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, where more standby nodes are involved.
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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 […]
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 […]
Last week I was pleased to attend Code Sprint 2016 in Paris, organised by the OSGeo Foundation: it has been an opportunity for many GIS users from all over the world to get together, discuss and actively work on many open tasks of some of the major open source frameworks on GIS. PostGIS was obviously […]
A few weeks ago I asked one of my colleagues why I should learn PostgreSQL. Harald’s answer was: “To start any new journey of learning, asking ‘why’ is an excellent question. It gives us both a direction to send us on our way and an expected destination. Without a clear path to follow, our brains […]
PostgreSQL 9.4 extends the SQL standard by inserting two new clauses that facilitate many operations required during the development of applications: the WITHIN GROUP and FILTER clauses.
The introduction of the JSONB data type in PostgreSQL, definitely makes the “NoSQL” side of this relational DBMS come out: this introduction meets the requirements of all those who prefer a data structure in a “key-value” array, dictionary style (widely used in the field of development) and, at the same time, ensures all the advantages […]
Written by Giuseppe Broccolo Since PostgreSQL 9.3, it is possible to update and insert into views directly, so long as the view refers to only one underlying table. PostgreSQL 9.4 allows us to use the CHECK clause for INSERTs into updatable views. For example, consider a table composed of just one integer column; and […]
Written by Francesco Canovai In the previous instalment, we introduced the logical replication feature which has been added to PostgreSQL 9.4. Let’s go on exploring the multitude of new features that version 9.4 brings to the Operation field, easing the management of PostgreSQL databases for system and database administrators. pg_prewarm pg_prewarm is a new extension to […]
Version 9.4 of PostgreSQL, soon to be released, has many innovations for administrators, including the introduction of support for logical replication, which is the first step towards the integration of multi-master replication into core PostgreSQL. In this two-part article we will show you the main new features for administrators; we begin with […]