diff --git a/source/de/anomic/kelondro/kelondroBytesIntMap.java b/source/de/anomic/kelondro/kelondroBytesIntMap.java
index 70451da3c..2fbd8de3b 100644
--- a/source/de/anomic/kelondro/kelondroBytesIntMap.java
+++ b/source/de/anomic/kelondro/kelondroBytesIntMap.java
@@ -56,6 +56,10 @@ public class kelondroBytesIntMap extends kelondroRowBufferedSet {
     }
     
     public int removei(byte[] key) {
+        if (size() == 0) {
+            if (System.currentTimeMillis() - this.lastTimeWrote > 10000) this.trim();
+            return -1;
+        }
         kelondroRow.Entry indexentry = remove(key);
         if (indexentry == null) return -1;
         return (int) indexentry.getColLongB256(1);
diff --git a/source/de/anomic/kelondro/kelondroIntBytesMap.java b/source/de/anomic/kelondro/kelondroIntBytesMap.java
index 104ab7156..952647522 100644
--- a/source/de/anomic/kelondro/kelondroIntBytesMap.java
+++ b/source/de/anomic/kelondro/kelondroIntBytesMap.java
@@ -56,6 +56,10 @@ public class kelondroIntBytesMap extends kelondroRowBufferedSet {
     }
     
     public byte[] removeb(int ii) {
+        if (size() == 0) {
+            if (System.currentTimeMillis() - this.lastTimeWrote > 10000) this.trim();
+            return null;
+        }
         kelondroRow.Entry indexentry = super.remove(kelondroNaturalOrder.encodeLong((long) ii, 4));
         if (indexentry == null) return null;
         return indexentry.getColBytes(1);
diff --git a/source/de/anomic/kelondro/kelondroRecords.java b/source/de/anomic/kelondro/kelondroRecords.java
index 607cacb73..682cd64b5 100644
--- a/source/de/anomic/kelondro/kelondroRecords.java
+++ b/source/de/anomic/kelondro/kelondroRecords.java
@@ -427,7 +427,7 @@ public class kelondroRecords {
                 this.cacheScore = new kelondroMScoreCluster(); // cache control of CP_HIGH caches
             }
             this.cacheHeaders = new kelondroIntBytesMap[]{
-                    new kelondroIntBytesMap(this.headchunksize, 0),
+                    new kelondroIntBytesMap(this.headchunksize, this.cacheSize / 2),
                     new kelondroIntBytesMap(this.headchunksize, 0),
                     new kelondroIntBytesMap(this.headchunksize, 0)
                     };
@@ -916,7 +916,7 @@ public class kelondroRecords {
                     // we simply clear the cache
                     String error = "cachScore error: " + e.getMessage() + "; cachesize=" + cacheSize + ", cache.size()=[" + cacheHeaders[0].size() + "," + cacheHeaders[1].size() + "," + cacheHeaders[2].size() + "], cacheScore.size()=" + cacheScore.size();
                     cacheScore = new kelondroMScoreCluster();
-                    cacheHeaders[CP_LOW]    = new kelondroIntBytesMap(headchunksize, 0);
+                    cacheHeaders[CP_LOW]    = new kelondroIntBytesMap(headchunksize, cacheSize / 2);
                     cacheHeaders[CP_MEDIUM] = new kelondroIntBytesMap(headchunksize, 0);
                     cacheHeaders[CP_HIGH]   = new kelondroIntBytesMap(headchunksize, 0);
                     cacheHeaders[0].setOrdering(kelondroNaturalOrder.naturalOrder, 0);
diff --git a/source/de/anomic/kelondro/kelondroRowCollection.java b/source/de/anomic/kelondro/kelondroRowCollection.java
index 760fcbd94..d24da88e3 100644
--- a/source/de/anomic/kelondro/kelondroRowCollection.java
+++ b/source/de/anomic/kelondro/kelondroRowCollection.java
@@ -47,6 +47,8 @@ public class kelondroRowCollection {
         this.sortColumn = 0;
         this.sortOrder = null;
         this.sortBound = 0;
+        this.lastTimeRead = System.currentTimeMillis();
+        this.lastTimeWrote = System.currentTimeMillis();
     }
     
     public kelondroRowCollection(kelondroRow rowdef, int objectCount, byte[] cache) {
@@ -56,6 +58,8 @@ public class kelondroRowCollection {
         this.sortColumn = 0;
         this.sortOrder = null;
         this.sortBound = 0;
+        this.lastTimeRead = System.currentTimeMillis();
+        this.lastTimeWrote = System.currentTimeMillis();
     }
     
     private final void ensureSize(int elements) {
@@ -68,6 +72,7 @@ public class kelondroRowCollection {
     }
     
     public void trim() {
+        if (chunkcache.length == 0) return;
         synchronized (chunkcache) {
             int needed = chunkcount * rowdef.objectsize();
             if (chunkcache.length == needed) return;
@@ -92,6 +97,7 @@ public class kelondroRowCollection {
         synchronized (chunkcache) {
             System.arraycopy(chunkcache, index * rowdef.objectsize(), a, 0, rowdef.objectsize());
         }
+        this.lastTimeRead = System.currentTimeMillis();
         return rowdef.newEntry(a);
     }
     
@@ -141,6 +147,7 @@ public class kelondroRowCollection {
     
     public final void remove(int p) {
         assert ((p >= 0) && (p < chunkcount) && (chunkcount > 0));
+        //System.out.println("REMOVE at pos " + p + ", chunkcount=" + chunkcount + ", sortBound=" + sortBound);
         synchronized (chunkcache) {
             System.arraycopy(chunkcache, (p + 1) * rowdef.objectsize(), chunkcache, p * rowdef.objectsize(), (chunkcount - p - 1) * rowdef.objectsize());
             chunkcount--;
@@ -160,6 +167,7 @@ public class kelondroRowCollection {
         this.chunkcache = new byte[0];
         this.chunkcount = 0;
         this.sortBound = 0;
+        this.lastTimeWrote = System.currentTimeMillis();
     }
     
     public int size() {
@@ -211,7 +219,7 @@ public class kelondroRowCollection {
     protected final void sort() {
         assert (this.sortOrder != null);
         if (this.sortBound == this.chunkcount) return; // this is already sorted
-        //System.out.println("SORT(chunkcount=" + this.chunkcount + ", sortbound=" + this.sortbound + ")");
+        //System.out.println("SORT(chunkcount=" + this.chunkcount + ", sortBound=" + this.sortBound + ")");
         if (this.sortBound > 1) {
             qsort(0, this.sortBound, this.chunkcount);
         } else {