Thread: pgsql: Don't Memoize lateral joins with volatile join conditions
Don't Memoize lateral joins with volatile join conditions The use of Memoize was already disabled in normal joins when the join conditions had volatile functions per the code in match_opclause_to_indexcol(). Ordinarily, the parameterization for the inner side of a nested loop will be an Index Scan or at least eventually lead to an index scan (perhaps nested several joins deep). However, for lateral joins, that's not the case and seq scans can be parameterized too, so we can't rely on match_opclause_to_indexcol(). Here we explicitly check the parameterization for volatile functions and don't consider the generation of a Memoize path when such functions are present. Author: Richard Guo Discussion: https://postgr.es/m/CAMbWs49nHFnHbpepLsv_yF3qkpCS4BdB-v8HoJVv8_=Oat0u_w@mail.gmail.com Backpatch-through: 14, where Memoize was introduced Branch ------ REL_16_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/ae89129aa3555c263b8c3ccc4c0f1ef7e46201aa Modified Files -------------- src/backend/optimizer/path/joinpath.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)