vacuumdb: Fix excluding multiple schemas with -N

When specifying multiple schemas to exclude with -N parameters, none
of the schemas are actually excluded (a single -N worked as expected).
This fixes the catalog query to handle multiple exclusions and adds a
test for this case.

Backpatch to v16 where this was introduced.

Author: Nathan Bossart <nathandbossart@gmail.com>
Author: Kuwamura Masaki <kuwamura@db.is.i.nagoya-u.ac.jp>
Reported-by: Kuwamura Masaki <kuwamura@db.is.i.nagoya-u.ac.jp>
Discussion: https://postgr.es/m/CAMyC8qp9mXPQd5D6s6CJxvmignsbTqGZwDDB6VYJOn1A8WG38w@mail.gmail.com
Backpatch-through: 16

src/bin/scripts/t/100_vacuumdb.pl

@@ -112,6 +112,8 @@
   CREATE INDEX i0 ON funcidx ((f1(x)));
   CREATE SCHEMA "Foo";
   CREATE TABLE "Foo".bar(id int);
+  CREATE SCHEMA "Bar";
+  CREATE TABLE "Bar".baz(id int);
 |);
 $node->command_ok([qw|vacuumdb -Z --table="need""q(uot"(")x") postgres|],
 	'column list');
@@ -159,10 +161,21 @@
 	[ 'vacuumdb', '--schema', '"Foo"', 'postgres' ],
 	qr/VACUUM \(SKIP_DATABASE_STATS\) "Foo".bar/,
 	'vacuumdb --schema');
+$node->issues_sql_like(
+	[ 'vacuumdb', '--schema', '"Foo"', '--schema', '"Bar"', 'postgres' ],
+	qr/VACUUM\ \(SKIP_DATABASE_STATS\)\ "Foo".bar
+		.*VACUUM\ \(SKIP_DATABASE_STATS\)\ "Bar".baz
+	/sx,
+	'vacuumdb multiple --schema switches');
 $node->issues_sql_like(
 	[ 'vacuumdb', '--exclude-schema', '"Foo"', 'postgres' ],
-	qr/(?:(?!VACUUM "Foo".bar).)*/,
+	qr/^(?!.*VACUUM \(SKIP_DATABASE_STATS\) "Foo".bar).*$/s,
 	'vacuumdb --exclude-schema');
+$node->issues_sql_like(
+	[ 'vacuumdb', '--exclude-schema', '"Foo"', '--exclude-schema', '"Bar"', 'postgres' ],
+	qr/^(?!.*VACUUM\ \(SKIP_DATABASE_STATS\)\ "Foo".bar
+	| VACUUM\ \(SKIP_DATABASE_STATS\)\ "Bar".baz).*$/sx,
+	'vacuumdb multiple --exclude-schema switches');
 $node->command_fails_like(
 	[ 'vacuumdb', '-N', 'pg_catalog', '-t', 'pg_class', 'postgres', ],
 	qr/cannot vacuum specific table\(s\) and exclude schema\(s\) at the same time/,

src/bin/scripts/vacuumdb.c

@@ -678,18 +678,22 @@ vacuum_one_database(ConnParams *cparams,
 	/* Used to match the tables or schemas listed by the user */
 	if (objects_listed)
 	{
-		appendPQExpBufferStr(&catalog_query, " JOIN listed_objects"
-							 " ON listed_objects.object_oid ");
-
-		if (objfilter & OBJFILTER_SCHEMA_EXCLUDE)
-			appendPQExpBufferStr(&catalog_query, "OPERATOR(pg_catalog.!=) ");
-		else
-			appendPQExpBufferStr(&catalog_query, "OPERATOR(pg_catalog.=) ");
+		appendPQExpBufferStr(&catalog_query, " LEFT JOIN listed_objects"
+							 " ON listed_objects.object_oid"
+							 " OPERATOR(pg_catalog.=) ");
 
 		if (objfilter & OBJFILTER_TABLE)
 			appendPQExpBufferStr(&catalog_query, "c.oid\n");
 		else
 			appendPQExpBufferStr(&catalog_query, "ns.oid\n");
+
+		if (objfilter & OBJFILTER_SCHEMA_EXCLUDE)
+			appendPQExpBuffer(&catalog_query,
+							  " WHERE listed_objects.object_oid IS NULL\n");
+		else
+			appendPQExpBuffer(&catalog_query,
+							  " WHERE listed_objects.object_oid IS NOT NULL\n");
+		has_where = true;
 	}
 
 	/*
@@ -700,9 +704,11 @@ vacuum_one_database(ConnParams *cparams,
 	 */
 	if ((objfilter & OBJFILTER_TABLE) == 0)
 	{
-		appendPQExpBufferStr(&catalog_query, " WHERE c.relkind OPERATOR(pg_catalog.=) ANY (array["
-							 CppAsString2(RELKIND_RELATION) ", "
-							 CppAsString2(RELKIND_MATVIEW) "])\n");
+		appendPQExpBuffer(&catalog_query,
+						  " %s c.relkind OPERATOR(pg_catalog.=) ANY (array["
+						  CppAsString2(RELKIND_RELATION) ", "
+						  CppAsString2(RELKIND_MATVIEW) "])\n",
+						  has_where ? "AND" : "WHERE");
 		has_where = true;
 	}