diff --git a/hyracks-fullstack/algebricks/algebricks-core/pom.xml b/hyracks-fullstack/algebricks/algebricks-core/pom.xml
index 6fdaec5..3c2912e 100644
--- a/hyracks-fullstack/algebricks/algebricks-core/pom.xml
+++ b/hyracks-fullstack/algebricks/algebricks-core/pom.xml
@@ -81,16 +81,5 @@
       <groupId>org.apache.commons</groupId>
       <artifactId>commons-lang3</artifactId>
     </dependency>
-    <dependency>
-      <groupId>com.e-movimento.tinytools</groupId>
-      <artifactId>privilegedaccessor</artifactId>
-      <version>1.2.2</version>
-      <scope>test</scope>
-    </dependency>
-    <dependency>
-      <groupId>junit</groupId>
-      <artifactId>junit</artifactId>
-      <scope>test</scope>
-    </dependency>
   </dependencies>
 </project>
diff --git a/hyracks-fullstack/algebricks/algebricks-core/src/main/java/org/apache/hyracks/algebricks/core/algebra/operators/physical/ExternalGroupByPOperator.java b/hyracks-fullstack/algebricks/algebricks-core/src/main/java/org/apache/hyracks/algebricks/core/algebra/operators/physical/ExternalGroupByPOperator.java
index 8555ade..9e7daf0 100644
--- a/hyracks-fullstack/algebricks/algebricks-core/src/main/java/org/apache/hyracks/algebricks/core/algebra/operators/physical/ExternalGroupByPOperator.java
+++ b/hyracks-fullstack/algebricks/algebricks-core/src/main/java/org/apache/hyracks/algebricks/core/algebra/operators/physical/ExternalGroupByPOperator.java
@@ -65,7 +65,6 @@
 import org.apache.hyracks.dataflow.std.group.HashSpillableTableFactory;
 import org.apache.hyracks.dataflow.std.group.IAggregatorDescriptorFactory;
 import org.apache.hyracks.dataflow.std.group.external.ExternalGroupOperatorDescriptor;
-import org.apache.hyracks.dataflow.std.structures.SerializableHashTable;
 
 public class ExternalGroupByPOperator extends AbstractPhysicalOperator {
 
@@ -259,8 +258,8 @@
         // Calculates the hash table size (# of unique hash values) based on the budget and a tuple size.
         int memoryBudgetInBytes = context.getFrameSize() * frameLimit;
         int groupByColumnsCount = gby.getGroupByList().size() + numFds;
-        int hashTableSize = calculateGroupByTableCardinality(memoryBudgetInBytes, groupByColumnsCount,
-                context.getFrameSize());
+        int hashTableSize = ExternalGroupOperatorDescriptor.calculateGroupByTableCardinality(memoryBudgetInBytes,
+                groupByColumnsCount, context.getFrameSize());
 
         ExternalGroupOperatorDescriptor gbyOpDesc = new ExternalGroupOperatorDescriptor(spec, hashTableSize, inputSize,
                 keyAndDecFields, frameLimit, comparatorFactories, normalizedKeyFactory, aggregatorFactory, mergeFactory,
@@ -282,51 +281,4 @@
         return true;
     }
 
-    /**
-     * Based on a rough estimation of a tuple (each field size: 4 bytes) size and the number of possible hash values
-     * for the given number of group-by columns, calculates the number of hash entries for the hash table in Group-by.
-     * The formula is min(# of possible hash values, # of possible tuples in the data table).
-     * This method assumes that the group-by table consists of hash table that stores hash value of tuple pointer
-     * and data table actually stores the aggregated tuple.
-     * For more details, refer to this JIRA issue: https://issues.apache.org/jira/browse/ASTERIXDB-1556
-     *
-     * @param memoryBudgetByteSize
-     * @param numberOfGroupByColumns
-     * @return group-by table size (the cardinality of group-by table)
-     */
-    public static int calculateGroupByTableCardinality(long memoryBudgetByteSize, int numberOfGroupByColumns,
-            int frameSize) {
-        // Estimates a minimum tuple size with n fields:
-        // (4:tuple offset in a frame, 4n:each field offset in a tuple, 4n:each field size 4 bytes)
-        int tupleByteSize = 4 + 8 * numberOfGroupByColumns;
-
-        // Maximum number of tuples
-        long maxNumberOfTuplesInDataTable = memoryBudgetByteSize / tupleByteSize;
-
-        // To calculate possible hash values, this counts the number of bits.
-        // We assume that each field consists of 4 bytes.
-        // Also, too high range that is greater than Long.MAXVALUE (64 bits) is not necessary for our calculation.
-        // And, this should not generate negative numbers when shifting the number.
-        int numberOfBits = Math.min(61, numberOfGroupByColumns * 4 * 8);
-
-        // Possible number of unique hash entries
-        long possibleNumberOfHashEntries = 2L << numberOfBits;
-
-        // Between # of entries in Data table and # of possible hash values, we choose the smaller one.
-        long groupByTableCardinality = Math.min(possibleNumberOfHashEntries, maxNumberOfTuplesInDataTable);
-        long groupByTableByteSize = SerializableHashTable.getExpectedTableByteSize(groupByTableCardinality, frameSize);
-
-        // Gets the ratio of hash-table size in the total size (hash + data table).
-        double hashTableRatio = (double) groupByTableByteSize / (groupByTableByteSize + memoryBudgetByteSize);
-
-        // Gets the table size based on the ratio that we have calculated.
-        long finalGroupByTableByteSize = (long) (hashTableRatio * memoryBudgetByteSize);
-
-        long finalGroupByTableCardinality = finalGroupByTableByteSize
-                / SerializableHashTable.getExpectedByteSizePerHashValue();
-
-        // The maximum cardinality of a hash table: Integer.MAX_VALUE
-        return finalGroupByTableCardinality > Integer.MAX_VALUE ? Integer.MAX_VALUE
-                : (int) finalGroupByTableCardinality;
-    }
 }
diff --git a/hyracks-fullstack/hyracks/hyracks-dataflow-std/pom.xml b/hyracks-fullstack/hyracks/hyracks-dataflow-std/pom.xml
index 72a1bb6..0285069 100644
--- a/hyracks-fullstack/hyracks/hyracks-dataflow-std/pom.xml
+++ b/hyracks-fullstack/hyracks/hyracks-dataflow-std/pom.xml
@@ -76,6 +76,12 @@
       <version>${project.version}</version>
     </dependency>
     <dependency>
+      <groupId>com.e-movimento.tinytools</groupId>
+      <artifactId>privilegedaccessor</artifactId>
+      <version>1.2.2</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
       <groupId>junit</groupId>
       <artifactId>junit</artifactId>
       <scope>test</scope>
diff --git a/hyracks-fullstack/hyracks/hyracks-dataflow-std/src/main/java/org/apache/hyracks/dataflow/std/group/external/ExternalGroupOperatorDescriptor.java b/hyracks-fullstack/hyracks/hyracks-dataflow-std/src/main/java/org/apache/hyracks/dataflow/std/group/external/ExternalGroupOperatorDescriptor.java
index 4e0724c..2d8433d 100644
--- a/hyracks-fullstack/hyracks/hyracks-dataflow-std/src/main/java/org/apache/hyracks/dataflow/std/group/external/ExternalGroupOperatorDescriptor.java
+++ b/hyracks-fullstack/hyracks/hyracks-dataflow-std/src/main/java/org/apache/hyracks/dataflow/std/group/external/ExternalGroupOperatorDescriptor.java
@@ -33,6 +33,7 @@
 import org.apache.hyracks.dataflow.std.base.AbstractOperatorDescriptor;
 import org.apache.hyracks.dataflow.std.group.IAggregatorDescriptorFactory;
 import org.apache.hyracks.dataflow.std.group.ISpillableTableFactory;
+import org.apache.hyracks.dataflow.std.structures.SerializableHashTable;
 
 /**
  *
@@ -151,4 +152,51 @@
 
     }
 
+    /**
+     * Based on a rough estimation of a tuple (each field size: 4 bytes) size and the number of possible hash values
+     * for the given number of group-by columns, calculates the number of hash entries for the hash table in Group-by.
+     * The formula is min(# of possible hash values, # of possible tuples in the data table).
+     * This method assumes that the group-by table consists of hash table that stores hash value of tuple pointer
+     * and data table actually stores the aggregated tuple.
+     * For more details, refer to this JIRA issue: https://issues.apache.org/jira/browse/ASTERIXDB-1556
+     *
+     * @param memoryBudgetByteSize
+     * @param numberOfGroupByColumns
+     * @return group-by table size (the cardinality of group-by table)
+     */
+    public static int calculateGroupByTableCardinality(long memoryBudgetByteSize, int numberOfGroupByColumns,
+            int frameSize) {
+        // Estimates a minimum tuple size with n fields:
+        // (4:tuple offset in a frame, 4n:each field offset in a tuple, 4n:each field size 4 bytes)
+        int tupleByteSize = 4 + 8 * numberOfGroupByColumns;
+
+        // Maximum number of tuples
+        long maxNumberOfTuplesInDataTable = memoryBudgetByteSize / tupleByteSize;
+
+        // To calculate possible hash values, this counts the number of bits.
+        // We assume that each field consists of 4 bytes.
+        // Also, too high range that is greater than Long.MAXVALUE (64 bits) is not necessary for our calculation.
+        // And, this should not generate negative numbers when shifting the number.
+        int numberOfBits = Math.min(61, numberOfGroupByColumns * 4 * 8);
+
+        // Possible number of unique hash entries
+        long possibleNumberOfHashEntries = 2L << numberOfBits;
+
+        // Between # of entries in Data table and # of possible hash values, we choose the smaller one.
+        long groupByTableCardinality = Math.min(possibleNumberOfHashEntries, maxNumberOfTuplesInDataTable);
+        long groupByTableByteSize = SerializableHashTable.getExpectedTableByteSize(groupByTableCardinality, frameSize);
+
+        // Gets the ratio of hash-table size in the total size (hash + data table).
+        double hashTableRatio = (double) groupByTableByteSize / (groupByTableByteSize + memoryBudgetByteSize);
+
+        // Gets the table size based on the ratio that we have calculated.
+        long finalGroupByTableByteSize = (long) (hashTableRatio * memoryBudgetByteSize);
+
+        long finalGroupByTableCardinality =
+                finalGroupByTableByteSize / SerializableHashTable.getExpectedByteSizePerHashValue();
+
+        // The maximum cardinality of a hash table: Integer.MAX_VALUE
+        return finalGroupByTableCardinality > Integer.MAX_VALUE ? Integer.MAX_VALUE
+                : (int) finalGroupByTableCardinality;
+    }
 }
diff --git a/hyracks-fullstack/hyracks/hyracks-dataflow-std/src/main/java/org/apache/hyracks/dataflow/std/group/external/ExternalGroupWriteOperatorNodePushable.java b/hyracks-fullstack/hyracks/hyracks-dataflow-std/src/main/java/org/apache/hyracks/dataflow/std/group/external/ExternalGroupWriteOperatorNodePushable.java
index b17215f..9a3668e 100644
--- a/hyracks-fullstack/hyracks/hyracks-dataflow-std/src/main/java/org/apache/hyracks/dataflow/std/group/external/ExternalGroupWriteOperatorNodePushable.java
+++ b/hyracks-fullstack/hyracks/hyracks-dataflow-std/src/main/java/org/apache/hyracks/dataflow/std/group/external/ExternalGroupWriteOperatorNodePushable.java
@@ -120,7 +120,13 @@
 
         for (int i = 0; i < runs.length; i++) {
             if (runs[i] != null) {
-                ISpillableTable partitionTable = spillableTableFactory.buildSpillableTable(ctx, numOfTuples[i],
+                // Calculates the hash table size (# of unique hash values) based on the budget and a tuple size.
+                int memoryBudgetInBytes = ctx.getInitialFrameSize() * frameLimit;
+                int groupByColumnsCount = mergeGroupFields.length;
+                int hashTableCardinality = ExternalGroupOperatorDescriptor.calculateGroupByTableCardinality(
+                        memoryBudgetInBytes, groupByColumnsCount, ctx.getInitialFrameSize());
+                hashTableCardinality = (int) Math.min(hashTableCardinality, numOfTuples[i]);
+                ISpillableTable partitionTable = spillableTableFactory.buildSpillableTable(ctx, hashTableCardinality,
                         runs[i].getFileSize(), mergeGroupFields, groupByComparators, nmkComputer,
                         mergeAggregatorFactory, partialAggRecordDesc, outRecordDesc, frameLimit, level);
                 RunFileWriter[] runFileWriters = new RunFileWriter[partitionTable.getNumPartitions()];
diff --git a/hyracks-fullstack/algebricks/algebricks-core/src/test/java/org/apache/hyracks/algebricks/core/algebra/operators/physical/ExternalGroupByPOperatorTest.java b/hyracks-fullstack/hyracks/hyracks-dataflow-std/src/test/java/org/apache/hyracks/dataflow/std/group/external/ExternalGroupOperatorDescriptorTest.java
similarity index 82%
rename from hyracks-fullstack/algebricks/algebricks-core/src/test/java/org/apache/hyracks/algebricks/core/algebra/operators/physical/ExternalGroupByPOperatorTest.java
rename to hyracks-fullstack/hyracks/hyracks-dataflow-std/src/test/java/org/apache/hyracks/dataflow/std/group/external/ExternalGroupOperatorDescriptorTest.java
index a633998..392aab5 100644
--- a/hyracks-fullstack/algebricks/algebricks-core/src/test/java/org/apache/hyracks/algebricks/core/algebra/operators/physical/ExternalGroupByPOperatorTest.java
+++ b/hyracks-fullstack/hyracks/hyracks-dataflow-std/src/test/java/org/apache/hyracks/dataflow/std/group/external/ExternalGroupOperatorDescriptorTest.java
@@ -17,33 +17,24 @@
  *  under the License.
  */
 
-package org.apache.hyracks.algebricks.core.algebra.operators.physical;
+package org.apache.hyracks.dataflow.std.group.external;
 
-import java.util.ArrayList;
-import java.util.List;
-
-import org.apache.commons.lang3.mutable.Mutable;
-import org.apache.commons.lang3.mutable.MutableObject;
-import org.apache.hyracks.algebricks.common.utils.Pair;
-import org.apache.hyracks.algebricks.core.algebra.base.ILogicalExpression;
-import org.apache.hyracks.algebricks.core.algebra.base.LogicalVariable;
-import org.apache.hyracks.algebricks.core.algebra.expressions.VariableReferenceExpression;
+import org.apache.hyracks.api.job.IOperatorDescriptorRegistry;
+import org.apache.hyracks.api.job.JobSpecification;
 import org.junit.Assert;
 import org.junit.Test;
 
 import junit.extensions.PA;
 
-public class ExternalGroupByPOperatorTest {
+public class ExternalGroupOperatorDescriptorTest {
 
     @Test
     public void testCalculateGroupByTableCardinality() throws Exception {
 
-        // Creates a dummy variable and an expression that are needed by the operator. They are not used by this test.
-        LogicalVariable v = new LogicalVariable(0);
-        MutableObject<ILogicalExpression> e = new MutableObject<ILogicalExpression>(new VariableReferenceExpression(v));
-        List<Pair<LogicalVariable, Mutable<ILogicalExpression>>> gbyList = new ArrayList<>();
-        gbyList.add(new Pair<>(v, e));
-        ExternalGroupByPOperator eGByOp = new ExternalGroupByPOperator(gbyList, 0, 0);
+        // Sets a dummy variable.
+        IOperatorDescriptorRegistry spec = new JobSpecification(32768);
+        ExternalGroupOperatorDescriptor eGByOp =
+                new ExternalGroupOperatorDescriptor(spec, 0, 0, null, 4, null, null, null, null, null, null, null);
 
         // Test 1: compiler.groupmemory: 512 bytes, frame size: 256 bytes, with 1 column group-by
         long memoryBudgetInBytes = 512;