Merge pull request #7929 from benbjohnson/tag-iteration-sigsegv

Fix series tag iteration segmentation fault

CHANGELOG.md

@@ -5,6 +5,7 @@
 - [#7877](https://github.com/influxdata/influxdb/issues/7877): Fix mapping of types when the measurement uses a regex
 - [#7888](https://github.com/influxdata/influxdb/pull/7888): Expand query dimensions from the subquery.
 - [#7910](https://github.com/influxdata/influxdb/issues/7910): Fix EvalType when a parenthesis expression is used.
+- [#7929](https://github.com/influxdata/influxdb/issues/7929): Fix series tag iteration segfault. (#7922)
 
 ## v1.2.0 [2017-01-24]
 

tsdb/meta.go

@@ -1620,6 +1620,15 @@ func (s *Series) ShardN() int {
 	return n
 }
 
+// ForEachTag executes fn for every tag. Iteration occurs under lock.
+func (s *Series) ForEachTag(fn func(models.Tag)) {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	for _, t := range s.Tags {
+		fn(t)
+	}
+}
+
 // Dereference removes references to a byte slice.
 func (s *Series) Dereference(b []byte) {
 	s.mu.Lock()

tsdb/store.go

@@ -926,14 +926,14 @@ func (s *Store) TagValues(database string, cond influxql.Expr) ([]TagValues, err
 		// Loop over all keys for each series.
 		m := make(map[KeyValue]struct{}, len(ss))
 		for _, series := range ss {
-			for _, t := range series.Tags {
+			series.ForEachTag(func(t models.Tag) {
 				if !ok {
 					// nop
 				} else if _, exists := keySet[string(t.Key)]; !exists {
-					continue
+					return
 				}
 				m[KeyValue{string(t.Key), string(t.Value)}] = struct{}{}
-			}
+			})
 		}
 
 		// Return an empty slice if there are no key/value matches.