Month: November 2018
Transactions in PostgreSQL: READ COMMITTED vs. REPEATABLE READ
The ability to run transactions is the core of every modern relational database system. The idea behind a transaction is to allow users to control the way data is written to PostgreSQL. However, a transaction is not only about writing – it is also important to understand the implications on reading data for whatever purpose […]
PostgreSQL: Implicit vs. explicit joins
If you happen to be an SQL developer, you will know that joins are really at the core of the language. Joins come in various flavors: Inner joins, left joins, full joins, natural joins, self joins, semi-joins, lateral joins, and so on. However, one of the most important distinctions is the difference between implicit and […]
Machine Learning in PostgreSQL Part 1: Kmeans clustering
By Hernan Resnizky – Machine Learning without leaving the Database – Kmeans Every company has the opportunity to improve its decision-making process with minimal effort through the use of machine learning. However, the drawback is that for most of the DBMS, you will need to perform your Machine Learning processes outside the database. This is […]
Killed index tuples
Since I only recently learned about the concept of “killed index tuples”, I thought there might be some others who are not yet familiar with this interesting PostgreSQL concept. This may give you an explanation the next time you encounter wildly varying execution times for the same execution plan of the same PostgreSQL query. […]