diff --git a/htroot/PerformanceMemory_p.html b/htroot/PerformanceMemory_p.html
index f4d028327..5437fdead 100644
--- a/htroot/PerformanceMemory_p.html
+++ b/htroot/PerformanceMemory_p.html
@@ -336,6 +336,32 @@ Increasing this cache may speed up crawling, but not much space is needed, so th
 </table>
 </p>
 
+<!-- other cache sizes -->
+<div class=small><b>Other caching structures:</b></div>
+	<table border="0" cellpadding="2" cellspacing="1">
+		<tr class="TableHeader" valign="bottom">
+			<td class="small">Type</td>
+			<td class="small">Amount</td>
+			<td class="small">Size</td>
+		</tr>
+		<tr class="TableCellDark">
+			<td class="small">EURL existsIndex</td>
+			<td class="small">#[eurl.existsIndexAmount]#</td>
+			<td class="small">#[eurl.existsIndexSize]#</td>	
+		</tr>
+		<tr class="TableCellLight">
+			<td class="small">NURL existsIndex</td>
+			<td class="small">#[nurl.existsIndexAmount]#</td>
+			<td class="small">#[nurl.existsIndexSize]#</td>		
+		</tr>
+		<tr class="TableCellDark">
+			<td class="small">LURL existsIndex</td>
+			<td class="small">#[lurl.existsIndexAmount]#</td>
+			<td class="small">#[lurl.existsIndexSize]#</td>	
+		</tr>		
+	</table>
+</p>
+
 #%env/templates/footer.template%#
 </body>
 </html>
diff --git a/htroot/PerformanceMemory_p.java b/htroot/PerformanceMemory_p.java
index 1c0e18e46..b03a73534 100644
--- a/htroot/PerformanceMemory_p.java
+++ b/htroot/PerformanceMemory_p.java
@@ -49,6 +49,8 @@ import java.io.File;
 
 import de.anomic.http.httpHeader;
 import de.anomic.plasma.plasmaSwitchboard;
+import de.anomic.plasma.plasmaURL;
+import de.anomic.server.serverMemory;
 import de.anomic.server.serverObjects;
 import de.anomic.server.serverSwitch;
 import de.anomic.server.serverFileUtils;
@@ -251,6 +253,17 @@ public class PerformanceMemory_p {
         prop.put("alive", Integer.toString(c));
         prop.put("heap" , Integer.toString(c));
         
+        // other caching structures
+        long amount = sb.urlPool.errorURL.existsIndexSize();
+        prop.put("eurl.existsIndexAmount",Long.toString(amount));
+        prop.put("eurl.existsIndexSize",serverMemory.bytesToString(amount*plasmaURL.urlHashLength));
+        amount = sb.urlPool.noticeURL.existsIndexSize();
+        prop.put("nurl.existsIndexAmount",Long.toString(amount));
+        prop.put("nurl.existsIndexSize",serverMemory.bytesToString(amount*plasmaURL.urlHashLength));
+        amount = sb.urlPool.loadedURL.existsIndexSize();
+        prop.put("lurl.existsIndexAmount",Long.toString(amount));
+        prop.put("lurl.existsIndexSize",serverMemory.bytesToString(amount*plasmaURL.urlHashLength));
+        
         // return rewrite values for templates
         return prop;
     }
diff --git a/source/de/anomic/plasma/plasmaURL.java b/source/de/anomic/plasma/plasmaURL.java
index 650d47d9d..2d0c1e7cb 100644
--- a/source/de/anomic/plasma/plasmaURL.java
+++ b/source/de/anomic/plasma/plasmaURL.java
@@ -424,7 +424,7 @@ public class plasmaURL {
     
     // the class object
     public kelondroTree urlHashCache;
-    private HashSet existsIndex;
+    private final HashSet existsIndex;
 
     public plasmaURL() {
         urlHashCache = null;
@@ -454,6 +454,10 @@ public class plasmaURL {
             }
         }
     }
+    
+    public long existsIndexSize() {
+        return this.existsIndex.size();
+    }
 
     public boolean remove(String urlHash) {
         synchronized (existsIndex) {
diff --git a/source/de/anomic/server/serverMemory.java b/source/de/anomic/server/serverMemory.java
index 623348d43..ab33cdfa1 100644
--- a/source/de/anomic/server/serverMemory.java
+++ b/source/de/anomic/server/serverMemory.java
@@ -45,6 +45,8 @@
 
 package de.anomic.server;
 
+import java.text.DecimalFormat;
+
 public class serverMemory {
 
     public static final long max = Runtime.getRuntime().maxMemory();
@@ -65,4 +67,28 @@ public class serverMemory {
         return runtime.totalMemory() - runtime.freeMemory();
     }
     
+    public static String bytesToString(long byteCount) {
+        try {
+            final StringBuffer byteString = new StringBuffer();
+
+            final DecimalFormat df = new DecimalFormat( "0.00" );
+            if (byteCount > 1073741824) {
+                byteString.append(df.format((double)byteCount / (double)1073741824 ))
+                          .append(" GB");
+            } else if (byteCount > 1048576) {
+                byteString.append(df.format((double)byteCount / (double)1048576))
+                          .append(" MB");
+            } else if (byteCount > 1024) {
+                byteString.append(df.format((double)byteCount / (double)1024))
+                          .append(" KB");
+            } else {
+                byteString.append(Long.toString(byteCount))
+                .append(" Bytes");
+            }
+
+            return byteString.toString();
+        } catch (Exception e) {
+            return "unknown";
+        }
+    }        
 }