diff --git a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/DataGenThread.java b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/DataGenThread.java
index e8d3d56..1a6f4df 100644
--- a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/DataGenThread.java
+++ b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/DataGenThread.java
@@ -1,3 +1,18 @@
+/*
+ * Copyright 2009-2012 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package edu.uci.ics.hyracks.storage.am.common.datagen;
 
 import java.io.IOException;
diff --git a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/DataGenUtils.java b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/DataGenUtils.java
index d4696df..b3914e6 100644
--- a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/DataGenUtils.java
+++ b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/DataGenUtils.java
@@ -1,3 +1,18 @@
+/*
+ * Copyright 2009-2012 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package edu.uci.ics.hyracks.storage.am.common.datagen;
 
 import java.util.Random;
diff --git a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/DocumentStringFieldValueGenerator.java b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/DocumentStringFieldValueGenerator.java
new file mode 100644
index 0000000..4746b06
--- /dev/null
+++ b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/DocumentStringFieldValueGenerator.java
@@ -0,0 +1,88 @@
+/*
+ * Copyright 2009-2012 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package edu.uci.ics.hyracks.storage.am.common.datagen;
+
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+
+public class DocumentStringFieldValueGenerator implements IFieldValueGenerator<String> {
+    private final String FIRST_NAMES_FILE = "data/dist.all.first.cleaned";
+    private final String LAST_NAMES_FILE = "data/dist.all.last.cleaned";
+
+    private final int docMinWords;
+    private final int docMaxWords;
+    private final int maxDictionarySize;
+    private final Random rnd;
+    private int[] cumulIntRanges;
+
+    private List<String> TOKEN_DICT = new ArrayList<String>();
+
+    public DocumentStringFieldValueGenerator(int docMinWords, int docMaxWords, int maxDictionarySize, Random rnd)
+            throws IOException {
+        this.docMinWords = docMinWords;
+        this.docMaxWords = docMaxWords;
+        this.maxDictionarySize = maxDictionarySize;
+        this.rnd = rnd;
+        initDictionary();
+        double[] zipfProbDist = ProbabilityHelper.getZipfProbDist(TOKEN_DICT.size(), 1);
+        cumulIntRanges = ProbabilityHelper.getCumulIntRanges(zipfProbDist);
+    }
+
+    private void initDictionary() throws IOException {
+        String line;
+        int count = 0;
+
+        // Read first names from data file.
+        BufferedReader firstNamesReader = new BufferedReader(new FileReader(FIRST_NAMES_FILE));
+        try {
+            while (count < maxDictionarySize && (line = firstNamesReader.readLine()) != null) {
+                TOKEN_DICT.add(line.trim());
+                count++;
+            }
+        } finally {
+            firstNamesReader.close();
+        }
+
+        // Read last names from data file.
+        BufferedReader lastNamesReader = new BufferedReader(new FileReader(LAST_NAMES_FILE));
+        try {
+            while (count < maxDictionarySize && (line = lastNamesReader.readLine()) != null) {
+                TOKEN_DICT.add(line.trim());
+                count++;
+            }
+        } finally {
+            lastNamesReader.close();
+        }
+    }
+
+    @Override
+    public String next() {
+        StringBuilder strBuilder = new StringBuilder();
+        int numWords = Math.abs(rnd.nextInt()) % (docMaxWords - docMinWords + 1) + docMinWords;
+        for (int i = 0; i < numWords; i++) {
+            int ix = ProbabilityHelper.choose(cumulIntRanges, rnd.nextInt());
+            strBuilder.append(TOKEN_DICT.get(ix));
+            if (i != numWords - 1) {
+                strBuilder.append(" ");
+            }
+        }
+        return strBuilder.toString();
+    }
+}
diff --git a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/DoubleFieldValueGenerator.java b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/DoubleFieldValueGenerator.java
index fcac93a..d535404 100644
--- a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/DoubleFieldValueGenerator.java
+++ b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/DoubleFieldValueGenerator.java
@@ -1,3 +1,18 @@
+/*
+ * Copyright 2009-2012 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package edu.uci.ics.hyracks.storage.am.common.datagen;
 
 import java.util.Random;
diff --git a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/FloatFieldValueGenerator.java b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/FloatFieldValueGenerator.java
index 6f21c77..53450f6 100644
--- a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/FloatFieldValueGenerator.java
+++ b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/FloatFieldValueGenerator.java
@@ -1,3 +1,18 @@
+/*
+ * Copyright 2009-2012 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package edu.uci.ics.hyracks.storage.am.common.datagen;
 
 import java.util.Random;
diff --git a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/IFieldValueGenerator.java b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/IFieldValueGenerator.java
index ee0d30b..6f743ac 100644
--- a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/IFieldValueGenerator.java
+++ b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/IFieldValueGenerator.java
@@ -1,3 +1,18 @@
+/*
+ * Copyright 2009-2012 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package edu.uci.ics.hyracks.storage.am.common.datagen;
 
 public interface IFieldValueGenerator<T> {
diff --git a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/IntegerFieldValueGenerator.java b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/IntegerFieldValueGenerator.java
index 134b1f7..88f7bab 100644
--- a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/IntegerFieldValueGenerator.java
+++ b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/IntegerFieldValueGenerator.java
@@ -1,3 +1,18 @@
+/*
+ * Copyright 2009-2012 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package edu.uci.ics.hyracks.storage.am.common.datagen;
 
 import java.util.Random;
diff --git a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/ProbabilityHelper.java b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/ProbabilityHelper.java
new file mode 100644
index 0000000..1674681
--- /dev/null
+++ b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/ProbabilityHelper.java
@@ -0,0 +1,64 @@
+/*
+ * Copyright 2009-2012 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package edu.uci.ics.hyracks.storage.am.common.datagen;
+
+import java.util.Arrays;
+
+public class ProbabilityHelper {
+    public static double[] getUniformProbDist(int numChoices) {
+        double[] probDist = new double[numChoices];
+        for (int i = 0; i < numChoices; i++) {
+            probDist[i] = 1.0 / (double) numChoices;
+        }
+        return probDist;
+    }
+
+    public static double[] getZipfProbDist(int numChoices, int zipfSkew) {
+        double[] probDist = new double[numChoices];
+        double divisor = 0;
+        for (int i = 1; i <= numChoices; i++) {
+            divisor += 1.0 / (double) Math.pow((double) i, (double) zipfSkew);
+        }
+        for (int i = 1; i <= numChoices; i++) {
+            probDist[i - 1] = (1.0 / (double) Math.pow((double) i, (double) zipfSkew)) / divisor;
+        }
+        return probDist;
+    }
+
+    public static int[] getCumulIntRanges(double[] probDist) {
+        int[] opRanges = new int[probDist.length];
+        if (opRanges.length > 1) {
+            opRanges[0] = (int) Math.floor(Integer.MAX_VALUE * probDist[0]);
+            for (int i = 1; i < opRanges.length - 1; i++) {
+                opRanges[i] = opRanges[i - 1] + (int) Math.floor(Integer.MAX_VALUE * probDist[i]);
+            }
+            opRanges[opRanges.length - 1] = Integer.MAX_VALUE;
+        } else {
+            opRanges[0] = Integer.MAX_VALUE;
+        }
+        return opRanges;
+    }
+
+    public static int choose(int[] cumulIntRanges, int randomInt) {
+        int rndVal = Math.abs(randomInt);
+        int ix = Arrays.binarySearch(cumulIntRanges, rndVal);
+        if (ix < 0) {
+            ix = -ix - 1;
+        }
+        return ix;
+    }
+
+}
diff --git a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/SortedDoubleFieldValueGenerator.java b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/SortedDoubleFieldValueGenerator.java
index 4193811..228d12e 100644
--- a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/SortedDoubleFieldValueGenerator.java
+++ b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/SortedDoubleFieldValueGenerator.java
@@ -1,3 +1,18 @@
+/*
+ * Copyright 2009-2012 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package edu.uci.ics.hyracks.storage.am.common.datagen;
 
 public class SortedDoubleFieldValueGenerator implements IFieldValueGenerator<Double> {
diff --git a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/SortedFloatFieldValueGenerator.java b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/SortedFloatFieldValueGenerator.java
index 1f6b315..13fd47b 100644
--- a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/SortedFloatFieldValueGenerator.java
+++ b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/SortedFloatFieldValueGenerator.java
@@ -1,3 +1,18 @@
+/*
+ * Copyright 2009-2012 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package edu.uci.ics.hyracks.storage.am.common.datagen;
 
 public class SortedFloatFieldValueGenerator implements IFieldValueGenerator<Float> {
diff --git a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/SortedIntegerFieldValueGenerator.java b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/SortedIntegerFieldValueGenerator.java
index 8f7fdcf..b4a13cb 100644
--- a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/SortedIntegerFieldValueGenerator.java
+++ b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/SortedIntegerFieldValueGenerator.java
@@ -1,3 +1,18 @@
+/*
+ * Copyright 2009-2012 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package edu.uci.ics.hyracks.storage.am.common.datagen;
 
 public class SortedIntegerFieldValueGenerator implements IFieldValueGenerator<Integer> {
diff --git a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/StringFieldValueGenerator.java b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/StringFieldValueGenerator.java
index 0218542..ef395ef 100644
--- a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/StringFieldValueGenerator.java
+++ b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/StringFieldValueGenerator.java
@@ -1,3 +1,18 @@
+/*
+ * Copyright 2009-2012 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package edu.uci.ics.hyracks.storage.am.common.datagen;
 
 import java.util.Random;
diff --git a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/TupleBatch.java b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/TupleBatch.java
index bfa523f..375aeb0 100644
--- a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/TupleBatch.java
+++ b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/TupleBatch.java
@@ -1,3 +1,18 @@
+/*
+ * Copyright 2009-2012 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package edu.uci.ics.hyracks.storage.am.common.datagen;
 
 import java.io.IOException;
diff --git a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/TupleGenerator.java b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/TupleGenerator.java
index 2801205..bfc56b6 100644
--- a/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/TupleGenerator.java
+++ b/hyracks-storage-am-common/src/main/java/edu/uci/ics/hyracks/storage/am/common/datagen/TupleGenerator.java
@@ -1,3 +1,18 @@
+/*
+ * Copyright 2009-2012 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package edu.uci.ics.hyracks.storage.am.common.datagen;
 
 import java.io.DataOutput;
diff --git a/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/btree/OrderedIndexMultiThreadTest.java b/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/btree/OrderedIndexMultiThreadTest.java
index d1c9293..d9423a7 100644
--- a/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/btree/OrderedIndexMultiThreadTest.java
+++ b/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/btree/OrderedIndexMultiThreadTest.java
@@ -31,7 +31,6 @@
 import edu.uci.ics.hyracks.dataflow.common.data.marshalling.UTF8StringSerializerDeserializer;
 import edu.uci.ics.hyracks.dataflow.common.util.SerdeUtils;
 import edu.uci.ics.hyracks.storage.am.common.ITreeIndexTestWorkerFactory;
-import edu.uci.ics.hyracks.storage.am.common.TestOperationSelector.TestOperation;
 import edu.uci.ics.hyracks.storage.am.common.TestWorkloadConf;
 import edu.uci.ics.hyracks.storage.am.common.TreeIndexMultiThreadTestDriver;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndex;
@@ -66,14 +65,6 @@
 
     protected abstract FileReference getFileReference();
 
-    protected static float[] getUniformOpProbs(TestOperation[] ops) {
-        float[] opProbs = new float[ops.length];
-        for (int i = 0; i < ops.length; i++) {
-            opProbs[i] = 1.0f / (float) ops.length;
-        }
-        return opProbs;
-    }
-
     protected void runTest(ISerializerDeserializer[] fieldSerdes, int numKeys, int numThreads, TestWorkloadConf conf,
             String dataMsg) throws InterruptedException, TreeIndexException, HyracksException {
         setUp();
diff --git a/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/common/TestOperationSelector.java b/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/common/TestOperationSelector.java
index 1ae79a1..47735e5 100644
--- a/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/common/TestOperationSelector.java
+++ b/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/common/TestOperationSelector.java
@@ -15,7 +15,8 @@
 
 package edu.uci.ics.hyracks.storage.am.common;
 
-import java.util.Arrays;
+import edu.uci.ics.hyracks.storage.am.common.datagen.ProbabilityHelper;
+
 
 public class TestOperationSelector {
 
@@ -32,15 +33,15 @@
     }
     
     private final TestOperation[] ops;
-    private final int[] opRanges;    
+    private final int[] cumulIntRanges;    
     
-    public TestOperationSelector(TestOperation[] ops, float[] opProbs) {
+    public TestOperationSelector(TestOperation[] ops, double[] opProbs) {
         sanityCheck(ops, opProbs);
         this.ops = ops;
-        this.opRanges = getOpRanges(opProbs);
+        this.cumulIntRanges = ProbabilityHelper.getCumulIntRanges(opProbs);
     }
     
-    private void sanityCheck(TestOperation[] ops, float[] opProbs) {
+    private void sanityCheck(TestOperation[] ops, double[] opProbs) {
         if (ops.length == 0) {
             throw new RuntimeException("Empty op array.");
         }
@@ -59,25 +60,8 @@
         }
     }
     
-    private int[] getOpRanges(float[] opProbabilities) {
-        int[] opRanges = new int[opProbabilities.length];
-        if (opRanges.length > 1) {
-            opRanges[0] = (int) Math.floor(Integer.MAX_VALUE * opProbabilities[0]);
-            for (int i = 1; i < opRanges.length - 1; i++) {
-                opRanges[i] = opRanges[i - 1] + (int) Math.floor(Integer.MAX_VALUE * opProbabilities[i]);
-            }
-            opRanges[opRanges.length - 1] = Integer.MAX_VALUE;
-        } else {
-            opRanges[0] = Integer.MAX_VALUE;
-        }
-        return opRanges;
-    }
-    
     public TestOperation getOp(int randomInt) {
-        int ix = Arrays.binarySearch(opRanges, randomInt);
-        if (ix < 0) {
-            ix = -ix - 1;
-        }
+        int ix = ProbabilityHelper.choose(cumulIntRanges, randomInt);
         return ops[ix];
     }
 }
diff --git a/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/common/TestWorkloadConf.java b/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/common/TestWorkloadConf.java
index 2437514..28845ed 100644
--- a/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/common/TestWorkloadConf.java
+++ b/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/common/TestWorkloadConf.java
@@ -19,9 +19,9 @@
 
 public class TestWorkloadConf {
     public final TestOperation[] ops;
-    public final float[] opProbs;
+    public final double[] opProbs;
 
-    public TestWorkloadConf(TestOperation[] ops, float[] opProbs) {
+    public TestWorkloadConf(TestOperation[] ops, double[] opProbs) {
         this.ops = ops;
         this.opProbs = opProbs;
     }
diff --git a/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/common/TreeIndexMultiThreadTestDriver.java b/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/common/TreeIndexMultiThreadTestDriver.java
index f4946d9..97cca35 100644
--- a/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/common/TreeIndexMultiThreadTestDriver.java
+++ b/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/common/TreeIndexMultiThreadTestDriver.java
@@ -34,7 +34,7 @@
     private final ITreeIndexTestWorkerFactory workerFactory;
 
     public TreeIndexMultiThreadTestDriver(ITreeIndex index, ITreeIndexTestWorkerFactory workerFactory,
-            ISerializerDeserializer[] fieldSerdes, TestOperation[] ops, float[] opProbs) {
+            ISerializerDeserializer[] fieldSerdes, TestOperation[] ops, double[] opProbs) {
         this.index = index;
         this.workerFactory = workerFactory;
         this.fieldSerdes = fieldSerdes;
diff --git a/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/AbstractRTreeMultiThreadTest.java b/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/AbstractRTreeMultiThreadTest.java
index cfacc69..9fb9cbe 100644
--- a/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/AbstractRTreeMultiThreadTest.java
+++ b/hyracks-test-support/src/main/java/edu/uci/ics/hyracks/storage/am/rtree/AbstractRTreeMultiThreadTest.java
@@ -33,7 +33,6 @@
 import edu.uci.ics.hyracks.dataflow.common.data.marshalling.IntegerSerializerDeserializer;
 import edu.uci.ics.hyracks.dataflow.common.util.SerdeUtils;
 import edu.uci.ics.hyracks.storage.am.common.ITreeIndexTestWorkerFactory;
-import edu.uci.ics.hyracks.storage.am.common.TestOperationSelector.TestOperation;
 import edu.uci.ics.hyracks.storage.am.common.TestWorkloadConf;
 import edu.uci.ics.hyracks.storage.am.common.TreeIndexMultiThreadTestDriver;
 import edu.uci.ics.hyracks.storage.am.common.api.IPrimitiveValueProviderFactory;
@@ -79,14 +78,6 @@
 
     protected abstract FileReference getFileReference();
 
-    protected static float[] getUniformOpProbs(TestOperation[] ops) {
-        float[] opProbs = new float[ops.length];
-        for (int i = 0; i < ops.length; i++) {
-            opProbs[i] = 1.0f / (float) ops.length;
-        }
-        return opProbs;
-    }
-
     protected void runTest(ISerializerDeserializer[] fieldSerdes,
             IPrimitiveValueProviderFactory[] valueProviderFactories, int numKeys, RTreePolicyType rtreePolicyType,
             int numThreads, TestWorkloadConf conf, String dataMsg) throws HyracksException, InterruptedException,
diff --git a/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/multithread/BTreeMultiThreadTest.java b/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/multithread/BTreeMultiThreadTest.java
index bc71052..a38b39b 100644
--- a/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/multithread/BTreeMultiThreadTest.java
+++ b/hyracks-tests/hyracks-storage-am-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/btree/multithread/BTreeMultiThreadTest.java
@@ -30,6 +30,7 @@
 import edu.uci.ics.hyracks.storage.am.common.TestWorkloadConf;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndex;
 import edu.uci.ics.hyracks.storage.am.common.api.TreeIndexException;
+import edu.uci.ics.hyracks.storage.am.common.datagen.ProbabilityHelper;
 
 public class BTreeMultiThreadTest extends OrderedIndexMultiThreadTest {
 
@@ -64,24 +65,26 @@
 
         // Insert only workload.
         TestOperation[] insertOnlyOps = new TestOperation[] { TestOperation.INSERT };
-        workloadConfs.add(new TestWorkloadConf(insertOnlyOps, getUniformOpProbs(insertOnlyOps)));
+        workloadConfs.add(new TestWorkloadConf(insertOnlyOps, ProbabilityHelper
+                .getUniformProbDist(insertOnlyOps.length)));
 
         // Inserts mixed with point searches and scans.
         TestOperation[] insertSearchOnlyOps = new TestOperation[] { TestOperation.INSERT, TestOperation.POINT_SEARCH,
                 TestOperation.SCAN, TestOperation.DISKORDER_SCAN };
-        workloadConfs.add(new TestWorkloadConf(insertSearchOnlyOps, getUniformOpProbs(insertSearchOnlyOps)));
+        workloadConfs.add(new TestWorkloadConf(insertSearchOnlyOps, ProbabilityHelper
+                .getUniformProbDist(insertSearchOnlyOps.length)));
 
         // Inserts, updates, deletes, and upserts.        
         TestOperation[] insertDeleteUpdateUpsertOps = new TestOperation[] { TestOperation.INSERT, TestOperation.DELETE,
                 TestOperation.UPDATE, TestOperation.UPSERT };
-        workloadConfs.add(new TestWorkloadConf(insertDeleteUpdateUpsertOps,
-                getUniformOpProbs(insertDeleteUpdateUpsertOps)));
+        workloadConfs.add(new TestWorkloadConf(insertDeleteUpdateUpsertOps, ProbabilityHelper
+                .getUniformProbDist(insertDeleteUpdateUpsertOps.length)));
 
         // All operations mixed.
         TestOperation[] allOps = new TestOperation[] { TestOperation.INSERT, TestOperation.DELETE,
                 TestOperation.UPDATE, TestOperation.UPSERT, TestOperation.POINT_SEARCH, TestOperation.SCAN,
                 TestOperation.DISKORDER_SCAN };
-        workloadConfs.add(new TestWorkloadConf(allOps, getUniformOpProbs(allOps)));
+        workloadConfs.add(new TestWorkloadConf(allOps, ProbabilityHelper.getUniformProbDist(allOps.length)));
 
         return workloadConfs;
     }
diff --git a/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/multithread/LSMBTreeMultiThreadTest.java b/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/multithread/LSMBTreeMultiThreadTest.java
index 0a16c4d..3ea59cf 100644
--- a/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/multithread/LSMBTreeMultiThreadTest.java
+++ b/hyracks-tests/hyracks-storage-am-lsm-btree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/btree/multithread/LSMBTreeMultiThreadTest.java
@@ -28,6 +28,7 @@
 import edu.uci.ics.hyracks.storage.am.common.TestWorkloadConf;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndex;
 import edu.uci.ics.hyracks.storage.am.common.api.TreeIndexException;
+import edu.uci.ics.hyracks.storage.am.common.datagen.ProbabilityHelper;
 import edu.uci.ics.hyracks.storage.am.lsm.btree.util.LSMBTreeTestHarness;
 import edu.uci.ics.hyracks.storage.am.lsm.btree.util.LSMBTreeUtils;
 
@@ -67,37 +68,42 @@
 
         // Insert only workload.
         TestOperation[] insertOnlyOps = new TestOperation[] { TestOperation.INSERT };
-        workloadConfs.add(new TestWorkloadConf(insertOnlyOps, getUniformOpProbs(insertOnlyOps)));
+        workloadConfs.add(new TestWorkloadConf(insertOnlyOps, ProbabilityHelper
+                .getUniformProbDist(insertOnlyOps.length)));
 
         // Insert and merge workload.
         TestOperation[] insertMergeOps = new TestOperation[] { TestOperation.INSERT, TestOperation.MERGE };
-        workloadConfs.add(new TestWorkloadConf(insertMergeOps, getUniformOpProbs(insertMergeOps)));
+        workloadConfs.add(new TestWorkloadConf(insertMergeOps, ProbabilityHelper
+                .getUniformProbDist(insertMergeOps.length)));
 
         // Inserts mixed with point searches and scans.
         TestOperation[] insertSearchOnlyOps = new TestOperation[] { TestOperation.INSERT, TestOperation.POINT_SEARCH,
                 TestOperation.SCAN };
-        workloadConfs.add(new TestWorkloadConf(insertSearchOnlyOps, getUniformOpProbs(insertSearchOnlyOps)));
+        workloadConfs.add(new TestWorkloadConf(insertSearchOnlyOps, ProbabilityHelper
+                .getUniformProbDist(insertSearchOnlyOps.length)));
 
         // Inserts, updates, and deletes.
         TestOperation[] insertDeleteUpdateOps = new TestOperation[] { TestOperation.INSERT, TestOperation.DELETE,
                 TestOperation.UPDATE };
-        workloadConfs.add(new TestWorkloadConf(insertDeleteUpdateOps, getUniformOpProbs(insertDeleteUpdateOps)));
+        workloadConfs.add(new TestWorkloadConf(insertDeleteUpdateOps, ProbabilityHelper
+                .getUniformProbDist(insertDeleteUpdateOps.length)));
 
         // Inserts, updates, deletes and merges.
         TestOperation[] insertDeleteUpdateMergeOps = new TestOperation[] { TestOperation.INSERT, TestOperation.DELETE,
                 TestOperation.UPDATE, TestOperation.MERGE };
-        workloadConfs.add(new TestWorkloadConf(insertDeleteUpdateMergeOps,
-                getUniformOpProbs(insertDeleteUpdateMergeOps)));
+        workloadConfs.add(new TestWorkloadConf(insertDeleteUpdateMergeOps, ProbabilityHelper
+                .getUniformProbDist(insertDeleteUpdateMergeOps.length)));
 
         // All operations except merge.
         TestOperation[] allNoMergeOps = new TestOperation[] { TestOperation.INSERT, TestOperation.DELETE,
                 TestOperation.UPDATE, TestOperation.POINT_SEARCH, TestOperation.SCAN };
-        workloadConfs.add(new TestWorkloadConf(allNoMergeOps, getUniformOpProbs(allNoMergeOps)));
+        workloadConfs.add(new TestWorkloadConf(allNoMergeOps, ProbabilityHelper
+                .getUniformProbDist(allNoMergeOps.length)));
 
         // All operations.
         TestOperation[] allOps = new TestOperation[] { TestOperation.INSERT, TestOperation.DELETE,
                 TestOperation.UPDATE, TestOperation.POINT_SEARCH, TestOperation.SCAN, TestOperation.MERGE };
-        workloadConfs.add(new TestWorkloadConf(allOps, getUniformOpProbs(allOps)));
+        workloadConfs.add(new TestWorkloadConf(allOps, ProbabilityHelper.getUniformProbDist(allOps.length)));
 
         return workloadConfs;
     }
diff --git a/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndexBulkLoadTest.java b/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndexBulkLoadTest.java
index 73537ce..97e6dc4 100644
--- a/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndexBulkLoadTest.java
+++ b/hyracks-tests/hyracks-storage-am-lsm-invertedindex-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/ondisk/OnDiskInvertedIndexBulkLoadTest.java
@@ -45,19 +45,10 @@
 import edu.uci.ics.hyracks.dataflow.common.data.marshalling.IntegerSerializerDeserializer;
 import edu.uci.ics.hyracks.dataflow.common.data.marshalling.UTF8StringSerializerDeserializer;
 import edu.uci.ics.hyracks.storage.am.btree.impls.BTree;
-import edu.uci.ics.hyracks.storage.am.btree.impls.RangePredicate;
 import edu.uci.ics.hyracks.storage.am.common.api.IIndexBulkLoader;
-import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexAccessor;
-import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndexCursor;
-import edu.uci.ics.hyracks.storage.am.common.impls.NoOpOperationCallback;
 import edu.uci.ics.hyracks.storage.am.common.ophelpers.IndexOp;
-import edu.uci.ics.hyracks.storage.am.common.ophelpers.MultiComparator;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.api.IInvertedListBuilder;
 import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.api.IInvertedListCursor;
-import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.ondisk.FixedSizeElementInvertedListBuilder;
-import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.ondisk.FixedSizeElementInvertedListCursor;
-import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.ondisk.OnDiskInvertedIndex;
-import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.ondisk.OnDiskInvertedIndexOpContext;
 import edu.uci.ics.hyracks.storage.common.buffercache.IBufferCache;
 import edu.uci.ics.hyracks.storage.common.file.IFileMapProvider;
 import edu.uci.ics.hyracks.test.support.TestStorageManagerComponentHolder;
@@ -173,13 +164,7 @@
 
         // ------- START VERIFICATION -----------
 
-        ITreeIndexAccessor btreeAccessor = invIndex.getBTree().createAccessor(NoOpOperationCallback.INSTANCE,
-                NoOpOperationCallback.INSTANCE);
-        ITreeIndexCursor btreeCursor = (ITreeIndexCursor) btreeAccessor.createSearchCursor();
         FrameTupleReference searchKey = new FrameTupleReference();
-        MultiComparator btreeCmp = MultiComparator.create(cmpFactories);
-        RangePredicate btreePred = new RangePredicate(searchKey, searchKey, true, true, btreeCmp, btreeCmp);
-
         IInvertedListCursor invListCursor = new FixedSizeElementInvertedListCursor(bufferCache,
                 fmp.lookupFileId(invListsFile), invListTypeTraits);
 
diff --git a/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/multithread/LSMRTreeMultiThreadTest.java b/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/multithread/LSMRTreeMultiThreadTest.java
index f3b8361..292650f 100644
--- a/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/multithread/LSMRTreeMultiThreadTest.java
+++ b/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/multithread/LSMRTreeMultiThreadTest.java
@@ -28,6 +28,7 @@
 import edu.uci.ics.hyracks.storage.am.common.api.IPrimitiveValueProviderFactory;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndex;
 import edu.uci.ics.hyracks.storage.am.common.api.TreeIndexException;
+import edu.uci.ics.hyracks.storage.am.common.datagen.ProbabilityHelper;
 import edu.uci.ics.hyracks.storage.am.lsm.rtree.util.LSMRTreeTestHarness;
 import edu.uci.ics.hyracks.storage.am.lsm.rtree.utils.LSMRTreeUtils;
 import edu.uci.ics.hyracks.storage.am.rtree.AbstractRTreeMultiThreadTest;
@@ -35,14 +36,14 @@
 
 public class LSMRTreeMultiThreadTest extends AbstractRTreeMultiThreadTest {
 
-	private LSMRTreeTestHarness harness = new LSMRTreeTestHarness();
+    private LSMRTreeTestHarness harness = new LSMRTreeTestHarness();
 
     private LSMRTreeTestWorkerFactory workerFactory = new LSMRTreeTestWorkerFactory();
 
     public LSMRTreeMultiThreadTest() {
-		super(false);
-	}
-    
+        super(false);
+    }
+
     @Override
     protected void setUp() throws HyracksException {
         harness.setUp();
@@ -75,34 +76,40 @@
 
         // Insert only workload.
         TestOperation[] insertOnlyOps = new TestOperation[] { TestOperation.INSERT };
-        workloadConfs.add(new TestWorkloadConf(insertOnlyOps, getUniformOpProbs(insertOnlyOps)));
+        workloadConfs.add(new TestWorkloadConf(insertOnlyOps, ProbabilityHelper
+                .getUniformProbDist(insertOnlyOps.length)));
 
         // Insert and merge workload.
         TestOperation[] insertMergeOps = new TestOperation[] { TestOperation.INSERT, TestOperation.MERGE };
-        workloadConfs.add(new TestWorkloadConf(insertMergeOps, getUniformOpProbs(insertMergeOps)));
+        workloadConfs.add(new TestWorkloadConf(insertMergeOps, ProbabilityHelper
+                .getUniformProbDist(insertMergeOps.length)));
 
         // Inserts mixed with scans.
         TestOperation[] insertSearchOnlyOps = new TestOperation[] { TestOperation.INSERT, TestOperation.SCAN };
-        workloadConfs.add(new TestWorkloadConf(insertSearchOnlyOps, getUniformOpProbs(insertSearchOnlyOps)));
+        workloadConfs.add(new TestWorkloadConf(insertSearchOnlyOps, ProbabilityHelper
+                .getUniformProbDist(insertSearchOnlyOps.length)));
 
         // Inserts and deletes.
         TestOperation[] insertDeleteOps = new TestOperation[] { TestOperation.INSERT, TestOperation.DELETE };
-        workloadConfs.add(new TestWorkloadConf(insertDeleteOps, getUniformOpProbs(insertDeleteOps)));
+        workloadConfs.add(new TestWorkloadConf(insertDeleteOps, ProbabilityHelper
+                .getUniformProbDist(insertDeleteOps.length)));
 
         // Inserts, deletes and merges.
         TestOperation[] insertDeleteMergeOps = new TestOperation[] { TestOperation.INSERT, TestOperation.DELETE,
                 TestOperation.MERGE };
-        workloadConfs.add(new TestWorkloadConf(insertDeleteMergeOps, getUniformOpProbs(insertDeleteMergeOps)));
+        workloadConfs.add(new TestWorkloadConf(insertDeleteMergeOps, ProbabilityHelper
+                .getUniformProbDist(insertDeleteMergeOps.length)));
 
         // All operations except merge.
         TestOperation[] allNoMergeOps = new TestOperation[] { TestOperation.INSERT, TestOperation.DELETE,
                 TestOperation.SCAN };
-        workloadConfs.add(new TestWorkloadConf(allNoMergeOps, getUniformOpProbs(allNoMergeOps)));
+        workloadConfs.add(new TestWorkloadConf(allNoMergeOps, ProbabilityHelper
+                .getUniformProbDist(allNoMergeOps.length)));
 
         // All operations.
         TestOperation[] allOps = new TestOperation[] { TestOperation.INSERT, TestOperation.DELETE, TestOperation.SCAN,
                 TestOperation.MERGE };
-        workloadConfs.add(new TestWorkloadConf(allOps, getUniformOpProbs(allOps)));
+        workloadConfs.add(new TestWorkloadConf(allOps, ProbabilityHelper.getUniformProbDist(allOps.length)));
 
         return workloadConfs;
     }
diff --git a/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/multithread/LSMRTreeWithAntiMatterTuplesMultiThreadTest.java b/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/multithread/LSMRTreeWithAntiMatterTuplesMultiThreadTest.java
index 0912504..7f8d7c9 100644
--- a/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/multithread/LSMRTreeWithAntiMatterTuplesMultiThreadTest.java
+++ b/hyracks-tests/hyracks-storage-am-lsm-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/lsm/rtree/multithread/LSMRTreeWithAntiMatterTuplesMultiThreadTest.java
@@ -28,6 +28,7 @@
 import edu.uci.ics.hyracks.storage.am.common.api.IPrimitiveValueProviderFactory;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndex;
 import edu.uci.ics.hyracks.storage.am.common.api.TreeIndexException;
+import edu.uci.ics.hyracks.storage.am.common.datagen.ProbabilityHelper;
 import edu.uci.ics.hyracks.storage.am.lsm.rtree.util.LSMRTreeTestHarness;
 import edu.uci.ics.hyracks.storage.am.lsm.rtree.utils.LSMRTreeUtils;
 import edu.uci.ics.hyracks.storage.am.rtree.AbstractRTreeMultiThreadTest;
@@ -35,14 +36,14 @@
 
 public class LSMRTreeWithAntiMatterTuplesMultiThreadTest extends AbstractRTreeMultiThreadTest {
 
-	private LSMRTreeTestHarness harness = new LSMRTreeTestHarness();
+    private LSMRTreeTestHarness harness = new LSMRTreeTestHarness();
 
     private LSMRTreeWithAntiMatterTuplesTestWorkerFactory workerFactory = new LSMRTreeWithAntiMatterTuplesTestWorkerFactory();
 
     public LSMRTreeWithAntiMatterTuplesMultiThreadTest() {
-		super(false);
-	}
-    
+        super(false);
+    }
+
     @Override
     protected void setUp() throws HyracksException {
         harness.setUp();
@@ -76,34 +77,40 @@
 
         // Insert only workload.
         TestOperation[] insertOnlyOps = new TestOperation[] { TestOperation.INSERT };
-        workloadConfs.add(new TestWorkloadConf(insertOnlyOps, getUniformOpProbs(insertOnlyOps)));
+        workloadConfs.add(new TestWorkloadConf(insertOnlyOps, ProbabilityHelper
+                .getUniformProbDist(insertOnlyOps.length)));
 
         // Insert and merge workload.
         TestOperation[] insertMergeOps = new TestOperation[] { TestOperation.INSERT, TestOperation.MERGE };
-        workloadConfs.add(new TestWorkloadConf(insertMergeOps, getUniformOpProbs(insertMergeOps)));
+        workloadConfs.add(new TestWorkloadConf(insertMergeOps, ProbabilityHelper
+                .getUniformProbDist(insertMergeOps.length)));
 
         // Inserts mixed with scans.
         TestOperation[] insertSearchOnlyOps = new TestOperation[] { TestOperation.INSERT, TestOperation.SCAN };
-        workloadConfs.add(new TestWorkloadConf(insertSearchOnlyOps, getUniformOpProbs(insertSearchOnlyOps)));
+        workloadConfs.add(new TestWorkloadConf(insertSearchOnlyOps, ProbabilityHelper
+                .getUniformProbDist(insertSearchOnlyOps.length)));
 
         // Inserts and deletes.
         TestOperation[] insertDeleteOps = new TestOperation[] { TestOperation.INSERT, TestOperation.DELETE };
-        workloadConfs.add(new TestWorkloadConf(insertDeleteOps, getUniformOpProbs(insertDeleteOps)));
+        workloadConfs.add(new TestWorkloadConf(insertDeleteOps, ProbabilityHelper
+                .getUniformProbDist(insertDeleteOps.length)));
 
         // Inserts, deletes and merges.
         TestOperation[] insertDeleteMergeOps = new TestOperation[] { TestOperation.INSERT, TestOperation.DELETE,
                 TestOperation.MERGE };
-        workloadConfs.add(new TestWorkloadConf(insertDeleteMergeOps, getUniformOpProbs(insertDeleteMergeOps)));
+        workloadConfs.add(new TestWorkloadConf(insertDeleteMergeOps, ProbabilityHelper
+                .getUniformProbDist(insertDeleteMergeOps.length)));
 
         // All operations except merge.
         TestOperation[] allNoMergeOps = new TestOperation[] { TestOperation.INSERT, TestOperation.DELETE,
                 TestOperation.SCAN };
-        workloadConfs.add(new TestWorkloadConf(allNoMergeOps, getUniformOpProbs(allNoMergeOps)));
+        workloadConfs.add(new TestWorkloadConf(allNoMergeOps, ProbabilityHelper
+                .getUniformProbDist(allNoMergeOps.length)));
 
         // All operations.
         TestOperation[] allOps = new TestOperation[] { TestOperation.INSERT, TestOperation.DELETE, TestOperation.SCAN,
                 TestOperation.MERGE };
-        workloadConfs.add(new TestWorkloadConf(allOps, getUniformOpProbs(allOps)));
+        workloadConfs.add(new TestWorkloadConf(allOps, ProbabilityHelper.getUniformProbDist(allOps.length)));
 
         return workloadConfs;
     }
diff --git a/hyracks-tests/hyracks-storage-am-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/rtree/multithread/RTreeMultiThreadTest.java b/hyracks-tests/hyracks-storage-am-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/rtree/multithread/RTreeMultiThreadTest.java
index c40f218..cc3c45c 100644
--- a/hyracks-tests/hyracks-storage-am-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/rtree/multithread/RTreeMultiThreadTest.java
+++ b/hyracks-tests/hyracks-storage-am-rtree-test/src/test/java/edu/uci/ics/hyracks/storage/am/rtree/multithread/RTreeMultiThreadTest.java
@@ -27,6 +27,7 @@
 import edu.uci.ics.hyracks.storage.am.common.api.IPrimitiveValueProviderFactory;
 import edu.uci.ics.hyracks.storage.am.common.api.ITreeIndex;
 import edu.uci.ics.hyracks.storage.am.common.api.TreeIndexException;
+import edu.uci.ics.hyracks.storage.am.common.datagen.ProbabilityHelper;
 import edu.uci.ics.hyracks.storage.am.rtree.AbstractRTreeMultiThreadTest;
 import edu.uci.ics.hyracks.storage.am.rtree.frames.RTreePolicyType;
 import edu.uci.ics.hyracks.storage.am.rtree.util.RTreeUtils;
@@ -35,10 +36,10 @@
 public class RTreeMultiThreadTest extends AbstractRTreeMultiThreadTest {
 
     public RTreeMultiThreadTest() {
-		super(true);
-	}
+        super(true);
+    }
 
-	private RTreeTestHarness harness = new RTreeTestHarness();
+    private RTreeTestHarness harness = new RTreeTestHarness();
 
     private RTreeTestWorkerFactory workerFactory = new RTreeTestWorkerFactory();
 
@@ -72,21 +73,24 @@
 
         // Insert only workload.
         TestOperation[] insertOnlyOps = new TestOperation[] { TestOperation.INSERT };
-        workloadConfs.add(new TestWorkloadConf(insertOnlyOps, getUniformOpProbs(insertOnlyOps)));
+        workloadConfs.add(new TestWorkloadConf(insertOnlyOps, ProbabilityHelper
+                .getUniformProbDist(insertOnlyOps.length)));
 
         // Inserts mixed with scans.
         TestOperation[] insertSearchOnlyOps = new TestOperation[] { TestOperation.INSERT, TestOperation.SCAN,
                 TestOperation.DISKORDER_SCAN };
-        workloadConfs.add(new TestWorkloadConf(insertSearchOnlyOps, getUniformOpProbs(insertSearchOnlyOps)));
+        workloadConfs.add(new TestWorkloadConf(insertSearchOnlyOps, ProbabilityHelper
+                .getUniformProbDist(insertSearchOnlyOps.length)));
 
         // Inserts and deletes.
         TestOperation[] insertDeleteOps = new TestOperation[] { TestOperation.INSERT, TestOperation.DELETE };
-        workloadConfs.add(new TestWorkloadConf(insertDeleteOps, getUniformOpProbs(insertDeleteOps)));
+        workloadConfs.add(new TestWorkloadConf(insertDeleteOps, ProbabilityHelper
+                .getUniformProbDist(insertDeleteOps.length)));
 
         // All operations mixed.
         TestOperation[] allOps = new TestOperation[] { TestOperation.INSERT, TestOperation.DELETE, TestOperation.SCAN,
                 TestOperation.DISKORDER_SCAN };
-        workloadConfs.add(new TestWorkloadConf(allOps, getUniformOpProbs(allOps)));
+        workloadConfs.add(new TestWorkloadConf(allOps, ProbabilityHelper.getUniformProbDist(allOps.length)));
 
         return workloadConfs;
     }