April 18, 2014

Running MySQL 5.6 on Amazon RDS: Webinar followup questions answered

Thanks to everyone who attended last week’s webinar, Running MySQL 5.6 on Amazon RDS.” If you weren’t able to attend, the recording and slides are available for viewing/download (or, if you were able to attend and just want to see it again). I’ve also answered the questions I didn’t have a chance to field during […]

MySQL and the SSB – Part 2 – MyISAM vs InnoDB low concurrency

This blog post is part two in what is now a continuing series on the Star Schema Benchmark. In my previous blog post I compared MySQL 5.5.30 to MySQL 5.6.10, both with default settings using only the InnoDB storage engine.  In my testing I discovered that innodb_old_blocks_time had an effect on performance of the benchmark.  There was […]

Finally. How to verify if all MySQL records were recovered

After nearly every recovery case the same question arises: How many MySQL records were recovered and how many were lost. Until now there was no way to answer the question without manual investigation. As it turned out a small change can make a big difference. There are two ways to know how many records an […]

Concatenating MyISAM files

Recently, I found myself involved in the migration of a large read-only InnoDB database to MyISAM (eventually packed). The only issue was that for one of the table, we were talking of 5 TB of data, 23B rows. Not small… I calculated that with something like insert into MyISAM_table… select * from Innodb_table… would take […]

Measuring the amount of writes in InnoDB redo logs

Choosing a good InnoDB log file size is key to InnoDB write performance. This can be done by measuring the amount of writes in the redo logs. You can find a detailed explanation in this post. To sum up, here are the main points: The redo logs should be large enough to store at most […]

Fishing with dynamite, brought to you by the randgen and dbqp

I tend to speak highly of the random query generator as a testing tool and thought I would share a story that shows how it can really shine. At our recent dev team meeting, we spent approximately 30 minutes of hack time to produce test cases for 3 rather hard to duplicate bugs. Of course, […]

Dynamic row format for MEMORY tables

The latest Percona Server release has one new feature: now MEMORY tables can have BLOB and TEXT columns, and VARCHAR columns will not waste space due to implicit extension to CHAR.

The two even more fundamental performance metrics

In a recent blog post, I wrote about four fundamental metrics for system performance analysis. These are throughput, residence time, “weighted time” (the sum of all residence times in the observation period — the terminology is mine for lack of a better name), and concurrency. I derived all of these metrics from two “even more […]

The four fundamental performance metrics

There are many ways to slice and aggregate metrics of activity on a system such as MySQL. In the best case, we want to know everything about the system’s activity: we want to know how many things happened, how big they were, and how long they took. We want to know precisely when they happened. […]

Intel Nehalem vs AMD Opteron shootout in sysbench workload

Having two big boxes in our lab, one based Intel Nehalem (Cisco UCS C250) and second on AMD Opteron (Dell PowerEdge R815), I decided to run some simple sysbench benchmark to compare how both CPUs perform and what kind of scalability we can expect.