Neues vom PostgreSQL Planet

OmniDB is an open-source, graphical database management tool developed by 2ndQuadrant, a world-leader in PostgreSQL technologies and services. OmniDB is a browser-based, universal client tool that can manage major database engines like PostgreSQL, MariaDB, MySQL, and Oracle. Other soon-to-be-supported engines include SQLite, Firebird, MS SQL Server, and IBM DB2. Like any excellent database client software, OmniDB […]

Overview

It has been a while since I have written about the new features in a major pgpool II release. Well pgpool II 4.2 is in the works and the plan is to release it towards the end of this year. As usual every major release of pgpool II is compatible with the parser of latest PG release so pgpool II 4.2 will be compatible with PG-13 parser. There are many nice features that will be part of next major release however the ones that particularly catches my attention is supporting LDAP authentication with pgpool II.

© Laurenz Albe 2020

There are three join strategies in PostgreSQL that work quite differently. If PostgreSQL chooses the wrong strategy, query performance can suffer a lot. This article explains the join strategies, how you can support them with indexes, what can go wrong with them and how you can tune your joins for better performance.

An important part of performing a migration from Oracle to PostgreSQL is selecting the right tool for helping with the conversion between systems. When people ask me how they can get the migration process started, I like to recommend a powerful open source utility called "ora2pg".

Before, during, and after the GDPR came into town in 2018, there have been many ideas to solve the problem of deleting or hiding user data, using various layers of the software stack but also using various approaches (hard deletion, soft deletion, anonymization). Anonymization has been one of them which is known to be popular among the PostgreSQL-based organizations/companies.

Active Record provides a great balance between the ability to perform simple queries simply, and also the ability to access the raw SQL sometimes required to get our jobs done. In this article, we will see a number of real-life examples of business needs that may arise at our jobs. They will come in the form of a request for data from someone else at the company, where we will first translate the request into SQL, and then into the Rails code necessary to find those records. We will be covering…

PostgreSQL has quite a few compelling advantages, some of which are not found in any other database management system. This article will outline the ones that are most interesting to the Oracle developer seeking to do a migration or investigate alternatives for new development. To prevent this article from becoming another list of PostgreSQL features, it […]

We’ve had a small flurry of customers asking about tuning their OS for the best PostgreSQL performance. While the answer to this question is always ‘that depends on your hardware and workload’ and involves a lot of iteration between changing a setting and benchmarking, I thought I’d take a moment to point out that once you do manage to dial-in the settings, you should be writing a profile and deploying to your systems for tuned to make use of. Please, for the love of $diety, stop editing sysctl.conf and friends!

With the advent of column store databases, there was an urge to make use of SIMD vector processing. It naturally fits into the way table data is arranged. Let's first briefly check what is SIMD. It stands for Single Instruction Multiple Data. Today, CPU instructions support this kind of mechanism where the same instruction can be executed simultaneously on multiple data elements. E.g. Say, you want to double all the column values. Or remove the red component of the RGB values of pixels of an image. For large data, these operations are CPU bottlenecks.

After my last post about ltree and recursive data in PostgreSQL people have asked me privately about performance issues. To share this information, I decided to come up with a follow up post to discuss this topic in a bit more detail. WITH RECURSIVE in PostgreSQL is efficient. However, ltree does have its strengths as well. Let us take a closer look …

Preparing sample data

In preparation for a test I have created a table which contains a balanced tree:

How can you force a table to have at most one row? It is actually very easy by creating a unique expression index on a constant, with no column name references:

PostgreSQL Person of the Week Interview with Simon Riggs: I live in the UK with my wife, and spend a lot of time with my extended family, though “kids” have now grown up and left home. Born a Londoner, so my favourite drink is Tea, but I’m partly Irish with a small hint of Chilean blood.

Finding relevant information quickly speeds up performance. For example, while reading a book in which you have to find a topic that you would like to read, if you know that it is in a certain chapter then you will simply go to that chapter, perhaps look through it and start reading the desired topic.

Last week, we examined Postgres XID wraparound complications in greater depth to see exactly how easily they can surprise even prepared enterprises. But we also found the real problem areas and how to mitigate them specifically. In this continuing series to plumb the depths of Postgres constructively, we’re going to focus on some of the […]

There are some very good responses in an email thread about whether to store binary data in Postgres or externally. The binary storage options discussed were:

1. Introduction

PostgreSQL backend is a collection of processes forked from the main process called Postmaster. Each forked process has different roles and responsibilities in the backend. This article describes the responsibility of core backend processes that power the PostgreSQL system as we know it today. The overall PostgreSQL backend architecture can be illustrated by the image below:

“If we had this data what would it mean?” – these kinds of questions can be answered using plain SQL. The technique you will need in PostgreSQL is a “hypothetical aggregate” which is of course part of the ANSI SQL standard. This post will show what an hypothetical aggregate is good for and how it works.

What happens if you try to drop a table that is referenced by another table?

ORA-2449 and the Constraint Dependencies

Oracle clients seems somehow a little goofy when you have to deal with dependencies.
Imagine you have two tables, a that references table b; you can generate the tables as follows:

My employer, EnterpriseDB, has been organizing events where potential customers and interested people can ask me questions while enjoying a meal. I thought the idea was strange, but I have done it ten times, and they have gone very well. The Q&A portion usually lasts one hour and forty-five minutes.