synchronized local searched to prevent that several searches are performed at the same time

see also: http://www.yacy-forum.de/viewtopic.php?p=19761#19761

git-svn-id: https://svn.berlios.de/svnroot/repos/yacy/trunk@1985 6c8d7289-2bf4-0310-a012-ef5d649a1542

source/de/anomic/plasma/plasmaSearchEvent.java

@@ -156,14 +156,23 @@ public final class plasmaSearchEvent extends Thread implements Runnable {
     public int localSearch() {
         // search for the set of hashes and return an array of urlEntry elements
         
+        // we synchronize with flushThreads to allow only one local search at a time,
+        // so all search tasks are queued
+        synchronized (flushThreads) {
+
             // retrieve entities that belong to the hashes
             profileLocal.startTimer();
-        Set containers = wordIndex.getContainers(query.queryHashes, true, true, profileLocal.getTargetTime(plasmaSearchTimingProfile.PROCESS_COLLECTION));
+            Set containers = wordIndex.getContainers(
+                            query.queryHashes,
+                            true,
+                            true,
+                            profileLocal.getTargetTime(plasmaSearchTimingProfile.PROCESS_COLLECTION));
             if (containers.size() < query.size()) containers = null; // prevent that only a subset is returned
             profileLocal.setYieldTime(plasmaSearchTimingProfile.PROCESS_COLLECTION);
             profileLocal.setYieldCount(plasmaSearchTimingProfile.PROCESS_COLLECTION, (containers == null) ? 0 : containers.size());
 
-        // since this is a conjunction we return an empty entity if any word is not known
+            // since this is a conjunction we return an empty entity if any word
+            // is not known
             if (containers == null) {
                 rcLocal = new plasmaWordIndexEntryContainer(null);
                 return 0;
@@ -171,12 +180,16 @@ public final class plasmaSearchEvent extends Thread implements Runnable {
 
             // join the result
             profileLocal.startTimer();
-        rcLocal = plasmaWordIndexEntryContainer.joinContainer(containers, profileLocal.getTargetTime(plasmaSearchTimingProfile.PROCESS_JOIN), query.maxDistance);
+            rcLocal = plasmaWordIndexEntryContainer.joinContainer(
+                            containers,
+                            profileLocal.getTargetTime(plasmaSearchTimingProfile.PROCESS_JOIN),
+                            query.maxDistance);
             profileLocal.setYieldTime(plasmaSearchTimingProfile.PROCESS_JOIN);
             profileLocal.setYieldCount(plasmaSearchTimingProfile.PROCESS_JOIN, rcLocal.size());
 
             return rcLocal.size();
         }
+    }
     
     public int globalSearch(int fetchpeers) {
         // do global fetching