"Dian M Fay" <dian.m....@gmail.com> writes:
> I've split the suppression for RelabelTypes with implicit cast check
> into a second patch over the core v7 change. As far as testing goes, \dC
> lists implicit casts, but most of those I've tried seem to wind up
> deparsing as Vars. I've been able to manifest RelabelTypes with varchar,
> cidr, and remote char to local varchar, but that's about it. Any ideas
> for validating it further, off the top of your head?
I thought about this some more and realized exactly why I wanted to
restrict the change to cases where the other side is a plain foreign Var:
that way, if anything surprising happens, we can blame it directly on the
user having declared a local column with a different type from the
remote column.
That being the case, I took a closer look at deparseVar and realized that
we can't simply check "IsA(node, Var)": some Vars in the expression can
belong to local tables. We need to verify that the Var is one that will
print as a remote column reference.
So that leads me to v8, attached. I think we are getting there.
regards, tom lane
diff --git a/contrib/postgres_fdw/deparse.c b/contrib/postgres_fdw/deparse.c
index d98bd66681..b27689d086 100644
--- a/contrib/postgres_fdw/deparse.c
+++ b/contrib/postgres_fdw/deparse.c
@@ -152,6 +152,7 @@ static void deparseParam(Param *node, deparse_expr_cxt *context);
static void deparseSubscriptingRef(SubscriptingRef *node, deparse_expr_cxt *context);
static void deparseFuncExpr(FuncExpr *node, deparse_expr_cxt *context);
static void deparseOpExpr(OpExpr *node, deparse_expr_cxt *context);
+static bool isPlainForeignVar(Expr *node, deparse_expr_cxt *context);
static void deparseOperatorName(StringInfo buf, Form_pg_operator opform);
static void deparseDistinctExpr(DistinctExpr *node, deparse_expr_cxt *context);
static void deparseScalarArrayOpExpr(ScalarArrayOpExpr *node,
@@ -2695,9 +2696,14 @@ deparseVar(Var *node, deparse_expr_cxt *context)
* Deparse given constant value into context->buf.
*
* This function has to be kept in sync with ruleutils.c's get_const_expr.
- * As for that function, showtype can be -1 to never show "::typename" decoration,
- * or +1 to always show it, or 0 to show it only if the constant wouldn't be assumed
- * to be the right type by default.
+ *
+ * As in that function, showtype can be -1 to never show "::typename"
+ * decoration, +1 to always show it, or 0 to show it only if the constant
+ * wouldn't be assumed to be the right type by default.
+ *
+ * In addition, this code allows showtype to be -2 to indicate that we should
+ * not show "::typename" decoration if the constant is printed as an untyped
+ * literal or NULL (while in other cases, behaving as for showtype == 0).
*/
static void
deparseConst(Const *node, deparse_expr_cxt *context, int showtype)
@@ -2707,6 +2713,7 @@ deparseConst(Const *node, deparse_expr_cxt *context, int showtype)
bool typIsVarlena;
char *extval;
bool isfloat = false;
+ bool isstring = false;
bool needlabel;
if (node->constisnull)
@@ -2762,13 +2769,14 @@ deparseConst(Const *node, deparse_expr_cxt *context, int showtype)
break;
default:
deparseStringLiteral(buf, extval);
+ isstring = true;
break;
}
pfree(extval);
- if (showtype < 0)
- return;
+ if (showtype == -1)
+ return; /* never print type label */
/*
* For showtype == 0, append ::typename unless the constant will be
@@ -2788,7 +2796,13 @@ deparseConst(Const *node, deparse_expr_cxt *context, int showtype)
needlabel = !isfloat || (node->consttypmod >= 0);
break;
default:
- needlabel = true;
+ if (showtype == -2)
+ {
+ /* label unless we printed it as an untyped string */
+ needlabel = !isstring;
+ }
+ else
+ needlabel = true;
break;
}
if (needlabel || showtype > 0)
@@ -2953,6 +2967,8 @@ deparseOpExpr(OpExpr *node, deparse_expr_cxt *context)
StringInfo buf = context->buf;
HeapTuple tuple;
Form_pg_operator form;
+ Expr *right;
+ bool canSuppressRightConstCast = false;
char oprkind;
/* Retrieve information about the operator from system catalog. */
@@ -2966,13 +2982,58 @@ deparseOpExpr(OpExpr *node, deparse_expr_cxt *context)
Assert((oprkind == 'l' && list_length(node->args) == 1) ||
(oprkind == 'b' && list_length(node->args) == 2));
+ right = llast(node->args);
+
/* Always parenthesize the expression. */
appendStringInfoChar(buf, '(');
/* Deparse left operand, if any. */
if (oprkind == 'b')
{
- deparseExpr(linitial(node->args), context);
+ Expr *left = linitial(node->args);
+ Oid leftType = exprType((Node *) left);
+ Oid rightType = exprType((Node *) right);
+ bool canSuppressLeftConstCast = false;
+
+ /*
+ * When considering a binary operator, if one operand is a Const that
+ * can be printed as a bare string literal or NULL (i.e., it will look
+ * like type UNKNOWN to the remote parser), the Const normally
+ * receives an explicit cast to the operator's input type. However,
+ * in Const-to-Var comparisons where both operands are of the same
+ * type, we prefer to suppress the explicit cast, leaving the Const's
+ * type resolution up to the remote parser. The remote's resolution
+ * heuristic will assume that an unknown input type being compared to
+ * a known input type is of that known type as well.
+ *
+ * This hack allows some cases to succeed where a remote column is
+ * declared with a different type in the local (foreign) table. By
+ * emitting "foreigncol = 'foo'" not "foreigncol = 'foo'::text" or the
+ * like, we allow the remote parser to pick an "=" operator that's
+ * compatible with whatever type the remote column really is, such as
+ * an enum.
+ *
+ * We allow cast suppression to happen only when the other operand is
+ * a plain foreign Var. Although the remote's unknown-type heuristic
+ * would apply to other cases just as well, we would be taking a
+ * bigger risk that the inferred type is something unexpected. With
+ * this restriction, if anything goes wrong it's the user's fault for
+ * not declaring the local column with the same type as the remote
+ * column.
+ */
+ if (leftType == rightType)
+ {
+ if (IsA(left, Const))
+ canSuppressLeftConstCast = isPlainForeignVar(right, context);
+ else if (IsA(right, Const))
+ canSuppressRightConstCast = isPlainForeignVar(left, context);
+ }
+
+ if (canSuppressLeftConstCast)
+ deparseConst((Const *) left, context, -2);
+ else
+ deparseExpr(left, context);
+
appendStringInfoChar(buf, ' ');
}
@@ -2981,13 +3042,52 @@ deparseOpExpr(OpExpr *node, deparse_expr_cxt *context)
/* Deparse right operand. */
appendStringInfoChar(buf, ' ');
- deparseExpr(llast(node->args), context);
+
+ if (canSuppressRightConstCast)
+ deparseConst((Const *) right, context, -2);
+ else
+ deparseExpr(right, context);
appendStringInfoChar(buf, ')');
ReleaseSysCache(tuple);
}
+/*
+ * Will "node" deparse as a plain foreign Var?
+ */
+static bool
+isPlainForeignVar(Expr *node, deparse_expr_cxt *context)
+{
+ /*
+ * We allow the foreign Var to have an implicit RelabelType, mainly so
+ * that this'll work with varchar columns. Note that deparseRelabelType
+ * will not print such a cast, so we're not breaking the restriction that
+ * the expression print as a plain Var. We won't risk it for an implicit
+ * cast that requires a function, nor for non-implicit RelabelType; such
+ * cases seem too likely to involve semantics changes compared to what
+ * would happen on the remote side.
+ */
+ if (IsA(node, RelabelType) &&
+ ((RelabelType *) node)->relabelformat == COERCE_IMPLICIT_CAST)
+ node = ((RelabelType *) node)->arg;
+
+ if (IsA(node, Var))
+ {
+ /*
+ * The Var must be one that'll deparse as a foreign column reference
+ * (cf. deparseVar).
+ */
+ Var *var = (Var *) node;
+ Relids relids = context->scanrel->relids;
+
+ if (bms_is_member(var->varno, relids) && var->varlevelsup == 0)
+ return true;
+ }
+
+ return false;
+}
+
/*
* Print the name of an operator.
*/
diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out b/contrib/postgres_fdw/expected/postgres_fdw.out
index fd141a0fa5..3cee0a8c12 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -341,11 +341,11 @@ SELECT * FROM ft1 WHERE false;
-- with WHERE clause
EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft1 t1 WHERE t1.c1 = 101 AND t1.c6 = '1' AND t1.c7 >= '1';
- QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------
+ QUERY PLAN
+----------------------------------------------------------------------------------------------------------------------------------
Foreign Scan on public.ft1 t1
Output: c1, c2, c3, c4, c5, c6, c7, c8
- Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE ((c7 >= '1'::bpchar)) AND (("C 1" = 101)) AND ((c6 = '1'::text))
+ Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE ((c7 >= '1')) AND (("C 1" = 101)) AND ((c6 = '1'))
(3 rows)
SELECT * FROM ft1 t1 WHERE t1.c1 = 101 AND t1.c6 = '1' AND t1.c7 >= '1';
@@ -707,11 +707,11 @@ EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft1 t1 WHERE c1 = (ARRAY[c1,c2,3])[1]
(3 rows)
EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft1 t1 WHERE c6 = E'foo''s\\bar'; -- check special chars
- QUERY PLAN
--------------------------------------------------------------------------------------------------------------
+ QUERY PLAN
+-------------------------------------------------------------------------------------------------------
Foreign Scan on public.ft1 t1
Output: c1, c2, c3, c4, c5, c6, c7, c8
- Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE ((c6 = E'foo''s\\bar'::text))
+ Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE ((c6 = E'foo''s\\bar'))
(3 rows)
EXPLAIN (VERBOSE, COSTS OFF) SELECT * FROM ft1 t1 WHERE c8 = 'foo'; -- can't be sent to remote
@@ -1130,20 +1130,20 @@ SELECT * FROM ft1 WHERE c1 > (CASE random()::integer WHEN 0 THEN 1 WHEN 2 THEN 5
-- these are shippable
EXPLAIN (VERBOSE, COSTS OFF)
SELECT * FROM ft1 WHERE CASE c6 WHEN 'foo' THEN true ELSE c3 < 'bar' END;
- QUERY PLAN
---------------------------------------------------------------------------------------------------------------------------------------------------
+ QUERY PLAN
+--------------------------------------------------------------------------------------------------------------------------------------------
Foreign Scan on public.ft1
Output: c1, c2, c3, c4, c5, c6, c7, c8
- Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE ((CASE c6 WHEN 'foo'::text THEN true ELSE (c3 < 'bar'::text) END))
+ Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE ((CASE c6 WHEN 'foo'::text THEN true ELSE (c3 < 'bar') END))
(3 rows)
EXPLAIN (VERBOSE, COSTS OFF)
SELECT * FROM ft1 WHERE CASE c3 WHEN c6 THEN true ELSE c3 < 'bar' END;
- QUERY PLAN
------------------------------------------------------------------------------------------------------------------------------------------
+ QUERY PLAN
+-----------------------------------------------------------------------------------------------------------------------------------
Foreign Scan on public.ft1
Output: c1, c2, c3, c4, c5, c6, c7, c8
- Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE ((CASE c3 WHEN c6 THEN true ELSE (c3 < 'bar'::text) END))
+ Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE ((CASE c3 WHEN c6 THEN true ELSE (c3 < 'bar') END))
(3 rows)
-- but this is not because of collation
@@ -3491,12 +3491,12 @@ ORDER BY ref_0."C 1";
Index Cond: (ref_0."C 1" < 10)
-> Foreign Scan on public.ft1 ref_1
Output: ref_1.c3, ref_0.c2
- Remote SQL: SELECT c3 FROM "S 1"."T 1" WHERE ((c3 = '00001'::text))
+ Remote SQL: SELECT c3 FROM "S 1"."T 1" WHERE ((c3 = '00001'))
-> Materialize
Output: ref_3.c3
-> Foreign Scan on public.ft2 ref_3
Output: ref_3.c3
- Remote SQL: SELECT c3 FROM "S 1"."T 1" WHERE ((c3 = '00001'::text))
+ Remote SQL: SELECT c3 FROM "S 1"."T 1" WHERE ((c3 = '00001'))
(15 rows)
SELECT ref_0.c2, subq_1.*
@@ -4114,11 +4114,11 @@ SELECT tableoid::regclass, * FROM ft1 t1 LIMIT 1;
EXPLAIN (VERBOSE, COSTS OFF)
SELECT * FROM ft1 t1 WHERE t1.ctid = '(0,2)';
- QUERY PLAN
--------------------------------------------------------------------------------------------------------
+ QUERY PLAN
+--------------------------------------------------------------------------------------------------
Foreign Scan on public.ft1 t1
Output: c1, c2, c3, c4, c5, c6, c7, c8
- Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE ((ctid = '(0,2)'::tid))
+ Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE ((ctid = '(0,2)'))
(3 rows)
SELECT * FROM ft1 t1 WHERE t1.ctid = '(0,2)';
@@ -4205,6 +4205,53 @@ ERROR: invalid input syntax for type integer: "foo"
CONTEXT: column "c8" of foreign table "ft1"
ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 TYPE user_enum;
-- ===================================================================
+-- local type can be different from remote type in some cases,
+-- in particular if similarly-named operators do equivalent things
+-- ===================================================================
+ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 TYPE text;
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM ft1 WHERE c8 = 'foo' LIMIT 1;
+ QUERY PLAN
+--------------------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1
+ Output: c1, c2, c3, c4, c5, c6, c7, c8
+ Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE ((c8 = 'foo')) LIMIT 1::bigint
+(3 rows)
+
+SELECT * FROM ft1 WHERE c8 = 'foo' LIMIT 1;
+ c1 | c2 | c3 | c4 | c5 | c6 | c7 | c8
+----+----+-------+------------------------------+--------------------------+----+------------+-----
+ 1 | 1 | 00001 | Fri Jan 02 00:00:00 1970 PST | Fri Jan 02 00:00:00 1970 | 1 | 1 | foo
+(1 row)
+
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM ft1 WHERE 'foo' = c8 LIMIT 1;
+ QUERY PLAN
+--------------------------------------------------------------------------------------------------------------
+ Foreign Scan on public.ft1
+ Output: c1, c2, c3, c4, c5, c6, c7, c8
+ Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (('foo' = c8)) LIMIT 1::bigint
+(3 rows)
+
+SELECT * FROM ft1 WHERE 'foo' = c8 LIMIT 1;
+ c1 | c2 | c3 | c4 | c5 | c6 | c7 | c8
+----+----+-------+------------------------------+--------------------------+----+------------+-----
+ 1 | 1 | 00001 | Fri Jan 02 00:00:00 1970 PST | Fri Jan 02 00:00:00 1970 | 1 | 1 | foo
+(1 row)
+
+-- we declared c8 to be text locally, but it's still the same type on
+-- the remote which will balk if we try to do anything incompatible
+-- with that remote type
+SELECT * FROM ft1 WHERE c8 LIKE 'foo' LIMIT 1; -- ERROR
+ERROR: operator does not exist: public.user_enum ~~ unknown
+HINT: No operator matches the given name and argument types. You might need to add explicit type casts.
+CONTEXT: remote SQL command: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE ((c8 ~~ 'foo')) LIMIT 1::bigint
+SELECT * FROM ft1 WHERE c8::text LIKE 'foo' LIMIT 1; -- ERROR; cast not pushed down
+ERROR: operator does not exist: public.user_enum ~~ unknown
+HINT: No operator matches the given name and argument types. You might need to add explicit type casts.
+CONTEXT: remote SQL command: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE ((c8 ~~ 'foo')) LIMIT 1::bigint
+ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 TYPE user_enum;
+-- ===================================================================
-- subtransaction
-- + local/remote error doesn't break cursor
-- ===================================================================
@@ -4254,35 +4301,35 @@ create foreign table ft3 (f1 text collate "C", f2 text, f3 varchar(10))
server loopback options (table_name 'loct3', use_remote_estimate 'true');
-- can be sent to remote
explain (verbose, costs off) select * from ft3 where f1 = 'foo';
- QUERY PLAN
-------------------------------------------------------------------------------
+ QUERY PLAN
+------------------------------------------------------------------------
Foreign Scan on public.ft3
Output: f1, f2, f3
- Remote SQL: SELECT f1, f2, f3 FROM public.loct3 WHERE ((f1 = 'foo'::text))
+ Remote SQL: SELECT f1, f2, f3 FROM public.loct3 WHERE ((f1 = 'foo'))
(3 rows)
explain (verbose, costs off) select * from ft3 where f1 COLLATE "C" = 'foo';
- QUERY PLAN
-------------------------------------------------------------------------------
+ QUERY PLAN
+------------------------------------------------------------------------
Foreign Scan on public.ft3
Output: f1, f2, f3
- Remote SQL: SELECT f1, f2, f3 FROM public.loct3 WHERE ((f1 = 'foo'::text))
+ Remote SQL: SELECT f1, f2, f3 FROM public.loct3 WHERE ((f1 = 'foo'))
(3 rows)
explain (verbose, costs off) select * from ft3 where f2 = 'foo';
- QUERY PLAN
-------------------------------------------------------------------------------
+ QUERY PLAN
+------------------------------------------------------------------------
Foreign Scan on public.ft3
Output: f1, f2, f3
- Remote SQL: SELECT f1, f2, f3 FROM public.loct3 WHERE ((f2 = 'foo'::text))
+ Remote SQL: SELECT f1, f2, f3 FROM public.loct3 WHERE ((f2 = 'foo'))
(3 rows)
explain (verbose, costs off) select * from ft3 where f3 = 'foo';
- QUERY PLAN
-------------------------------------------------------------------------------
+ QUERY PLAN
+------------------------------------------------------------------------
Foreign Scan on public.ft3
Output: f1, f2, f3
- Remote SQL: SELECT f1, f2, f3 FROM public.loct3 WHERE ((f3 = 'foo'::text))
+ Remote SQL: SELECT f1, f2, f3 FROM public.loct3 WHERE ((f3 = 'foo'))
(3 rows)
explain (verbose, costs off) select * from ft3 f, loct3 l
@@ -4384,22 +4431,22 @@ INSERT INTO ft2 (c1,c2,c3)
INSERT INTO ft2 (c1,c2,c3) VALUES (1104,204,'ddd'), (1105,205,'eee');
EXPLAIN (verbose, costs off)
UPDATE ft2 SET c2 = c2 + 300, c3 = c3 || '_update3' WHERE c1 % 10 = 3; -- can be pushed down
- QUERY PLAN
-----------------------------------------------------------------------------------------------------------------------
+ QUERY PLAN
+----------------------------------------------------------------------------------------------------------------
Update on public.ft2
-> Foreign Update on public.ft2
- Remote SQL: UPDATE "S 1"."T 1" SET c2 = (c2 + 300), c3 = (c3 || '_update3'::text) WHERE ((("C 1" % 10) = 3))
+ Remote SQL: UPDATE "S 1"."T 1" SET c2 = (c2 + 300), c3 = (c3 || '_update3') WHERE ((("C 1" % 10) = 3))
(3 rows)
UPDATE ft2 SET c2 = c2 + 300, c3 = c3 || '_update3' WHERE c1 % 10 = 3;
EXPLAIN (verbose, costs off)
UPDATE ft2 SET c2 = c2 + 400, c3 = c3 || '_update7' WHERE c1 % 10 = 7 RETURNING *; -- can be pushed down
- QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ QUERY PLAN
+------------------------------------------------------------------------------------------------------------------------------------------------------------
Update on public.ft2
Output: c1, c2, c3, c4, c5, c6, c7, c8
-> Foreign Update on public.ft2
- Remote SQL: UPDATE "S 1"."T 1" SET c2 = (c2 + 400), c3 = (c3 || '_update7'::text) WHERE ((("C 1" % 10) = 7)) RETURNING "C 1", c2, c3, c4, c5, c6, c7, c8
+ Remote SQL: UPDATE "S 1"."T 1" SET c2 = (c2 + 400), c3 = (c3 || '_update7') WHERE ((("C 1" % 10) = 7)) RETURNING "C 1", c2, c3, c4, c5, c6, c7, c8
(4 rows)
UPDATE ft2 SET c2 = c2 + 400, c3 = c3 || '_update7' WHERE c1 % 10 = 7 RETURNING *;
@@ -4512,11 +4559,11 @@ UPDATE ft2 SET c2 = c2 + 400, c3 = c3 || '_update7' WHERE c1 % 10 = 7 RETURNING
EXPLAIN (verbose, costs off)
UPDATE ft2 SET c2 = ft2.c2 + 500, c3 = ft2.c3 || '_update9', c7 = DEFAULT
FROM ft1 WHERE ft1.c1 = ft2.c2 AND ft1.c1 % 10 = 9; -- can be pushed down
- QUERY PLAN
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ QUERY PLAN
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Update on public.ft2
-> Foreign Update
- Remote SQL: UPDATE "S 1"."T 1" r1 SET c2 = (r1.c2 + 500), c3 = (r1.c3 || '_update9'::text), c7 = 'ft2 '::character(10) FROM "S 1"."T 1" r2 WHERE ((r1.c2 = r2."C 1")) AND (((r2."C 1" % 10) = 9))
+ Remote SQL: UPDATE "S 1"."T 1" r1 SET c2 = (r1.c2 + 500), c3 = (r1.c3 || '_update9'), c7 = 'ft2 '::character(10) FROM "S 1"."T 1" r2 WHERE ((r1.c2 = r2."C 1")) AND (((r2."C 1" % 10) = 9))
(3 rows)
UPDATE ft2 SET c2 = ft2.c2 + 500, c3 = ft2.c3 || '_update9', c7 = DEFAULT
@@ -8129,7 +8176,7 @@ select tableoid::regclass, * FROM locp;
update utrtest set a = 2 where b = 'foo' returning *;
ERROR: new row for relation "loct" violates check constraint "loct_a_check"
DETAIL: Failing row contains (2, foo).
-CONTEXT: remote SQL command: UPDATE public.loct SET a = 2 WHERE ((b = 'foo'::text)) RETURNING a, b
+CONTEXT: remote SQL command: UPDATE public.loct SET a = 2 WHERE ((b = 'foo')) RETURNING a, b
-- But the reverse is allowed
update utrtest set a = 1 where b = 'qux' returning *;
ERROR: cannot route tuples into foreign table to be updated "remp"
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql b/contrib/postgres_fdw/sql/postgres_fdw.sql
index 43c30d492d..e40112e41d 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -1167,6 +1167,24 @@ SELECT sum(c2), array_agg(c8) FROM ft1 GROUP BY c8; -- ERROR
ANALYZE ft1; -- ERROR
ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 TYPE user_enum;
+-- ===================================================================
+-- local type can be different from remote type in some cases,
+-- in particular if similarly-named operators do equivalent things
+-- ===================================================================
+ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 TYPE text;
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM ft1 WHERE c8 = 'foo' LIMIT 1;
+SELECT * FROM ft1 WHERE c8 = 'foo' LIMIT 1;
+EXPLAIN (VERBOSE, COSTS OFF)
+SELECT * FROM ft1 WHERE 'foo' = c8 LIMIT 1;
+SELECT * FROM ft1 WHERE 'foo' = c8 LIMIT 1;
+-- we declared c8 to be text locally, but it's still the same type on
+-- the remote which will balk if we try to do anything incompatible
+-- with that remote type
+SELECT * FROM ft1 WHERE c8 LIKE 'foo' LIMIT 1; -- ERROR
+SELECT * FROM ft1 WHERE c8::text LIKE 'foo' LIMIT 1; -- ERROR; cast not pushed down
+ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 TYPE user_enum;
+
-- ===================================================================
-- subtransaction
-- + local/remote error doesn't break cursor
