build_child_join_sjinfo creates a derived SpecialJoinInfo in
the short-lived GEQO context, but afterwards the semi_rhs_exprs
from that may be used in a UniquePath for a child base relation.
This breaks the expectation that all base-relation-level structures
are in the planning-lifespan context, leading to use of a dangling
pointer with probable ensuing crash later on in create_unique_plan.
To fix, copy the expression trees when making a UniquePath.
Per bug #18360 from Alexander Lakhin. This has been broken since
partitionwise joins were added, so back-patch to all supported
branches.
Discussion: https://postgr.es/m/18360-
a23caf3157f34e62@postgresql.org
pathnode->path.pathkeys = NIL;
pathnode->subpath = subpath;
- pathnode->in_operators = sjinfo->semi_operators;
- pathnode->uniq_exprs = sjinfo->semi_rhs_exprs;
+
+ /*
+ * Under GEQO, the sjinfo might be short-lived, so we'd better make copies
+ * of data structures we extract from it.
+ */
+ pathnode->in_operators = copyObject(sjinfo->semi_operators);
+ pathnode->uniq_exprs = copyObject(sjinfo->semi_rhs_exprs);
/*
* If the input is a relation and it has a unique index that proves the