remove synchronization

Author: dnhatn

server/src/main/java/org/elasticsearch/index/seqno/LocalCheckpointTracker.java

@@ -161,15 +161,19 @@ public synchronized void waitForOpsToComplete(final long seqNo) throws Interrupt
     /**
      * Checks if the given sequence number was marked as completed in this tracker.
      */
-    public synchronized boolean contains(long seqNo) {
+    public boolean contains(long seqNo) {
+        assert seqNo >= 0 : "invalid seq_no [" + seqNo + "]";
         if (seqNo >= nextSeqNo) {
             return false;
         }
         if (seqNo <= checkpoint) {
             return true;
         }
         final long bitSetKey = getBitSetKey(seqNo);
-        final CountedBitSet bitSet = processedSeqNo.get(bitSetKey);
+        final CountedBitSet bitSet;
+        synchronized (this) {
+            bitSet = processedSeqNo.get(bitSetKey);
+        }
         return bitSet != null && bitSet.get(seqNoToBitSetOffset(seqNo));
     }
 
@@ -221,7 +225,6 @@ private long lastSeqNoInBitSet(final long bitSetKey) {
      * @return the bit set corresponding to the provided sequence number
      */
     private long getBitSetKey(final long seqNo) {
-        assert Thread.holdsLock(this);
         return seqNo / BIT_SET_SIZE;
     }
 
@@ -247,7 +250,6 @@ private CountedBitSet getBitSetForSeqNo(final long seqNo) {
      * @return the position in the bit set corresponding to the provided sequence number
      */
     private int seqNoToBitSetOffset(final long seqNo) {
-        assert Thread.holdsLock(this);
         return Math.toIntExact(seqNo % BIT_SET_SIZE);
     }
 

server/src/test/java/org/elasticsearch/index/seqno/LocalCheckpointTrackerTests.java

@@ -295,4 +295,23 @@ public void describeTo(Description description) {
         });
         assertThat(tracker.generateSeqNo(), equalTo((long) (maxSeqNo + 1)));
     }
+
+    public void testContains() {
+        final long maxSeqNo = randomLongBetween(SequenceNumbers.NO_OPS_PERFORMED, 100);
+        final long localCheckpoint = randomLongBetween(SequenceNumbers.NO_OPS_PERFORMED, maxSeqNo);
+        final LocalCheckpointTracker tracker = new LocalCheckpointTracker(maxSeqNo, localCheckpoint);
+        if (localCheckpoint >= 0) {
+            assertThat(tracker.contains(randomLongBetween(0, localCheckpoint)), equalTo(true));
+        }
+        assertThat(tracker.contains(randomLongBetween(localCheckpoint + 1, Long.MAX_VALUE)), equalTo(false));
+        final int numOps = between(1, 100);
+        final List<Long> seqNos = new ArrayList<>();
+        for (int i = 0; i < numOps; i++) {
+            long seqNo = randomLongBetween(0, 1000);
+            seqNos.add(seqNo);
+            tracker.markSeqNoAsCompleted(seqNo);
+        }
+        final long seqNo = randomNonNegativeLong();
+        assertThat(tracker.contains(seqNo), equalTo(seqNo <= localCheckpoint || seqNos.contains(seqNo)));
+    }
 }