diff --git a/src/main/java/org/elasticsearch/action/search/type/TransportSearchCache.java b/src/main/java/org/elasticsearch/action/search/type/TransportSearchCache.java
index 631bac8014f..2c238edfcbe 100644
--- a/src/main/java/org/elasticsearch/action/search/type/TransportSearchCache.java
+++ b/src/main/java/org/elasticsearch/action/search/type/TransportSearchCache.java
@@ -20,7 +20,6 @@
 package org.elasticsearch.action.search.type;
 
 import jsr166y.LinkedTransferQueue;
-import org.elasticsearch.action.search.ShardSearchFailure;
 import org.elasticsearch.common.util.concurrent.ConcurrentCollections;
 import org.elasticsearch.search.SearchShardTarget;
 import org.elasticsearch.search.dfs.DfsSearchResult;
@@ -37,8 +36,6 @@ import java.util.Queue;
  */
 public class TransportSearchCache {
 
-    private final Queue<Collection<ShardSearchFailure>> cacheShardFailures = new LinkedTransferQueue<Collection<ShardSearchFailure>>();
-
     private final Queue<Collection<DfsSearchResult>> cacheDfsResults = new LinkedTransferQueue<Collection<DfsSearchResult>>();
 
     private final Queue<Map<SearchShardTarget, QuerySearchResultProvider>> cacheQueryResults = new LinkedTransferQueue<Map<SearchShardTarget, QuerySearchResultProvider>>();
@@ -48,19 +45,6 @@ public class TransportSearchCache {
     private final Queue<Map<SearchShardTarget, QueryFetchSearchResult>> cacheQueryFetchResults = new LinkedTransferQueue<Map<SearchShardTarget, QueryFetchSearchResult>>();
 
 
-    public Collection<ShardSearchFailure> obtainShardFailures() {
-        Collection<ShardSearchFailure> shardFailures;
-        while ((shardFailures = cacheShardFailures.poll()) == null) {
-            cacheShardFailures.offer(new LinkedTransferQueue<ShardSearchFailure>());
-        }
-        return shardFailures;
-    }
-
-    public void releaseShardFailures(Collection<ShardSearchFailure> shardFailures) {
-        shardFailures.clear();
-        cacheShardFailures.offer(shardFailures);
-    }
-
     public Collection<DfsSearchResult> obtainDfsResults() {
         Collection<DfsSearchResult> dfsSearchResults;
         while ((dfsSearchResults = cacheDfsResults.poll()) == null) {
diff --git a/src/main/java/org/elasticsearch/action/search/type/TransportSearchDfsQueryAndFetchAction.java b/src/main/java/org/elasticsearch/action/search/type/TransportSearchDfsQueryAndFetchAction.java
index 20bc390d890..3f2aa17e33f 100644
--- a/src/main/java/org/elasticsearch/action/search/type/TransportSearchDfsQueryAndFetchAction.java
+++ b/src/main/java/org/elasticsearch/action/search/type/TransportSearchDfsQueryAndFetchAction.java
@@ -153,7 +153,7 @@ public class TransportSearchDfsQueryAndFetchAction extends TransportSearchTypeAc
                     if (logger.isDebugEnabled()) {
                         logger.debug("[{}] Failed to execute query phase", t, querySearchRequest.id());
                     }
-                    AsyncAction.this.shardFailures.add(new ShardSearchFailure(t));
+                    AsyncAction.this.addShardFailure(new ShardSearchFailure(t));
                     successulOps.decrementAndGet();
                     if (counter.decrementAndGet() == 0) {
                         finishHim();
diff --git a/src/main/java/org/elasticsearch/action/search/type/TransportSearchDfsQueryThenFetchAction.java b/src/main/java/org/elasticsearch/action/search/type/TransportSearchDfsQueryThenFetchAction.java
index 4eb0ecb0a88..53a0aee72c9 100644
--- a/src/main/java/org/elasticsearch/action/search/type/TransportSearchDfsQueryThenFetchAction.java
+++ b/src/main/java/org/elasticsearch/action/search/type/TransportSearchDfsQueryThenFetchAction.java
@@ -160,7 +160,7 @@ public class TransportSearchDfsQueryThenFetchAction extends TransportSearchTypeA
                     if (logger.isDebugEnabled()) {
                         logger.debug("[{}] Failed to execute query phase", t, querySearchRequest.id());
                     }
-                    AsyncAction.this.shardFailures.add(new ShardSearchFailure(t));
+                    AsyncAction.this.addShardFailure(new ShardSearchFailure(t));
                     successulOps.decrementAndGet();
                     if (counter.decrementAndGet() == 0) {
                         executeFetchPhase();
@@ -251,7 +251,7 @@ public class TransportSearchDfsQueryThenFetchAction extends TransportSearchTypeA
                     if (logger.isDebugEnabled()) {
                         logger.debug("[{}] Failed to execute fetch phase", t, fetchSearchRequest.id());
                     }
-                    AsyncAction.this.shardFailures.add(new ShardSearchFailure(t));
+                    AsyncAction.this.addShardFailure(new ShardSearchFailure(t));
                     successulOps.decrementAndGet();
                     if (counter.decrementAndGet() == 0) {
                         finishHim();
diff --git a/src/main/java/org/elasticsearch/action/search/type/TransportSearchHelper.java b/src/main/java/org/elasticsearch/action/search/type/TransportSearchHelper.java
index c7425f1942b..1baa5aed7ba 100644
--- a/src/main/java/org/elasticsearch/action/search/type/TransportSearchHelper.java
+++ b/src/main/java/org/elasticsearch/action/search/type/TransportSearchHelper.java
@@ -26,7 +26,6 @@ import org.elasticsearch.ElasticSearchIllegalStateException;
 import org.elasticsearch.action.search.SearchRequest;
 import org.elasticsearch.action.search.SearchScrollRequest;
 import org.elasticsearch.action.search.SearchType;
-import org.elasticsearch.action.search.ShardSearchFailure;
 import org.elasticsearch.cluster.routing.ShardRouting;
 import org.elasticsearch.common.Base64;
 import org.elasticsearch.common.Nullable;
@@ -47,20 +46,6 @@ import java.util.Map;
 public abstract class TransportSearchHelper {
 
 
-    /**
-     * Builds the shard failures, and releases the cache (meaning this should only be called once!).
-     */
-    public static ShardSearchFailure[] buildShardFailures(Collection<ShardSearchFailure> shardFailures, TransportSearchCache searchCache) {
-        ShardSearchFailure[] ret;
-        if (shardFailures.isEmpty()) {
-            ret = ShardSearchFailure.EMPTY_ARRAY;
-        } else {
-            ret = shardFailures.toArray(ShardSearchFailure.EMPTY_ARRAY);
-        }
-        searchCache.releaseShardFailures(shardFailures);
-        return ret;
-    }
-
     public static InternalSearchRequest internalSearchRequest(ShardRouting shardRouting, int numberOfShards, SearchRequest request, String[] filteringAliases, long nowInMillis) {
         InternalSearchRequest internalRequest = new InternalSearchRequest(shardRouting, numberOfShards, request.searchType());
         internalRequest.source(request.source(), request.sourceOffset(), request.sourceLength());
diff --git a/src/main/java/org/elasticsearch/action/search/type/TransportSearchQueryThenFetchAction.java b/src/main/java/org/elasticsearch/action/search/type/TransportSearchQueryThenFetchAction.java
index 6ba16d447f1..b4ef8124a8a 100644
--- a/src/main/java/org/elasticsearch/action/search/type/TransportSearchQueryThenFetchAction.java
+++ b/src/main/java/org/elasticsearch/action/search/type/TransportSearchQueryThenFetchAction.java
@@ -161,7 +161,7 @@ public class TransportSearchQueryThenFetchAction extends TransportSearchTypeActi
                     if (logger.isDebugEnabled()) {
                         logger.debug("[{}] Failed to execute fetch phase", t, fetchSearchRequest.id());
                     }
-                    AsyncAction.this.shardFailures.add(new ShardSearchFailure(t));
+                    AsyncAction.this.addShardFailure(new ShardSearchFailure(t));
                     successulOps.decrementAndGet();
                     if (counter.decrementAndGet() == 0) {
                         finishHim();
diff --git a/src/main/java/org/elasticsearch/action/search/type/TransportSearchScrollQueryAndFetchAction.java b/src/main/java/org/elasticsearch/action/search/type/TransportSearchScrollQueryAndFetchAction.java
index 8ee85f779d3..b5e6afcff35 100644
--- a/src/main/java/org/elasticsearch/action/search/type/TransportSearchScrollQueryAndFetchAction.java
+++ b/src/main/java/org/elasticsearch/action/search/type/TransportSearchScrollQueryAndFetchAction.java
@@ -19,6 +19,7 @@
 
 package org.elasticsearch.action.search.type;
 
+import jsr166y.LinkedTransferQueue;
 import org.elasticsearch.action.ActionListener;
 import org.elasticsearch.action.search.*;
 import org.elasticsearch.cluster.ClusterService;
@@ -37,11 +38,9 @@ import org.elasticsearch.search.fetch.QueryFetchSearchResult;
 import org.elasticsearch.search.internal.InternalSearchResponse;
 import org.elasticsearch.threadpool.ThreadPool;
 
-import java.util.Collection;
 import java.util.Map;
 import java.util.concurrent.atomic.AtomicInteger;
 
-import static org.elasticsearch.action.search.type.TransportSearchHelper.buildShardFailures;
 import static org.elasticsearch.action.search.type.TransportSearchHelper.internalScrollSearchRequest;
 
 /**
@@ -85,7 +84,7 @@ public class TransportSearchScrollQueryAndFetchAction extends AbstractComponent
 
         private final DiscoveryNodes nodes;
 
-        protected final Collection<ShardSearchFailure> shardFailures = searchCache.obtainShardFailures();
+        private volatile LinkedTransferQueue<ShardSearchFailure> shardFailures;
 
         private final Map<SearchShardTarget, QueryFetchSearchResult> queryFetchResults = searchCache.obtainQueryFetchResults();
 
@@ -104,6 +103,23 @@ public class TransportSearchScrollQueryAndFetchAction extends AbstractComponent
             this.counter = new AtomicInteger(scrollId.context().length);
         }
 
+        protected final ShardSearchFailure[] buildShardFailures() {
+            LinkedTransferQueue<ShardSearchFailure> localFailures = shardFailures;
+            if (localFailures == null) {
+                return ShardSearchFailure.EMPTY_ARRAY;
+            }
+            return localFailures.toArray(ShardSearchFailure.EMPTY_ARRAY);
+        }
+
+        // we do our best to return the shard failures, but its ok if its not fully concurrently safe
+        // we simply try and return as much as possible
+        protected final void addShardFailure(ShardSearchFailure failure) {
+            if (shardFailures == null) {
+                shardFailures = new LinkedTransferQueue<ShardSearchFailure>();
+            }
+            shardFailures.add(failure);
+        }
+
         public void start() {
             if (scrollId.context().length == 0) {
                 listener.onFailure(new SearchPhaseExecutionException("query", "no nodes to search on", null));
@@ -193,7 +209,7 @@ public class TransportSearchScrollQueryAndFetchAction extends AbstractComponent
                     if (logger.isDebugEnabled()) {
                         logger.debug("[{}] Failed to execute query phase", t, searchId);
                     }
-                    shardFailures.add(new ShardSearchFailure(t));
+                    addShardFailure(new ShardSearchFailure(t));
                     successfulOps.decrementAndGet();
                     if (counter.decrementAndGet() == 0) {
                         finishHim();
@@ -206,7 +222,7 @@ public class TransportSearchScrollQueryAndFetchAction extends AbstractComponent
             try {
                 innerFinishHim();
             } catch (Exception e) {
-                listener.onFailure(new ReduceSearchPhaseException("fetch", "", e, buildShardFailures(shardFailures, searchCache)));
+                listener.onFailure(new ReduceSearchPhaseException("fetch", "", e, buildShardFailures()));
             }
         }
 
@@ -219,7 +235,7 @@ public class TransportSearchScrollQueryAndFetchAction extends AbstractComponent
             }
             searchCache.releaseQueryFetchResults(queryFetchResults);
             listener.onResponse(new SearchResponse(internalResponse, scrollId, this.scrollId.context().length, successfulOps.get(),
-                    System.currentTimeMillis() - startTime, buildShardFailures(shardFailures, searchCache)));
+                    System.currentTimeMillis() - startTime, buildShardFailures()));
         }
     }
 }
\ No newline at end of file
diff --git a/src/main/java/org/elasticsearch/action/search/type/TransportSearchScrollQueryThenFetchAction.java b/src/main/java/org/elasticsearch/action/search/type/TransportSearchScrollQueryThenFetchAction.java
index 928a737f89f..4eabc61af75 100644
--- a/src/main/java/org/elasticsearch/action/search/type/TransportSearchScrollQueryThenFetchAction.java
+++ b/src/main/java/org/elasticsearch/action/search/type/TransportSearchScrollQueryThenFetchAction.java
@@ -19,6 +19,7 @@
 
 package org.elasticsearch.action.search.type;
 
+import jsr166y.LinkedTransferQueue;
 import org.elasticsearch.action.ActionListener;
 import org.elasticsearch.action.search.*;
 import org.elasticsearch.cluster.ClusterService;
@@ -41,11 +42,9 @@ import org.elasticsearch.search.query.QuerySearchResult;
 import org.elasticsearch.search.query.QuerySearchResultProvider;
 import org.elasticsearch.threadpool.ThreadPool;
 
-import java.util.Collection;
 import java.util.Map;
 import java.util.concurrent.atomic.AtomicInteger;
 
-import static org.elasticsearch.action.search.type.TransportSearchHelper.buildShardFailures;
 import static org.elasticsearch.action.search.type.TransportSearchHelper.internalScrollSearchRequest;
 
 /**
@@ -89,7 +88,7 @@ public class TransportSearchScrollQueryThenFetchAction extends AbstractComponent
 
         private final DiscoveryNodes nodes;
 
-        protected final Collection<ShardSearchFailure> shardFailures = searchCache.obtainShardFailures();
+        protected volatile LinkedTransferQueue<ShardSearchFailure> shardFailures;
 
         private final Map<SearchShardTarget, QuerySearchResultProvider> queryResults = searchCache.obtainQueryResults();
 
@@ -109,6 +108,23 @@ public class TransportSearchScrollQueryThenFetchAction extends AbstractComponent
             this.successfulOps = new AtomicInteger(scrollId.context().length);
         }
 
+        protected final ShardSearchFailure[] buildShardFailures() {
+            LinkedTransferQueue<ShardSearchFailure> localFailures = shardFailures;
+            if (localFailures == null) {
+                return ShardSearchFailure.EMPTY_ARRAY;
+            }
+            return localFailures.toArray(ShardSearchFailure.EMPTY_ARRAY);
+        }
+
+        // we do our best to return the shard failures, but its ok if its not fully concurrently safe
+        // we simply try and return as much as possible
+        protected final void addShardFailure(ShardSearchFailure failure) {
+            if (shardFailures == null) {
+                shardFailures = new LinkedTransferQueue<ShardSearchFailure>();
+            }
+            shardFailures.add(failure);
+        }
+
         public void start() {
             if (scrollId.context().length == 0) {
                 listener.onFailure(new SearchPhaseExecutionException("query", "no nodes to search on", null));
@@ -185,7 +201,7 @@ public class TransportSearchScrollQueryThenFetchAction extends AbstractComponent
                     if (logger.isDebugEnabled()) {
                         logger.debug("[{}] Failed to execute query phase", t, searchId);
                     }
-                    shardFailures.add(new ShardSearchFailure(t));
+                    addShardFailure(new ShardSearchFailure(t));
                     successfulOps.decrementAndGet();
                     if (counter.decrementAndGet() == 0) {
                         executeFetchPhase();
@@ -237,7 +253,7 @@ public class TransportSearchScrollQueryThenFetchAction extends AbstractComponent
             try {
                 innerFinishHim();
             } catch (Exception e) {
-                listener.onFailure(new ReduceSearchPhaseException("fetch", "", e, buildShardFailures(shardFailures, searchCache)));
+                listener.onFailure(new ReduceSearchPhaseException("fetch", "", e, buildShardFailures()));
             }
         }
 
@@ -248,7 +264,7 @@ public class TransportSearchScrollQueryThenFetchAction extends AbstractComponent
                 scrollId = request.scrollId();
             }
             listener.onResponse(new SearchResponse(internalResponse, scrollId, this.scrollId.context().length, successfulOps.get(),
-                    System.currentTimeMillis() - startTime, buildShardFailures(shardFailures, searchCache)));
+                    System.currentTimeMillis() - startTime, buildShardFailures()));
             searchCache.releaseQueryResults(queryResults);
             searchCache.releaseFetchResults(fetchResults);
         }
diff --git a/src/main/java/org/elasticsearch/action/search/type/TransportSearchScrollScanAction.java b/src/main/java/org/elasticsearch/action/search/type/TransportSearchScrollScanAction.java
index 4b9bfa1be0a..b417573ced9 100644
--- a/src/main/java/org/elasticsearch/action/search/type/TransportSearchScrollScanAction.java
+++ b/src/main/java/org/elasticsearch/action/search/type/TransportSearchScrollScanAction.java
@@ -19,6 +19,7 @@
 
 package org.elasticsearch.action.search.type;
 
+import jsr166y.LinkedTransferQueue;
 import org.apache.lucene.search.ScoreDoc;
 import org.elasticsearch.action.ActionListener;
 import org.elasticsearch.action.search.*;
@@ -41,11 +42,9 @@ import org.elasticsearch.search.internal.InternalSearchResponse;
 import org.elasticsearch.threadpool.ThreadPool;
 
 import java.io.IOException;
-import java.util.Collection;
 import java.util.Map;
 import java.util.concurrent.atomic.AtomicInteger;
 
-import static org.elasticsearch.action.search.type.TransportSearchHelper.buildShardFailures;
 import static org.elasticsearch.action.search.type.TransportSearchHelper.internalScrollSearchRequest;
 
 /**
@@ -89,7 +88,7 @@ public class TransportSearchScrollScanAction extends AbstractComponent {
 
         private final DiscoveryNodes nodes;
 
-        protected final Collection<ShardSearchFailure> shardFailures = searchCache.obtainShardFailures();
+        protected volatile LinkedTransferQueue<ShardSearchFailure> shardFailures;
 
         private final Map<SearchShardTarget, QueryFetchSearchResult> queryFetchResults = searchCache.obtainQueryFetchResults();
 
@@ -108,11 +107,28 @@ public class TransportSearchScrollScanAction extends AbstractComponent {
             this.counter = new AtomicInteger(scrollId.context().length);
         }
 
+        protected final ShardSearchFailure[] buildShardFailures() {
+            LinkedTransferQueue<ShardSearchFailure> localFailures = shardFailures;
+            if (localFailures == null) {
+                return ShardSearchFailure.EMPTY_ARRAY;
+            }
+            return localFailures.toArray(ShardSearchFailure.EMPTY_ARRAY);
+        }
+
+        // we do our best to return the shard failures, but its ok if its not fully concurrently safe
+        // we simply try and return as much as possible
+        protected final void addShardFailure(ShardSearchFailure failure) {
+            if (shardFailures == null) {
+                shardFailures = new LinkedTransferQueue<ShardSearchFailure>();
+            }
+            shardFailures.add(failure);
+        }
+
         public void start() {
             if (scrollId.context().length == 0) {
                 final InternalSearchResponse internalResponse = new InternalSearchResponse(new InternalSearchHits(InternalSearchHits.EMPTY, Long.parseLong(this.scrollId.attributes().get("total_hits")), 0.0f), null, false);
                 searchCache.releaseQueryFetchResults(queryFetchResults);
-                listener.onResponse(new SearchResponse(internalResponse, request.scrollId(), 0, 0, 0l, TransportSearchHelper.buildShardFailures(shardFailures, searchCache)));
+                listener.onResponse(new SearchResponse(internalResponse, request.scrollId(), 0, 0, 0l, buildShardFailures()));
                 return;
             }
 
@@ -199,7 +215,7 @@ public class TransportSearchScrollScanAction extends AbstractComponent {
                     if (logger.isDebugEnabled()) {
                         logger.debug("[{}] Failed to execute query phase", t, searchId);
                     }
-                    shardFailures.add(new ShardSearchFailure(t));
+                    addShardFailure(new ShardSearchFailure(t));
                     successfulOps.decrementAndGet();
                     if (counter.decrementAndGet() == 0) {
                         finishHim();
@@ -212,7 +228,7 @@ public class TransportSearchScrollScanAction extends AbstractComponent {
             try {
                 innerFinishHim();
             } catch (Exception e) {
-                ReduceSearchPhaseException failure = new ReduceSearchPhaseException("fetch", "", e, buildShardFailures(shardFailures, searchCache));
+                ReduceSearchPhaseException failure = new ReduceSearchPhaseException("fetch", "", e, buildShardFailures());
                 if (logger.isDebugEnabled()) {
                     logger.debug("failed to reduce search", failure);
                 }
@@ -252,7 +268,7 @@ public class TransportSearchScrollScanAction extends AbstractComponent {
                 scrollId = TransportSearchHelper.buildScrollId(this.scrollId.type(), queryFetchResults.values(), this.scrollId.attributes()); // continue moving the total_hits
             }
             listener.onResponse(new SearchResponse(internalResponse, scrollId, this.scrollId.context().length, successfulOps.get(),
-                    System.currentTimeMillis() - startTime, buildShardFailures(shardFailures, searchCache)));
+                    System.currentTimeMillis() - startTime, buildShardFailures()));
         }
     }
 }
\ No newline at end of file
diff --git a/src/main/java/org/elasticsearch/action/search/type/TransportSearchTypeAction.java b/src/main/java/org/elasticsearch/action/search/type/TransportSearchTypeAction.java
index 7ab9f545640..53f77710399 100644
--- a/src/main/java/org/elasticsearch/action/search/type/TransportSearchTypeAction.java
+++ b/src/main/java/org/elasticsearch/action/search/type/TransportSearchTypeAction.java
@@ -19,6 +19,7 @@
 
 package org.elasticsearch.action.search.type;
 
+import jsr166y.LinkedTransferQueue;
 import org.elasticsearch.action.ActionListener;
 import org.elasticsearch.action.search.*;
 import org.elasticsearch.action.support.TransportAction;
@@ -44,7 +45,6 @@ import org.elasticsearch.search.query.QuerySearchResultProvider;
 import org.elasticsearch.threadpool.ThreadPool;
 
 import java.util.Arrays;
-import java.util.Collection;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -92,7 +92,7 @@ public abstract class TransportSearchTypeAction extends TransportAction<SearchRe
 
         private final AtomicInteger totalOps = new AtomicInteger();
 
-        protected final Collection<ShardSearchFailure> shardFailures = searchCache.obtainShardFailures();
+        private volatile LinkedTransferQueue<ShardSearchFailure> shardFailures;
 
         protected volatile ShardDoc[] sortedShardList;
 
@@ -248,9 +248,9 @@ public abstract class TransportSearchTypeAction extends TransportAction<SearchRe
                 // no more shards, add a failure
                 if (t == null) {
                     // no active shards
-                    shardFailures.add(new ShardSearchFailure("No active shards", new SearchShardTarget(null, shardIt.shardId().index().name(), shardIt.shardId().id())));
+                    addShardFailure(new ShardSearchFailure("No active shards", new SearchShardTarget(null, shardIt.shardId().index().name(), shardIt.shardId().id())));
                 } else {
-                    shardFailures.add(new ShardSearchFailure(t));
+                    addShardFailure(new ShardSearchFailure(t));
                 }
                 if (successulOps.get() == 0) {
                     // no successful ops, raise an exception
@@ -290,9 +290,9 @@ public abstract class TransportSearchTypeAction extends TransportAction<SearchRe
                     }
                     if (t == null) {
                         // no active shards
-                        shardFailures.add(new ShardSearchFailure("No active shards", new SearchShardTarget(null, shardIt.shardId().index().name(), shardIt.shardId().id())));
+                        addShardFailure(new ShardSearchFailure("No active shards", new SearchShardTarget(null, shardIt.shardId().index().name(), shardIt.shardId().id())));
                     } else {
-                        shardFailures.add(new ShardSearchFailure(t));
+                        addShardFailure(new ShardSearchFailure(t));
                     }
                 }
             }
@@ -305,11 +305,21 @@ public abstract class TransportSearchTypeAction extends TransportAction<SearchRe
             return System.currentTimeMillis() - startTime;
         }
 
-        /**
-         * Builds the shard failures, and releases the cache (meaning this should only be called once!).
-         */
         protected final ShardSearchFailure[] buildShardFailures() {
-            return TransportSearchHelper.buildShardFailures(shardFailures, searchCache);
+            LinkedTransferQueue<ShardSearchFailure> localFailures = shardFailures;
+            if (localFailures == null) {
+                return ShardSearchFailure.EMPTY_ARRAY;
+            }
+            return localFailures.toArray(ShardSearchFailure.EMPTY_ARRAY);
+        }
+
+        // we do our best to return the shard failures, but its ok if its not fully concurrently safe
+        // we simply try and return as much as possible
+        protected final void addShardFailure(ShardSearchFailure failure) {
+            if (shardFailures == null) {
+                shardFailures = new LinkedTransferQueue<ShardSearchFailure>();
+            }
+            shardFailures.add(failure);
         }
 
         /**