MySQL is not a strictly typed database. Given that and the different character types some tricky situation might arise. Especially when it comes to trailing spaces. Since this caused some head scratching hours to a colleague of mine I thought it’s worth a bit more explanation.
To understand the problem first … Continue reading
Recordsize on data volume
This is the first thing you read when it comes to running MySQL on ZFS. InnoDB is using 16k pages so in theory this makes absolute sense. But as in many situation reality beats theory. We had a competing hypothesis about the optimal recordsize so we setup a … Continue reading
A long time ago I was writing about a very simple technic which can be used to quickly provide auto-suggest for websites with the support of Solr: Incredibly fast Solr autosuggest . This was using the terms function of Solr which enables us to search for terms, surprisingly.
This solution … Continue reading
I ran into an issue while trying to setup a simple test system for myself to move from CentOS 6 to 7. When I was about to start a standby slave systemd reported PostgreSQL startup timeout and stopped it. Although it was running perfectly fine doing recovery.
In var … Continue reading
Redis list is great to use it as a processing queue. So great that it sort of became the standard and many people using that instead of dedicated queues such as ZeroMQ or RabbitMQ because it also gives further features that are useful. It’s main idea is to provide programming … Continue reading
There are a lot of python driver available for MySQL and two stand out the most. The one, traditionally everybody’s choice, sort of industrial standard MySQLdb. It uses a C module to link to MySQL’s client library. Oracle’s mysql-connector on the other hand is pure python so no MySQL libraries and … Continue reading
I’ve read a lot of discussions lately around different versions of experimenting/testing. People are seemed to be very religious about the subject and two cardinal questions are separating the groups. Frequentist vs. Bayesian approach and AB testing vs. Multi-armed bandit solutions. Right now I’m mostly interested in the second problem … Continue reading
Managing servers is a tedious work we all have to do to some extent. But it doesn’t have to fill our whole day. What if I tell you that you can build a self-managing system with some discipline and effort? I went through implementing a self-managing database infrastructure of thousands of … Continue reading
In web applications it’s very common to try to limit the results by group. For example showing all the new posts with the the two latest comments on them. Or have the best selling categories in an e-commerce website showing the 3 most popular products in those categories.
In MySQL … Continue reading
I have a database migrated from MySQL to PostgreSQL (I had my good reasons but this post is not about that). In MySQL because of MVCC behaviour it makes sense and it’s actually a recommendation to split frequently updated columns from large tables especially if using a web framework like Django … Continue reading