diff options
Diffstat (limited to 'src/backend/optimizer/plan/setrefs.c')
| -rw-r--r-- | src/backend/optimizer/plan/setrefs.c | 29 |
1 files changed, 17 insertions, 12 deletions
diff --git a/src/backend/optimizer/plan/setrefs.c b/src/backend/optimizer/plan/setrefs.c index 90c4a26b995..e6fbe6acde1 100644 --- a/src/backend/optimizer/plan/setrefs.c +++ b/src/backend/optimizer/plan/setrefs.c @@ -1929,16 +1929,21 @@ search_indexed_tlist_for_sortgroupref(Node *node, * relation target lists. Also perform opcode lookup and add * regclass OIDs to root->glob->relationOids. * - * This is used in two different scenarios: a normal join clause, where all - * the Vars in the clause *must* be replaced by OUTER_VAR or INNER_VAR - * references; and a RETURNING clause, which may contain both Vars of the - * target relation and Vars of other relations. In the latter case we want - * to replace the other-relation Vars by OUTER_VAR references, while leaving - * target Vars alone. - * - * For a normal join, acceptable_rel should be zero so that any failure to - * match a Var will be reported as an error. For the RETURNING case, pass - * inner_itlist = NULL and acceptable_rel = the ID of the target relation. + * This is used in three different scenarios: + * 1) a normal join clause, where all the Vars in the clause *must* be + * replaced by OUTER_VAR or INNER_VAR references. In this case + * acceptable_rel should be zero so that any failure to match a Var will be + * reported as an error. + * 2) RETURNING clauses, which may contain both Vars of the target relation + * and Vars of other relations. In this case we want to replace the + * other-relation Vars by OUTER_VAR references, while leaving target Vars + * alone. Thus inner_itlist = NULL and acceptable_rel = the ID of the + * target relation should be passed. + * 3) ON CONFLICT UPDATE SET/WHERE clauses. Here references to EXCLUDED are + * to be replaced with INNER_VAR references, while leaving target Vars (the + * to-be-updated relation) alone. Correspondingly inner_itlist is to be + * EXCLUDED elements, outer_itlist = NULL and acceptable_rel the target + * relation. * * 'clauses' is the targetlist or list of join clauses * 'outer_itlist' is the indexed target list of the outer join relation, @@ -1981,7 +1986,7 @@ fix_join_expr_mutator(Node *node, fix_join_expr_context *context) { Var *var = (Var *) node; - /* First look for the var in the input tlists */ + /* Look for the var in the input tlists, first in the outer */ if (context->outer_itlist) { newvar = search_indexed_tlist_for_var(var, @@ -1992,7 +1997,7 @@ fix_join_expr_mutator(Node *node, fix_join_expr_context *context) return (Node *) newvar; } - /* Then in the outer */ + /* then in the inner. */ if (context->inner_itlist) { newvar = search_indexed_tlist_for_var(var, |