diff options
Diffstat (limited to 'src/backend/optimizer/path/equivclass.c')
| -rw-r--r-- | src/backend/optimizer/path/equivclass.c | 43 |
1 files changed, 17 insertions, 26 deletions
diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c index b99cec00cb7..b68a5a0ec71 100644 --- a/src/backend/optimizer/path/equivclass.c +++ b/src/backend/optimizer/path/equivclass.c @@ -490,10 +490,6 @@ process_equivalence(PlannerInfo *root, * work to not label the collation at all in EC members, but this is risky * since some parts of the system expect exprCollation() to deliver the * right answer for a sort key.) - * - * Note this code assumes that the expression has already been through - * eval_const_expressions, so there are no CollateExprs and no redundant - * RelabelTypes. */ Expr * canonicalize_ec_expression(Expr *expr, Oid req_type, Oid req_collation) @@ -514,29 +510,24 @@ canonicalize_ec_expression(Expr *expr, Oid req_type, Oid req_collation) exprCollation((Node *) expr) != req_collation) { /* - * Strip any existing RelabelType, then add a new one if needed. This - * is to preserve the invariant of no redundant RelabelTypes. - * - * If we have to change the exposed type of the stripped expression, - * set typmod to -1 (since the new type may not have the same typmod - * interpretation). If we only have to change collation, preserve the - * exposed typmod. + * If we have to change the type of the expression, set typmod to -1, + * since the new type may not have the same typmod interpretation. + * When we only have to change collation, preserve the exposed typmod. + */ + int32 req_typmod; + + if (expr_type != req_type) + req_typmod = -1; + else + req_typmod = exprTypmod((Node *) expr); + + /* + * Use applyRelabelType so that we preserve const-flatness. This is + * important since eval_const_expressions has already been applied. */ - while (expr && IsA(expr, RelabelType)) - expr = (Expr *) ((RelabelType *) expr)->arg; - - if (exprType((Node *) expr) != req_type) - expr = (Expr *) makeRelabelType(expr, - req_type, - -1, - req_collation, - COERCE_IMPLICIT_CAST); - else if (exprCollation((Node *) expr) != req_collation) - expr = (Expr *) makeRelabelType(expr, - req_type, - exprTypmod((Node *) expr), - req_collation, - COERCE_IMPLICIT_CAST); + expr = (Expr *) applyRelabelType((Node *) expr, + req_type, req_typmod, req_collation, + COERCE_IMPLICIT_CAST, -1, false); } return expr; |