>>> Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Introduce JOIN_SEMI and JOIN_ANTI join types, the former replacing
> JOIN_IN. Unify the InClauseInfo and OuterJoinInfo infrastructure
into
> "SpecialJoinInfo". Convert IN, EXISTS, and NOT EXISTS clauses at
top
> level of WHERE into semi and anti joins respectively.
It just struck me that this may cause additional joins to count
against the join_collapse_limit. If so, that could cause some
borderline queries to optimize poorly if the limit isn't raised. Is
that a reasonable concern? Possibly something to document in the
release notes?
-Kevin