are:Find all points of interests (i.e. coffee shops) around...
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The power of MySQL’s GROUP_CONCAT
In the very early days of Percona Vadim wrote very nice post about GROUP_CONCAT.But I want to show you a bit more about it.When is GROUP_CONCAT useful? Usually while working with Support customers I...
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QA: Advanced Option Combinatorics (Pairwise Testing): Combinatorial mysqld...
How do we ensure that, when we have 35+ testable option combinations for mysqld, we test each and every combination of them? For example: will a different innodb_log_file_size combined with more...
View Articleinnodb_stats_on_metadata and slow queries on INFORMATION_SCHEMA
INFORMATION_SCHEMA is usually the place to go when you want to get facts about a system (how many tables do we have? what are the 10 largest tables? What is data size and index size for table t?, etc)....
View Article2 cases for MySQL server overload
Your MySQL server is overloaded. You see hundreds of running queries in the SHOW PROCESSLIST taking many seconds to run, or can’t connect at all because all connections slots are busy. If you have...
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Analyzing WordPress MySQL queries with Query Analytics
This blog, MySQLPerformanceBlog.com, is powered by WordPress, but we never really looked into what kind of queries to MySQL are used by WordPress. So for couple months we ran a Query Analytics (part of...
View ArticleMySQL server memory usage troubleshooting tips
There are many blog posts already written on topics related to “MySQL server memory usage,” but nevertheless there are some who still get confused when troubleshooting issues associated with memory...
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MySQL performance optimization: Don’t guess! Measure with Percona Cloud Tools
In our practice we often see that MySQL performance optimization is done in a sort of “black magic” way. A common opinion is: “If there is a performance problem – then it must be a database issue,...
View ArticlePercona Toolkit collection: pt-visual-explain
This is the first in a series of posts highlighting a few of the seldom-used but still handy Percona Toolkit tools.Have you ever had a problem understanding the EXPLAIN statement output? And are you...
View ArticlePERFORMANCE_SCHEMA vs Slow Query Log
A couple of weeks ago, shortly after Vadim wrote about Percona Cloud Tools and using Slow Query Log to capture the data, Mark Leith asked why don’t we just use Performance Schema instead? This is an...
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8 common (but deadly) MySQL operations mistakes and how to avoid them
January 22 I gave a presentation on “How to Avoid Common (but Deadly) MySQL Operations Mistakes” for Percona MySQL Webinars. If you missed it, you can still register to view the recording and my...
View ArticleHow to monitor ALTER TABLE progress in MySQL
While working on a recent support issue as a Percona Support Engineer, I got one question from a customer asking how to monitor ALTER TABLE progress. Actually, for MySQL 5.5 and prior versions, it’s...
View ArticleHow rows_sent can be more than rows_examined?
When looking at queries that are candidates for optimization I often recommend that people look at rows_sent and rows_examined values as available in the slow query log (as well as some other places)....
View ArticleMany-table joins in MySQL 5.6
I recently worked on an uncommon slow query: less than 100 rows were read and returned, the whole dataset was fitting in memory but the query took several seconds to run. Long story short: the query...
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Q&A: Common (but deadly) MySQL Development Mistakes
On Wednesday I gave a presentation on “How to Avoid Common (but Deadly) MySQL Development Mistakes” for Percona MySQL Webinars. If you missed it, you can still register to view the recording and my...
View ArticleHow to log slow queries on Slave in MySQL 5.0 with pt-query-digest
Working as a Percona Support Engineer, every day we are seeing lots of issues related to MySQL replication. One very common issue is slave lagging. There are many reasons for slave lag but one common...
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A conversation with 5 Facebook MySQL gurus
Facebook, the undisputed king of online social networks, has 1.23 billion monthly active users collectively contributing to an ocean of data-intensive tasks – making the company one of the world’s top...
View ArticleParallel Query for MySQL with Shard-Query
While Shard-Query can work over multiple nodes, this blog post focuses on using Shard-Query with a single node. Shard-Query can add parallelism to queries which use partitioned tables. Very large...
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How to identify and cure MySQL replication slave lag
Here on the Percona MySQL Support team, we often see issues where a customer is complaining about replication delays – and many times the problem ends up being tied to MySQL replication slave lag. This...
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