SOLR-18035 Remove pauseBeforeStart parameter from leader election (#3966)

Remove a parameter which was never set to cleanup the code.

Author: psalagnac

changelog/unreleased/SOLR-18035-remove-election-pause-parameter.yml

@@ -0,0 +1,7 @@
+title: Remove unused parameter pauseBeforeStart from leader election code
+type: removed
+authors:
+  - name: Pierre Salagnac
+links:
+  - name: SOLR-18035
+    url: https://issues.apache.org/jira/browse/SOLR-18035

solr/core/src/java/org/apache/solr/cloud/ElectionContext.java

@@ -65,7 +65,7 @@ public void cancelElection() throws InterruptedException, KeeperException {
     }
   }
 
-  abstract void runLeaderProcess(boolean weAreReplacement, int pauseBeforeStartMs)
+  abstract void runLeaderProcess(boolean weAreReplacement)
       throws KeeperException, InterruptedException;
 
   public void checkIfIamLeaderFired() {}

solr/core/src/java/org/apache/solr/cloud/LeaderElector.java

@@ -165,7 +165,7 @@ context.leaderSeqPath, watchedNode, getSeq(context.leaderSeqPath), context),
 
   protected void runIamLeaderProcess(final ElectionContext context, boolean weAreReplacement)
       throws KeeperException, InterruptedException {
-    context.runLeaderProcess(weAreReplacement, 0);
+    context.runLeaderProcess(weAreReplacement);
   }
 
   /**

solr/core/src/java/org/apache/solr/cloud/OverseerElectionContext.java

@@ -53,8 +53,7 @@ public OverseerElectionContext(
   }
 
   @Override
-  void runLeaderProcess(boolean weAreReplacement, int pauseBeforeStartMs)
-      throws KeeperException, InterruptedException {
+  void runLeaderProcess(boolean weAreReplacement) throws KeeperException, InterruptedException {
     if (isClosed) {
       return;
     }
@@ -63,14 +62,7 @@ void runLeaderProcess(boolean weAreReplacement, int pauseBeforeStartMs)
     ZkNodeProps myProps = new ZkNodeProps(ID, id);
 
     zkClient.makePath(leaderPath, Utils.toJSON(myProps), CreateMode.EPHEMERAL);
-    if (pauseBeforeStartMs > 0) {
-      try {
-        Thread.sleep(pauseBeforeStartMs);
-      } catch (InterruptedException e) {
-        Thread.interrupted();
-        log.warn("Wait interrupted ", e);
-      }
-    }
+
     synchronized (this) {
       if (!this.isClosed && !overseer.getZkController().getCoreContainer().isShutDown()) {
         overseer.start(id);

solr/core/src/java/org/apache/solr/cloud/ShardLeaderElectionContext.java

@@ -103,8 +103,7 @@ public ElectionContext copy() {
    * weAreReplacement: has someone else been the leader already?
    */
   @Override
-  void runLeaderProcess(boolean weAreReplacement, int pauseBeforeStart)
-      throws KeeperException, InterruptedException {
+  void runLeaderProcess(boolean weAreReplacement) throws KeeperException, InterruptedException {
     String coreName = leaderProps.getStr(ZkStateReader.CORE_NAME_PROP);
     ActionThrottle lt;
     try (SolrCore core = cc.getCore(coreName)) {
@@ -296,7 +295,7 @@ void runLeaderProcess(boolean weAreReplacement, int pauseBeforeStart)
                 coreNodeName);
             zkController.getShardTerms(collection, shardId).setTermEqualsToLeader(coreNodeName);
           }
-          super.runLeaderProcess(weAreReplacement, 0);
+          super.runLeaderProcess(weAreReplacement);
           try (SolrCore core = cc.getCore(coreName)) {
             if (core != null) {
               core.getCoreDescriptor().getCloudDescriptor().setLeader(true);

solr/core/src/java/org/apache/solr/cloud/ShardLeaderElectionContextBase.java

@@ -121,8 +121,7 @@ public void cancelElection() throws InterruptedException, KeeperException {
   }
 
   @Override
-  void runLeaderProcess(boolean weAreReplacement, int pauseBeforeStartMs)
-      throws KeeperException, InterruptedException {
+  void runLeaderProcess(boolean weAreReplacement) throws KeeperException, InterruptedException {
     // register as leader - if an ephemeral is already there, wait to see if it goes away
 
     String parent = ZkMaintenanceUtils.getZkParent(leaderPath);

solr/core/src/test/org/apache/solr/cloud/LeaderElectionTest.java

@@ -93,9 +93,8 @@ public TestLeaderElectionContext(
     }
 
     @Override
-    void runLeaderProcess(boolean weAreReplacement, int pauseBeforeStartMs)
-        throws KeeperException, InterruptedException {
-      super.runLeaderProcess(weAreReplacement, pauseBeforeStartMs);
+    void runLeaderProcess(boolean weAreReplacement) throws KeeperException, InterruptedException {
+      super.runLeaderProcess(weAreReplacement);
       if (runLeaderDelay > 0) {
         log.info("Sleeping for {}ms to simulate leadership takeover delay", runLeaderDelay);
         Thread.sleep(runLeaderDelay);