From 7f77cfada076b96b7c91f00360f36cf5f8c76a1f Mon Sep 17 00:00:00 2001
From: Igor Motov <igor@motovs.org>
Date: Mon, 25 Jun 2012 20:33:21 -0400
Subject: [PATCH] Add support for zero queue size in the search thread pool

---
 .../java/org/elasticsearch/threadpool/ThreadPool.java  | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/main/java/org/elasticsearch/threadpool/ThreadPool.java b/src/main/java/org/elasticsearch/threadpool/ThreadPool.java
index a79d3fe92fb..3b40b180689 100644
--- a/src/main/java/org/elasticsearch/threadpool/ThreadPool.java
+++ b/src/main/java/org/elasticsearch/threadpool/ThreadPool.java
@@ -241,9 +241,17 @@ public class ThreadPool extends AbstractComponent {
                 throw new ElasticSearchIllegalArgumentException("reject_policy [" + rejectSetting + "] not valid for [" + name + "] thread pool");
             }
             logger.debug("creating thread_pool [{}], type [{}], size [{}], queue_size [{}], reject_policy [{}]", name, type, size, capacity, rejectSetting);
+            BlockingQueue<Runnable> workQueue;
+            if (capacity == null) {
+                workQueue = new LinkedTransferQueue<Runnable>();
+            } else if ((int) capacity.singles() > 0) {
+                workQueue = new ArrayBlockingQueue<Runnable>((int) capacity.singles());
+            } else {
+                workQueue = new SynchronousQueue<Runnable>();
+            }
             Executor executor = new EsThreadPoolExecutor(size, size,
                     0L, TimeUnit.MILLISECONDS,
-                    capacity == null ? new LinkedTransferQueue<Runnable>() : new ArrayBlockingQueue<Runnable>((int) capacity.singles()),
+                    workQueue,
                     threadFactory, rejectedExecutionHandler);
             return new ExecutorHolder(executor, new Info(name, type, size, size, null, capacity));
         } else if ("scaling".equals(type)) {