Merge pull request #5833 from jonseymour/jss-5832-snapshot-may-not-be-sorted

tsm: cache: need to check that snapshot has been sorted

CHANGELOG.md

@@ -46,6 +46,7 @@
 - [#5753](https://github.com/influxdata/influxdb/pull/5753): Ensures that drop-type commands work correctly in a cluster
 - [#5814](https://github.com/influxdata/influxdb/issues/5814): Run CQs with the same name from different databases
 - [#5699](https://github.com/influxdata/influxdb/issues/5699): Fix potential thread safety issue in cache @jonseymour
+- [#5832](https://github.com/influxdata/influxdb/issues/5832): tsm: cache: need to check that snapshot has been sorted @jonseymour
 
 ## v0.10.1 [2016-02-18]
 

tsdb/engine/tsm1/cache.go

@@ -316,6 +316,7 @@ func (c *Cache) merged(key string) Values {
 	if c.snapshot != nil {
 		snapshotEntries := c.snapshot.store[key]
 		if snapshotEntries != nil {
+			snapshotEntries.deduplicate() // guarantee we are deduplicated
 			entries = append(entries, snapshotEntries)
 			sz += snapshotEntries.count()
 		}

tsdb/engine/tsm1/cache_test.go

@@ -140,6 +140,8 @@ func TestCache_CacheSnapshot(t *testing.T) {
 	v3 := NewValue(time.Unix(5, 0).UTC(), 4.0)
 	v4 := NewValue(time.Unix(6, 0).UTC(), 5.0)
 	v5 := NewValue(time.Unix(1, 0).UTC(), 5.0)
+	v6 := NewValue(time.Unix(7, 0).UTC(), 5.0)
+	v7 := NewValue(time.Unix(2, 0).UTC(), 5.0)
 
 	c := NewCache(512, "")
 	if err := c.Write("foo", Values{v0, v1, v2, v3}); err != nil {
@@ -178,10 +180,31 @@ func TestCache_CacheSnapshot(t *testing.T) {
 
 	// Clear snapshot, ensuring non-snapshot data untouched.
 	c.ClearSnapshot(true)
+
 	expValues = Values{v5, v4}
 	if deduped := c.Values("foo"); !reflect.DeepEqual(expValues, deduped) {
 		t.Fatalf("post-clear values for foo incorrect, exp: %v, got %v", expValues, deduped)
 	}
+
+	// Create another snapshot
+	snapshot = c.Snapshot()
+
+	if err := c.Write("foo", Values{v4, v5}); err != nil {
+		t.Fatalf("failed to write post-snap value, key foo to cache: %s", err.Error())
+	}
+
+	c.ClearSnapshot(true)
+
+	snapshot = c.Snapshot()
+
+	if err := c.Write("foo", Values{v6, v7}); err != nil {
+		t.Fatalf("failed to write post-snap value, key foo to cache: %s", err.Error())
+	}
+
+	expValues = Values{v5, v7, v4, v6}
+	if deduped := c.Values("foo"); !reflect.DeepEqual(expValues, deduped) {
+		t.Fatalf("post-snapshot out-of-order write values for foo incorrect, exp: %v, got %v", expValues, deduped)
+	}
 }
 
 func TestCache_CacheEmptySnapshot(t *testing.T) {