Re: Experimental evaluation of PostgreSQL's query optimizer

On 16 December 2015 at 09:51, Viktor Leis <leis(at)in(dot)tum(dot)de> wrote:

> Hi,
>
> We have recently performed an experimental evaluation of PostgreSQL's
> query optimizer. For example, we measured the contributions of
> cardinality estimation and the cost model on the overall query
> performance. You can download the resulting paper here:
> http://www.vldb.org/pvldb/vol9/p204-leis.pdf

Thank you, an excellent contribution.

> Some findings:
> 1. Perhaps unsurprisingly, we found that cardinality
> estimation is the biggest problem in query optimization.
> 2. The quality of Postgres' cardinality estimates is not generally worse
> than that of the major commerical systems.
>

Good to hear, though we have found problems there that alter plan selection
adversely for TPC-H with the current optimizer. We have some improvements
which may be in the next release.

--
Simon Riggs http://www.2ndQuadrant.com/
<http://www.2ndquadrant.com/>
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