diff --git a/source/net/yacy/kelondro/blob/ArrayStack.java b/source/net/yacy/kelondro/blob/ArrayStack.java
index 3563acb57..8b0d30e19 100755
--- a/source/net/yacy/kelondro/blob/ArrayStack.java
+++ b/source/net/yacy/kelondro/blob/ArrayStack.java
@@ -5,8 +5,8 @@
 // This is a part of YaCy, a peer-to-peer based web search engine
 //
 // $LastChangedDate: 2006-04-02 22:40:07 +0200 (So, 02 Apr 2006) $
-// $LastChangedRevision: 1986 $
-// $LastChangedBy: orbiter $
+// $LastChangedRevision$
+// $LastChangedBy$
 //
 // LICENSE
 // 
@@ -270,6 +270,14 @@ public class ArrayStack implements BLOB {
         unmountBLOB(bestMatch[0], false);
         return bestMatch;
     }
+
+    public synchronized File unmountOldest() {
+        if (this.blobs.size() == 0) return null;
+        if (System.currentTimeMillis() - this.blobs.get(0).creation.getTime() < this.fileAgeLimit) return null;
+        File f = this.blobs.get(0).location;
+        unmountBLOB(f, false);
+        return f;
+    }
     
     public synchronized File[] unmountSmallest(long maxResultSize) {
     	if (this.blobs.size() < 2) return null;
@@ -731,23 +739,52 @@ public class ArrayStack implements BLOB {
         blobs = null;
     }
     
+    /**
+     * merge two blob files into one. If the second file is given as null,
+     * then the first file is only rewritten into a new one.
+     * @param f1
+     * @param f2 (may also be null)
+     * @param factory
+     * @param payloadrow
+     * @param newFile
+     * @param writeBuffer
+     * @return the target file where the given files are merged in
+     */
     public File mergeMount(File f1, File f2,
             ReferenceFactory<? extends Reference> factory,
             Row payloadrow, File newFile, int writeBuffer) {
-        Log.logInfo("BLOBArray", "merging " + f1.getName() + " with " + f2.getName());
-        File resultFile = mergeWorker(factory, this.keylength, this.ordering, f1, f2, payloadrow, newFile, writeBuffer);
-        if (resultFile == null) {
-            Log.logWarning("BLOBArray", "merge of files " + f1 + ", " + f2 + " returned null. newFile = " + newFile);
-            return null;
-        }
-        try {
-            mountBLOB(resultFile, false);
-        } catch (IOException e) {
-            Log.logWarning("BLOBArray", "merge of files " + f1 + ", " + f2 + " successfull, but read failed. resultFile = " + resultFile);
-            return null;
+        if (f2 == null) {
+            // this is a rewrite
+            Log.logInfo("BLOBArray", "rewrite of " + f1.getName());
+            File resultFile = rewriteWorker(factory, this.keylength, this.ordering, f1, payloadrow, newFile, writeBuffer);
+            if (resultFile == null) {
+                Log.logWarning("BLOBArray", "rewrite of file " + f1 + " returned null. newFile = " + newFile);
+                return null;
+            }
+            try {
+                mountBLOB(resultFile, false);
+            } catch (IOException e) {
+                Log.logWarning("BLOBArray", "rewrite of file " + f1 + " successfull, but read failed. resultFile = " + resultFile);
+                return null;
+            }
+            Log.logInfo("BLOBArray", "rewrite of " + f1.getName() + " into " + resultFile);
+            return resultFile;
+        } else {
+            Log.logInfo("BLOBArray", "merging " + f1.getName() + " with " + f2.getName());
+            File resultFile = mergeWorker(factory, this.keylength, this.ordering, f1, f2, payloadrow, newFile, writeBuffer);
+            if (resultFile == null) {
+                Log.logWarning("BLOBArray", "merge of files " + f1 + ", " + f2 + " returned null. newFile = " + newFile);
+                return null;
+            }
+            try {
+                mountBLOB(resultFile, false);
+            } catch (IOException e) {
+                Log.logWarning("BLOBArray", "merge of files " + f1 + ", " + f2 + " successfull, but read failed. resultFile = " + resultFile);
+                return null;
+            }
+            Log.logInfo("BLOBArray", "merged " + f1.getName() + " with " + f2.getName() + " into " + resultFile);
+            return resultFile;
         }
-        Log.logInfo("BLOBArray", "merged " + f1.getName() + " with " + f2.getName() + " into " + resultFile);
-        return resultFile;
     }
     
     private static <ReferenceType extends Reference> File mergeWorker(
@@ -806,6 +843,44 @@ public class ArrayStack implements BLOB {
         return newFile;
     }
     
+    private static <ReferenceType extends Reference> File rewriteWorker(
+            ReferenceFactory<ReferenceType> factory,
+            int keylength, ByteOrder order, File f, Row payloadrow, File newFile, int writeBuffer) {
+        // iterate both files and write a new one
+        
+        CloneableIterator<ReferenceContainer<ReferenceType>> i = null;
+        try {
+            i = new ReferenceIterator<ReferenceType>(f, factory, payloadrow);
+        } catch (IOException e) {
+            Log.logSevere("ArrayStack", "cannot rewrite because input file cannot be read, f = " + f.toString() + ": " + e.getMessage(), e);
+            return null;
+        }
+        if (!i.hasNext()) {
+            FileUtils.deletedelete(f);
+            return null;
+        }
+        assert i.hasNext();
+        File tmpFile = new File(newFile.getParentFile(), newFile.getName() + ".prt");
+        try {
+            HeapWriter writer = new HeapWriter(tmpFile, newFile, keylength, order, writeBuffer);
+            rewrite(i, order, writer);
+            writer.close(true);
+        } catch (IOException e) {
+            Log.logSevere("ArrayStack", "cannot writing or close writing rewrite, newFile = " + newFile.toString() + ", tmpFile = " + tmpFile.toString() + ": " + e.getMessage(), e);
+            FileUtils.deletedelete(tmpFile);
+            FileUtils.deletedelete(newFile);
+            return null;
+        } catch (RowSpaceExceededException e) {
+            Log.logSevere("ArrayStack", "cannot rewrite because of memory failure: " + e.getMessage(), e);
+            FileUtils.deletedelete(tmpFile);
+            FileUtils.deletedelete(newFile);
+            return null;
+        }
+        // we don't need the old files any more
+        FileUtils.deletedelete(f);
+        return newFile;
+    }
+    
     private static <ReferenceType extends Reference> void merge(
             CloneableIterator<ReferenceContainer<ReferenceType>> i1,
             CloneableIterator<ReferenceContainer<ReferenceType>> i2,
@@ -879,6 +954,26 @@ public class ArrayStack implements BLOB {
         }
         // finished with writing
     }
+    
+    private static <ReferenceType extends Reference> void rewrite(
+            CloneableIterator<ReferenceContainer<ReferenceType>> i,
+            ByteOrder ordering, HeapWriter writer) throws IOException, RowSpaceExceededException {
+        assert i.hasNext();
+        ReferenceContainer<ReferenceType> c, co;
+        c = i.next();
+        while (true) {
+            assert c != null;
+            writer.add(c.getTermHash(), c.exportCollection());
+            if (i.hasNext()) {
+                co = c;
+                c = i.next();
+                assert ordering.compare(c.getTermHash(), co.getTermHash()) > 0;
+                continue;
+            }
+            break;
+        }
+        // finished with writing
+    }
 
 
     public static void main(final String[] args) {
diff --git a/source/net/yacy/kelondro/rwi/IODispatcher.java b/source/net/yacy/kelondro/rwi/IODispatcher.java
index 891968698..7054725c5 100644
--- a/source/net/yacy/kelondro/rwi/IODispatcher.java
+++ b/source/net/yacy/kelondro/rwi/IODispatcher.java
@@ -109,7 +109,11 @@ public class IODispatcher extends Thread {
     
     public synchronized void merge(File f1, File f2, ReferenceFactory<? extends Reference> factory, ArrayStack array, Row payloadrow, File newFile) {
         if (mergeQueue == null || controlQueue == null || !this.isAlive()) {
-            Log.logWarning("IODispatcher", "emergency merge of files " + f1.getName() + ", " + f2.getName() + " to " + newFile.getName());
+            if (f2 == null) {
+                Log.logWarning("IODispatcher", "emergency rewrite of file " + f1.getName() + " to " + newFile.getName());
+            } else {
+                Log.logWarning("IODispatcher", "emergency merge of files " + f1.getName() + ", " + f2.getName() + " to " + newFile.getName());
+            }
             array.mergeMount(f1, f2, factory, payloadrow, newFile, (int) Math.min(MemoryControl.available() / 3, writeBufferSize));
         } else {
             MergeJob job = new MergeJob(f1, f2, factory, array, payloadrow, newFile);
@@ -117,10 +121,18 @@ public class IODispatcher extends Thread {
                 if (this.isAlive()) {
                     this.mergeQueue.put(job);
                     this.controlQueue.release();
-                    Log.logInfo("IODispatcher", "appended merge job of files " + f1.getName() + ", " + f2.getName() + " to " + newFile.getName());
+                    if (f2 == null) {
+                        Log.logInfo("IODispatcher", "appended rewrite job of file " + f1.getName() + " to " + newFile.getName());
+                    } else {
+                        Log.logInfo("IODispatcher", "appended merge job of files " + f1.getName() + ", " + f2.getName() + " to " + newFile.getName());
+                    }
                 } else {
                     job.merge();
-                    Log.logWarning("IODispatcher", "dispatcher not running, merged files " + f1.getName() + ", " + f2.getName() + " to " + newFile.getName());
+                    if (f2 == null) {
+                        Log.logWarning("IODispatcher", "dispatcher not running, merged files " + f1.getName() + " to " + newFile.getName());
+                    } else {
+                        Log.logWarning("IODispatcher", "dispatcher not running, rewrote file " + f1.getName() + ", " + f2.getName() + " to " + newFile.getName());
+                    }
                 }
             } catch (InterruptedException e) {
                 Log.logWarning("IODispatcher", "interrupted: " + e.getMessage(), e);
@@ -166,7 +178,11 @@ public class IODispatcher extends Thread {
                         Log.logSevere("IODispatcher", "main run job was interrupted (2)", e);
                         Log.logException(e);
                     } catch (Exception e) {
-                        Log.logSevere("IODispatcher", "main run job had errors (2), dump to " + f + " failed. Input files are " + f1 + " and " + f2, e);
+                        if (f2 == null) {
+                        Log.logSevere("IODispatcher", "main run job had errors (2), dump to " + f + " failed. Input file is " + f1, e);
+                        } else {
+                            Log.logSevere("IODispatcher", "main run job had errors (2), dump to " + f + " failed. Input files are " + f1 + " and " + f2, e);
+                        }
                         Log.logException(e);
                     }
                     continue loop;
@@ -243,7 +259,7 @@ public class IODispatcher extends Thread {
         		Log.logWarning("IODispatcher", "merge of file (1) " + f1.getName() + " failed: file does not exists");
         		return null;
         	}
-        	if (!f2.exists()) {
+        	if (f2 != null && !f2.exists()) {
         		Log.logWarning("IODispatcher", "merge of file (2) " + f2.getName() + " failed: file does not exists");
         		return null;
         	}
diff --git a/source/net/yacy/kelondro/rwi/ReferenceContainerArray.java b/source/net/yacy/kelondro/rwi/ReferenceContainerArray.java
index 503766696..45b3a0292 100644
--- a/source/net/yacy/kelondro/rwi/ReferenceContainerArray.java
+++ b/source/net/yacy/kelondro/rwi/ReferenceContainerArray.java
@@ -310,6 +310,15 @@ public final class ReferenceContainerArray<ReferenceType extends Reference> {
             donesomething = true;
         }
 
+        // merge very old files with it self (hack from sixcooler, see http://forum.yacy-websuche.de/viewtopic.php?p=15004#p15004)
+        while (this.merger.queueLength() < 1) {
+            File ff = this.array.unmountOldest();
+            if (ff == null) break;
+            Log.logInfo("RICELL-shrink4/rewrite", "unmountOldest()");
+            merger.merge(ff, null, this.factory, this.array, this.payloadrow, newContainerBLOBFile());
+            donesomething = true;
+        }
+
         return donesomething;
     }