April 20, 2014

MySQL Query Patterns, Optimized – Webinar questions followup

On Friday I gave a presentation on “MySQL Query Patterns, Optimized” for Percona MySQL Webinars.  If you missed it, you can still register to view the recording and my slides. Thanks to everyone who attended, and especially to folks who asked the great questions.  I answered as many as we had time for  during the session, but here […]

Webinar: SQL Query Patterns, Optimized

Next Friday, May 31 at 10 a.m. Pacific, I’ll present Percona’s next webinar, “SQL Query Patterns, Optimized.” Based on my experiences solving tough SQL problems for Percona training and consulting, I’ll classify several common types of queries with which developers struggle. I’ll test several SQL solutions for each type of query objective, and show how […]

Is it query which needs to be optimized ?

Last few days I had a lot of a lot of questions at MySQL Performance Forum as well as from our customers regarding query optimization… which had one thing in common – It is not query which needed to be optimized. Way too frequently people design schema first and then think how the queries they […]

How can we bring query to the data?

Baron recently wrote about sending the query to the data looking at distributed systems like Cassandra. I want to take a look at more simple systems like MySQL and see how we’re doing in this space. It is obvious getting computations as closer to the data as possible is the most efficient as we will […]

How to obtain the “LES” (Last Executed Statement) from an Optimized Core Dump?

Ever ran into a situation where you saw “some important variable you really needed to know about=<optimized out>” while debugging?

What do we optimize with mk-query-digest ?

When we’re looking at mk-query-digest report we typically look at the Queries causing the most impact (sum of the query execution times) as well as queries having some longest samples. Why are we looking at these ? Queries with highest Impact are important because looking at these queries and optimizing them typically helps to improve […]

Feature Idea: Finding columns which query needs to access

In query examinations it is often interesting which columns query needs to access to provide result set as it gives you ideas if you can use covering indexes to speed things up or even cache some data by denormalizing tables. So far it has to be done manually – look at SELECT clause, WHERE clause, […]

How to find bugs in MySQL

Finding bugs in MySQL is not only fun, it’s also something I have been doing the last four years of my life. Whether you want to become the next Shane Bester (who is generally considered the most skilled MySQL bug hunter worldwide), or just want to prove you can outsmart some of the world’s best […]

percona-millipede – Sub-second replication monitor

I recently helped a client implement a custom replication delay monitor and wanted to share the experience and discuss some of the iterations and decisions that were made. percona-millipede was developed in conjunction with Vimeo with the following high-level goal in mind: implement a millisecond level replication delay monitor and graph the results.  Please visit […]

How 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). If rows_examined is by far larger than rows_sent, say 100 larger, then the query is a great candidate for optimization. Optimization could […]