14th September 2023: PostgreSQL 16 Released!

PoWA 2: Finding the Missing Index !

Posted on 2015-03-02 by Dalibo

Paris, March 2 2015

DALIBO is proud to present the second release of PoWA, the PostgreSQL Workload Analyzer.

Complete rewrite of the User Interface

The first major change is the new graphic design : we've rebuilt the web interface from scratch and placed it on a separate module called powa-web. It is now easier to move the PoWA interface out of the database server.

The new interface is based on the previous version and it adds many improvements, including:

  • More graphs
  • New types of graph : Bar / Pie Charts
  • New configuration view
  • New index suggestion widget
  • New physical resource consumption graphs
  • Better Global Query Chart
  • Breadcrumbs
  • Python 2.6, 2.7 and 3.4 compatibility
  • Better browser compatibility




Advanced Filesystem Stats

Second, the core-engine of PoWA is now a separate module too: it's called powa-archivist and we've extended it to archive any kind of internal stats. The main source of stats remains the pg_stat_statements extension but we've integrated 2 other extensions: pg_qualstats and pg_stat_kcache.

With pg_stat_kcache, PoWA is now able to gather statistics about the physical disk access and the CPU consumption of each PostgreSQL backend. This allows the DBA to get a glimpse of the OS-level cache hit ratio.



Missing Index Finder + Advanced WHERE Clause Analyzer

Third major improvement, with pg_qualstats PoWA is now collecting metrics about the operations in the WHERE clause of each query. With this data, you can know what are the most common values in your SQL statements and evaluate their "selectivity". And for columns with a very high selectivity and no index, PoWA will suggest index creation to speed up you queries.



Disruptive changes

It was a hard choice but if we want to implement ground-breaking features like the Missing Index Finder, we need to use the latest capacities of PostgreSQL and thus we decided to drop the compatibility with PostgreSQL 9.3.

Of course, we will continue to maintain PoWA v1.2 and you can continue to use it on your PostgreSQL 9.3 servers. In a nutshell, If you already use PoWA here's what you need to know:

  • If you're running PostgreSQL 9.4, we recommend that you switch to PoWA 2.0
  • If you're running PostgreSQL 9.3, you can either keep PoWA 1.2 or upgrade your PostgreSQL instance and switch to PoWA 2.0


Here's a detailed explanation on why we are Moving Fast and Breaking Things

Credits & Licence

DALIBO would like to thank all the developers who contributed to this release: Rodolphe Quiedeville, Hyunjun Kim, Grégoire Pineau, Ahmed Bessifi, exordium-frozen, Christopher Liu, menardorama and especially Ronan Dunklau and Julien Rouhaud for the hard work on the GUI.

POWA is an open project available under the PostgreSQL License. Any contribution to build a better tool is welcome. You just have to send your ideas, features requests or patches using the GitHub tools or directly to powa@dalibo.com

Links :

For PoWA 2.0:


For the new stats extensions:


For the complete list of changes, please checkout the release note on http://powa.readthedocs.org/en/latest/releases/v2.0.html

About POWA :

PoWA is a PostgreSQL Workload Analyzer that gathers performance stats and provides real-time charts and graph to help monitor and tune your PostgreSQL servers. It is similar to Oracle AWR or SQL Server MDW.

Code & Demo at http://dalibo.github.io/powa/

About DALIBO :

DALIBO is the leading PostgreSQL company in France, providing support, trainings and consulting to its customers since 2005. The company contributes to the PostgreSQL community in various ways, including : code, articles, translations, free conferences and workshops

Check out DALIBO's open source projects at http://dalibo.github.io