static void deparseBoolExpr(BoolExpr *node, deparse_expr_cxt *context);
static void deparseNullTest(NullTest *node, deparse_expr_cxt *context);
static void deparseArrayExpr(ArrayExpr *node, deparse_expr_cxt *context);
+static void printRemoteParam(int paramindex, Oid paramtype, int32 paramtypmod,
+ deparse_expr_cxt *context);
+static void printRemotePlaceholder(Oid paramtype, int32 paramtypmod,
+ deparse_expr_cxt *context);
/*
*context->params_list = lappend(*context->params_list, node);
}
- appendStringInfo(buf, "$%d", pindex);
- appendStringInfo(buf, "::%s",
- format_type_with_typemod(node->vartype,
- node->vartypmod));
+ printRemoteParam(pindex, node->vartype, node->vartypmod, context);
}
else
{
- appendStringInfo(buf, "(SELECT null::%s)",
- format_type_with_typemod(node->vartype,
- node->vartypmod));
+ printRemotePlaceholder(node->vartype, node->vartypmod, context);
}
}
}
*
* If we're generating the query "for real", add the Param to
* context->params_list if it's not already present, and then use its index
- * in that list as the remote parameter number.
- *
- * If we're just generating the query for EXPLAIN, replace the Param with
- * a dummy expression "(SELECT null::<type>)". In all extant versions of
- * Postgres, the planner will see that as an unknown constant value, which is
- * what we want. (If we sent a Param, recent versions might try to use the
- * value supplied for the Param as an estimated or even constant value, which
- * we don't want.) This might need adjustment if we ever make the planner
- * flatten scalar subqueries.
- *
- * Note: we label the Param's type explicitly rather than relying on
- * transmitting a numeric type OID in PQexecParams(). This allows us to
- * avoid assuming that types have the same OIDs on the remote side as they
- * do locally --- they need only have the same names.
+ * in that list as the remote parameter number. During EXPLAIN, there's
+ * no need to identify a parameter number.
*/
static void
deparseParam(Param *node, deparse_expr_cxt *context)
{
- StringInfo buf = context->buf;
-
if (context->params_list)
{
int pindex = 0;
*context->params_list = lappend(*context->params_list, node);
}
- appendStringInfo(buf, "$%d", pindex);
- appendStringInfo(buf, "::%s",
- format_type_with_typemod(node->paramtype,
- node->paramtypmod));
+ printRemoteParam(pindex, node->paramtype, node->paramtypmod, context);
}
else
{
- appendStringInfo(buf, "(SELECT null::%s)",
- format_type_with_typemod(node->paramtype,
- node->paramtypmod));
+ printRemotePlaceholder(node->paramtype, node->paramtypmod, context);
}
}
appendStringInfo(buf, "::%s",
format_type_with_typemod(node->array_typeid, -1));
}
+
+/*
+ * Print the representation of a parameter to be sent to the remote side.
+ *
+ * Note: we always label the Param's type explicitly rather than relying on
+ * transmitting a numeric type OID in PQexecParams(). This allows us to
+ * avoid assuming that types have the same OIDs on the remote side as they
+ * do locally --- they need only have the same names.
+ */
+static void
+printRemoteParam(int paramindex, Oid paramtype, int32 paramtypmod,
+ deparse_expr_cxt *context)
+{
+ StringInfo buf = context->buf;
+ char *ptypename = format_type_with_typemod(paramtype, paramtypmod);
+
+ appendStringInfo(buf, "$%d::%s", paramindex, ptypename);
+}
+
+/*
+ * Print the representation of a placeholder for a parameter that will be
+ * sent to the remote side at execution time.
+ *
+ * This is used when we're just trying to EXPLAIN the remote query.
+ * We don't have the actual value of the runtime parameter yet, and we don't
+ * want the remote planner to generate a plan that depends on such a value
+ * anyway. Thus, we can't do something simple like "$1::paramtype".
+ * Instead, we emit "((SELECT null::paramtype)::paramtype)".
+ * In all extant versions of Postgres, the planner will see that as an unknown
+ * constant value, which is what we want. This might need adjustment if we
+ * ever make the planner flatten scalar subqueries. Note: the reason for the
+ * apparently useless outer cast is to ensure that the representation as a
+ * whole will be parsed as an a_expr and not a select_with_parens; the latter
+ * would do the wrong thing in the context "x = ANY(...)".
+ */
+static void
+printRemotePlaceholder(Oid paramtype, int32 paramtypmod,
+ deparse_expr_cxt *context)
+{
+ StringInfo buf = context->buf;
+ char *ptypename = format_type_with_typemod(paramtype, paramtypmod);
+
+ appendStringInfo(buf, "((SELECT null::%s)::%s)", ptypename, ptypename);
+}
996 | 6 | 00996 | Tue Apr 07 00:00:00 1970 PST | Tue Apr 07 00:00:00 1970 | 6 | 6 | foo | 996 | 6 | 00996 | Tue Apr 07 00:00:00 1970 PST | Tue Apr 07 00:00:00 1970 | 6 | 6 | foo
(100 rows)
+-- bug before 9.3.5 due to sloppy handling of remote-estimate parameters
+SELECT * FROM ft1 WHERE c1 = ANY (ARRAY(SELECT c1 FROM ft2 WHERE c1 < 5));
+ 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
+ 2 | 2 | 00002 | Sat Jan 03 00:00:00 1970 PST | Sat Jan 03 00:00:00 1970 | 2 | 2 | foo
+ 3 | 3 | 00003 | Sun Jan 04 00:00:00 1970 PST | Sun Jan 04 00:00:00 1970 | 3 | 3 | foo
+ 4 | 4 | 00004 | Mon Jan 05 00:00:00 1970 PST | Mon Jan 05 00:00:00 1970 | 4 | 4 | foo
+(4 rows)
+
+SELECT * FROM ft2 WHERE c1 = ANY (ARRAY(SELECT c1 FROM ft1 WHERE c1 < 5));
+ 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
+ 2 | 2 | 00002 | Sat Jan 03 00:00:00 1970 PST | Sat Jan 03 00:00:00 1970 | 2 | 2 | foo
+ 3 | 3 | 00003 | Sun Jan 04 00:00:00 1970 PST | Sun Jan 04 00:00:00 1970 | 3 | 3 | foo
+ 4 | 4 | 00004 | Mon Jan 05 00:00:00 1970 PST | Mon Jan 05 00:00:00 1970 | 4 | 4 | foo
+(4 rows)
+
-- ===================================================================
-- parameterized queries
-- ===================================================================