IGNITE-28105 reduce contention on HLC

Author: Egor Kuts

modules/core/src/main/java/org/apache/ignite/internal/hlc/HybridClockImpl.java

@@ -31,7 +31,6 @@
 import org.apache.ignite.internal.logger.Loggers;
 import org.apache.ignite.internal.tostring.S;
 import org.jetbrains.annotations.Nullable;
-import org.jetbrains.annotations.TestOnly;
 
 /**
  * A Hybrid Logical Clock implementation.
@@ -51,7 +50,6 @@ public class HybridClockImpl implements HybridClock {
 
     private final List<ClockUpdateListener> updateListeners = new CopyOnWriteArrayList<>();
 
-    @TestOnly
     public HybridClockImpl() {
         this.failureProcessor = null;
     }

modules/raft/src/integrationTest/java/org/apache/ignite/raft/server/ItNewLeaderClockTest.java

@@ -38,7 +38,6 @@
 import org.apache.ignite.internal.replicator.TestReplicationGroupId;
 import org.apache.ignite.raft.server.counter.CounterListener;
 import org.junit.jupiter.api.Test;
-import org.junit.jupiter.api.Timeout;
 
 /**
  * Integration test for verifying that a new leader's clock doesn't step down after leadership transfer.
@@ -78,7 +77,7 @@ private void startClusterWithSlowClock() throws Exception {
         }, opts -> {
             opts.setClock(slowClock);
         });
-        // Start second clock with advanced clock. This node is initial leader.
+        // Start second clock with advanced clock. This node is the initial leader.
         startServer(1, raftServer -> {
             String localNodeName = raftServer.clusterService().topologyService().localMember().name();
 
@@ -126,27 +125,22 @@ private void startClusterWithSlowClock() throws Exception {
     /**
      * Tests that a new leader's clock doesn't step down after leadership transfer.
      * Verifies that:
-     * 1. Writes succeed with node 1 as leader (regular clock)
-     * 2. After stopping node 1, a new leader is elected (node 0 or 2 with slow clock)
-     * 3. The new leader's clock is not lower than the last applied command time
+     * 1. Writes succeed with node 1 as leader (advanced clock).
+     * 2. After stopping node 1, a new leader is elected (node 0 or 2 with slow clock).
+     * 3. The new leader's clock is not lower than the last applied command time.
      *
      * @throws Exception If test fails.
      */
     @Test
-    @Timeout(120)
     public void testNewLeaderClockDoesNotStepDown() throws Exception {
         startClusterWithSlowClock();
-
         RaftGroupService client = clients.get(0);
-
         client.refreshLeader().get();
         assertNotNull(client.leader(), "Initial leader should be elected");
-
         // Force leadership to node 1 (server index 1).
         String node1Name = servers.get(1).clusterService().topologyService().localMember().name();
         Peer node1Peer = initialMembersConf.peer(node1Name);
         client.transferLeadership(node1Peer).get();
-
         assertTrue(
                 waitForCondition(() -> {
                     client.refreshLeader().join();
@@ -165,8 +159,7 @@ public void testNewLeaderClockDoesNotStepDown() throws Exception {
         // Verify the writes succeeded.
         Long valueBeforeUnisolate = client.<Long>run(getValueCommand()).get();
         assertEquals(expectedValue, valueBeforeUnisolate, "All writes should have succeeded");
-        HybridTimestamp latestLeaderTime = advancedClock.update(HybridTimestamp.MIN_VALUE);
-
+        HybridTimestamp lastAppliedCmdTsFromAdvancedClockLeader = advancedClock.update(HybridTimestamp.MIN_VALUE);
         RaftNodeId node1RaftNodeId = new RaftNodeId(TEST_GROUP, node1Peer);
         servers.get(1).blockMessages(node1RaftNodeId, (msg, peerId) -> true);
         // Now stop the leader.
@@ -176,13 +169,13 @@ public void testNewLeaderClockDoesNotStepDown() throws Exception {
                 waitForCondition(() -> {
                     client.refreshLeader().join();
                     return !node1Peer.equals(client.leader());
-                }, 60_000),
+                }, 30_000),
                 "Leadership should transfer to a slow node"
         );
         HybridTimestamp slow = slowClock.update(HybridTimestamp.MIN_VALUE);
-        log.info("clocks slow: {}, reg: {}", slow, latestLeaderTime);
+        log.info("clocks slow: {}, reg: {}", slow, lastAppliedCmdTsFromAdvancedClockLeader);
         // Verify that new leader's clock is not lower than the last applied command time.
-        assertTrue(slow.longValue() >= latestLeaderTime.longValue());
+        assertTrue(slow.compareTo(lastAppliedCmdTsFromAdvancedClockLeader) >= 0);
     }
 
     /**

modules/raft/src/main/java/org/apache/ignite/raft/jraft/core/NodeImpl.java

@@ -157,6 +157,8 @@ public class NodeImpl implements Node, RaftServerService {
 
     private volatile HybridClock clock;
 
+    private final HybridClock lastAppliedOpClock = new HybridClockImpl();
+
     /**
      * Internal states
      */
@@ -1588,6 +1590,7 @@ private void becomeLeader() {
 
         resetElectionTimeoutToInitial();
         this.stepDownTimer.start();
+        this.clock.update(this.lastAppliedOpClock.current());
     }
 
     // should be in writeLock
@@ -2639,7 +2642,7 @@ public Message handleAppendEntriesRequest(final AppendEntriesRequest request, fi
                 this.currTerm
             );
             if (request.timestamp() != null) {
-                clock.update(request.timestamp());
+                lastAppliedOpClock.update(request.timestamp());
             }
             this.logManager.appendEntries(entries, closure);
             // update configuration after _log_manager updated its memory status