From 6f2d99e574888227a29ea173e52f6ff6a19e23db Mon Sep 17 00:00:00 2001
From: Shalin Shekhar Mangar <shalin@apache.org>
Date: Mon, 26 Feb 2018 11:22:38 +0530
Subject: [PATCH] SOLR-10720: Aggressive removal of a collection breaks cluster
 status API

---
 solr/CHANGES.txt                              |  2 ++
 .../OverseerCollectionMessageHandler.java     | 34 -------------------
 .../solr/handler/admin/ClusterStatus.java     | 20 +++++++----
 3 files changed, 15 insertions(+), 41 deletions(-)

diff --git a/solr/CHANGES.txt b/solr/CHANGES.txt
index c6a2dd00285..c915aa48e36 100644
--- a/solr/CHANGES.txt
+++ b/solr/CHANGES.txt
@@ -223,6 +223,8 @@ Bug Fixes
 
 * SOLR-12021: Fixed a bug in ApiSpec and other JSON resource loading that was causing unclosed file handles (hossman)
 
+* SOLR-10720: Aggressive removal of a collection breaks cluster status API. (Alexey Serba, shalin)
+
 Optimizations
 ----------------------
 
diff --git a/solr/core/src/java/org/apache/solr/cloud/api/collections/OverseerCollectionMessageHandler.java b/solr/core/src/java/org/apache/solr/cloud/api/collections/OverseerCollectionMessageHandler.java
index 2143d1e7155..b7cf013e603 100644
--- a/solr/core/src/java/org/apache/solr/cloud/api/collections/OverseerCollectionMessageHandler.java
+++ b/solr/core/src/java/org/apache/solr/cloud/api/collections/OverseerCollectionMessageHandler.java
@@ -23,7 +23,6 @@ import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
-import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Random;
@@ -372,39 +371,6 @@ public class OverseerCollectionMessageHandler implements OverseerMessageHandler,
     inQueue.offer(Utils.toJSON(new ZkNodeProps(propMap)));
   }
 
-  /**
-   * Walks the tree of collection status to verify that any replicas not reporting a "down" status is
-   * on a live node, if any replicas reporting their status as "active" but the node is not live is
-   * marked as "down"; used by CLUSTERSTATUS.
-   * @param liveNodes List of currently live node names.
-   * @param collectionProps Map of collection status information pulled directly from ZooKeeper.
-   */
-
-  @SuppressWarnings("unchecked")
-  protected void crossCheckReplicaStateWithLiveNodes(List<String> liveNodes, NamedList<Object> collectionProps) {
-    Iterator<Map.Entry<String,Object>> colls = collectionProps.iterator();
-    while (colls.hasNext()) {
-      Map.Entry<String,Object> next = colls.next();
-      Map<String,Object> collMap = (Map<String,Object>)next.getValue();
-      Map<String,Object> shards = (Map<String,Object>)collMap.get("shards");
-      for (Object nextShard : shards.values()) {
-        Map<String,Object> shardMap = (Map<String,Object>)nextShard;
-        Map<String,Object> replicas = (Map<String,Object>)shardMap.get("replicas");
-        for (Object nextReplica : replicas.values()) {
-          Map<String,Object> replicaMap = (Map<String,Object>)nextReplica;
-          if (Replica.State.getState((String) replicaMap.get(ZkStateReader.STATE_PROP)) != Replica.State.DOWN) {
-            // not down, so verify the node is live
-            String node_name = (String)replicaMap.get(ZkStateReader.NODE_NAME_PROP);
-            if (!liveNodes.contains(node_name)) {
-              // node is not live, so this replica is actually down
-              replicaMap.put(ZkStateReader.STATE_PROP, Replica.State.DOWN.toString());
-            }
-          }
-        }
-      }
-    }
-  }
-
   /**
    * Get collection status from cluster state.
    * Can return collection status by given shard name.
diff --git a/solr/core/src/java/org/apache/solr/handler/admin/ClusterStatus.java b/solr/core/src/java/org/apache/solr/handler/admin/ClusterStatus.java
index 0f159544f0f..9ebac776cdc 100644
--- a/solr/core/src/java/org/apache/solr/handler/admin/ClusterStatus.java
+++ b/solr/core/src/java/org/apache/solr/handler/admin/ClusterStatus.java
@@ -17,6 +17,7 @@
 package org.apache.solr.handler.admin;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
@@ -53,7 +54,7 @@ public class ClusterStatus {
   }
 
   @SuppressWarnings("unchecked")
-  public  void getClusterStatus(NamedList results)
+  public void getClusterStatus(NamedList results)
       throws KeeperException, InterruptedException {
     // read aliases
     Aliases aliases = zkStateReader.getAliases();
@@ -116,9 +117,7 @@ public class ClusterStatus {
       }
       if (shard != null) {
         String[] paramShards = shard.split(",");
-        for(String paramShard : paramShards){
-            requestedShards.add(paramShard);
-        }
+        requestedShards.addAll(Arrays.asList(paramShards));
       }
 
       if (clusterStateCollection.getStateFormat() > 1) {
@@ -133,9 +132,16 @@ public class ClusterStatus {
       if (collectionVsAliases.containsKey(name) && !collectionVsAliases.get(name).isEmpty()) {
         collectionStatus.put("aliases", collectionVsAliases.get(name));
       }
-      String configName = zkStateReader.readConfigName(name);
-      collectionStatus.put("configName", configName);
-      collectionProps.add(name, collectionStatus);
+      try {
+        String configName = zkStateReader.readConfigName(name);
+        collectionStatus.put("configName", configName);
+        collectionProps.add(name, collectionStatus);
+      } catch (SolrException e) {
+        if (e.getCause() instanceof KeeperException.NoNodeException)  {
+          // skip this collection because the collection's znode has been deleted
+          // which can happen during aggressive collection removal, see SOLR-10720
+        } else throw e;
+      }
     }
 
     List<String> liveNodes = zkStateReader.getZkClient().getChildren(ZkStateReader.LIVE_NODES_ZKNODE, null, true);