Graph databases are great. But if I read more FUD about RDBMSs, I’m going to have another flashback to the 80’s where someone is telling me about how you don’t want to dismantle your car every time you park it in the garage (OODBMS reference for the oldies).
I recently read a graph-database book that explained that every SQL join requires computing a cartesian product. And yesterday, a post that explained that equijoins have an exponential order of complexity. (I guess… if the exponent is 1.) It’s getting very frustrating to read through the inaccuracies and FUD, and now, to me, it is all just turning into

Which is why it was nice to see @guyharrison‘s even-handed and accurate treatment in his new book …

It was a long time since I updated mysqljsonimport or mysqljsonexport and I had a few things I wanted to do with them. This release is significant enough for me to bump it up to 2.0, and the same is in the works for mysqljsonexport. The one big thing that is now implemented is reasonably advanced support for MariaDB Dynamic Columns, and it is actually pretty flexible, allowing you to load a nested JSON object into a MariaDB Dynamic Column. But don't worry, it will still link and run with MySQL if that is what you want to do (but then you will not have the dynamic column features, for obvious reasons),

Download from Sourceforge as usual (yes, I know I am oldfashioned and that I should have put it on github). Also as usual is the documentation in pdf format that is also downloadable separately.

/Karlsson …

This article is the follow-up on discussion started around MySQL 5.7 results on OLTP_RW Benchmark.. -- the point was about the impact of PERFORMANCE_SCHEMA (PFS) enabled, and InnoDB checksums on MySQL 5.7 performance within this OLTP_RW workload.

As promised, here are the results:

Just in case if the legend naming in graphs is not obvious :

• PS-off : "performance_schema=off" was used
• PS-def : "performance_schema=on" was used (default PFS instrumentation)
• chksum0 : "innodb_checksums=0" was used
• chksum1 : "innodb_checksums=0, innodb_checksum_algorithm=crc32" was used

OLTP_RW 1M x8-tables MySQL 5.7 (config: trx_commit=2 double_write=0) :


OLTP_RW 1M x8-tables MySQL 5.7 …

MySQL has supported the GET_LOCK() function for a large part of its history. As the manual notes, GET_LOCK() can be used to implement application locks or to simulate record locks.

Changes in MySQL 5.7

In MySQL 5.7 we improved GET_LOCK() to be based on our internal meta-data locking system (MDL).…

This blog will address how the MariaDB Auditing Plugin can help monitor database activity to help with security, accountability and troubleshooting.

Why Audit Your Databases?

Auditing is an essential task for monitoring your database environment. By auditing your database, you can achieve accountability for actions taken or content accessed within your environment. You will also deter users (or others) from inappropriate actions.

If there is any bad behavior, you can investigate suspicious activity. For example, if a user is deleting data from tables, the admins could audit all connections to the database and all deletions of rows. You can also use auditing to notify admins when an unauthorized user manipulates or deletes data or that a user has more privileges than expected.

Auditing Plugins Available for MySQL

As Sergei Glushchenko said in a …

Saturday I was in my favorite grocery store, standing in the line, browsing the net on my phone. I read Vadim Tkachenko‘s blog post about Measuring Percona Server Docker CPU/network overhead and his findings were opposite than mine – he didn’t found any measurable difference. Reading his post, he did found huge impact in networking […]

I use Pingdom's free service to monitor slaptijack.com. Apparently, late Friday night, oom-killer decided that the server needed more memory and took out the MySQL server. To make matters worse, I missed the alarm from Pingdom, and slaptijack.com was down for pretty much all of Saturday. The fact that oom-killer was invoked is annoying, but more on that later.

The beauty of using Pelican rather than Wordpress (or any other database-driven content engine) is one less point of failure for the site. Obviously, I don't have all of slaptijack.com converted to Pelican yet (and perhaps never will), but at least parts of the site were up and working despite MySQL being down. If nothing else, this incident is enough to convince me that moving to Pelican was a good idea.

OOM'ed

…

Saturday I was in my favourite grocery store, standing in the line, browsing the net on my phone. I read Vadim Tkachenko‘s blog post about Measuring Percona Server Docker CPU/network overhead and his findings were the opposite than mine – he didn’t found any measurable difference. Reading his post, he did found huge impact in networking which I didn’t […]

VividCortex is all about optimizing your queries. Many of our users asked us to analyse their queries, searching for common errors and mistakes.

It's true that there are some excellent tools out there to perform the same tasks, such as pt-query-advisor from the great Percona Toolkit. But having this information available right in our web application is something we always wanted to do, too. And today we released that!

Today we added Query Analysis to our Profiler tool, so as of now, you will have less trouble finding your bad queries. Query Analysis analyzes queries with heuristics. It can find bad application patterns, SQL bugs, and all kinds of other obvious and subtle issues.

The notifications count in the Profiler now …

This will be another post on using Percona Server via a Docker image. I want to follow up on my previous post regarding CPU/Network overhead in Docker “Measuring Percona Server Docker CPU/network overhead” by measuring  if there is any docker IO overhead on operations.

After running several tests, it appears (spoiler alert) that there is no Docker IO overhead. I still think it is useful to understand the different ways Docker can be used with data volumes, however. Docker’s philosophy is to provide ephemeral containers, but ephemeral does not work well for data – we do not want our data to disappear.

So, the first pattern is to create data inside a docker container. This …