diff --git a/source/de/anomic/kelondro/blob/BLOBArray.java b/source/de/anomic/kelondro/blob/BLOBArray.java
index 499ddda4d..f87d5c97e 100755
--- a/source/de/anomic/kelondro/blob/BLOBArray.java
+++ b/source/de/anomic/kelondro/blob/BLOBArray.java
@@ -64,7 +64,7 @@ public class BLOBArray implements BLOB {
      */
     
     public static final long oneMonth    = 1000L * 60L * 60L * 24L * 365L / 12L;
-    public static final long oneGigabyte = 1024 * 1024 * 1024;
+    public static final long oneGigabyte = 1024L * 1024L * 1024L;
     
     private int keylength;
     private ByteOrder ordering;
diff --git a/source/de/anomic/kelondro/blob/HeapReader.java b/source/de/anomic/kelondro/blob/HeapReader.java
index 7459d4796..c7f4ec534 100644
--- a/source/de/anomic/kelondro/blob/HeapReader.java
+++ b/source/de/anomic/kelondro/blob/HeapReader.java
@@ -45,6 +45,8 @@ import de.anomic.kelondro.util.Log;
 
 public class HeapReader {
 
+    public final static long keepFreeMem = 20 * 1024 * 1024;
+    
     protected int                keylength;  // the length of the primary key
     protected LongHandleIndex    index;      // key/seek relation for used records
     protected Gap                free;       // set of {seek, size} pairs denoting space and position of free records
@@ -234,8 +236,8 @@ public class HeapReader {
         // access the file and read the container
         file.seek(pos);
         final int len = file.readInt() - index.row().primaryKeyLength;
-        if (MemoryControl.available() < len) {
-            if (!MemoryControl.request(len, true)) return null; // not enough memory available for this blob
+        if (MemoryControl.available() < len * 2 + keepFreeMem) {
+            if (!MemoryControl.request(len * 2 + keepFreeMem, true)) return null; // not enough memory available for this blob
         }
         
         // read the key