I showed in an earlier post how to drop a whole database in a very safe way (no replication lag at all) and that technique is usable to drop a single table too, but cleaning up a table can take hours if not days to finish, so this is not the most comfortable way to do that. We also don’t want to have even a small spike of replication lag, so we need to find an another solution.

How to remove database in a safe way
When you have to drop a large database, you’ll encounter some problems, mainly replication…
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What happens when you issue a DROP TABLE command? The table has to be removed from the table dictionary – which is a fast, atomic operation – and has to be removed from file system too. If you use older version than 5.5.10 you have to calculate with a huge amount of time if your buffer pool is big, because the server will scan through the pages there, checking if anything is in memory from that …

Last month I wrote a blog about the closing of MongoDB ticket SERVER-1240, which brings Collection Level Locking (CLL) to the MMAPV1 storage engine in MongoDB 2.8. In MongoDB 2.6 there is a writer lock at the database level, so each database only allows one writer at a time. In concurrent write workloads, this means that all writers essentially form a single line and do their writes one at a time. In MongoDB 2.8 this lock has been moved to the collection level. Better yet is document level locking, but even though this feature was shown at MongoDB World 2014 it's not going to ship. But it did make for one amazing demo by …

MySQL 5.5.41 was recently released (it is the latest MySQL 5.5, is GA), and is available for download here:

http://dev.mysql.com/downloads/mysql/5.5.html

< Forgive me for the flurry of my latest release "Overview and Highlights" that will follow, as I had a serious-at-the-time health issue that delayed me for about a month. Back on track now though. :) >

This release, similar to the last 5.5 release, is mostly uneventful.

There was only 1 “Functionality Added or Changed” bugs this time, and 14 bugs overall fixed.

Out of the 14 bugs, there were 6 InnoDB bugs, and 2 replication bugs, all of which seemed rather minor or obscure. The one worth noting is the “Functionality Added or Changed” item, which was:

• yaSSL was upgraded to version 2.3.5. (Bug #19695101)

With the recent yaSSL issues, …

Tue, 2015-01-13 10:59vilho_raatikka_l

Applications are often built on top of single MySQL-compliant database instance but often there is a need for more performance and/or availability than what one database instance can provide. Adding slaves or replacing standalone database server with full-fledged MySQL-compliant cluster often requires changes to the application.

MaxScale and its Read Write Split router (rwsplit, for short) attempts to hide the complexity brought by multiple backend servers and to minimize the need for application changes by taking care of authentication, managing connections and providing session management on behalf of the client.

Read Write Split router is a plug-in module, which can be used with MaxScale to receive, examine and forward queries sent by clients. Routing decision is based on query type and some other criteria, such as transaction state, and replication lag. For rwsplit, every cluster …

MySQL 5.6 has an extensive list of new features and changes, so upgrading from a previous version can be risky if not tested extensively. For this reason, we recommend our users to read and understand the changes before doing the upgrade. If you are on older MySQL versions, it is probably time to think about upgrading. MySQL 5.6 was released in February 2013, that’s almost two years ago!

A major upgrade, e.g., from MySQL 5.5 to 5.6 or MariaDB 5.5 to 10, requires the former MySQL/MariaDB server related packages to be uninstalled. In Galera Cluster, there are two ways to upgrade; either by performing offline upgrade (safer, simpler, requires service downtime) or online upgrade (more complex, no downtime). 

In this blog post, we are going to show you how to perform an offline upgrade on Galera-based …

There will be a MySQL & Friends Devroom at the FOSDEM 2015 this year.And surprisingly my talk - not sure you can call 15 min a talk  - had been accepted. (There are other accepted talks of course.) 
It will be a dense talk about Docker/MySQL/Galera :)
We are (at least me) are going to have fun \o/ Erkan
I hope there will be an official announcement too.  

Fri, 2015-01-09 13:19maria-luisaraviol

MariaDB MaxScale is now RC and together with all the MariaDB team that has been involved in the project we need to thank all the companies that agreed to become part of the MaxScale Beta Test Plan. This major step in the MaxScale life (read more here) had an important impact on the MaxScale QA process.

We have asked some companies to help us in testing MaxScale in “real” environments with different custom settings, different configurations and with traffic load as close to reality as possible.

Colt Engine, an Italian hosting company based in Turin (Italy) applied immediately. They have been a great fan of MariaDB MaxScale and have been enthusiastic early testers of MaxScale since early 2014 when it still was Alpha. Actually they have suggested some of the MaxScale filter plugins.

I started …

Covering Indexes not being chosen by optimizer I noticed this problem about a year ago when writing this blogpost. In short problem is when adding a covering index and keeping old non-covering index the optimizer opted to use old non-covering index. Only solution was to FORCE optimizer to use covering index which meant you needed to modify your DML or remove old index.
Using the same test setup as in my old blogpost but when you add new covering index do not drop the old index.
So, instead of running: mysql> ALTER TABLE big DROP INDEX CountryCode;
mysql> ALTER TABLE big ADD INDEX conPop (CountryCode, Population);
We run only statement for adding new covering index and do not remove old index: …

Join 29,000 others and follow Sean Hull on twitter @hullsean. Oh RDS, you offer such promise, but damn it if the devil isn’t always buried in the details. Diving into a recent project, I’ve been looking at upgrading RDS MySQL. Major MySQL upgrades can be a bit messy. Since the entire engine is rebuilt, queries […]

"Should vegetarians open steakhouse restaurants?"

Though someone will probably give me several examples of why they should, I'll argue that they absolutely should not. How can someone who doesn't eat steak convince others to eat at their "steak-only" restaurant?

But this is something a "professional technology benchmarker" (PTB) struggles with on a regular basis. Hello, I'm Tim Callaghan, and I'm a PTB.
professional technology benchmarker, or PTB (noun) : One who compares two technologies as part of their job. One of these technologies is usually the product of the PTB's employer, the other is almost always not. In a past experience I was tasked with comparing the performance of a fully in-memory database with Oracle and MySQL on a "TPC-C like" workload. At the time I was an Oracle expert and working for the in-memory database company, but had never started a single MySQL server in my life. At …