SAI-5162: Add sysprop solrcloud.publishDownOnStart to controller wh…

…ether publish down on node start or not (#233)

* Add sysprop `solrcloud.skipPublishDownOnStart` to controller whether publish down on node start or not

* Use RTimer instead

* Added timer for the whole publish down ops, including persist ops

* ./gradlew tidy

* Changed solrcloud.skipPublishDownOnStart to solrcloud.publishDownOnStart

which means if such flag is NOT defined (hence solrcloud.publishDownOnStart=false), then by default it will bypass publishAndWaitForDownStates

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

@@ -1023,7 +1023,8 @@ private void init() {
       }
 
       Stat stat = zkClient.exists(ZkStateReader.LIVE_NODES_ZKNODE, null, true);
-      if (stat != null && stat.getNumChildren() > 0) {
+      boolean publishDownOnStart = Boolean.getBoolean("solrcloud.publishDownOnStart");
+      if (stat != null && stat.getNumChildren() > 0 && publishDownOnStart) {
         publishAndWaitForDownStates();
       }
 
@@ -2901,11 +2902,15 @@ public boolean checkIfCoreNodeNameAlreadyExists(CoreDescriptor dcore) {
    * @return the names of the collections that have replicas on the given node
    */
   public Collection<String> publishNodeAsDown(String nodeName) {
+    final RTimer publishDownTimer = new RTimer();
     log.info("Publish node={} as DOWN", nodeName);
 
     ClusterState clusterState = getClusterState();
+    final RTimer zkFetchTimer = new RTimer();
     Map<String, List<Replica>> replicasPerCollectionOnNode =
         clusterState.getReplicaNamesPerCollectionOnNode(nodeName);
+    long zkFetchDuration = (long) zkFetchTimer.getTime();
+    log.info("Spent {} ms on ClusterState#getReplicaNamesPerCollectionOnNode", zkFetchDuration);
     if (distributedClusterStateUpdater.isDistributedStateUpdate()) {
       // Note that with the current implementation, when distributed cluster state updates are
       // enabled, we mark the node down synchronously from this thread, whereas the Overseer cluster
@@ -2958,6 +2963,9 @@ public Collection<String> publishNodeAsDown(String nodeName) {
         log.warn("Could not publish node as down: ", e);
       }
     }
+    long publishDownDuration = (long) publishDownTimer.getTime();
+    log.info("Spent {} ms on ZKController#publishNodeAsDown", publishDownDuration);
+
     return replicasPerCollectionOnNode.keySet();
   }