Test to reproduce the deadlock

Signed-off-by: alanprot <alanprot@gmail.com>

tsdb/db_test.go

@@ -3726,6 +3726,66 @@ func testChunkQuerierShouldNotPanicIfHeadChunkIsTruncatedWhileReadingQueriedChun
 	}
 }
 
+func TestMMapHeadChunksAndCompactConcurrently(t *testing.T) {
+	opts := DefaultOptions()
+	ctx := context.Background()
+	blockDuration := int64(1000)
+	opts.MinBlockDuration = blockDuration
+	opts.MaxBlockDuration = blockDuration
+	opts.OutOfOrderTimeWindow = 3 * DefaultBlockDuration
+	db := openTestDB(t, opts, nil)
+	db.DisableCompactions()
+	defer func() {
+		require.NoError(t, db.Close())
+	}()
+	app := db.Appender(ctx)
+	for j := 0; j < 50000; j++ {
+		_, err := app.Append(0, labels.FromStrings(labels.MetricName, fmt.Sprintf("metric_to_be_gced_%v", j)), 0, float64(0))
+		require.NoError(t, err)
+	}
+
+	// Adding one series with 2x block duration to make the head compactable.
+	_, err := app.Append(0, labels.FromStrings(labels.MetricName, "metric"), 2*blockDuration, float64(0))
+	require.NoError(t, err)
+	require.NoError(t, app.Commit())
+	done := make(chan struct{})
+
+	// Create 2 go routines to Compact the head and ForceHeadMMap  at the same time
+	go func() {
+		defer close(done)
+		err := db.Compact(ctx)
+		require.NoError(t, err)
+	}()
+
+	go func() {
+		for {
+			select {
+			case <-done:
+				return
+			default:
+				db.ForceHeadMMap()
+			}
+		}
+	}()
+
+	timeout := time.After(time.Second * 10)
+	for {
+		select {
+		case <-done:
+			return
+		case <-timeout:
+			t.Fatalf("timeout waiting for compaction")
+			return
+		default:
+			// Lets also keep creating new series so we make sure the stripped series are changing and there is no race
+			app := db.Appender(ctx)
+			_, err := app.Append(0, labels.FromStrings(labels.MetricName, fmt.Sprintf("newSeries_%v", rand.Int63())), 2*blockDuration, float64(0))
+			require.NoError(t, err)
+			require.NoError(t, app.Commit())
+		}
+	}
+}
+
 func TestQuerierShouldNotFailIfOOOCompactionOccursAfterRetrievingQuerier(t *testing.T) {
 	opts := DefaultOptions()
 	opts.OutOfOrderTimeWindow = 3 * DefaultBlockDuration