When VACUUM or ANALYZE skips a concurrently dropped table, log it.

Hopefully, the additional logging will help avoid confusion that
could otherwise result.

Nathan Bossart, reviewed by Michael Paquier, Fabrízio Mello, and me

2 files changed, 84 insertions, 11 deletions

diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index 760d19142ec..f952b3c7328 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -120,6 +120,7 @@ analyze_rel(Oid relid, RangeVar *relation, int options,
 	int			elevel;
 	AcquireSampleRowsFunc acquirefunc = NULL;
 	BlockNumber relpages = 0;
+	bool		rel_lock = true;
 
 	/* Select logging level */
 	if (options & VACOPT_VERBOSE)
@@ -149,15 +150,50 @@ analyze_rel(Oid relid, RangeVar *relation, int options,
 	else
 	{
 		onerel = NULL;
-		if (relation &&
-			IsAutoVacuumWorkerProcess() && params->log_min_duration >= 0)
-			ereport(LOG,
+		rel_lock = false;
+	}
+
+	/*
+	 * If we failed to open or lock the relation, emit a log message before
+	 * exiting.
+	 */
+	if (!onerel)
+	{
+		/*
+		 * If the RangeVar is not defined, we do not have enough information
+		 * to provide a meaningful log statement.  Chances are that
+		 * analyze_rel's caller has intentionally not provided this
+		 * information so that this logging is skipped, anyway.
+		 */
+		if (relation == NULL)
+			return;
+
+		/*
+		 * Determine the log level.  For autovacuum logs, we emit a LOG if
+		 * log_autovacuum_min_duration is not disabled.  For manual ANALYZE,
+		 * we emit a WARNING to match the log statements in the permissions
+		 * checks.
+		 */
+		if (!IsAutoVacuumWorkerProcess())
+			elevel = WARNING;
+		else if (params->log_min_duration >= 0)
+			elevel = LOG;
+		else
+			return;
+
+		if (!rel_lock)
+			ereport(elevel,
 					(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
 					 errmsg("skipping analyze of \"%s\" --- lock not available",
 							relation->relname)));
-	}
-	if (!onerel)
+		else
+			ereport(elevel,
+					(errcode(ERRCODE_UNDEFINED_TABLE),
+					 errmsg("skipping analyze of \"%s\" --- relation no longer exists",
+							relation->relname)));
+
 		return;
+	}
 
 	/*
 	 * Check permissions --- this should match vacuum's check!
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index cbd6e9b1616..4abe6b15e0d 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -1330,6 +1330,7 @@ vacuum_rel(Oid relid, RangeVar *relation, int options, VacuumParams *params)
 	Oid			save_userid;
 	int			save_sec_context;
 	int			save_nestlevel;
+	bool		rel_lock = true;
 
 	Assert(params != NULL);
 
@@ -1400,16 +1401,52 @@ vacuum_rel(Oid relid, RangeVar *relation, int options, VacuumParams *params)
 	else
 	{
 		onerel = NULL;
-		if (relation &&
-			IsAutoVacuumWorkerProcess() && params->log_min_duration >= 0)
-			ereport(LOG,
-					(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
-					 errmsg("skipping vacuum of \"%s\" --- lock not available",
-							relation->relname)));
+		rel_lock = false;
 	}
 
+	/*
+	 * If we failed to open or lock the relation, emit a log message before
+	 * exiting.
+	 */
 	if (!onerel)
 	{
+		int			elevel = 0;
+
+		/*
+		 * Determine the log level.
+		 *
+		 * If the RangeVar is not defined, we do not have enough information
+		 * to provide a meaningful log statement.  Chances are that
+		 * vacuum_rel's caller has intentionally not provided this information
+		 * so that this logging is skipped, anyway.
+		 *
+		 * Otherwise, for autovacuum logs, we emit a LOG if
+		 * log_autovacuum_min_duration is not disabled.  For manual VACUUM, we
+		 * emit a WARNING to match the log statements in the permission
+		 * checks.
+		 */
+		if (relation != NULL)
+		{
+			if (!IsAutoVacuumWorkerProcess())
+				elevel = WARNING;
+			else if (params->log_min_duration >= 0)
+				elevel = LOG;
+		}
+
+		if (elevel != 0)
+		{
+			if (!rel_lock)
+				ereport(elevel,
+						(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
+						 errmsg("skipping vacuum of \"%s\" --- lock not available",
+								relation->relname)));
+			else
+				ereport(elevel,
+						(errcode(ERRCODE_UNDEFINED_TABLE),
+						 errmsg("skipping vacuum of \"%s\" --- relation no longer exists",
+								relation->relname)));
+		}
+
 		PopActiveSnapshot();
 		CommitTransactionCommand();
 		return false;