The devroom’s schedule is now published on Fosdem’s website.
As you can see, it will be a heavy day full of good content. You can also notice that there won’t be any lunch-time break.
We advise you to then bring your lunch (like a sandwich) with you in the room and eat it between talks or prepare in advance when you will take your break during a talk you don’t want to attend (is it even possible ?).
| Event | Speakers | Start | End |
|---|---|---|---|
| Sunday | |||
| Welcome to MySQL & Friends Devroom | … |
This blog explains how relay log recovery happens in a scenario
where an applier thread (SQL_Thread) is starting for the first
time and its starting position is not available for relay log
recovery operations. If you are using GTIDs with MASTER_AUTO_POSITION then the
following is more or less irrelevant since we then employ a more
resilient repositioning scheme. The potential issue described
here will also not occur if you have employed crash-safe replication settings,
including --sync_master_info=1. With those
disclaimers out of the way, let’s proceed.
Background
A crash-safe slave in MySQL …
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Silly pun, we know. We couldn’t help ourselves.
A while ago I blogged about a potential workaround for MySQL error 1070 that could be used to add a unique constraint with more than 16 columns.
As a reminder here's the error you get when you try to create a unique constraint with more than 16 columns in MySQL:
ERROR 1070 (42000): Too many key parts specified; max 16
parts allowed
The solution I proposed should work, but when I started to implement it I made a couple of changes that merit this follow-up post. One change is fairly generic, and the other is specific to my use case.
The generic change was to only concatenate some of the columns, rather than all of them. Specifically I only need to concatenate N-15 columns. So if I want to have a unique constraint on 20 columns, I can include 15 of those actual columns and then …
[Read more]MySQL 5.6.22 was recently released (it is the latest MySQL 5.6, is GA), and is available for download here.
For this release, there is 1 “Security Note”, 2 “Functionality Changed”, and 5 “Compilation Notes”, all benign, but let me address them:
MariaDB 5.5.41 was recently released (it is the latest MariaDB 5.5), and is available for download here:
https://downloads.mariadb.org/mariadb/5.5.41/
This is a maintenance release, and so there were not too many changes, *but* please take notice as there are 2 very important bug fixes:
2014 was a productive year for the MariaDB Foundation.
Here is a list of some of the things MariaDB Foundation employees
have
accomplished during 2014:
The 3 full-time MariaDB Foundation developers have worked hard to
make MariaDB better:
Some of the main new features Foundation developers have worked
on in 2014 are:
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…
Read more
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 …
[Read more]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:
With the recent yaSSL issues, …
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