From f5b0f63c50cb8436bed093f280124fb2e2709af1 Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@paquier.xyz>
Date: Tue, 21 Aug 2018 10:25:05 +0900
Subject: [PATCH 2/2] Improve VACUUM and ANALYZE by avoiding early lock queue

A caller of VACUUM can perform early lookup obtention which can cause
other sessions to block on the request done, causing potentially DOS
attacks as even a non-privileged user can attempt a truncation of a
critical catalog table to block even all incoming connection attempts.

Contrary to TRUNCATE, a client could attempt a system-wide VACUUM after
building the list of relations to VACUUM, which can cause vacuum_rel()
to try to lock the relation but the thing would just lock.  When the
client specifies a list of relations and the relation needs to be
skipped, fail hard so as there is no conflict with any relation a user
has no rights to work on.

vacuum_rel() already had the sanity checks needed, except that those
were applied too late.  This commit refactors the code so as relation
skips are checked beforehand, making it safer to avoid too early lock,
for both manual VACUUM with and without a list of relations specified.

Reported-by: Lloyd Albin, Jeremy Schneider
Author: Michael Paquier
Reviewed by: Nathan Bossart, Kyotaro Horiguchi
Discussion: https://postgr.es/m/152512087100.19803.12733865831237526317@wrigleys.postgresql.org
---
 src/backend/commands/analyze.c                |  28 ++--
 src/backend/commands/vacuum.c                 | 153 +++++++++++++-----
 src/include/commands/vacuum.h                 |   3 +
 .../isolation/expected/vacuum-conflict.out    | 149 +++++++++++++++++
 src/test/isolation/isolation_schedule         |   1 +
 src/test/isolation/specs/vacuum-conflict.spec |  51 ++++++
 6 files changed, 329 insertions(+), 56 deletions(-)
 create mode 100644 src/test/isolation/expected/vacuum-conflict.out
 create mode 100644 src/test/isolation/specs/vacuum-conflict.spec

diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index 3e148f03d0..4f0753e02a 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -196,27 +196,17 @@ analyze_rel(Oid relid, RangeVar *relation, int options,
 	}
 
 	/*
-	 * Check permissions --- this should match vacuum's check!
+	 * Check if relation needs to be skipped based on ownership.  This
+	 * check happens also when building the relation list to analyze
+	 * for a manual operation, and needs to be done additionally here
+	 * as ANALYZE could happen across multiple transactions where relation
+	 * ownership could have changed in-between.  Make sure to generate
+	 * only logs for ANALYZE in this case.
 	 */
-	if (!(pg_class_ownercheck(RelationGetRelid(onerel), GetUserId()) ||
-		  (pg_database_ownercheck(MyDatabaseId, GetUserId()) && !onerel->rd_rel->relisshared)))
+	if (!vacuum_is_relation_owner(RelationGetRelid(onerel),
+								  onerel->rd_rel,
+								  options & VACOPT_ANALYZE))
 	{
-		/* No need for a WARNING if we already complained during VACUUM */
-		if (!(options & VACOPT_VACUUM))
-		{
-			if (onerel->rd_rel->relisshared)
-				ereport(WARNING,
-						(errmsg("skipping \"%s\" --- only superuser can analyze it",
-								RelationGetRelationName(onerel))));
-			else if (onerel->rd_rel->relnamespace == PG_CATALOG_NAMESPACE)
-				ereport(WARNING,
-						(errmsg("skipping \"%s\" --- only superuser or database owner can analyze it",
-								RelationGetRelationName(onerel))));
-			else
-				ereport(WARNING,
-						(errmsg("skipping \"%s\" --- only table or database owner can analyze it",
-								RelationGetRelationName(onerel))));
-		}
 		relation_close(onerel, ShareUpdateExclusiveLock);
 		return;
 	}
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index ee32fe8871..2cf2393ce1 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -68,8 +68,8 @@ static BufferAccessStrategy vac_strategy;
 
 
 /* non-export function prototypes */
-static List *expand_vacuum_rel(VacuumRelation *vrel);
-static List *get_all_vacuum_rels(void);
+static List *expand_vacuum_rel(VacuumRelation *vrel, int options);
+static List *get_all_vacuum_rels(int options);
 static void vac_truncate_clog(TransactionId frozenXID,
 				  MultiXactId minMulti,
 				  TransactionId lastSaneFrozenXid,
@@ -257,7 +257,7 @@ vacuum(int options, List *relations, VacuumParams *params,
 			List	   *sublist;
 			MemoryContext old_context;
 
-			sublist = expand_vacuum_rel(vrel);
+			sublist = expand_vacuum_rel(vrel, options);
 			old_context = MemoryContextSwitchTo(vac_context);
 			newrels = list_concat(newrels, sublist);
 			MemoryContextSwitchTo(old_context);
@@ -265,7 +265,7 @@ vacuum(int options, List *relations, VacuumParams *params,
 		relations = newrels;
 	}
 	else
-		relations = get_all_vacuum_rels();
+		relations = get_all_vacuum_rels(options);
 
 	/*
 	 * Decide whether we need to start/commit our own transactions.
@@ -408,6 +408,79 @@ vacuum(int options, List *relations, VacuumParams *params,
 	vac_context = NULL;
 }
 
+/*
+ * Check if a given relation can be safely vacuumed or analyzed.  If the
+ * user is not the relation owner, issue a WARNING log message and return
+ * false to let the caller decide what to do with this relation.  This
+ * routine is used for the decision-making of VACUUM and ANALYZE.
+ */
+bool
+vacuum_is_relation_owner(Oid relid, Form_pg_class reltuple, int options)
+{
+	char		   *relname;
+
+	Assert((options & (VACOPT_VACUUM | VACOPT_ANALYZE)) != 0);
+
+	/*
+	 * Check permissions.
+	 *
+	 * We allow the user to vacuum or analyze a table if he is superuser, the
+	 * table owner, or the database owner (but in the latter case, only if
+	 * it's not a shared relation).  pg_class_ownercheck includes the
+	 * superuser case.
+	 *
+	 * Note we choose to treat permissions failure as a WARNING and keep
+	 * trying to vacuum or analyze the rest of the DB --- is this appropriate?
+	 */
+	if (pg_class_ownercheck(relid, GetUserId()) ||
+		(pg_database_ownercheck(MyDatabaseId, GetUserId()) && !reltuple->relisshared))
+		return true;
+
+	relname = NameStr(reltuple->relname);
+
+	if ((options & VACOPT_VACUUM) != 0)
+	{
+		if (reltuple->relisshared)
+			ereport(WARNING,
+					(errmsg("skipping \"%s\" --- only superuser can vacuum it",
+							relname)));
+		else if (reltuple->relnamespace == PG_CATALOG_NAMESPACE)
+			ereport(WARNING,
+					(errmsg("skipping \"%s\" --- only superuser or database owner can vacuum it",
+							relname)));
+		else
+			ereport(WARNING,
+					(errmsg("skipping \"%s\" --- only table or database owner can vacuum it",
+							relname)));
+
+		/*
+		 * For VACUUM ANALYZE, both logs could show up, but just generate
+		 * information for VACUUM as that would be the first one to
+		 * process.
+		 */
+		return;
+	}
+
+	if ((options & VACOPT_ANALYZE) != 0)
+	{
+		if (reltuple->relisshared)
+			ereport(WARNING,
+					(errmsg("skipping \"%s\" --- only superuser can analyze it",
+							relname)));
+		else if (reltuple->relnamespace == PG_CATALOG_NAMESPACE)
+			ereport(WARNING,
+					(errmsg("skipping \"%s\" --- only superuser or database owner can analyze it",
+							relname)));
+		else
+			ereport(WARNING,
+					(errmsg("skipping \"%s\" --- only table or database owner can analyze it",
+							relname)));
+	}
+
+	return false;
+}
+
+
 /*
  * Given a VacuumRelation, fill in the table OID if it wasn't specified,
  * and optionally add VacuumRelations for partitions of the table.
@@ -423,7 +496,7 @@ vacuum(int options, List *relations, VacuumParams *params,
  * are made in vac_context.
  */
 static List *
-expand_vacuum_rel(VacuumRelation *vrel)
+expand_vacuum_rel(VacuumRelation *vrel, int options)
 {
 	List	   *vacrels = NIL;
 	MemoryContext oldcontext;
@@ -456,6 +529,28 @@ expand_vacuum_rel(VacuumRelation *vrel)
 		 */
 		relid = RangeVarGetRelid(vrel->relation, AccessShareLock, false);
 
+		/*
+		 * To check whether the relation is a partitioned table and its
+		 * ownership, fetch its syscache entry.
+		 */
+		tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
+		if (!HeapTupleIsValid(tuple))
+			elog(ERROR, "cache lookup failed for relation %u", relid);
+		classForm = (Form_pg_class) GETSTRUCT(tuple);
+
+		/* check permissions of relation */
+		if (!vacuum_is_relation_owner(relid, classForm, options))
+		{
+			ReleaseSysCache(tuple);
+
+			/*
+			 * Release lock again with AccessShareLock -- see below for
+			 * the reason why this lock is released.
+			 */
+			UnlockRelationOid(relid, AccessShareLock);
+			return vacrels;
+		}
+
 		/*
 		 * Make a returnable VacuumRelation for this rel.
 		 */
@@ -465,14 +560,6 @@ expand_vacuum_rel(VacuumRelation *vrel)
 													  vrel->va_cols));
 		MemoryContextSwitchTo(oldcontext);
 
-		/*
-		 * To check whether the relation is a partitioned table, fetch its
-		 * syscache entry.
-		 */
-		tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
-		if (!HeapTupleIsValid(tuple))
-			elog(ERROR, "cache lookup failed for relation %u", relid);
-		classForm = (Form_pg_class) GETSTRUCT(tuple);
 		include_parts = (classForm->relkind == RELKIND_PARTITIONED_TABLE);
 		ReleaseSysCache(tuple);
 
@@ -530,7 +617,7 @@ expand_vacuum_rel(VacuumRelation *vrel)
  * the current database.  The list is built in vac_context.
  */
 static List *
-get_all_vacuum_rels(void)
+get_all_vacuum_rels(int options)
 {
 	List	   *vacrels = NIL;
 	Relation	pgclass;
@@ -545,6 +632,11 @@ get_all_vacuum_rels(void)
 	{
 		Form_pg_class classForm = (Form_pg_class) GETSTRUCT(tuple);
 		MemoryContext oldcontext;
+		Oid			relid = HeapTupleGetOid(tuple);
+
+		/* check permissions of relation */
+		if (!vacuum_is_relation_owner(relid, classForm, options))
+			continue;
 
 		/*
 		 * We include partitioned tables here; depending on which operation is
@@ -563,7 +655,7 @@ get_all_vacuum_rels(void)
 		 */
 		oldcontext = MemoryContextSwitchTo(vac_context);
 		vacrels = lappend(vacrels, makeVacuumRelation(NULL,
-													  HeapTupleGetOid(tuple),
+													  relid,
 													  NIL));
 		MemoryContextSwitchTo(oldcontext);
 	}
@@ -1436,30 +1528,17 @@ vacuum_rel(Oid relid, RangeVar *relation, int options, VacuumParams *params)
 	}
 
 	/*
-	 * Check permissions.
-	 *
-	 * We allow the user to vacuum a table if he is superuser, the table
-	 * owner, or the database owner (but in the latter case, only if it's not
-	 * a shared relation).  pg_class_ownercheck includes the superuser case.
-	 *
-	 * Note we choose to treat permissions failure as a WARNING and keep
-	 * trying to vacuum the rest of the DB --- is this appropriate?
+	 * Check if relation needs to be skipped based on ownership.  This
+	 * check happens also when building the relation list to vacuum
+	 * for a manual operation, and needs to be done additionally here
+	 * as VACUUM could happen across multiple transactions where relation
+	 * ownership could have changed in-between.  Make sure to only generate
+	 * logs for VACUUM in this case.
 	 */
-	if (!(pg_class_ownercheck(RelationGetRelid(onerel), GetUserId()) ||
-		  (pg_database_ownercheck(MyDatabaseId, GetUserId()) && !onerel->rd_rel->relisshared)))
+	if (!vacuum_is_relation_owner(RelationGetRelid(onerel),
+								  onerel->rd_rel,
+								  options & VACOPT_VACUUM))
 	{
-		if (onerel->rd_rel->relisshared)
-			ereport(WARNING,
-					(errmsg("skipping \"%s\" --- only superuser can vacuum it",
-							RelationGetRelationName(onerel))));
-		else if (onerel->rd_rel->relnamespace == PG_CATALOG_NAMESPACE)
-			ereport(WARNING,
-					(errmsg("skipping \"%s\" --- only superuser or database owner can vacuum it",
-							RelationGetRelationName(onerel))));
-		else
-			ereport(WARNING,
-					(errmsg("skipping \"%s\" --- only table or database owner can vacuum it",
-							RelationGetRelationName(onerel))));
 		relation_close(onerel, lmode);
 		PopActiveSnapshot();
 		CommitTransactionCommand();
diff --git a/src/include/commands/vacuum.h b/src/include/commands/vacuum.h
index 85d472f0a5..85b181bf2f 100644
--- a/src/include/commands/vacuum.h
+++ b/src/include/commands/vacuum.h
@@ -15,6 +15,7 @@
 #define VACUUM_H
 
 #include "access/htup.h"
+#include "catalog/pg_class.h"
 #include "catalog/pg_statistic.h"
 #include "catalog/pg_type.h"
 #include "nodes/parsenodes.h"
@@ -185,6 +186,8 @@ extern void vacuum_set_xid_limits(Relation rel,
 					  MultiXactId *mxactFullScanLimit);
 extern void vac_update_datfrozenxid(void);
 extern void vacuum_delay_point(void);
+extern bool vacuum_is_relation_owner(Oid relid, Form_pg_class reltuple,
+									 int options);
 
 /* in commands/vacuumlazy.c */
 extern void lazy_vacuum_rel(Relation onerel, int options,
diff --git a/src/test/isolation/expected/vacuum-conflict.out b/src/test/isolation/expected/vacuum-conflict.out
new file mode 100644
index 0000000000..06ac75ef23
--- /dev/null
+++ b/src/test/isolation/expected/vacuum-conflict.out
@@ -0,0 +1,149 @@
+Parsed test spec with 2 sessions
+
+starting permutation: s1_begin s1_lock s2_auth s2_vacuum s1_commit s2_reset
+step s1_begin: BEGIN;
+step s1_lock: LOCK vacuum_tab IN SHARE UPDATE EXCLUSIVE MODE;
+step s2_auth: SET ROLE regress_vacuum_conflict;
+WARNING:  skipping "vacuum_tab" --- only table or database owner can vacuum it
+step s2_vacuum: VACUUM vacuum_tab;
+step s1_commit: COMMIT;
+step s2_reset: RESET ROLE;
+
+starting permutation: s1_begin s2_auth s2_vacuum s1_lock s1_commit s2_reset
+step s1_begin: BEGIN;
+step s2_auth: SET ROLE regress_vacuum_conflict;
+WARNING:  skipping "vacuum_tab" --- only table or database owner can vacuum it
+step s2_vacuum: VACUUM vacuum_tab;
+step s1_lock: LOCK vacuum_tab IN SHARE UPDATE EXCLUSIVE MODE;
+step s1_commit: COMMIT;
+step s2_reset: RESET ROLE;
+
+starting permutation: s1_begin s2_auth s1_lock s2_vacuum s1_commit s2_reset
+step s1_begin: BEGIN;
+step s2_auth: SET ROLE regress_vacuum_conflict;
+step s1_lock: LOCK vacuum_tab IN SHARE UPDATE EXCLUSIVE MODE;
+WARNING:  skipping "vacuum_tab" --- only table or database owner can vacuum it
+step s2_vacuum: VACUUM vacuum_tab;
+step s1_commit: COMMIT;
+step s2_reset: RESET ROLE;
+
+starting permutation: s2_auth s2_vacuum s1_begin s1_lock s1_commit s2_reset
+step s2_auth: SET ROLE regress_vacuum_conflict;
+WARNING:  skipping "vacuum_tab" --- only table or database owner can vacuum it
+step s2_vacuum: VACUUM vacuum_tab;
+step s1_begin: BEGIN;
+step s1_lock: LOCK vacuum_tab IN SHARE UPDATE EXCLUSIVE MODE;
+step s1_commit: COMMIT;
+step s2_reset: RESET ROLE;
+
+starting permutation: s1_begin s1_lock s2_auth s2_analyze s1_commit s2_reset
+step s1_begin: BEGIN;
+step s1_lock: LOCK vacuum_tab IN SHARE UPDATE EXCLUSIVE MODE;
+step s2_auth: SET ROLE regress_vacuum_conflict;
+WARNING:  skipping "vacuum_tab" --- only table or database owner can analyze it
+step s2_analyze: ANALYZE vacuum_tab;
+step s1_commit: COMMIT;
+step s2_reset: RESET ROLE;
+
+starting permutation: s1_begin s2_auth s2_analyze s1_lock s1_commit s2_reset
+step s1_begin: BEGIN;
+step s2_auth: SET ROLE regress_vacuum_conflict;
+WARNING:  skipping "vacuum_tab" --- only table or database owner can analyze it
+step s2_analyze: ANALYZE vacuum_tab;
+step s1_lock: LOCK vacuum_tab IN SHARE UPDATE EXCLUSIVE MODE;
+step s1_commit: COMMIT;
+step s2_reset: RESET ROLE;
+
+starting permutation: s1_begin s2_auth s1_lock s2_analyze s1_commit s2_reset
+step s1_begin: BEGIN;
+step s2_auth: SET ROLE regress_vacuum_conflict;
+step s1_lock: LOCK vacuum_tab IN SHARE UPDATE EXCLUSIVE MODE;
+WARNING:  skipping "vacuum_tab" --- only table or database owner can analyze it
+step s2_analyze: ANALYZE vacuum_tab;
+step s1_commit: COMMIT;
+step s2_reset: RESET ROLE;
+
+starting permutation: s2_auth s2_analyze s1_begin s1_lock s1_commit s2_reset
+step s2_auth: SET ROLE regress_vacuum_conflict;
+WARNING:  skipping "vacuum_tab" --- only table or database owner can analyze it
+step s2_analyze: ANALYZE vacuum_tab;
+step s1_begin: BEGIN;
+step s1_lock: LOCK vacuum_tab IN SHARE UPDATE EXCLUSIVE MODE;
+step s1_commit: COMMIT;
+step s2_reset: RESET ROLE;
+
+starting permutation: s1_begin s2_grant s1_lock s2_auth s2_vacuum s1_commit s2_reset
+step s1_begin: BEGIN;
+step s2_grant: ALTER TABLE vacuum_tab OWNER TO regress_vacuum_conflict;
+step s1_lock: LOCK vacuum_tab IN SHARE UPDATE EXCLUSIVE MODE;
+step s2_auth: SET ROLE regress_vacuum_conflict;
+step s2_vacuum: VACUUM vacuum_tab; <waiting ...>
+step s1_commit: COMMIT;
+step s2_vacuum: <... completed>
+step s2_reset: RESET ROLE;
+
+starting permutation: s1_begin s2_grant s2_auth s2_vacuum s1_lock s1_commit s2_reset
+step s1_begin: BEGIN;
+step s2_grant: ALTER TABLE vacuum_tab OWNER TO regress_vacuum_conflict;
+step s2_auth: SET ROLE regress_vacuum_conflict;
+step s2_vacuum: VACUUM vacuum_tab;
+step s1_lock: LOCK vacuum_tab IN SHARE UPDATE EXCLUSIVE MODE;
+step s1_commit: COMMIT;
+step s2_reset: RESET ROLE;
+
+starting permutation: s1_begin s2_grant s2_auth s1_lock s2_vacuum s1_commit s2_reset
+step s1_begin: BEGIN;
+step s2_grant: ALTER TABLE vacuum_tab OWNER TO regress_vacuum_conflict;
+step s2_auth: SET ROLE regress_vacuum_conflict;
+step s1_lock: LOCK vacuum_tab IN SHARE UPDATE EXCLUSIVE MODE;
+step s2_vacuum: VACUUM vacuum_tab; <waiting ...>
+step s1_commit: COMMIT;
+step s2_vacuum: <... completed>
+step s2_reset: RESET ROLE;
+
+starting permutation: s2_grant s2_auth s2_vacuum s1_begin s1_lock s1_commit s2_reset
+step s2_grant: ALTER TABLE vacuum_tab OWNER TO regress_vacuum_conflict;
+step s2_auth: SET ROLE regress_vacuum_conflict;
+step s2_vacuum: VACUUM vacuum_tab;
+step s1_begin: BEGIN;
+step s1_lock: LOCK vacuum_tab IN SHARE UPDATE EXCLUSIVE MODE;
+step s1_commit: COMMIT;
+step s2_reset: RESET ROLE;
+
+starting permutation: s1_begin s2_grant s1_lock s2_auth s2_analyze s1_commit s2_reset
+step s1_begin: BEGIN;
+step s2_grant: ALTER TABLE vacuum_tab OWNER TO regress_vacuum_conflict;
+step s1_lock: LOCK vacuum_tab IN SHARE UPDATE EXCLUSIVE MODE;
+step s2_auth: SET ROLE regress_vacuum_conflict;
+step s2_analyze: ANALYZE vacuum_tab; <waiting ...>
+step s1_commit: COMMIT;
+step s2_analyze: <... completed>
+step s2_reset: RESET ROLE;
+
+starting permutation: s1_begin s2_grant s2_auth s2_analyze s1_lock s1_commit s2_reset
+step s1_begin: BEGIN;
+step s2_grant: ALTER TABLE vacuum_tab OWNER TO regress_vacuum_conflict;
+step s2_auth: SET ROLE regress_vacuum_conflict;
+step s2_analyze: ANALYZE vacuum_tab;
+step s1_lock: LOCK vacuum_tab IN SHARE UPDATE EXCLUSIVE MODE;
+step s1_commit: COMMIT;
+step s2_reset: RESET ROLE;
+
+starting permutation: s1_begin s2_grant s2_auth s1_lock s2_analyze s1_commit s2_reset
+step s1_begin: BEGIN;
+step s2_grant: ALTER TABLE vacuum_tab OWNER TO regress_vacuum_conflict;
+step s2_auth: SET ROLE regress_vacuum_conflict;
+step s1_lock: LOCK vacuum_tab IN SHARE UPDATE EXCLUSIVE MODE;
+step s2_analyze: ANALYZE vacuum_tab; <waiting ...>
+step s1_commit: COMMIT;
+step s2_analyze: <... completed>
+step s2_reset: RESET ROLE;
+
+starting permutation: s2_grant s2_auth s2_analyze s1_begin s1_lock s1_commit s2_reset
+step s2_grant: ALTER TABLE vacuum_tab OWNER TO regress_vacuum_conflict;
+step s2_auth: SET ROLE regress_vacuum_conflict;
+step s2_analyze: ANALYZE vacuum_tab;
+step s1_begin: BEGIN;
+step s1_lock: LOCK vacuum_tab IN SHARE UPDATE EXCLUSIVE MODE;
+step s1_commit: COMMIT;
+step s2_reset: RESET ROLE;
diff --git a/src/test/isolation/isolation_schedule b/src/test/isolation/isolation_schedule
index 48ae740739..c23b401225 100644
--- a/src/test/isolation/isolation_schedule
+++ b/src/test/isolation/isolation_schedule
@@ -66,6 +66,7 @@ test: async-notify
 test: vacuum-reltuples
 test: timeouts
 test: vacuum-concurrent-drop
+test: vacuum-conflict
 test: predicate-hash
 test: predicate-gist
 test: predicate-gin
diff --git a/src/test/isolation/specs/vacuum-conflict.spec b/src/test/isolation/specs/vacuum-conflict.spec
new file mode 100644
index 0000000000..9b45d26c65
--- /dev/null
+++ b/src/test/isolation/specs/vacuum-conflict.spec
@@ -0,0 +1,51 @@
+# Tests for locking conflicts with VACUUM and ANALYZE commands.
+
+setup
+{
+	CREATE ROLE regress_vacuum_conflict;
+	CREATE TABLE vacuum_tab (a int);
+}
+
+teardown
+{
+	DROP TABLE vacuum_tab;
+	DROP ROLE regress_vacuum_conflict;
+}
+
+session "s1"
+step "s1_begin"          { BEGIN; }
+step "s1_lock"           { LOCK vacuum_tab IN SHARE UPDATE EXCLUSIVE MODE; }
+step "s1_commit"         { COMMIT; }
+
+session "s2"
+step "s2_grant"          { ALTER TABLE vacuum_tab OWNER TO regress_vacuum_conflict; }
+step "s2_auth"           { SET ROLE regress_vacuum_conflict; }
+step "s2_vacuum"         { VACUUM vacuum_tab; }
+step "s2_analyze"        { ANALYZE vacuum_tab; }
+step "s2_reset"          { RESET ROLE; }
+
+# The role doesn't have privileges to vacuum the table, so VACUUM should
+# immediately skip the table without waiting for a lock.
+permutation "s1_begin" "s1_lock" "s2_auth" "s2_vacuum" "s1_commit" "s2_reset"
+permutation "s1_begin" "s2_auth" "s2_vacuum" "s1_lock" "s1_commit" "s2_reset"
+permutation "s1_begin" "s2_auth" "s1_lock" "s2_vacuum" "s1_commit" "s2_reset"
+permutation "s2_auth" "s2_vacuum" "s1_begin" "s1_lock" "s1_commit" "s2_reset"
+
+# Same as previously for ANALYZE
+permutation "s1_begin" "s1_lock" "s2_auth" "s2_analyze" "s1_commit" "s2_reset"
+permutation "s1_begin" "s2_auth" "s2_analyze" "s1_lock" "s1_commit" "s2_reset"
+permutation "s1_begin" "s2_auth" "s1_lock" "s2_analyze" "s1_commit" "s2_reset"
+permutation "s2_auth" "s2_analyze" "s1_begin" "s1_lock" "s1_commit" "s2_reset"
+
+# The role has privileges to vacuum the table, VACUUM will block if
+# another session holds a lock on the table and succeed in all cases.
+permutation "s1_begin" "s2_grant" "s1_lock" "s2_auth" "s2_vacuum" "s1_commit" "s2_reset"
+permutation "s1_begin" "s2_grant" "s2_auth" "s2_vacuum" "s1_lock" "s1_commit" "s2_reset"
+permutation "s1_begin" "s2_grant" "s2_auth" "s1_lock" "s2_vacuum" "s1_commit" "s2_reset"
+permutation "s2_grant" "s2_auth" "s2_vacuum" "s1_begin" "s1_lock" "s1_commit" "s2_reset"
+
+# Same as previously for ANALYZE
+permutation "s1_begin" "s2_grant" "s1_lock" "s2_auth" "s2_analyze" "s1_commit" "s2_reset"
+permutation "s1_begin" "s2_grant" "s2_auth" "s2_analyze" "s1_lock" "s1_commit" "s2_reset"
+permutation "s1_begin" "s2_grant" "s2_auth" "s1_lock" "s2_analyze" "s1_commit" "s2_reset"
+permutation "s2_grant" "s2_auth" "s2_analyze" "s1_begin" "s1_lock" "s1_commit" "s2_reset"
-- 
2.18.0

