From 268d92e5336d25b296a5ccf8ccf803a2adb40251 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 11 Aug 2016 11:22:25 -0400
Subject: [PATCH] Fix busted Assert for CREATE MATVIEW ... WITH NO DATA.

Commit 874fe3aea changed the command tag returned for CREATE MATVIEW/CREATE
TABLE AS ... WITH NO DATA, but missed that there was code in spi.c that
expected the command tag to always be "SELECT".  Fortunately, the
consequence was only an Assert failure, so this oversight should have no
impact in production builds.

Since this code path was evidently un-exercised, add a regression test.

Per report from Shivam Saxena. Back-patch to 9.3, like the previous commit.

Michael Paquier

Report: <97218716-480B-4527-B5CD-D08D798A0C7B@dresources.com>
---
 src/backend/executor/spi.c            | 16 ++++++++++++----
 src/test/regress/expected/matview.out | 25 +++++++++++++++++++++++++
 src/test/regress/sql/matview.sql      | 14 ++++++++++++++
 3 files changed, 51 insertions(+), 4 deletions(-)

diff --git a/src/backend/executor/spi.c b/src/backend/executor/spi.c
index 649040e8fd7..82d5005e872 100644
--- a/src/backend/executor/spi.c
+++ b/src/backend/executor/spi.c
@@ -2186,15 +2186,23 @@ _SPI_execute_plan(SPIPlanPtr plan, ParamListInfo paramLI,
 				 */
 				if (IsA(stmt, CreateTableAsStmt))
 				{
-					Assert(strncmp(completionTag, "SELECT ", 7) == 0);
-					_SPI_current->processed = strtoul(completionTag + 7,
-													  NULL, 10);
+					CreateTableAsStmt *ctastmt = (CreateTableAsStmt *) stmt;
+
+					if (strncmp(completionTag, "SELECT ", 7) == 0)
+						_SPI_current->processed =
+							strtoul(completionTag + 7, NULL, 10);
+					else
+					{
+						/* Must be a CREATE ... WITH NO DATA */
+						Assert(ctastmt->into->skipData);
+						_SPI_current->processed = 0;
+					}
 
 					/*
 					 * For historical reasons, if CREATE TABLE AS was spelled
 					 * as SELECT INTO, return a special return code.
 					 */
-					if (((CreateTableAsStmt *) stmt)->is_select_into)
+					if (ctastmt->is_select_into)
 						res = SPI_OK_SELINTO;
 				}
 				else if (IsA(stmt, CopyStmt))
diff --git a/src/test/regress/expected/matview.out b/src/test/regress/expected/matview.out
index 716daa2b713..4aa91f41644 100644
--- a/src/test/regress/expected/matview.out
+++ b/src/test/regress/expected/matview.out
@@ -553,3 +553,28 @@ REFRESH MATERIALIZED VIEW mv_foo;
 REFRESH MATERIALIZED VIEW CONCURRENTLY mv_foo;
 DROP OWNED BY user_dw CASCADE;
 DROP ROLE user_dw;
+-- make sure that create WITH NO DATA works via SPI
+BEGIN;
+CREATE FUNCTION mvtest_func()
+  RETURNS void AS $$
+BEGIN
+  CREATE MATERIALIZED VIEW mvtest1 AS SELECT 1 AS x;
+  CREATE MATERIALIZED VIEW mvtest2 AS SELECT 1 AS x WITH NO DATA;
+END;
+$$ LANGUAGE plpgsql;
+SELECT mvtest_func();
+ mvtest_func 
+-------------
+ 
+(1 row)
+
+SELECT * FROM mvtest1;
+ x 
+---
+ 1
+(1 row)
+
+SELECT * FROM mvtest2;
+ERROR:  materialized view "mvtest2" has not been populated
+HINT:  Use the REFRESH MATERIALIZED VIEW command.
+ROLLBACK;
diff --git a/src/test/regress/sql/matview.sql b/src/test/regress/sql/matview.sql
index 7c2a93d5560..20588d189f4 100644
--- a/src/test/regress/sql/matview.sql
+++ b/src/test/regress/sql/matview.sql
@@ -224,3 +224,17 @@ REFRESH MATERIALIZED VIEW mv_foo;
 REFRESH MATERIALIZED VIEW CONCURRENTLY mv_foo;
 DROP OWNED BY user_dw CASCADE;
 DROP ROLE user_dw;
+
+-- make sure that create WITH NO DATA works via SPI
+BEGIN;
+CREATE FUNCTION mvtest_func()
+  RETURNS void AS $$
+BEGIN
+  CREATE MATERIALIZED VIEW mvtest1 AS SELECT 1 AS x;
+  CREATE MATERIALIZED VIEW mvtest2 AS SELECT 1 AS x WITH NO DATA;
+END;
+$$ LANGUAGE plpgsql;
+SELECT mvtest_func();
+SELECT * FROM mvtest1;
+SELECT * FROM mvtest2;
+ROLLBACK;