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powa-team / powa

PostgreSQL Workload Analyzer
http://powa.readthedocs.io/
PostgreSQL License
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Document performance impact #11

Closed sciurus closed 9 years ago

sciurus commented 9 years ago

It would be nice to know the anticipated performance impact of enabling pg_stat_statements, and then the anticipated impact of enabling POWA on top of that.

marco44 commented 9 years ago

It's hard to tell precisely. For pg_stat_statements, there are a few benchmarks, such as http://pgsnaga.blogspot.fr/2011/10/performance-impact-of-pgstatstatements.html, which show there is an impact, but not that big. Nothing comparable to being in the dark and not knowing what is running on your database, and much lower than enablig log_statement_min_duration of course.

POWA should have a very low impact, but of course that depends on the frequency at which you collect data. If you do it every 5 seconds, you'll definitely see something. At 5 minutes, the impact should be minimal. We have enabled it on our productions servers, and It didn't change anything on the load.

Using the GUI, on the other side, has an obvious impact :)

sciurus commented 9 years ago

Thanks! I asked because this came up at https://news.ycombinator.com/item?id=8212072

daamien commented 9 years ago

I just included the Marc's comment in the README

https://github.com/dalibo/powa/blob/master/README.md#impact-on-performances

marco44 commented 9 years ago

mmm, assigned ? Isn't it solved ?

daamien commented 9 years ago

well we should publish somewhere the benchmark you did and provide a link to it in the README.

I'm sure you can't wait to write a blog post or a wiki page about it :-)

marco44 commented 9 years ago

You must be mistaking me with someone else. Blogging isn't a very important part of my life :)

daamien commented 9 years ago

Poor thing. How about that :

https://github.com/dalibo/powa/wiki/POWA-vs-pgBadger

https://github.com/dalibo/powa/commit/820593993994bbd3ae7f6bdb65f5f517eba693d6#diff-04c6e90faac2675aa89e2176d2eec7d8

I think you owe me a beer now :P