November 28, 2014

Virident vCache vs. FlashCache: Part 2

This is the second part in a two-part series comparing Virident’s vCache to FlashCache. The first part was focused on usability and feature comparison; in this post, we’ll look at some sysbench test results. Disclosure: The research and testing conducted for this post were sponsored by Virident. First, some background information. All tests were conducted […]

When the subselect runs faster

A few weeks ago, we had a query optimization request from one of our customer. The query was very simple like:

This column in the table is looks like this:

The table have 549252 rows and of course, there is an index on the col1. MySQL estimated the cardinality of that index as […]

MySQL: what read_buffer_size value is optimal ?

The more I work with MySQL Performance Optimization and Optimization for other applications the better I understand I have to less believe in common sense or common sense of documentation writers and do more benchmarks and performance research. I just recently wrote about rather surprising results with sort performance and today I’ve discovered even read_buffer_size […]

What MySQL buffer cache hit rate should you target

“What cache hit rate is good for optimal MySQL Performance” is typical question I’m asked. It could by MyISAM key_buffer or Innodb innodb_buffer_pool it does not really matter. In both cases trying to come up with constant “good” hit rate is looking for trouble. Well of course you can name 100% hit rate and all […]

Reference architecture for a write-intensive MySQL deployment

We designed Percona Cloud Tools (both hardware and software setup) to handle a very high-intensive MySQL write workload. For example, we already observe inserts of 1bln+ datapoints per day. So I wanted to share what kind of hardware we use to achieve this result. Let me describe what we use, and later I will explain […]

ScaleArc: Benchmarking with sysbench

ScaleArc recently hired Percona to perform various tests on its database traffic management product. This post is the outcome of the benchmarks carried out by Uday Sawant (ScaleArc) and myself. You can also download the report directly as a PDF here. The goal of these benchmarks is to identify the potential overhead of the ScaleArc […]

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 […]

Missing Data – rows used to generate result set

As Baron writes it is not the number of rows returned by the query but number of rows accessed by the query will most likely be defining query performance. Of course not all row accessed are created equal (such as full table scan row accesses may be much faster than random index lookups row accesses […]

Heikki Tuuri Innodb answers – Part I

Its almost a month since I promised Heikki Tuuri to answer Innodb Questions. Heikki is a busy man so I got answers to only some of the questions but as people still poking me about this I decided to publish the answers I have so far. Plus we may get some interesting follow up questions […]

Using CHAR keys for joins, how much is the overhead ?

I prefer to use Integers for joins whenever possible and today I worked with client which used character keys, in my opinion without a big need. I told them this is suboptimal but was challenged with rightful question about the difference. I did not know so I decided to benchmark. The results below are for […]