Posts Tagged "replication"

When autovacuum does not vacuum

A few weeks ago I explained basics of autovacuum tuning. At the end of that post I promised to look into problems with vacuuming soon. Well, it took a bit longer than I planned, but here we go. To quickly recap, autovacuum is a background process cleaning up dead rows, e.g. old deleted row versions….

repmgr 3.3

repmgr 3.3 introduces a number of additional options for setting up and managing replication clusters, with particular emphasis on cascading replication support. These changes will also make it easier to set up complex clusters using provisioning scripts. Additionally there are changes to the repmgr command line utility’s logging behaviour which you should take into consideration…

pglogical 1.2 with PostgreSQL 9.6 support

PostgreSQL 9.6 is now out and so is an updated version of pglogical that works with it. For quick guide on how to upgrade the database with pglogical you can check my post which announced 9.6beta support. The main change besides the support for 9.6.x release of PostgreSQL is in the way we handle the…

Back to the Future Part 3: pg_rewind with PostgreSQL 9.6

This is the third and last part of blog articles dedicated to pg_rewind. In the two previous articles we have seen how pg_rewind is useful to fix split-brain events due to mistakes in the switchover procedures, avoiding the need of new base backups. We have also seen that this is true for simple replication clusters,…

repmgr 3.2 is here with Barman support and Brand New High Availability features

repmgr 3.2 has recently been released with a number of enhancements, particularly support for 2ndQuadrant’s Barman archive management server, additional cluster monitoring functionality and improvements to the standby cloning process. One aim of this release is to remove the requirement to set up passwordless SSH between servers, which means when using repmgr’s standard functionality to…

Back to the Future Pt. 2: How to use pg_rewind with PostgreSQL 9.5

In the previous blog article we have seen how pg_rewind works with a simple HA cluster, composed of a master node replicating to a standby. In this context, an eventual switchover involves just two nodes that have to be aligned. But what happens with HA clusters when there are several (also cascading) standbys? Now, consider…

BDR is coming to PostgreSQL 9.6

I’m pleased to say that Postgres-BDR is on its way to PostgreSQL 9.6, and even better, it works without a patched PostgreSQL. BDR has always been an extension, but on 9.4 it required a heavily patched PostgreSQL, one that isn’t fully on-disk-format compatible with stock community PostgreSQL 9.4. The goal all along has been to…

Back to the Future Pt. 1: Introduction to pg_rewind

Since PostgreSQL 9.5, pg_rewind has been able to make a former master follow up a promoted standby although, in the meantime, it proceeded with its own timeline. Consider, for instance, the case of a switchover that didn’t work properly. Have you ever experienced a “split brain” during a switchover operation? You know, when the goal…

Evolution of Fault Tolerance in PostgreSQL: Synchronous Commit

PostgreSQL is an awesome project and it evolves at an amazing rate. We’ll focus on evolution of fault tolerance capabilities in PostgreSQL throughout its versions with a series of blog posts. This is the fourth post of the series and we’ll talk about synchronous commit and its effects on fault tolerance and dependability of PostgreSQL….

Thoughts on Uber’s List of Postgres Limitations

An Uber technical blog of July 2016 described the perception of “many Postgres limitations”. Regrettably, a number of important technical points are either not correct or not wholly correct because they overlook many optimizations in PostgreSQL that were added specifically to address the cases discussed. In most cases, those limitations were actually true in the…

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