Merge pull request #1325 from rqlite/handle-db-stats-error

Detect DB stats error and log

CHANGELOG.md

@@ -3,6 +3,7 @@
 - [PR #1321](https://github.com/rqlite/rqlite/pull/1321): Check for errors in responses during load testing.
 - [PR #1323](https://github.com/rqlite/rqlite/pull/1323): Add codec for v2 snapshots.
 - [PR #1324](https://github.com/rqlite/rqlite/pull/1324): Close Snapshot after we're finished restoring from it.
+- [PR #1325](https://github.com/rqlite/rqlite/pull/1325): Handle getting an error when asking for database stats.
 
 ## 7.21.1 (June 26th 2023)
 This release changes the mode of SQLite, when rqlite is running in _on-disk_ mode. SQLite now runs in WAL mode, when previously it was in DELETE mode. Testing shows this results in a ~30% increase in write-performance.

db/db.go

@@ -515,6 +515,9 @@ func (db *DB) Size() (int64, error) {
 	if err != nil {
 		return 0, err
 	}
+	if rows[0].Error != "" {
+		return 0, fmt.Errorf(rows[0].Error)
+	}
 
 	return rows[0].Values[0].Parameters[0].GetI(), nil
 }
@@ -1298,6 +1301,9 @@ func (db *DB) memStats() (map[string]int64, error) {
 		if err != nil {
 			return nil, err
 		}
+		if res[0].Error != "" {
+			return nil, fmt.Errorf(res[0].Error)
+		}
 		ms[p] = res[0].Values[0].Parameters[0].GetI()
 	}
 	return ms, nil

store/store.go

@@ -95,6 +95,7 @@ const (
 	numJoins                 = "num_joins"
 	numIgnoredJoins          = "num_ignored_joins"
 	numRemovedBeforeJoins    = "num_removed_before_joins"
+	numDBStatsErrors         = "num_db_stats_errors"
 	snapshotCreateDuration   = "snapshot_create_duration"
 	snapshotPersistDuration  = "snapshot_persist_duration"
 	snapshotDBSerializedSize = "snapshot_db_serialized_size"
@@ -130,6 +131,7 @@ func ResetStats() {
 	stats.Add(numJoins, 0)
 	stats.Add(numIgnoredJoins, 0)
 	stats.Add(numRemovedBeforeJoins, 0)
+	stats.Add(numDBStatsErrors, 0)
 	stats.Add(snapshotCreateDuration, 0)
 	stats.Add(snapshotPersistDuration, 0)
 	stats.Add(snapshotDBSerializedSize, 0)
@@ -846,7 +848,8 @@ func (s *Store) Stats() (map[string]interface{}, error) {
 	}()
 	dbStatus, err := s.db.Stats()
 	if err != nil {
-		return nil, err
+		stats.Add(numDBStatsErrors, 1)
+		s.logger.Printf("failed to get database stats: %s", err.Error())
 	}
 
 	nodes, err := s.Nodes()