MySQL

I won USD$100 and you can, too

Last week, I won USD$100*.  Gazzang is giving away $100 every Friday in October, in honor of National Cyber Security Awareness Month.  There are only 2 more weeks left — all you have to do is tweet @Gazzang_Inc one way to improve your own cyber security. My winning tweet: @Gazzang_Inc one way is to secure MySQL!…

Exporting the mysql.slow_log table into slow query log format

Using pt-query-digest is an excellent way to perform a SQL review. However, sometimes you don’t have access to the slow_query_log_file. For example, when MySQL runs on Amazon RDS, the slow_query_log_file is unavailable (see the RDS FAQ). To get around this, export the mysql.slow_log table. To export the data, run the following SQL command from an…

Percona Live:London, RightScale and Eucalyptus training discounts!

(Tune in tomorrow where I tell you how you can win USD$100, like I did last week!) Not signed up for Percona Live:London and need some motivation to do so?  How about a £40.00 discount?  That means the Expo Hall is free, regular registration is £260.00 and the tutorials + conference price is £500.00.  Use discount code “PDBUK”….

The Empty Error Log

The MySQL errorlog is an important point of reference when administering a MySQL Server. We can grasp much about the state of our MySQL instance by the informational and error messages written out to it by our MySQL daemon. I was asked to investigate some replication outage alerts a colleague had received overnight. One of the primary directions I took was the error log file. This is where I would expect find any evidence of replication being stopped or crashes etc. When I ran the command to tail the log I was shocked to see the log was totally empty.

Important Caveats When Using pt-online-schema-change

Using pt-online-schema-change is a great way to change a table without downtime or switching over to a secondary database first. While using it on production systems, we found some interesting issues to consider. 1) There were foreign_keys referencing the table we were altering. There are two options to handle this. They are specified with “–update-foreign-keys-method…

New replication features in MySQL 5.6

This post was thought of as an attempt to make some performance test with new multi-threaded replication in 5.6, at least that was my initial intention. Based on Luis Soarez – Replication Team Leader in Oracle – post. I wanted to play with new set of variables and features in order to understand how new multi-threaded replication works and make some performance tests.

The Magic of kSar for one-time system graphs

I forget from whom I first learned about kSar, but I am in debt to that person once again.  I first learned about it about a year ago, and it has been extremely useful whenever I am trying to debug system where I do not have access to trending graphs.  kSar is an open source…

PalominoDB at PerconaLive

PalominoDB is very excited about our participation in the upcoming PerconaLiveconference in London.  We’ll have two of our European staff presenting.  On Monday, Jonathan Levin will be doing a tutorial on Advanced MySQL Scaling Strategies for Developers, and on Tuesday Rene Cannao will be presenting on MySQL Backup and Recovery Tools and Techniques.  Rene and Jonathan…

Why are your indexes larger than your actual data?

I sometimes encounter this phenomenon when a database has tables in which the indexes are larger—sometimes much larger—than the actual data stored in the table. Often, the table becomes unwieldy, which generates a number of questions: Should I partition? Should I shard? Should I use a different database entirely?   The problem is especially common…

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