postgresql

While the active session history extension for PostgreSQL is still in beta, some information is added to it.

The pg_active_session_history view is currently made of:

Introduction

You may have noticed that a beta version of the pgsentinel extension (providing active session history for postgresql) is publicly available in this github repository.

We can rely on docker to facilitate and automate the testing of the extension on a particular postgreSQL version (has to be >= 10).

Let’s share a Dockerfile so that we can easly build a docker image for testing pgsentinel (on a postgreSQL version of our choice).

Description

The dockerfile used to provision a pgsentinel testing docker image:

By Franck Pachot

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In pgSentinel: the sampling approach for PostgreSQL I mentioned that one of the advantages of the ASH approach is the ability to drill down from an overview of the database activity, down to the details where we can do some tuning. The idea is to always focus on the components which are relevant to our tuning goal:

Publicly available

A quick one to let you know that the pgsentinel extension providing active session history sampling is now publicly available.

You can find more details on it into this previous blog post and also from some early beta testers:

By Franck Pachot

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Here is the first test I did with the beta of pgSentinel. This Active Session History sampling is a new approach to Postgres tuning. For people coming from Oracle, this is something that has made our life a lot easier to optimize database applications. Here is a quick example showing how it links together some information that are missing without this extension.

The installation of the extension is really easy (nore details on Daniel’s post):

cp pgsentinel.control /usr/pgsql-10/share/extension
cp pgsentinel--1.0.sql /usr/pgsql-10/share/extension
cp pgsentinel.so /usr/pgsql-10/lib


Why active session history?

What if you could record and query an history of the active sessions? Would not it be useful for performance tuning activities?

With active session history in place you could have a look to the “near” past database activity. You could answer questions like:

• What wait events type were taking most time?
• What wait events were taking most time?
• Which application name was taking most time?
• What was a session doing?
• What does a SQL statement wait for?
• How many sessions were running in CPU?
• Which database was taking most time?
• Which backend type was taking most time?
• On which wait event was the session waiting for?
• And so on….

How does it look like?

Let’s have a look to the pg_active_session_history view (more details on how to create it later on):

Since last October I’ve been periodically writing up summaries of interesting content I see on the internet related to PostgreSQL (generally blog posts). My original motivation was just to learn more about PostgreSQL – but I’ve started sharing them with a few colleagues and received positive feedback.  Thought I’d try posting one of these digests here on the Ardent blog – who knows, maybe a few old readers will find it interesting? Here’s the update that I put together last week – let me know what you think!

Hello from California!

Part of my team is here in Palo Alto and I’m visiting for a few days this week. You know… for all the remote work I’ve done over the years, I still really value this in-person, face-to-face time. These little trips from Seattle to other locations where my teammates physically sit are important to me.

Since last October I’ve been periodically writing up summaries of interesting content I see on the internet related to PostgreSQL (generally blog posts). My original motivation was just to learn more about PostgreSQL – but I’ve started sharing them with a few colleagues and received positive feedback.  Thought I’d try posting one of these digests here on the Ardent blog – who knows, maybe a few old readers will find it interesting? Here’s the update that I put together last week – let me know what you think!

Hello from California!

Part of my team is here in Palo Alto and I’m visiting for a few days this week. You know… for all the remote work I’ve done over the years, I still really value this in-person, face-to-face time. These little trips from Seattle to other locations where my teammates physically sit are important to me.

Since last October I’ve been periodically writing up summaries of interesting content I see on the internet related to PostgreSQL (generally blog posts). My original motivation was just to learn more about PostgreSQL – but I’ve started sharing them with a few colleagues and received positive feedback.  Thought I’d try posting one of these digests here on the Ardent blog – who knows, maybe a few old readers will find it interesting? Here’s the update that I put together last week – let me know what you think!

Hello from California!

Part of my team is here in Palo Alto and I’m visiting for a few days this week. You know… for all the remote work I’ve done over the years, I still really value this in-person, face-to-face time. These little trips from Seattle to other locations where my teammates physically sit are important to me.

You might want to replicate a PostgreSQL database thanks to DRBD. In this case you should measure the impact of your DRBD setup, especially if you plan to use DRBD in sync mode. As I am a lucky beta tester of pgio (the SLOB method for PostgreSQL), let’s use it to measure the impact.

DRBD configuration

The purpose of this post is not to explain how to set up DRBD. The DRBD configuration that will be used in this post is the following:

• Primary host: ubdrbd1
• Secondary host: ubdrbd2

Configuration: