Emergency

Monthly Archives: July 2010

Why you can’t rely on a replica for disaster recovery

A couple of weeks ago one of my colleagues and I worked on a data corruption case that reminded me that sometimes people make unsafe assumptions without knowing it. This one involved SAN snapshotting that …

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Storing MySQL Binary logs on NFS Volume

There is a lot of discussions whenever running MySQL storing data on NFS is a good idea. There is a lot of things for and against this and this post is not about them. The …

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MariaDB and the MySQL Sandbox

Tokutek tests its TokuDB Fractal Tree storage engine with multiple MySQL distributions. We make extensive use of the MySQL Sandbox in our test automation. We tweaked the regular expressions that match binary tarball names in …

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Caching could be the last thing you want to do

I recently had a run-in with a very popular PHP ecommerce package which makes me want to voice a recurring mistake I see in how many web applications are architected. What is that mistake? The …

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On “Replace Into”, “Insert Ignore”, and Secondary Keys

In posts on June 30 and July 6, I explained how implementing the commands “replace into” and “insert ignore” with TokuDB’s fractal trees data structures can be two orders of magnitude faster than implementing them …

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Estimating Replication Capacity

It is easy for MySQL replication to become bottleneck when Master server is not seriously loaded and the more cores and hard drives the get the larger the difference becomes, as long as replication remains …

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SSD: Free space and write performance

( cross posting from SSD Performance Blog ) In previous post On Benchmarks on SSD, commenter touched another interesting point. Available free space affects write performance on SSD card significantly. The reason is still garbage …

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Analyzing the distribution of InnoDB log file writes

I recently did a quick analysis of the distribution of writes to InnoDB’s log files. On a high-traffic commodity MySQL server running Percona XtraDB for a gaming workload (mostly inserts to the “moves” table), I …

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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. …

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On Benchmarks on SSD

(cross post from SSD Performance Blog ) To get meaningful performance results on SSD storage is not easy task, let’s see why. There is graph from sysbench fileio random write benchmark with 4 threads. The …

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