July 29, 2014

What’s a good buffer pool read/write ratio?

At Percona Live last week, someone showed me a graph from their Cacti monitoring system, using the templates that I wrote. It was the buffer pool pages read, written, and created. He asked me if the graph was okay. Shouldn’t there be a lot more pages read than written, he asked? It’s a great question. […]

Should we give a MySQL Query Cache a second chance ?

Over last few years I’ve been suggesting more people to disable Query Cache than to enable it. It can cause contention problems as well as stalls and due to coarse invalidation is not as efficient as it could be. These are however mostly due to neglect Query Cache received over almost 10 years, with very […]

Choosing an appropriate benchmark length

The duration of a benchmark is an important factor that helps determine how meaningful it is. Most systems have some “burstable capacity,” and this can influence the results a lot. You can see this in all areas of life — you can sprint much faster than you can run a 10k race. Your stereo system […]

Is VoltDB really as scalable as they claim?

Before I begin, a disclaimer. VoltDB is not a customer, and did not pay Percona or me to investigate VoltDB’s scalability or publish this blog post. More disclaimers at the end. Short version: VoltDB is very scalable; it should scale to 120 partitions, 39 servers, and 1.6 million complex transactions per second at over 300 […]

Data mart or data warehouse?

This is part two in my six part series on business intelligence, with a focus on OLAP analysis. Part 1 – Intro to OLAP Identifying the differences between a data warehouse and a data mart. (this post) Introduction to MDX and the kind of SQL which a ROLAP tool must generate to answer those queries. […]

Intro to OLAP

This is the first of a series of posts about business intelligence tools, particularly OLAP (or online analytical processing) tools using MySQL and other free open source software. OLAP tools are a part of the larger topic of business intelligence, a topic that has not had a lot of coverage on MPB. Because of this, […]

Why you should ignore MySQL’s key cache hit ratio

I have not caused a fist fight in a while, so it’s time to take off the gloves. I claim that somewhere around of 99% of advice about tuning MySQL’s key cache hit ratio is wrong, even when you hear it from experts. There are two major problems with the key buffer hit ratio, and […]

MySQL-Memcached or NOSQL Tokyo Tyrant – part 1

All to often people force themselves into using a database like MySQL with no thought into whether if its the best solution to there problem. Why?  Because their other applications use it, so why not the new application?  Over the past couple of months I have been doing a ton of work for clients who […]

High-Performance Click Analysis with MySQL

We have a lot of customers who do click analysis, site analytics, search engine marketing, online advertising, user behavior analysis, and many similar types of work.  The first thing these have in common is that they’re generally some kind of loggable event. The next characteristic of a lot of these systems (real or planned) is […]

MySQL for Hosting Providers – how do they manage ?

Working with number of hosting providers I always wonder how do they manage to keep things up given MySQL gives you so little ways to really restrict how much resources single user can consume. I have written over a year ago about 10+ ways to crash or overload MySQL and since that people have come […]