On 16 December 2015 at 09:51, Viktor Leis <leis@in.tum.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.
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Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
