Andres Freund <and...@anarazel.de> writes: > This also explains why I saw nearly no improvement during the genetic search > itself. The paths out of random_init_pool were already hugely selected, so > there were not that many improvements to find and a change was relatively > like > to yield a impossible ordering.
Yeah, I suspect most of the variants tried during that phase simply failed. > I do even less know how feasible this is, but given that joins in the right > hand side of a LEFT JOIN are not really useful to study from the outside in > the general case, would it be possible to "hide" them below the join during > join order planning? We could refrain from collapsing the sub-problem during joinlist formation. But the trouble with that is it creates a "hard" join order restriction. Most of the restrictions are "soft" to some extent, ie, you can do some rearrangements but not others. It might be worth looking at though; in the cases where there is no chance of a rearrangement, it would save cycles for either regular or GEQO planning. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers