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MySQL Feed

Oracle MySQL resources, news, and support articles.

What are MySQL’s deleted temp files?

If you’ve ever looked at the lsof or listing of /proc/$pid/fd for a running MySQL server, you’ve probably seen files like these:

Intel SSD 910 vs HDD RAID in tpcc-mysql benchmark

I continue my benchmarks of Intel SSD 910, previous time I compared it with Fusion-io ioDrive Now I want to test this card against RAID over spinning disks.

How to find MySQL queries worth optimizing ?

One question I often get is how one can find out queries which should be optimized. By looking at pt-query-digest report it is easy to find slow queries or queries which cause the large portion of the load on the system but how do we know whenever there is any possibility to make this query run better ? The full answer to this question will indeed require complex analyses as there are many possible ways query can be optimized. There is however one extremely helpful metric which you can use – ratio between rows sent and rows analyzed. Lets look at this example:

PyTexas 2012

PyTexas 2012 will be held in College Station this weekend. I will be speaking on MySQL Update — MySQL 5.6, Cluster 7.3, and Beyond and Seven Database Tricks.

I always trip on level ground

On the lighter side: I’ve always had trouble with mysqldump’s expected syntax. You know, as the author of a book and all that, you might think I can get this to work. But pretty much every time I run this tool, it humiliates me. Witness:

$ mysqldump --host localhost --password secr3t --all-databases
Usage: mysqldump [OPTIONS] database [tables]
OR     mysqldump [OPTIONS] --databases [OPTIONS] DB1 [DB2 DB3...]
OR     mysqldump [OPTIONS] --all-databases [OPTIONS]
For more options, use mysqldump --help


My speaking engagements - Q4 2012

After a long pause in the speaking game, I am back.

It's since April that I haven't been on stage, and it is now time to resume my public duties.

New strength for Continuent

It is public news now that Continuent has three new hires. I am particularly pleased with the news, as we are improving the team in three different directions:

  • Services and management, with Ronald Bradford, with whom we have crossed paths several times, first in the MySQL community activities, then as colleagues at MySQL AB, and again in community cyberspace.

Joining the Continuent Team

This month I have joined the team at Continuent. No stranger to the MySQL ecosystem, Continuent provides replication and clustering technology for managing data between MySQL, Oracle, PostgreSQL, Vertica and a growing list of data stores.

How to lag a slave behind to avoid a disaster

MySQL Replication is useful and easy to setup. It is used for very different purposes. For example:

  • split read and writes
  • run data mining or reporting processes on them
  • disaster recovery

Is important to mention that a replication server is not a backup by itself. A mistake on the master, for example a DROP DATABASE or an UPDATE without a WHERE clause will be replicated nearly instantly to all slave servers and just having a slave is not going to be helpful here. How can we avoid that kind of mistakes? Having a slave server lagging behind.

How common_schema installs itself

Up till common_schema version 1.1, the user would need to choose from distinct distribution files: an install compatible with MySQL 5.1, one compatible with InnoDB Plugin enabled servers, and one compatible with Percona Server. The difference between the three is the availability of certain INFORMATION_SCHEMA tables.

With 1.1, this is no longer the case: common_schema auto-detects the server and available feature set, and installs accordingly.

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