Horton

Re: Additional improvements to extended statistics

Tomas Vondra <tomas.vondra@2ndquadrant.com>

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From: Tomas Vondra <tomas.vondra@2ndquadrant.com>
To: pgsql-hackers@postgresql.org
Date: 2020-03-06T00:15:56Z
Lists: pgsql-hackers

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Hi,

Here is a rebased version of this patch series. I've polished the first
two parts a bit - estimation of OR clauses and (Var op Var) clauses, and
added a bunch of regression tests to exercise this code. It's not quite
there yet, but I think it's feasible to get this committed for PG13.

The last part (extended stats on expressions) is far from complete, and
it's not feasible to get it into PG13. There's too much missing stuff.

regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Commits

  1. Improve estimation of ANDs under ORs using extended statistics.

  2. Improve estimation of OR clauses using multiple extended statistics.

  3. Improve estimation of OR clauses using extended statistics.

  4. Prevent functional dependency estimates from exceeding column estimates.

  5. Fix wording of several extended stats comments

  6. Improve test coverage for multi-column MCV lists

  7. Improve test coverage for functional dependencies