Varchar vs Char in MySQL : understanding trailing spaces

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

Typeahead and autosuggest with pure Solr and Nginx

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

Postgresql server fails to start in recovery with systemd

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.

Issue

In var … Continue reading

Python MySQLdb vs mysql-connector query performance

Query times for random PK using MySQLdb and mysql-connector

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 ‚Ķ Continue reading

Multi variant AB testing vs Multi-Armed bandit

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 ‚Ķ Continue reading

5 steps to self-managing server infrastructure

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 ‚Ķ Continue reading