On 31 October 2012 19:44, Tom Lane <[email protected]> wrote: > Before 9.2, we didn't have this problem in this guise because we didn't > generate parameterized paths bottom-up; instead, given that we had > already decided to join t2 and t3 for some reason, we would look to see > what indexpaths we could make for t1 using values from t2 and/or t3. > However, that approach had big problems of its own: it couldn't find > plans that involved pushing parameters down through an intervening join.
Given that most joins patterns are repeated consistently across multiple SQL statements, is it possible to pre-calculate paths at ANALYZE time, or perhaps cache them (persistently?) when first generated? That way we just look up best paths, which would make join planning much faster. -- Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list ([email protected]) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
