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Displaying posts with tag: mariadb (reset)
MySQL removes the FRM (7 years after Drizzle did)

The new MySQL 8.0.0 milestone release that was recently announced brings something that has been a looooong time coming: the removal of the FRM file. I was the one who implemented this in Drizzle way back in 2009 (July 28th 2009 according to Brian)- and I may have had a flashback to removing the tentacles of the FRM when reading the MySQL 8.0.0 announcement.

As an idea for how long this has been on the cards, I’ll quote Brian from when we removed it in Drizzle:

We have been talking about getting rid of FRM since around 2003. I remember a drive up to northern Finland with Kaj Arnö, where we spent an hour …

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Common Table Expressions in MySQL

In a recent labs release a new feature was introduced by Oracle, or actually two very related new features were introduced. The first new feature is Common Table Expressions (CTEs), which is also known as WITH. The second feature is recursive CTEs, also known as WITH RECURSIVE.

An example of WITH:

WITH non_root_users AS (SELECT User, Host FROM mysql.user WHERE User<>'root')
SELECT Host FROM non_root_users WHERE User = ?

The non-CTE equivalent is this:

SELECT Host FROM 
(SELECT User, Host FROM mysql.user WHERE User<>'root') non_root_users
WHERE User = ?

This makes it easier to understand the query, especially if there are many subqueries.

Besides using regular subqueries or CTEs you could also put the subquery in a view, but this requires more …

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Replication from MySQL 5.6 to MariaDB 10 may fail when using fractional seconds

One of the most interesting features  introduced in MariaDB 10 was without doubt multi source replication, or the ability for a slave to have multiple masters.

Tired of hearing complaints from developers who couldn't join tables because they were on different servers, I decided to give MariaDB a try to see if I could leverage this neat feature.
At the time, we had 5 main clusters, classic multi-master active/standby configuration, with some slaves under each of them. I wanted to create a "super slave" that would contain the dataset from all the five clusters, so that developers could connect to it and join at will.
The initial creation of the MariaDB superslave was easy. After installing the binaries, I just bootstrapped it with an xtrabackup copy of our main cluster and set up replication. All went just fine as expected.
Suddendly I realized that I couldn't use xtrabackup to bring the datasets from other …

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Lesson 124 in why scales on a graph matter…

The original article presented two graphs: one of MariaDB searches (which are increasing) and the other showing MySQL searches (decreasing or leveling out). It turns out that the y axis REALLY matters.

I honestly expected better….

@mariadb that Trends graph is misleading. Steady over 12months, flattening from peak 12+y ago, well before MariaDB. pic.twitter.com/sP6H65FEvR

— Stewart Smith (@stewartsmith) September 22, 2016

Try “Will @mariadb ever replace @postgresql “. At current rate, equal on Google Trends in 12-20 years if no pg growth. …

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Replication from Oracle to MariaDB - Part 3

This is the third part of a series of blogs on how to do Change Data Capture from Oracle in an effort to be able to replicate that data to MariaDB. Part 1 dealt with some basics on the Oracle side of things regarding the Oracle redo log which we use as a source for out CDC efforts and Part 2 was about how to get this to work. We left part2 with an example of how to Replicate INSERTs from Oracle to MariaDB, but that is hardly good enough, we also have to deal with UPDATE and DELETE to make it at least somewhat complete, and this is what we will have a look at in this post.

And I know what you are asking your selves now, you spent all that …

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Replication from Oracle to MariaDB - Part 2

In part 1 on this series of blogs on how to replcate from Oracle to MariaDB, we looked at how to get data out from Oracle, and in an effort to look more modern than I really am, let's say that what we were attempting was CDC (Change Data Capture). Hey, I feel like I'm 18 again! Modern, cool! Maybe I should start to wear a baseball cap backwards and have my jeans no higher than my knees. Or again, maybe not. But CDC it is.

When I left you in the previous post we have just started to get some data. reluctantly, out of Oracle. But the SQL statement we got from the LogMiner was hardly useful. But fact is, we can fix that. Before we do that we need to look at a few other functions in LogMiner. The two functions we want to loot at are called …

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Replication from Oracle to MariaDB - Part 1

If you have read my blog before, you know that I have shown a couple of ways of getting data from an Oracle database and into something more approachable, such as a text-file or even, surprise, MariaDB (or MySQL for that matter). Not that the Oracle database really likes you doing this and some tweaking is necessary. One way I have shown before to do this is by using triggers, a UDF, UPD-communication and a simple server, this was a series of blogposts starting with this one: Replication from Oracle to MariaDB the simple way. Another means is to exports data from Oracle in some text format, something Oracle really doesn't like you do it, it really likes to keep the data to itself, but yours …

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Please register to the Percona Live Amsterdam Community Dinner 2016

Percona Live Amsterdam is in 3 weeks, and on the evening of the second day of the conference (Tuesday October 4th 2016), there is the traditional Community Dinner.

As last year, Booking.com is hosting the event and as last year, canal boats will bring attendees from the conference venue to Booking.com headquarters.

This event involves some planning: Percona needs to arrange for canal boats and

Speaking in September 2016

A few events, but mostly circling around London:

  • Open collaboration – an O’Reilly Online Conference, at 10am PT, Tuesday September 13 2016 – I’m going to be giving a new talk titled Forking Successfully. I’ve seen how the platform works, and I’m looking forward to trying this method out (its like a webminar but not quite!)
  • September MySQL London Meetup – I’m going to focus on MySQL, a branch, Percona Server and the fork MariaDB Server. This will be interesting because one of the reasons you don’t see a huge Emacs/XEmacs push after about 20 years? Feature parity. And the work that’s going into MySQL 8.0 is mighty interesting.
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Fun with Bugs #45 - On Some Bugs Fixed in MySQL 5.7.15

Oracle released MySQL 5.7.15 recently, earlier than expected. The reason for this "unexpected" release is not clear to me, but it could happen because of a couple of security related internal bug reports that got fixed:

  • "It was possible to write log files ending with .ini or .cnf that later could be parsed as option files. The general query log and slow query log can no longer be written to a file ending with .ini or .cnf. (Bug #24388753)
  • Privilege escalation was possible by exploiting the way REPAIR TABLE used temporary files. (Bug #24388746)"

Let me concentrate on the most important fixes to bugs and problems reported by Community users. …

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