diff options
Diffstat (limited to 'src/backend/optimizer/util/orclauses.c')
| -rw-r--r-- | src/backend/optimizer/util/orclauses.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/src/backend/optimizer/util/orclauses.c b/src/backend/optimizer/util/orclauses.c index 9e954d0d35f..8fecabbcda1 100644 --- a/src/backend/optimizer/util/orclauses.c +++ b/src/backend/optimizer/util/orclauses.c @@ -178,6 +178,7 @@ extract_or_clause(RestrictInfo *or_rinfo, RelOptInfo *rel) { Node *orarg = (Node *) lfirst(lc); List *subclauses = NIL; + Node *subclause; /* OR arguments should be ANDs or sub-RestrictInfos */ if (and_clause(orarg)) @@ -226,9 +227,16 @@ extract_or_clause(RestrictInfo *or_rinfo, RelOptInfo *rel) /* * OK, add subclause(s) to the result OR. If we found more than one, - * we need an AND node. + * we need an AND node. But if we found only one, and it is itself an + * OR node, add its subclauses to the result instead; this is needed + * to preserve AND/OR flatness (ie, no OR directly underneath OR). */ - clauselist = lappend(clauselist, make_ands_explicit(subclauses)); + subclause = (Node *) make_ands_explicit(subclauses); + if (or_clause(subclause)) + clauselist = list_concat(clauselist, + list_copy(((BoolExpr *) subclause)->args)); + else + clauselist = lappend(clauselist, subclause); } /* |