Fix CREATE MATVIEW/CREATE TABLE AS ... WITH NO DATA to not plan the query.

Previously, these commands always planned the given query and went through
executor startup before deciding not to actually run the query if WITH NO
DATA is specified.  This behavior is problematic for pg_dump because it
may cause errors to be raised that we would rather not see before a
REFRESH MATERIALIZED VIEW command is issued.  See for example bug #13907
from Marian Krucina.  This change is not sufficient to fix that particular
bug, because we also need to tweak pg_dump to issue the REFRESH later,
but it's a necessary step on the way.

A user-visible side effect of doing things this way is that the returned
command tag for WITH NO DATA cases will now be "CREATE MATERIALIZED VIEW"
or "CREATE TABLE AS", not "SELECT 0".  We could preserve the old behavior
but it would take more code, and arguably that was just an implementation
artifact not intended behavior anyhow.

In 9.5 and HEAD, also get rid of the static variable CreateAsReladdr, which
was trouble waiting to happen; there is not any prohibition on nested
CREATE commands.

Back-patch to 9.3 where CREATE MATERIALIZED VIEW was introduced.

Michael Paquier and Tom Lane

Report: <20160202161407.2778.24659@wrigleys.postgresql.org>

src/backend/commands/view.c

@@ -82,25 +82,14 @@ DefineVirtualRelation(RangeVar *relation, List *tlist, bool replace,
 	attrList = NIL;
 	foreach(t, tlist)
 	{
-		TargetEntry *tle = lfirst(t);
+		TargetEntry *tle = (TargetEntry *) lfirst(t);
 
 		if (!tle->resjunk)
 		{
-			ColumnDef  *def = makeNode(ColumnDef);
-
-			def->colname = pstrdup(tle->resname);
-			def->typeName = makeTypeNameFromOid(exprType((Node *) tle->expr),
-											 exprTypmod((Node *) tle->expr));
-			def->inhcount = 0;
-			def->is_local = true;
-			def->is_not_null = false;
-			def->is_from_type = false;
-			def->storage = 0;
-			def->raw_default = NULL;
-			def->cooked_default = NULL;
-			def->collClause = NULL;
-			def->collOid = exprCollation((Node *) tle->expr);
-			def->location = -1;
+			ColumnDef  *def = makeColumnDef(tle->resname,
+											exprType((Node *) tle->expr),
+											exprTypmod((Node *) tle->expr),
+										  exprCollation((Node *) tle->expr));
 
 			/*
 			 * It's possible that the column is of a collatable type but the
@@ -117,7 +106,6 @@ DefineVirtualRelation(RangeVar *relation, List *tlist, bool replace,
 			}
 			else
 				Assert(!OidIsValid(def->collOid));
-			def->constraints = NIL;
 
 			attrList = lappend(attrList, def);
 		}

src/backend/nodes/makefuncs.c

@@ -476,6 +476,36 @@ makeTypeNameFromOid(Oid typeOid, int32 typmod)
 	return n;
 }
 
+/*
+ * makeColumnDef -
+ *	build a ColumnDef node to represent a simple column definition.
+ *
+ * Type and collation are specified by OID.
+ * Other properties are all basic to start with.
+ */
+ColumnDef *
+makeColumnDef(const char *colname, Oid typeOid, int32 typmod, Oid collOid)
+{
+	ColumnDef  *n = makeNode(ColumnDef);
+
+	n->colname = pstrdup(colname);
+	n->typeName = makeTypeNameFromOid(typeOid, typmod);
+	n->inhcount = 0;
+	n->is_local = true;
+	n->is_not_null = false;
+	n->is_from_type = false;
+	n->storage = 0;
+	n->raw_default = NULL;
+	n->cooked_default = NULL;
+	n->collClause = NULL;
+	n->collOid = collOid;
+	n->constraints = NIL;
+	n->fdwoptions = NIL;
+	n->location = -1;
+
+	return n;
+}
+
 /*
  * makeFuncExpr -
  *	build an expression tree representing a function call.

src/include/nodes/makefuncs.h

@@ -72,6 +72,9 @@ extern TypeName *makeTypeName(char *typnam);
 extern TypeName *makeTypeNameFromNameList(List *names);
 extern TypeName *makeTypeNameFromOid(Oid typeOid, int32 typmod);
 
+extern ColumnDef *makeColumnDef(const char *colname,
+			  Oid typeOid, int32 typmod, Oid collOid);
+
 extern FuncExpr *makeFuncExpr(Oid funcid, Oid rettype, List *args,
 			 Oid funccollid, Oid inputcollid, CoercionForm fformat);
 

src/test/regress/expected/matview.out

@@ -455,13 +455,23 @@ DROP TABLE mvtest_boxes CASCADE;
 NOTICE:  drop cascades to materialized view mvtest_boxmv
 -- make sure that column names are handled correctly
 CREATE TABLE mvtest_v (i int, j int);
-CREATE MATERIALIZED VIEW mvtest_mv_v (ii) AS SELECT i, j AS jj FROM mvtest_v;
+CREATE MATERIALIZED VIEW mvtest_mv_v (ii, jj, kk) AS SELECT i, j FROM mvtest_v; -- error
+ERROR:  too many column names were specified
+CREATE MATERIALIZED VIEW mvtest_mv_v (ii, jj) AS SELECT i, j FROM mvtest_v; -- ok
+CREATE MATERIALIZED VIEW mvtest_mv_v_2 (ii) AS SELECT i, j FROM mvtest_v; -- ok
+CREATE MATERIALIZED VIEW mvtest_mv_v_3 (ii, jj, kk) AS SELECT i, j FROM mvtest_v WITH NO DATA; -- error
+ERROR:  too many column names were specified
+CREATE MATERIALIZED VIEW mvtest_mv_v_3 (ii, jj) AS SELECT i, j FROM mvtest_v WITH NO DATA; -- ok
+CREATE MATERIALIZED VIEW mvtest_mv_v_4 (ii) AS SELECT i, j FROM mvtest_v WITH NO DATA; -- ok
 ALTER TABLE mvtest_v RENAME COLUMN i TO x;
 INSERT INTO mvtest_v values (1, 2);
 CREATE UNIQUE INDEX mvtest_mv_v_ii ON mvtest_mv_v (ii);
 REFRESH MATERIALIZED VIEW mvtest_mv_v;
 UPDATE mvtest_v SET j = 3 WHERE x = 1;
 REFRESH MATERIALIZED VIEW CONCURRENTLY mvtest_mv_v;
+REFRESH MATERIALIZED VIEW mvtest_mv_v_2;
+REFRESH MATERIALIZED VIEW mvtest_mv_v_3;
+REFRESH MATERIALIZED VIEW mvtest_mv_v_4;
 SELECT * FROM mvtest_v;
  x | j 
 ---+---
@@ -474,8 +484,37 @@ SELECT * FROM mvtest_mv_v;
   1 |  3
 (1 row)
 
+SELECT * FROM mvtest_mv_v_2;
+ ii | j 
+----+---
+  1 | 3
+(1 row)
+
+SELECT * FROM mvtest_mv_v_3;
+ ii | jj 
+----+----
+  1 |  3
+(1 row)
+
+SELECT * FROM mvtest_mv_v_4;
+ ii | j 
+----+---
+  1 | 3
+(1 row)
+
 DROP TABLE mvtest_v CASCADE;
-NOTICE:  drop cascades to materialized view mvtest_mv_v
+NOTICE:  drop cascades to 4 other objects
+DETAIL:  drop cascades to materialized view mvtest_mv_v
+drop cascades to materialized view mvtest_mv_v_2
+drop cascades to materialized view mvtest_mv_v_3
+drop cascades to materialized view mvtest_mv_v_4
+-- make sure that create WITH NO DATA does not plan the query (bug #13907)
+create materialized view mvtest_error as select 1/0 as x;  -- fail
+ERROR:  division by zero
+create materialized view mvtest_error as select 1/0 as x with no data;
+refresh materialized view mvtest_error;  -- fail here
+ERROR:  division by zero
+drop materialized view mvtest_error;
 -- make sure that matview rows can be referenced as source rows (bug #9398)
 CREATE TABLE mvtest_v AS SELECT generate_series(1,10) AS a;
 CREATE MATERIALIZED VIEW mvtest_mv_v AS SELECT a FROM mvtest_v WHERE a <= 5;

src/test/regress/expected/select_into.out

@@ -50,6 +50,44 @@ DETAIL:  drop cascades to table selinto_schema.tmp1
 drop cascades to table selinto_schema.tmp2
 drop cascades to table selinto_schema.tmp3
 DROP USER selinto_user;
+-- Tests for WITH NO DATA and column name consistency
+CREATE TABLE ctas_base (i int, j int);
+INSERT INTO ctas_base VALUES (1, 2);
+CREATE TABLE ctas_nodata (ii, jj, kk) AS SELECT i, j FROM ctas_base; -- Error
+ERROR:  too many column names were specified
+CREATE TABLE ctas_nodata (ii, jj, kk) AS SELECT i, j FROM ctas_base WITH NO DATA; -- Error
+ERROR:  too many column names were specified
+CREATE TABLE ctas_nodata (ii, jj) AS SELECT i, j FROM ctas_base; -- OK
+CREATE TABLE ctas_nodata_2 (ii, jj) AS SELECT i, j FROM ctas_base WITH NO DATA; -- OK
+CREATE TABLE ctas_nodata_3 (ii) AS SELECT i, j FROM ctas_base; -- OK
+CREATE TABLE ctas_nodata_4 (ii) AS SELECT i, j FROM ctas_base WITH NO DATA; -- OK
+SELECT * FROM ctas_nodata;
+ ii | jj 
+----+----
+  1 |  2
+(1 row)
+
+SELECT * FROM ctas_nodata_2;
+ ii | jj 
+----+----
+(0 rows)
+
+SELECT * FROM ctas_nodata_3;
+ ii | j 
+----+---
+  1 | 2
+(1 row)
+
+SELECT * FROM ctas_nodata_4;
+ ii | j 
+----+---
+(0 rows)
+
+DROP TABLE ctas_base;
+DROP TABLE ctas_nodata;
+DROP TABLE ctas_nodata_2;
+DROP TABLE ctas_nodata_3;
+DROP TABLE ctas_nodata_4;
 --
 -- CREATE TABLE AS/SELECT INTO as last command in a SQL function
 -- have been known to cause problems

src/test/regress/sql/matview.sql

@@ -176,17 +176,34 @@ DROP TABLE mvtest_boxes CASCADE;
 
 -- make sure that column names are handled correctly
 CREATE TABLE mvtest_v (i int, j int);
-CREATE MATERIALIZED VIEW mvtest_mv_v (ii) AS SELECT i, j AS jj FROM mvtest_v;
+CREATE MATERIALIZED VIEW mvtest_mv_v (ii, jj, kk) AS SELECT i, j FROM mvtest_v; -- error
+CREATE MATERIALIZED VIEW mvtest_mv_v (ii, jj) AS SELECT i, j FROM mvtest_v; -- ok
+CREATE MATERIALIZED VIEW mvtest_mv_v_2 (ii) AS SELECT i, j FROM mvtest_v; -- ok
+CREATE MATERIALIZED VIEW mvtest_mv_v_3 (ii, jj, kk) AS SELECT i, j FROM mvtest_v WITH NO DATA; -- error
+CREATE MATERIALIZED VIEW mvtest_mv_v_3 (ii, jj) AS SELECT i, j FROM mvtest_v WITH NO DATA; -- ok
+CREATE MATERIALIZED VIEW mvtest_mv_v_4 (ii) AS SELECT i, j FROM mvtest_v WITH NO DATA; -- ok
 ALTER TABLE mvtest_v RENAME COLUMN i TO x;
 INSERT INTO mvtest_v values (1, 2);
 CREATE UNIQUE INDEX mvtest_mv_v_ii ON mvtest_mv_v (ii);
 REFRESH MATERIALIZED VIEW mvtest_mv_v;
 UPDATE mvtest_v SET j = 3 WHERE x = 1;
 REFRESH MATERIALIZED VIEW CONCURRENTLY mvtest_mv_v;
+REFRESH MATERIALIZED VIEW mvtest_mv_v_2;
+REFRESH MATERIALIZED VIEW mvtest_mv_v_3;
+REFRESH MATERIALIZED VIEW mvtest_mv_v_4;
 SELECT * FROM mvtest_v;
 SELECT * FROM mvtest_mv_v;
+SELECT * FROM mvtest_mv_v_2;
+SELECT * FROM mvtest_mv_v_3;
+SELECT * FROM mvtest_mv_v_4;
 DROP TABLE mvtest_v CASCADE;
 
+-- make sure that create WITH NO DATA does not plan the query (bug #13907)
+create materialized view mvtest_error as select 1/0 as x;  -- fail
+create materialized view mvtest_error as select 1/0 as x with no data;
+refresh materialized view mvtest_error;  -- fail here
+drop materialized view mvtest_error;
+
 -- make sure that matview rows can be referenced as source rows (bug #9398)
 CREATE TABLE mvtest_v AS SELECT generate_series(1,10) AS a;
 CREATE MATERIALIZED VIEW mvtest_mv_v AS SELECT a FROM mvtest_v WHERE a <= 5;

src/test/regress/sql/select_into.sql

@@ -53,6 +53,25 @@ RESET SESSION AUTHORIZATION;
 DROP SCHEMA selinto_schema CASCADE;
 DROP USER selinto_user;
 
+-- Tests for WITH NO DATA and column name consistency
+CREATE TABLE ctas_base (i int, j int);
+INSERT INTO ctas_base VALUES (1, 2);
+CREATE TABLE ctas_nodata (ii, jj, kk) AS SELECT i, j FROM ctas_base; -- Error
+CREATE TABLE ctas_nodata (ii, jj, kk) AS SELECT i, j FROM ctas_base WITH NO DATA; -- Error
+CREATE TABLE ctas_nodata (ii, jj) AS SELECT i, j FROM ctas_base; -- OK
+CREATE TABLE ctas_nodata_2 (ii, jj) AS SELECT i, j FROM ctas_base WITH NO DATA; -- OK
+CREATE TABLE ctas_nodata_3 (ii) AS SELECT i, j FROM ctas_base; -- OK
+CREATE TABLE ctas_nodata_4 (ii) AS SELECT i, j FROM ctas_base WITH NO DATA; -- OK
+SELECT * FROM ctas_nodata;
+SELECT * FROM ctas_nodata_2;
+SELECT * FROM ctas_nodata_3;
+SELECT * FROM ctas_nodata_4;
+DROP TABLE ctas_base;
+DROP TABLE ctas_nodata;
+DROP TABLE ctas_nodata_2;
+DROP TABLE ctas_nodata_3;
+DROP TABLE ctas_nodata_4;
+
 --
 -- CREATE TABLE AS/SELECT INTO as last command in a SQL function
 -- have been known to cause problems