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Citus Blog

Articles tagged: deep dive

Joe Nelson

Faster PostgreSQL Counting

Written byBy Joe Nelson | October 12, 2016Oct 12, 2016

Everybody counts, but not always quickly. This article is a close look into how PostgreSQL optimizes counting. If you know the tricks there are ways to count rows orders of magnitude faster than you do already.

The problem is actually underdescribed...

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Eren Basak

How Distributed Outer Joins on PostgreSQL with Citus Work

Written byBy Eren Basak | October 10, 2016Oct 10, 2016

SQL is a very powerful language for analyzing and reporting against data. At the core of SQL is the idea of joins and how you combine various tables together. One such type of join: outer joins are useful when we need to retain rows, even if it has no match on the other side.

And while the most common type of join, inner join, against tables A and B would bring only the tuples that have a match for both A and B, outer joins give us the ability to bring together from say all of table A even if they don’t have a corresponding match in table B. For example, let’s say you keep customers in one table and purchases in another table. When you want to see all purchases of customers, you may want to see all customers in the result even if they did not do any purchases yet. Then, you need an outer join. Within this post we’ll analyze a bit on what outer joins are, and then how we support them in a distributed fashion on Citus.

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It may surprise you that pagination, pervasive as it is in web applications, is easy to implement inefficiently. In this article we’ll examine several methods of server-side pagination and discuss their tradeoffs when implemented in PostgreSQL. This article will help you identify which technique is appropriate for your situation, including some you may not have seen before which rely on physical clustering and the database stats collector.

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Metin Doslu

Linux memory manager and your big data

Written byBy Metin Doslu | November 23, 2013Nov 23, 2013

Disclaimer: We always assume that when we have an issue and think it’s the operating system, 99% of the time, it turns out to be something else. We therefore caution against assuming that the problem is with your operating system, unless your use-case...

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