severalnines.com severalnines.com

A Guide to MySQL Indexes

When MySQL query optimization is mentioned, indexes are one of the first things that get covered. Today, we will try to see why they are so important. What are Indexes? In general, an index is an alphabetical list of records with references to the pages on which they are mentioned. In MySQL, an index is a data structure used to quickly find rows. Indexes are also called keys and those keys are critical for good performance - as the...

severalnines.com severalnines.com

How to Prevent Rollbacks in MongoDB

Replication in MongoDB involves replica sets by members with an architecture of a primary and secondary members but at times with a non data bearing member called an arbiter. The replication process is that, whenever the data has been written to the primary node, the changes are recorded on an oplog file from which the secondary members apply the same changes. Read operations can be made from any data bearing member hence creating a...

severalnines.com severalnines.com

An Overview of Trusted Extensions in PostgreSQL 13

In my previous blog, we explored new capabilities of Logical replication with Partition tables in PostgreSQL 13. Needless to say that there are multitude of such features in the mentioned release which will soon enhance experience for DBA and application developers alike. While looking at PostgreSQL 13, I observed an entry which caught my attention: PostgreSQL 13 introduces the concept of a "trusted extension", which allows...