diff --git a/hivesterix/hivesterix-translator/pom.xml b/hivesterix/hivesterix-translator/pom.xml
new file mode 100644
index 0000000..b99d652
--- /dev/null
+++ b/hivesterix/hivesterix-translator/pom.xml
@@ -0,0 +1,61 @@
+<?xml version="1.0"?>
+<project
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
+	xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+	<modelVersion>4.0.0</modelVersion>
+	<artifactId>hivesterix-translator</artifactId>
+	<name>hivesterix-translator</name>
+
+	<parent>
+		<artifactId>hivesterix</artifactId>
+		<groupId>edu.uci.ics.hyracks</groupId>
+		<version>0.2.3-SNAPSHOT</version>
+	</parent>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-compiler-plugin</artifactId>
+				<version>2.0.2</version>
+				<configuration>
+					<source>1.7</source>
+					<target>1.7</target>
+					<encoding>UTF-8</encoding>
+					<fork>true</fork>
+				</configuration>
+			</plugin>
+		</plugins>
+	</build>
+
+	<dependencies>
+		<dependency>
+			<groupId>org.apache.hadoop.hive</groupId>
+			<artifactId>hive-exec</artifactId>
+			<version>0.7.0</version>
+			<type>jar</type>
+			<scope>compile</scope>
+		</dependency>
+		<dependency>
+			<groupId>edu.uci.ics.hyracks</groupId>
+			<artifactId>algebricks-compiler</artifactId>
+			<version>0.2.3-SNAPSHOT</version>
+			<type>jar</type>
+			<scope>compile</scope>
+		</dependency>
+		<dependency>
+			<groupId>edu.uci.ics.hyracks</groupId>
+			<artifactId>hivesterix-common</artifactId>
+			<version>0.2.3-SNAPSHOT</version>
+			<type>jar</type>
+			<scope>compile</scope>
+		</dependency>
+		<dependency>
+			<groupId>edu.uci.ics.hyracks</groupId>
+			<artifactId>hivesterix-runtime</artifactId>
+			<version>0.2.3-SNAPSHOT</version>
+			<type>jar</type>
+			<scope>compile</scope>
+		</dependency>
+	</dependencies>
+</project>
diff --git a/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/HiveAlgebricksTranslator.java b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/HiveAlgebricksTranslator.java
new file mode 100644
index 0000000..80b3fef
--- /dev/null
+++ b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/HiveAlgebricksTranslator.java
@@ -0,0 +1,807 @@
+package edu.uci.ics.hivesterix.logical.plan;
+
+import java.io.OutputStreamWriter;
+import java.io.PrintWriter;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+
+import org.apache.commons.lang3.mutable.Mutable;
+import org.apache.commons.lang3.mutable.MutableObject;
+import org.apache.hadoop.hive.ql.exec.ColumnInfo;
+import org.apache.hadoop.hive.ql.exec.ExtractOperator;
+import org.apache.hadoop.hive.ql.exec.FileSinkOperator;
+import org.apache.hadoop.hive.ql.exec.FilterOperator;
+import org.apache.hadoop.hive.ql.exec.GroupByOperator;
+import org.apache.hadoop.hive.ql.exec.JoinOperator;
+import org.apache.hadoop.hive.ql.exec.LateralViewJoinOperator;
+import org.apache.hadoop.hive.ql.exec.LimitOperator;
+import org.apache.hadoop.hive.ql.exec.MapJoinOperator;
+import org.apache.hadoop.hive.ql.exec.Operator;
+import org.apache.hadoop.hive.ql.exec.ReduceSinkOperator;
+import org.apache.hadoop.hive.ql.exec.SelectOperator;
+import org.apache.hadoop.hive.ql.exec.TableScanOperator;
+import org.apache.hadoop.hive.ql.exec.UDF;
+import org.apache.hadoop.hive.ql.exec.UDTFOperator;
+import org.apache.hadoop.hive.ql.exec.UnionOperator;
+import org.apache.hadoop.hive.ql.plan.AggregationDesc;
+import org.apache.hadoop.hive.ql.plan.ExprNodeColumnDesc;
+import org.apache.hadoop.hive.ql.plan.ExprNodeConstantDesc;
+import org.apache.hadoop.hive.ql.plan.ExprNodeDesc;
+import org.apache.hadoop.hive.ql.plan.ExprNodeFieldDesc;
+import org.apache.hadoop.hive.ql.plan.ExprNodeGenericFuncDesc;
+import org.apache.hadoop.hive.ql.plan.ExprNodeNullDesc;
+import org.apache.hadoop.hive.ql.plan.PartitionDesc;
+import org.apache.hadoop.hive.ql.plan.UDTFDesc;
+import org.apache.hadoop.hive.ql.plan.api.OperatorType;
+import org.apache.hadoop.hive.ql.udf.generic.GenericUDF;
+import org.apache.hadoop.hive.ql.udf.generic.GenericUDFBridge;
+import org.apache.hadoop.hive.serde2.typeinfo.TypeInfo;
+
+import edu.uci.ics.hivesterix.logical.expression.ExpressionConstant;
+import edu.uci.ics.hivesterix.logical.expression.HiveAlgebricksBuiltInFunctionMap;
+import edu.uci.ics.hivesterix.logical.expression.HiveFunctionInfo;
+import edu.uci.ics.hivesterix.logical.expression.HivesterixConstantValue;
+import edu.uci.ics.hivesterix.logical.plan.visitor.ExtractVisitor;
+import edu.uci.ics.hivesterix.logical.plan.visitor.FilterVisitor;
+import edu.uci.ics.hivesterix.logical.plan.visitor.GroupByVisitor;
+import edu.uci.ics.hivesterix.logical.plan.visitor.JoinVisitor;
+import edu.uci.ics.hivesterix.logical.plan.visitor.LateralViewJoinVisitor;
+import edu.uci.ics.hivesterix.logical.plan.visitor.LimitVisitor;
+import edu.uci.ics.hivesterix.logical.plan.visitor.MapJoinVisitor;
+import edu.uci.ics.hivesterix.logical.plan.visitor.ProjectVisitor;
+import edu.uci.ics.hivesterix.logical.plan.visitor.SortVisitor;
+import edu.uci.ics.hivesterix.logical.plan.visitor.TableScanWriteVisitor;
+import edu.uci.ics.hivesterix.logical.plan.visitor.UnionVisitor;
+import edu.uci.ics.hivesterix.logical.plan.visitor.base.Translator;
+import edu.uci.ics.hivesterix.logical.plan.visitor.base.Visitor;
+import edu.uci.ics.hivesterix.runtime.jobgen.Schema;
+import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalExpression;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalPlan;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalVariable;
+import edu.uci.ics.hyracks.algebricks.core.algebra.expressions.AggregateFunctionCallExpression;
+import edu.uci.ics.hyracks.algebricks.core.algebra.expressions.ConstantExpression;
+import edu.uci.ics.hyracks.algebricks.core.algebra.expressions.ScalarFunctionCallExpression;
+import edu.uci.ics.hyracks.algebricks.core.algebra.expressions.UnnestingFunctionCallExpression;
+import edu.uci.ics.hyracks.algebricks.core.algebra.expressions.VariableReferenceExpression;
+import edu.uci.ics.hyracks.algebricks.core.algebra.functions.FunctionIdentifier;
+import edu.uci.ics.hyracks.algebricks.core.algebra.metadata.IMetadataProvider;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.AssignOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.ReplicateOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.plan.ALogicalPlanImpl;
+import edu.uci.ics.hyracks.algebricks.core.algebra.prettyprint.LogicalOperatorPrettyPrintVisitor;
+import edu.uci.ics.hyracks.algebricks.core.algebra.prettyprint.PlanPrettyPrinter;
+
+@SuppressWarnings("rawtypes")
+public class HiveAlgebricksTranslator implements Translator {
+
+    private int currentVariable = 0;
+
+    private List<Mutable<ILogicalOperator>> logicalOp = new ArrayList<Mutable<ILogicalOperator>>();
+
+    private boolean continueTraverse = true;
+
+    private IMetadataProvider<PartitionDesc, Object> metaData;
+
+    /**
+     * map variable name to the logical variable
+     */
+    private HashMap<String, LogicalVariable> nameToLogicalVariableMap = new HashMap<String, LogicalVariable>();
+
+    /**
+     * map field name to LogicalVariable
+     */
+    private HashMap<String, LogicalVariable> fieldToLogicalVariableMap = new HashMap<String, LogicalVariable>();
+
+    /**
+     * map logical variable to name
+     */
+    private HashMap<LogicalVariable, String> logicalVariableToFieldMap = new HashMap<LogicalVariable, String>();
+
+    /**
+     * asterix root operators
+     */
+    private List<Mutable<ILogicalOperator>> rootOperators = new ArrayList<Mutable<ILogicalOperator>>();
+
+    /**
+     * a list of visitors
+     */
+    private List<Visitor> visitors = new ArrayList<Visitor>();
+
+    /**
+     * output writer to print things out
+     */
+    private static PrintWriter outputWriter = new PrintWriter(new OutputStreamWriter(System.out));
+
+    /**
+     * map a logical variable to type info
+     */
+    private HashMap<LogicalVariable, TypeInfo> variableToType = new HashMap<LogicalVariable, TypeInfo>();
+
+    @Override
+    public LogicalVariable getVariable(String fieldName, TypeInfo type) {
+        LogicalVariable var = fieldToLogicalVariableMap.get(fieldName);
+        if (var == null) {
+            currentVariable++;
+            var = new LogicalVariable(currentVariable);
+            fieldToLogicalVariableMap.put(fieldName, var);
+            nameToLogicalVariableMap.put(var.toString(), var);
+            variableToType.put(var, type);
+            logicalVariableToFieldMap.put(var, fieldName);
+        }
+        return var;
+    }
+
+    @Override
+    public LogicalVariable getNewVariable(String fieldName, TypeInfo type) {
+        currentVariable++;
+        LogicalVariable var = new LogicalVariable(currentVariable);
+        fieldToLogicalVariableMap.put(fieldName, var);
+        nameToLogicalVariableMap.put(var.toString(), var);
+        variableToType.put(var, type);
+        logicalVariableToFieldMap.put(var, fieldName);
+        return var;
+    }
+
+    @Override
+    public void replaceVariable(LogicalVariable oldVar, LogicalVariable newVar) {
+        String name = this.logicalVariableToFieldMap.get(oldVar);
+        if (name != null) {
+            fieldToLogicalVariableMap.put(name, newVar);
+            nameToLogicalVariableMap.put(newVar.toString(), newVar);
+            nameToLogicalVariableMap.put(oldVar.toString(), newVar);
+            logicalVariableToFieldMap.put(newVar, name);
+        }
+    }
+
+    @Override
+    public IMetadataProvider<PartitionDesc, Object> getMetadataProvider() {
+        return metaData;
+    }
+
+    /**
+     * only get an variable, without rewriting it
+     * 
+     * @param fieldName
+     * @return
+     */
+    private LogicalVariable getVariableOnly(String fieldName) {
+        return fieldToLogicalVariableMap.get(fieldName);
+    }
+
+    private void updateVariable(String fieldName, LogicalVariable variable) {
+        LogicalVariable var = fieldToLogicalVariableMap.get(fieldName);
+        if (var == null) {
+            fieldToLogicalVariableMap.put(fieldName, variable);
+            nameToLogicalVariableMap.put(fieldName, variable);
+        } else if (!var.equals(variable)) {
+            fieldToLogicalVariableMap.put(fieldName, variable);
+            nameToLogicalVariableMap.put(fieldName, variable);
+        }
+    }
+
+    /**
+     * get a list of logical variables from the schema
+     * 
+     * @param schema
+     * @return
+     */
+    @Override
+    public List<LogicalVariable> getVariablesFromSchema(Schema schema) {
+        List<LogicalVariable> variables = new ArrayList<LogicalVariable>();
+        List<String> names = schema.getNames();
+
+        for (String name : names)
+            variables.add(nameToLogicalVariableMap.get(name));
+        return variables;
+    }
+
+    /**
+     * get variable to typeinfo map
+     * 
+     * @return
+     */
+    public HashMap<LogicalVariable, TypeInfo> getVariableContext() {
+        return this.variableToType;
+    }
+
+    /**
+     * get the number of variables s
+     * 
+     * @return
+     */
+    public int getVariableCounter() {
+        return currentVariable + 1;
+    }
+
+    /**
+     * translate from hive operator tree to asterix operator tree
+     * 
+     * @param hive
+     *            roots
+     * @return Algebricks roots
+     */
+    public void translate(List<Operator> hiveRoot, ILogicalOperator parentOperator,
+            HashMap<String, PartitionDesc> aliasToPathMap) throws AlgebricksException {
+        /**
+         * register visitors
+         */
+        visitors.add(new FilterVisitor());
+        visitors.add(new GroupByVisitor());
+        visitors.add(new JoinVisitor());
+        visitors.add(new LateralViewJoinVisitor());
+        visitors.add(new UnionVisitor());
+        visitors.add(new LimitVisitor());
+        visitors.add(new MapJoinVisitor());
+        visitors.add(new ProjectVisitor());
+        visitors.add(new SortVisitor());
+        visitors.add(new ExtractVisitor());
+        visitors.add(new TableScanWriteVisitor(aliasToPathMap));
+
+        List<Mutable<ILogicalOperator>> refList = translate(hiveRoot, new MutableObject<ILogicalOperator>(
+                parentOperator));
+        insertReplicateOperator(refList);
+        if (refList != null)
+            rootOperators.addAll(refList);
+    }
+
+    /**
+     * translate operator DAG
+     * 
+     * @param hiveRoot
+     * @param AlgebricksParentOperator
+     * @return
+     */
+    private List<Mutable<ILogicalOperator>> translate(List<Operator> hiveRoot,
+            Mutable<ILogicalOperator> AlgebricksParentOperator) throws AlgebricksException {
+
+        for (Operator hiveOperator : hiveRoot) {
+            continueTraverse = true;
+            Mutable<ILogicalOperator> currentOperatorRef = null;
+            if (hiveOperator.getType() == OperatorType.FILTER) {
+                FilterOperator fop = (FilterOperator) hiveOperator;
+                for (Visitor visitor : visitors) {
+                    currentOperatorRef = visitor.visit(fop, AlgebricksParentOperator, this);
+                    if (currentOperatorRef != null)
+                        break;
+                }
+            } else if (hiveOperator.getType() == OperatorType.REDUCESINK) {
+                ReduceSinkOperator fop = (ReduceSinkOperator) hiveOperator;
+                for (Visitor visitor : visitors) {
+                    currentOperatorRef = visitor.visit(fop, AlgebricksParentOperator, this);
+                    if (currentOperatorRef != null)
+                        break;
+                }
+            } else if (hiveOperator.getType() == OperatorType.JOIN) {
+                JoinOperator fop = (JoinOperator) hiveOperator;
+                for (Visitor visitor : visitors) {
+                    currentOperatorRef = visitor.visit(fop, AlgebricksParentOperator, this);
+                    if (currentOperatorRef != null) {
+                        continueTraverse = true;
+                        break;
+                    } else
+                        continueTraverse = false;
+                }
+                if (currentOperatorRef == null)
+                    return null;
+            } else if (hiveOperator.getType() == OperatorType.LATERALVIEWJOIN) {
+                LateralViewJoinOperator fop = (LateralViewJoinOperator) hiveOperator;
+                for (Visitor visitor : visitors) {
+                    currentOperatorRef = visitor.visit(fop, AlgebricksParentOperator, this);
+                    if (currentOperatorRef != null)
+                        break;
+                }
+                if (currentOperatorRef == null)
+                    return null;
+            } else if (hiveOperator.getType() == OperatorType.MAPJOIN) {
+                MapJoinOperator fop = (MapJoinOperator) hiveOperator;
+                for (Visitor visitor : visitors) {
+                    currentOperatorRef = visitor.visit(fop, AlgebricksParentOperator, this);
+                    if (currentOperatorRef != null) {
+                        continueTraverse = true;
+                        break;
+                    } else
+                        continueTraverse = false;
+                }
+                if (currentOperatorRef == null)
+                    return null;
+            } else if (hiveOperator.getType() == OperatorType.SELECT) {
+                SelectOperator fop = (SelectOperator) hiveOperator;
+                for (Visitor visitor : visitors) {
+                    currentOperatorRef = visitor.visit(fop, AlgebricksParentOperator, this);
+                    if (currentOperatorRef != null)
+                        break;
+                }
+            } else if (hiveOperator.getType() == OperatorType.EXTRACT) {
+                ExtractOperator fop = (ExtractOperator) hiveOperator;
+                for (Visitor visitor : visitors) {
+                    currentOperatorRef = visitor.visit(fop, AlgebricksParentOperator, this);
+                    if (currentOperatorRef != null)
+                        break;
+                }
+            } else if (hiveOperator.getType() == OperatorType.GROUPBY) {
+                GroupByOperator fop = (GroupByOperator) hiveOperator;
+                for (Visitor visitor : visitors) {
+                    currentOperatorRef = visitor.visit(fop, AlgebricksParentOperator, this);
+                    if (currentOperatorRef != null)
+                        break;
+                }
+            } else if (hiveOperator.getType() == OperatorType.TABLESCAN) {
+                TableScanOperator fop = (TableScanOperator) hiveOperator;
+                for (Visitor visitor : visitors) {
+                    currentOperatorRef = visitor.visit(fop, AlgebricksParentOperator, this);
+                    if (currentOperatorRef != null)
+                        break;
+                }
+            } else if (hiveOperator.getType() == OperatorType.FILESINK) {
+                FileSinkOperator fop = (FileSinkOperator) hiveOperator;
+                for (Visitor visitor : visitors) {
+                    currentOperatorRef = visitor.visit(fop, AlgebricksParentOperator, this);
+                    if (currentOperatorRef != null)
+                        break;
+                }
+            } else if (hiveOperator.getType() == OperatorType.LIMIT) {
+                LimitOperator lop = (LimitOperator) hiveOperator;
+                for (Visitor visitor : visitors) {
+                    currentOperatorRef = visitor.visit(lop, AlgebricksParentOperator, this);
+                    if (currentOperatorRef != null)
+                        break;
+                }
+            } else if (hiveOperator.getType() == OperatorType.UDTF) {
+                UDTFOperator lop = (UDTFOperator) hiveOperator;
+                for (Visitor visitor : visitors) {
+                    currentOperatorRef = visitor.visit(lop, AlgebricksParentOperator, this);
+                    if (currentOperatorRef != null)
+                        break;
+                }
+            } else if (hiveOperator.getType() == OperatorType.UNION) {
+                UnionOperator lop = (UnionOperator) hiveOperator;
+                for (Visitor visitor : visitors) {
+                    currentOperatorRef = visitor.visit(lop, AlgebricksParentOperator, this);
+                    if (currentOperatorRef != null) {
+                        continueTraverse = true;
+                        break;
+                    } else
+                        continueTraverse = false;
+                }
+            } else
+                ;
+            if (hiveOperator.getChildOperators() != null && hiveOperator.getChildOperators().size() > 0
+                    && continueTraverse) {
+                @SuppressWarnings("unchecked")
+                List<Operator> children = hiveOperator.getChildOperators();
+                if (currentOperatorRef == null)
+                    currentOperatorRef = AlgebricksParentOperator;
+                translate(children, currentOperatorRef);
+            }
+            if (hiveOperator.getChildOperators() == null || hiveOperator.getChildOperators().size() == 0)
+                logicalOp.add(currentOperatorRef);
+        }
+        return logicalOp;
+    }
+
+    /**
+     * used in select, group by to get no-column-expression columns
+     * 
+     * @param cols
+     * @return
+     */
+    public ILogicalOperator getAssignOperator(Mutable<ILogicalOperator> parent, List<ExprNodeDesc> cols,
+            ArrayList<LogicalVariable> variables) {
+
+        ArrayList<Mutable<ILogicalExpression>> expressions = new ArrayList<Mutable<ILogicalExpression>>();
+
+        /**
+         * variables to be appended in the assign operator
+         */
+        ArrayList<LogicalVariable> appendedVariables = new ArrayList<LogicalVariable>();
+
+        // one variable can only be assigned once
+        for (ExprNodeDesc hiveExpr : cols) {
+            rewriteExpression(hiveExpr);
+
+            if (hiveExpr instanceof ExprNodeColumnDesc) {
+                ExprNodeColumnDesc desc2 = (ExprNodeColumnDesc) hiveExpr;
+                String fieldName = desc2.getTabAlias() + "." + desc2.getColumn();
+
+                // System.out.println("project expr: " + fieldName);
+
+                if (fieldName.indexOf("$$") < 0) {
+                    LogicalVariable var = getVariable(fieldName, hiveExpr.getTypeInfo());
+                    desc2.setColumn(var.toString());
+                    desc2.setTabAlias("");
+                    variables.add(var);
+                } else {
+                    LogicalVariable var = nameToLogicalVariableMap.get(desc2.getColumn());
+                    String name = this.logicalVariableToFieldMap.get(var);
+                    var = this.getVariableOnly(name);
+                    variables.add(var);
+                }
+            } else {
+                Mutable<ILogicalExpression> asterixExpr = translateScalarFucntion(hiveExpr);
+                expressions.add(asterixExpr);
+                LogicalVariable var = getVariable(hiveExpr.getExprString() + asterixExpr.hashCode(),
+                        hiveExpr.getTypeInfo());
+                variables.add(var);
+                appendedVariables.add(var);
+            }
+        }
+
+        /**
+         * create an assign operator to deal with appending
+         */
+        ILogicalOperator assignOp = null;
+        if (appendedVariables.size() > 0) {
+            assignOp = new AssignOperator(appendedVariables, expressions);
+            assignOp.getInputs().add(parent);
+        }
+        return assignOp;
+    }
+
+    private ILogicalPlan plan;
+
+    public ILogicalPlan genLogicalPlan() {
+        plan = new ALogicalPlanImpl(rootOperators);
+        return plan;
+    }
+
+    public void printOperators() throws AlgebricksException {
+        LogicalOperatorPrettyPrintVisitor pvisitor = new LogicalOperatorPrettyPrintVisitor();
+        StringBuilder buffer = new StringBuilder();
+        PlanPrettyPrinter.printPlan(plan, buffer, pvisitor, 0);
+        outputWriter.println(buffer);
+        outputWriter.println("rewritten variables: ");
+        outputWriter.flush();
+        printVariables();
+
+    }
+
+    public static void setOutputPrinter(PrintWriter writer) {
+        outputWriter = writer;
+    }
+
+    private void printVariables() {
+        Set<Entry<String, LogicalVariable>> entries = fieldToLogicalVariableMap.entrySet();
+
+        for (Entry<String, LogicalVariable> entry : entries) {
+            outputWriter.println(entry.getKey() + " -> " + entry.getValue());
+        }
+        outputWriter.flush();
+    }
+
+    /**
+     * generate the object inspector for the output of an operator
+     * 
+     * @param operator
+     *            The Hive operator
+     * @return an ObjectInspector object
+     */
+    public Schema generateInputSchema(Operator operator) {
+        List<String> variableNames = new ArrayList<String>();
+        List<TypeInfo> typeList = new ArrayList<TypeInfo>();
+        List<ColumnInfo> columns = operator.getSchema().getSignature();
+
+        for (ColumnInfo col : columns) {
+            // typeList.add();
+            TypeInfo type = col.getType();
+            typeList.add(type);
+
+            String fieldName = col.getInternalName();
+            variableNames.add(fieldName);
+        }
+
+        return new Schema(variableNames, typeList);
+    }
+
+    /**
+     * rewrite the names of output columns for feature expression evaluators to
+     * use
+     * 
+     * @param operator
+     */
+    public void rewriteOperatorOutputSchema(Operator operator) {
+        List<ColumnInfo> columns = operator.getSchema().getSignature();
+
+        for (ColumnInfo column : columns) {
+            String columnName = column.getTabAlias() + "." + column.getInternalName();
+            if (columnName.indexOf("$$") < 0) {
+                LogicalVariable var = getVariable(columnName, column.getType());
+                column.setInternalName(var.toString());
+            }
+        }
+    }
+
+    @Override
+    public void rewriteOperatorOutputSchema(List<LogicalVariable> variables, Operator operator) {
+
+        //printOperatorSchema(operator);
+        List<ColumnInfo> columns = operator.getSchema().getSignature();
+        if (variables.size() != columns.size()) {
+            throw new IllegalStateException("output cardinality error " + operator.getName() + " variable size: "
+                    + variables.size() + " expected " + columns.size());
+        }
+
+        for (int i = 0; i < variables.size(); i++) {
+            LogicalVariable var = variables.get(i);
+            ColumnInfo column = columns.get(i);
+            String fieldName = column.getTabAlias() + "." + column.getInternalName();
+            if (fieldName.indexOf("$$") < 0) {
+                updateVariable(fieldName, var);
+                column.setInternalName(var.toString());
+            }
+        }
+        //printOperatorSchema(operator);
+    }
+
+    /**
+     * rewrite an expression and substitute variables
+     * 
+     * @param expr
+     *            hive expression
+     */
+    public void rewriteExpression(ExprNodeDesc expr) {
+        if (expr instanceof ExprNodeColumnDesc) {
+            ExprNodeColumnDesc desc = (ExprNodeColumnDesc) expr;
+            String fieldName = desc.getTabAlias() + "." + desc.getColumn();
+            if (fieldName.indexOf("$$") < 0) {
+                LogicalVariable var = getVariableOnly(fieldName);
+                if (var == null) {
+                    fieldName = "." + desc.getColumn();
+                    var = getVariableOnly(fieldName);
+                    if (var == null) {
+                        fieldName = "null." + desc.getColumn();
+                        var = getVariableOnly(fieldName);
+                        if (var == null) {
+                            throw new IllegalStateException(fieldName + " is wrong!!! ");
+                        }
+                    }
+                }
+                String name = this.logicalVariableToFieldMap.get(var);
+                var = getVariableOnly(name);
+                desc.setColumn(var.toString());
+            }
+        } else {
+            if (expr.getChildren() != null && expr.getChildren().size() > 0) {
+                List<ExprNodeDesc> children = expr.getChildren();
+                for (ExprNodeDesc desc : children)
+                    rewriteExpression(desc);
+            }
+        }
+    }
+
+    /**
+     * rewrite an expression and substitute variables
+     * 
+     * @param expr
+     *            hive expression
+     */
+    public void rewriteExpressionPartial(ExprNodeDesc expr) {
+        if (expr instanceof ExprNodeColumnDesc) {
+            ExprNodeColumnDesc desc = (ExprNodeColumnDesc) expr;
+            String fieldName = desc.getTabAlias() + "." + desc.getColumn();
+            if (fieldName.indexOf("$$") < 0) {
+                LogicalVariable var = getVariableOnly(fieldName);
+                desc.setColumn(var.toString());
+            }
+        } else {
+            if (expr.getChildren() != null && expr.getChildren().size() > 0) {
+                List<ExprNodeDesc> children = expr.getChildren();
+                for (ExprNodeDesc desc : children)
+                    rewriteExpressionPartial(desc);
+            }
+        }
+    }
+
+    // private void printOperatorSchema(Operator operator) {
+    // // System.out.println(operator.getName());
+    // // List<ColumnInfo> columns = operator.getSchema().getSignature();
+    // // for (ColumnInfo column : columns) {
+    // // System.out.print(column.getTabAlias() + "." +
+    // // column.getInternalName() + "  ");
+    // // }
+    // // System.out.println();
+    // }
+
+    /**
+     * translate scalar function expression
+     * 
+     * @param hiveExpr
+     * @return
+     */
+    public Mutable<ILogicalExpression> translateScalarFucntion(ExprNodeDesc hiveExpr) {
+        ILogicalExpression AlgebricksExpr;
+
+        if (hiveExpr instanceof ExprNodeGenericFuncDesc) {
+            List<Mutable<ILogicalExpression>> arguments = new ArrayList<Mutable<ILogicalExpression>>();
+            List<ExprNodeDesc> children = hiveExpr.getChildren();
+
+            for (ExprNodeDesc child : children)
+                arguments.add(translateScalarFucntion(child));
+
+            ExprNodeGenericFuncDesc funcExpr = (ExprNodeGenericFuncDesc) hiveExpr;
+            GenericUDF genericUdf = funcExpr.getGenericUDF();
+            UDF udf = null;
+            if (genericUdf instanceof GenericUDFBridge) {
+                GenericUDFBridge bridge = (GenericUDFBridge) genericUdf;
+                try {
+                    udf = bridge.getUdfClass().newInstance();
+                } catch (Exception e) {
+                    e.printStackTrace();
+                }
+            }
+
+            /**
+             * set up the hive function
+             */
+            Object hiveFunction = genericUdf;
+            if (udf != null)
+                hiveFunction = udf;
+
+            FunctionIdentifier funcId = HiveAlgebricksBuiltInFunctionMap.INSTANCE.getAlgebricksFunctionId(hiveFunction
+                    .getClass());
+            if (funcId == null) {
+                funcId = new FunctionIdentifier(ExpressionConstant.NAMESPACE, hiveFunction.getClass().getName());
+            }
+
+            Object functionInfo = null;
+            if (genericUdf instanceof GenericUDFBridge) {
+                functionInfo = funcExpr;
+            }
+
+            /**
+             * generate the function call expression
+             */
+            ScalarFunctionCallExpression AlgebricksFuncExpr = new ScalarFunctionCallExpression(new HiveFunctionInfo(
+                    funcId, functionInfo), arguments);
+            AlgebricksExpr = AlgebricksFuncExpr;
+
+        } else if (hiveExpr instanceof ExprNodeColumnDesc) {
+            ExprNodeColumnDesc column = (ExprNodeColumnDesc) hiveExpr;
+            LogicalVariable var = this.getVariable(column.getColumn());
+            AlgebricksExpr = new VariableReferenceExpression(var);
+
+        } else if (hiveExpr instanceof ExprNodeFieldDesc) {
+            FunctionIdentifier funcId;
+            funcId = new FunctionIdentifier(ExpressionConstant.NAMESPACE, ExpressionConstant.FIELDACCESS);
+
+            ScalarFunctionCallExpression AlgebricksFuncExpr = new ScalarFunctionCallExpression(new HiveFunctionInfo(
+                    funcId, hiveExpr));
+            AlgebricksExpr = AlgebricksFuncExpr;
+        } else if (hiveExpr instanceof ExprNodeConstantDesc) {
+            ExprNodeConstantDesc hiveConst = (ExprNodeConstantDesc) hiveExpr;
+            Object value = hiveConst.getValue();
+            AlgebricksExpr = new ConstantExpression(new HivesterixConstantValue(value));
+        } else if (hiveExpr instanceof ExprNodeNullDesc) {
+            FunctionIdentifier funcId;
+            funcId = new FunctionIdentifier(ExpressionConstant.NAMESPACE, ExpressionConstant.NULL);
+
+            ScalarFunctionCallExpression AlgebricksFuncExpr = new ScalarFunctionCallExpression(new HiveFunctionInfo(
+                    funcId, hiveExpr));
+
+            AlgebricksExpr = AlgebricksFuncExpr;
+        } else {
+            throw new IllegalStateException("unknown hive expression");
+        }
+        return new MutableObject<ILogicalExpression>(AlgebricksExpr);
+    }
+
+    /**
+     * translate aggregation function expression
+     * 
+     * @param aggregateDesc
+     * @return
+     */
+    public Mutable<ILogicalExpression> translateAggregation(AggregationDesc aggregateDesc) {
+
+        String UDAFName = aggregateDesc.getGenericUDAFName();
+
+        List<Mutable<ILogicalExpression>> arguments = new ArrayList<Mutable<ILogicalExpression>>();
+        List<ExprNodeDesc> children = aggregateDesc.getParameters();
+
+        for (ExprNodeDesc child : children)
+            arguments.add(translateScalarFucntion(child));
+
+        FunctionIdentifier funcId = new FunctionIdentifier(ExpressionConstant.NAMESPACE, UDAFName + "("
+                + aggregateDesc.getMode() + ")");
+        HiveFunctionInfo funcInfo = new HiveFunctionInfo(funcId, aggregateDesc);
+        AggregateFunctionCallExpression aggregationExpression = new AggregateFunctionCallExpression(funcInfo, false,
+                arguments);
+        return new MutableObject<ILogicalExpression>(aggregationExpression);
+    }
+
+    /**
+     * translate aggregation function expression
+     * 
+     * @param aggregator
+     * @return
+     */
+    public Mutable<ILogicalExpression> translateUnnestFunction(UDTFDesc udtfDesc, Mutable<ILogicalExpression> argument) {
+
+        String UDTFName = udtfDesc.getUDTFName();
+
+        FunctionIdentifier funcId = new FunctionIdentifier(ExpressionConstant.NAMESPACE, UDTFName);
+        UnnestingFunctionCallExpression unnestingExpression = new UnnestingFunctionCallExpression(new HiveFunctionInfo(
+                funcId, udtfDesc));
+        unnestingExpression.getArguments().add(argument);
+        return new MutableObject<ILogicalExpression>(unnestingExpression);
+    }
+
+    /**
+     * get typeinfo
+     */
+    @Override
+    public TypeInfo getType(LogicalVariable var) {
+        return variableToType.get(var);
+    }
+
+    /**
+     * get variable from variable name
+     */
+    @Override
+    public LogicalVariable getVariable(String name) {
+        return nameToLogicalVariableMap.get(name);
+    }
+
+    @Override
+    public LogicalVariable getVariableFromFieldName(String fieldName) {
+        return this.getVariableOnly(fieldName);
+    }
+
+    /**
+     * set the metadata provider
+     */
+    @Override
+    public void setMetadataProvider(IMetadataProvider<PartitionDesc, Object> metadata) {
+        this.metaData = metadata;
+    }
+
+    /**
+     * insert ReplicateOperator when necessary
+     */
+    private void insertReplicateOperator(List<Mutable<ILogicalOperator>> roots) {
+        Map<Mutable<ILogicalOperator>, List<Mutable<ILogicalOperator>>> childToParentsMap = new HashMap<Mutable<ILogicalOperator>, List<Mutable<ILogicalOperator>>>();
+        buildChildToParentsMapping(roots, childToParentsMap);
+        for (Entry<Mutable<ILogicalOperator>, List<Mutable<ILogicalOperator>>> entry : childToParentsMap.entrySet()) {
+            List<Mutable<ILogicalOperator>> pList = entry.getValue();
+            if (pList.size() > 1) {
+                ILogicalOperator rop = new ReplicateOperator(pList.size());
+                Mutable<ILogicalOperator> ropRef = new MutableObject<ILogicalOperator>(rop);
+                Mutable<ILogicalOperator> childRef = entry.getKey();
+                rop.getInputs().add(childRef);
+                for (Mutable<ILogicalOperator> parentRef : pList) {
+                    ILogicalOperator parentOp = parentRef.getValue();
+                    int index = parentOp.getInputs().indexOf(childRef);
+                    parentOp.getInputs().set(index, ropRef);
+                }
+            }
+        }
+    }
+
+    /**
+     * build the mapping from child to Parents
+     * 
+     * @param roots
+     * @param childToParentsMap
+     */
+    private void buildChildToParentsMapping(List<Mutable<ILogicalOperator>> roots,
+            Map<Mutable<ILogicalOperator>, List<Mutable<ILogicalOperator>>> map) {
+        for (Mutable<ILogicalOperator> opRef : roots) {
+            List<Mutable<ILogicalOperator>> childRefs = opRef.getValue().getInputs();
+            for (Mutable<ILogicalOperator> childRef : childRefs) {
+                List<Mutable<ILogicalOperator>> parentList = map.get(childRef);
+                if (parentList == null) {
+                    parentList = new ArrayList<Mutable<ILogicalOperator>>();
+                    map.put(childRef, parentList);
+                }
+                if (!parentList.contains(opRef))
+                    parentList.add(opRef);
+            }
+            buildChildToParentsMapping(childRefs, map);
+        }
+    }
+}
diff --git a/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/HiveLogicalPlanAndMetaData.java b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/HiveLogicalPlanAndMetaData.java
new file mode 100644
index 0000000..d5801a3
--- /dev/null
+++ b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/HiveLogicalPlanAndMetaData.java
@@ -0,0 +1,35 @@
+package edu.uci.ics.hivesterix.logical.plan;
+
+import edu.uci.ics.hyracks.algebricks.common.constraints.AlgebricksPartitionConstraint;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalPlan;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalPlanAndMetadata;
+import edu.uci.ics.hyracks.algebricks.core.algebra.metadata.IMetadataProvider;
+
+@SuppressWarnings({ "rawtypes", "unchecked" })
+public class HiveLogicalPlanAndMetaData implements ILogicalPlanAndMetadata {
+
+    IMetadataProvider metadata;
+    ILogicalPlan plan;
+
+    public HiveLogicalPlanAndMetaData(ILogicalPlan plan, IMetadataProvider metadata) {
+        this.plan = plan;
+        this.metadata = metadata;
+    }
+
+    @Override
+    public IMetadataProvider getMetadataProvider() {
+        return metadata;
+    }
+
+    @Override
+    public ILogicalPlan getPlan() {
+        return plan;
+    }
+
+    @Override
+    public AlgebricksPartitionConstraint getClusterLocations() {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+}
diff --git a/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/HiveOperatorAnnotations.java b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/HiveOperatorAnnotations.java
new file mode 100644
index 0000000..0ea4e01
--- /dev/null
+++ b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/HiveOperatorAnnotations.java
@@ -0,0 +1,8 @@
+package edu.uci.ics.hivesterix.logical.plan;
+
+public class HiveOperatorAnnotations {
+
+    // hints
+    public static final String LOCAL_GROUP_BY = "LOCAL_GROUP_BY";
+
+}
diff --git a/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/ExtractVisitor.java b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/ExtractVisitor.java
new file mode 100644
index 0000000..1c67bae
--- /dev/null
+++ b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/ExtractVisitor.java
@@ -0,0 +1,26 @@
+package edu.uci.ics.hivesterix.logical.plan.visitor;
+
+import java.util.List;
+
+import org.apache.commons.lang3.mutable.Mutable;
+import org.apache.hadoop.hive.ql.exec.ExtractOperator;
+
+import edu.uci.ics.hivesterix.logical.plan.visitor.base.DefaultVisitor;
+import edu.uci.ics.hivesterix.logical.plan.visitor.base.Translator;
+import edu.uci.ics.hivesterix.runtime.jobgen.Schema;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalVariable;
+
+public class ExtractVisitor extends DefaultVisitor {
+
+    @Override
+    public Mutable<ILogicalOperator> visit(ExtractOperator operator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) {
+        Schema currentSchema = t.generateInputSchema(operator.getParentOperators().get(0));
+        operator.setSchema(operator.getParentOperators().get(0).getSchema());
+        List<LogicalVariable> latestOutputSchema = t.getVariablesFromSchema(currentSchema);
+        t.rewriteOperatorOutputSchema(latestOutputSchema, operator);
+        return null;
+    }
+
+}
diff --git a/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/FilterVisitor.java b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/FilterVisitor.java
new file mode 100644
index 0000000..9279144
--- /dev/null
+++ b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/FilterVisitor.java
@@ -0,0 +1,41 @@
+package edu.uci.ics.hivesterix.logical.plan.visitor;
+
+import java.util.List;
+
+import org.apache.commons.lang3.mutable.Mutable;
+import org.apache.commons.lang3.mutable.MutableObject;
+import org.apache.hadoop.hive.ql.exec.FilterOperator;
+import org.apache.hadoop.hive.ql.plan.ExprNodeDesc;
+import org.apache.hadoop.hive.ql.plan.FilterDesc;
+
+import edu.uci.ics.hivesterix.logical.plan.visitor.base.DefaultVisitor;
+import edu.uci.ics.hivesterix.logical.plan.visitor.base.Translator;
+import edu.uci.ics.hivesterix.runtime.jobgen.Schema;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalExpression;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalVariable;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.SelectOperator;
+
+public class FilterVisitor extends DefaultVisitor {
+
+    @Override
+    public Mutable<ILogicalOperator> visit(FilterOperator operator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) {
+        Schema currentSchema = t.generateInputSchema(operator.getParentOperators().get(0));
+
+        FilterDesc desc = (FilterDesc) operator.getConf();
+        ExprNodeDesc predicate = desc.getPredicate();
+        t.rewriteExpression(predicate);
+
+        Mutable<ILogicalExpression> exprs = t.translateScalarFucntion(desc.getPredicate());
+        ILogicalOperator currentOperator = new SelectOperator(exprs);
+        currentOperator.getInputs().add(AlgebricksParentOperatorRef);
+
+        // populate the schema from upstream operator
+        operator.setSchema(operator.getParentOperators().get(0).getSchema());
+        List<LogicalVariable> latestOutputSchema = t.getVariablesFromSchema(currentSchema);
+        t.rewriteOperatorOutputSchema(latestOutputSchema, operator);
+        return new MutableObject<ILogicalOperator>(currentOperator);
+    }
+
+}
diff --git a/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/GroupByVisitor.java b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/GroupByVisitor.java
new file mode 100644
index 0000000..b7d5779
--- /dev/null
+++ b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/GroupByVisitor.java
@@ -0,0 +1,264 @@
+package edu.uci.ics.hivesterix.logical.plan.visitor;
+
+import java.lang.reflect.Field;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+
+import org.apache.commons.lang3.mutable.Mutable;
+import org.apache.commons.lang3.mutable.MutableObject;
+import org.apache.hadoop.hive.conf.HiveConf;
+import org.apache.hadoop.hive.ql.exec.ColumnInfo;
+import org.apache.hadoop.hive.ql.exec.GroupByOperator;
+import org.apache.hadoop.hive.ql.exec.Operator;
+import org.apache.hadoop.hive.ql.exec.ReduceSinkOperator;
+import org.apache.hadoop.hive.ql.plan.AggregationDesc;
+import org.apache.hadoop.hive.ql.plan.ExprNodeColumnDesc;
+import org.apache.hadoop.hive.ql.plan.ExprNodeDesc;
+import org.apache.hadoop.hive.ql.plan.GroupByDesc;
+import org.apache.hadoop.hive.ql.plan.ReduceSinkDesc;
+import org.apache.hadoop.hive.ql.plan.api.OperatorType;
+import org.apache.hadoop.hive.ql.udf.generic.GenericUDAFEvaluator;
+import org.apache.hadoop.hive.ql.udf.generic.GenericUDAFEvaluator.AggregationBuffer;
+import org.apache.hadoop.hive.ql.udf.generic.GenericUDAFEvaluator.Mode;
+import org.apache.hadoop.hive.serde2.typeinfo.TypeInfo;
+import org.apache.hadoop.hive.serde2.typeinfo.TypeInfoFactory;
+
+import edu.uci.ics.hivesterix.common.config.ConfUtil;
+import edu.uci.ics.hivesterix.logical.plan.HiveOperatorAnnotations;
+import edu.uci.ics.hivesterix.logical.plan.visitor.base.DefaultVisitor;
+import edu.uci.ics.hivesterix.logical.plan.visitor.base.Translator;
+import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException;
+import edu.uci.ics.hyracks.algebricks.common.utils.Pair;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalExpression;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalPlan;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalVariable;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.OperatorAnnotations;
+import edu.uci.ics.hyracks.algebricks.core.algebra.expressions.AbstractFunctionCallExpression;
+import edu.uci.ics.hyracks.algebricks.core.algebra.expressions.AggregateFunctionCallExpression;
+import edu.uci.ics.hyracks.algebricks.core.algebra.expressions.VariableReferenceExpression;
+import edu.uci.ics.hyracks.algebricks.core.algebra.functions.IFunctionInfo;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.AggregateOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.DistinctOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.NestedTupleSourceOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.plan.ALogicalPlanImpl;
+
+@SuppressWarnings({ "rawtypes", "unchecked" })
+public class GroupByVisitor extends DefaultVisitor {
+
+    private List<Mutable<ILogicalExpression>> AlgebricksAggs = new ArrayList<Mutable<ILogicalExpression>>();
+    private List<IFunctionInfo> localAggs = new ArrayList<IFunctionInfo>();
+    private boolean isDistinct = false;
+    private boolean gbyKeyNotRedKey = false;
+
+    @Override
+    public Mutable<ILogicalOperator> visit(GroupByOperator operator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) throws AlgebricksException {
+
+        // get descriptors
+        GroupByDesc desc = (GroupByDesc) operator.getConf();
+        GroupByDesc.Mode mode = desc.getMode();
+
+        List<ExprNodeDesc> keys = desc.getKeys();
+        List<AggregationDesc> aggregators = desc.getAggregators();
+
+        Operator child = operator.getChildOperators().get(0);
+
+        if (child.getType() == OperatorType.REDUCESINK) {
+            List<ExprNodeDesc> partKeys = ((ReduceSinkDesc) child.getConf()).getPartitionCols();
+            if (keys.size() != partKeys.size())
+                gbyKeyNotRedKey = true;
+        }
+
+        if (mode == GroupByDesc.Mode.PARTIAL1 || mode == GroupByDesc.Mode.HASH || mode == GroupByDesc.Mode.COMPLETE
+                || (aggregators.size() == 0 && isDistinct == false) || gbyKeyNotRedKey) {
+            AlgebricksAggs.clear();
+            // add an assign operator if the key is not a column expression
+            ArrayList<LogicalVariable> keyVariables = new ArrayList<LogicalVariable>();
+            ILogicalOperator currentOperator = null;
+            ILogicalOperator assignOperator = t.getAssignOperator(AlgebricksParentOperatorRef, keys, keyVariables);
+            if (assignOperator != null) {
+                currentOperator = assignOperator;
+                AlgebricksParentOperatorRef = new MutableObject<ILogicalOperator>(currentOperator);
+            }
+
+            // get key variable expression list
+            List<Mutable<ILogicalExpression>> keyExprs = new ArrayList<Mutable<ILogicalExpression>>();
+            for (LogicalVariable var : keyVariables) {
+                keyExprs.add(t.translateScalarFucntion(new ExprNodeColumnDesc(TypeInfoFactory.intTypeInfo, var
+                        .toString(), "", false)));
+            }
+
+            if (aggregators.size() == 0) {
+                List<Mutable<ILogicalExpression>> distinctExprs = new ArrayList<Mutable<ILogicalExpression>>();
+                for (LogicalVariable var : keyVariables) {
+                    Mutable<ILogicalExpression> varExpr = new MutableObject<ILogicalExpression>(
+                            new VariableReferenceExpression(var));
+                    distinctExprs.add(varExpr);
+                }
+                t.rewriteOperatorOutputSchema(keyVariables, operator);
+                isDistinct = true;
+                ILogicalOperator lop = new DistinctOperator(distinctExprs);
+                lop.getInputs().add(AlgebricksParentOperatorRef);
+                return new MutableObject<ILogicalOperator>(lop);
+            }
+
+            // get the pair<LogicalVariable, ILogicalExpression> list
+            List<Pair<LogicalVariable, Mutable<ILogicalExpression>>> keyParameters = new ArrayList<Pair<LogicalVariable, Mutable<ILogicalExpression>>>();
+            keyVariables.clear();
+            for (Mutable<ILogicalExpression> expr : keyExprs) {
+                LogicalVariable keyVar = t.getVariable(expr.getValue().toString(), TypeInfoFactory.unknownTypeInfo);
+                keyParameters.add(new Pair(keyVar, expr));
+                keyVariables.add(keyVar);
+            }
+
+            // get the parameters for the aggregator operator
+            ArrayList<LogicalVariable> aggVariables = new ArrayList<LogicalVariable>();
+            ArrayList<Mutable<ILogicalExpression>> aggExprs = new ArrayList<Mutable<ILogicalExpression>>();
+
+            // get the type of each aggregation function
+            HashMap<AggregationDesc, TypeInfo> aggToType = new HashMap<AggregationDesc, TypeInfo>();
+            List<ColumnInfo> columns = operator.getSchema().getSignature();
+            int offset = keys.size();
+            for (int i = offset; i < columns.size(); i++) {
+                aggToType.put(aggregators.get(i - offset), columns.get(i).getType());
+            }
+
+            localAggs.clear();
+            // rewrite parameter expressions for all aggregators
+            for (AggregationDesc aggregator : aggregators) {
+                for (ExprNodeDesc parameter : aggregator.getParameters()) {
+                    t.rewriteExpression(parameter);
+                }
+                Mutable<ILogicalExpression> aggExpr = t.translateAggregation(aggregator);
+                AbstractFunctionCallExpression localAggExpr = (AbstractFunctionCallExpression) aggExpr.getValue();
+                localAggs.add(localAggExpr.getFunctionInfo());
+
+                AggregationDesc logicalAgg = new AggregationDesc(aggregator.getGenericUDAFName(),
+                        aggregator.getGenericUDAFEvaluator(), aggregator.getParameters(), aggregator.getDistinct(),
+                        Mode.COMPLETE);
+                Mutable<ILogicalExpression> logicalAggExpr = t.translateAggregation(logicalAgg);
+
+                AlgebricksAggs.add(logicalAggExpr);
+                if (!gbyKeyNotRedKey)
+                    aggExprs.add(logicalAggExpr);
+                else
+                    aggExprs.add(aggExpr);
+
+                aggVariables.add(t.getVariable(aggregator.getExprString() + aggregator.getMode(),
+                        aggToType.get(aggregator)));
+            }
+
+            if (child.getType() != OperatorType.REDUCESINK)
+                gbyKeyNotRedKey = false;
+
+            // get the sub plan list
+            AggregateOperator aggOperator = new AggregateOperator(aggVariables, aggExprs);
+            NestedTupleSourceOperator nestedTupleSource = new NestedTupleSourceOperator(
+                    new MutableObject<ILogicalOperator>());
+            aggOperator.getInputs().add(new MutableObject<ILogicalOperator>(nestedTupleSource));
+
+            List<Mutable<ILogicalOperator>> subRoots = new ArrayList<Mutable<ILogicalOperator>>();
+            subRoots.add(new MutableObject<ILogicalOperator>(aggOperator));
+            ILogicalPlan subPlan = new ALogicalPlanImpl(subRoots);
+            List<ILogicalPlan> subPlans = new ArrayList<ILogicalPlan>();
+            subPlans.add(subPlan);
+
+            // create the group by operator
+            currentOperator = new edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.GroupByOperator(
+                    keyParameters, new ArrayList<Pair<LogicalVariable, Mutable<ILogicalExpression>>>(), subPlans);
+            currentOperator.getInputs().add(AlgebricksParentOperatorRef);
+            nestedTupleSource.getDataSourceReference().setValue(currentOperator);
+
+            List<LogicalVariable> outputVariables = new ArrayList<LogicalVariable>();
+            outputVariables.addAll(keyVariables);
+            outputVariables.addAll(aggVariables);
+            t.rewriteOperatorOutputSchema(outputVariables, operator);
+
+            if (gbyKeyNotRedKey) {
+                currentOperator.getAnnotations().put(HiveOperatorAnnotations.LOCAL_GROUP_BY, Boolean.TRUE);
+            }
+
+            HiveConf conf = ConfUtil.getHiveConf();
+            Boolean extGby = conf.getBoolean("hive.algebricks.groupby.external", false);
+
+            if (extGby && isSerializable(aggregators)) {
+                currentOperator.getAnnotations().put(OperatorAnnotations.USE_EXTERNAL_GROUP_BY, Boolean.TRUE);
+            }
+            return new MutableObject<ILogicalOperator>(currentOperator);
+        } else {
+            isDistinct = false;
+            // rewrite parameter expressions for all aggregators
+            int i = 0;
+            for (AggregationDesc aggregator : aggregators) {
+                for (ExprNodeDesc parameter : aggregator.getParameters()) {
+                    t.rewriteExpression(parameter);
+                }
+                Mutable<ILogicalExpression> agg = t.translateAggregation(aggregator);
+                AggregateFunctionCallExpression originalAgg = (AggregateFunctionCallExpression) AlgebricksAggs.get(i)
+                        .getValue();
+                originalAgg.setStepOneAggregate(localAggs.get(i));
+                AggregateFunctionCallExpression currentAgg = (AggregateFunctionCallExpression) agg.getValue();
+                if (currentAgg.getFunctionInfo() != null) {
+                    originalAgg.setTwoStep(true);
+                    originalAgg.setStepTwoAggregate(currentAgg.getFunctionInfo());
+                }
+                i++;
+            }
+            return null;
+        }
+    }
+
+    @Override
+    public Mutable<ILogicalOperator> visit(ReduceSinkOperator operator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) {
+        Operator downStream = (Operator) operator.getChildOperators().get(0);
+        if (!(downStream instanceof GroupByOperator)) {
+            return null;
+        }
+
+        ReduceSinkDesc desc = (ReduceSinkDesc) operator.getConf();
+        List<ExprNodeDesc> keys = desc.getKeyCols();
+        List<ExprNodeDesc> values = desc.getValueCols();
+
+        // insert assign for keys
+        ArrayList<LogicalVariable> keyVariables = new ArrayList<LogicalVariable>();
+        t.getAssignOperator(AlgebricksParentOperatorRef, keys, keyVariables);
+
+        // insert assign for values
+        ArrayList<LogicalVariable> valueVariables = new ArrayList<LogicalVariable>();
+        t.getAssignOperator(AlgebricksParentOperatorRef, values, valueVariables);
+
+        ArrayList<LogicalVariable> columns = new ArrayList<LogicalVariable>();
+        columns.addAll(keyVariables);
+        columns.addAll(valueVariables);
+
+        t.rewriteOperatorOutputSchema(columns, operator);
+        return null;
+    }
+
+    private boolean isSerializable(List<AggregationDesc> descs) throws AlgebricksException {
+        try {
+            for (AggregationDesc desc : descs) {
+                GenericUDAFEvaluator udaf = desc.getGenericUDAFEvaluator();
+                AggregationBuffer buf = udaf.getNewAggregationBuffer();
+                Class<?> bufferClass = buf.getClass();
+                Field[] fields = bufferClass.getDeclaredFields();
+                for (Field field : fields) {
+                    field.setAccessible(true);
+                    String type = field.getType().toString();
+                    if (!(type.equals("int") || type.equals("long") || type.equals("float") || type.equals("double") || type
+                            .equals("boolean"))) {
+                        return false;
+                    }
+                }
+
+            }
+            return true;
+        } catch (Exception e) {
+            throw new AlgebricksException(e);
+        }
+    }
+
+}
diff --git a/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/JoinVisitor.java b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/JoinVisitor.java
new file mode 100644
index 0000000..ef346bc
--- /dev/null
+++ b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/JoinVisitor.java
@@ -0,0 +1,417 @@
+package edu.uci.ics.hivesterix.logical.plan.visitor;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+
+import org.apache.commons.lang3.mutable.Mutable;
+import org.apache.commons.lang3.mutable.MutableObject;
+import org.apache.hadoop.hive.ql.exec.JoinOperator;
+import org.apache.hadoop.hive.ql.exec.Operator;
+import org.apache.hadoop.hive.ql.exec.ReduceSinkOperator;
+import org.apache.hadoop.hive.ql.plan.ExprNodeConstantDesc;
+import org.apache.hadoop.hive.ql.plan.ExprNodeDesc;
+import org.apache.hadoop.hive.ql.plan.ExprNodeGenericFuncDesc;
+import org.apache.hadoop.hive.ql.plan.JoinCondDesc;
+import org.apache.hadoop.hive.ql.plan.JoinDesc;
+import org.apache.hadoop.hive.ql.plan.ReduceSinkDesc;
+import org.apache.hadoop.hive.ql.udf.generic.GenericUDFOPAnd;
+import org.apache.hadoop.hive.ql.udf.generic.GenericUDFOPEqual;
+import org.apache.hadoop.hive.serde2.typeinfo.TypeInfo;
+import org.apache.hadoop.hive.serde2.typeinfo.TypeInfoFactory;
+
+import edu.uci.ics.hivesterix.logical.plan.visitor.base.DefaultVisitor;
+import edu.uci.ics.hivesterix.logical.plan.visitor.base.Translator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalExpression;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalVariable;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.InnerJoinOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.LeftOuterJoinOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.ProjectOperator;
+
+@SuppressWarnings("rawtypes")
+public class JoinVisitor extends DefaultVisitor {
+
+    /**
+     * reduce sink operator to variables
+     */
+    private HashMap<Operator, List<LogicalVariable>> reduceSinkToKeyVariables = new HashMap<Operator, List<LogicalVariable>>();
+
+    /**
+     * reduce sink operator to variables
+     */
+    private HashMap<Operator, List<String>> reduceSinkToFieldNames = new HashMap<Operator, List<String>>();
+
+    /**
+     * reduce sink operator to variables
+     */
+    private HashMap<Operator, List<TypeInfo>> reduceSinkToTypes = new HashMap<Operator, List<TypeInfo>>();
+
+    /**
+     * map a join operator (in hive) to its parent operators (in hive)
+     */
+    private HashMap<Operator, List<Operator>> operatorToHiveParents = new HashMap<Operator, List<Operator>>();
+
+    /**
+     * map a join operator (in hive) to its parent operators (in asterix)
+     */
+    private HashMap<Operator, List<ILogicalOperator>> operatorToAsterixParents = new HashMap<Operator, List<ILogicalOperator>>();
+
+    /**
+     * the latest traversed reduce sink operator
+     */
+    private Operator latestReduceSink = null;
+
+    /**
+     * the latest generated parent for join
+     */
+    private ILogicalOperator latestAlgebricksOperator = null;
+
+    /**
+     * process a join operator
+     */
+    @Override
+    public Mutable<ILogicalOperator> visit(JoinOperator operator, Mutable<ILogicalOperator> AlgebricksParentOperator,
+            Translator t) {
+        latestAlgebricksOperator = AlgebricksParentOperator.getValue();
+        translateJoinOperatorPreprocess(operator, t);
+        List<Operator> parents = operatorToHiveParents.get(operator);
+        if (parents.size() < operator.getParentOperators().size()) {
+            return null;
+        } else {
+            ILogicalOperator joinOp = translateJoinOperator(operator, AlgebricksParentOperator, t);
+            // clearStatus();
+            return new MutableObject<ILogicalOperator>(joinOp);
+        }
+    }
+
+    private void reorder(Byte[] order, List<ILogicalOperator> parents, List<Operator> hiveParents) {
+        ILogicalOperator[] lops = new ILogicalOperator[parents.size()];
+        Operator[] ops = new Operator[hiveParents.size()];
+
+        for (Operator op : hiveParents) {
+            ReduceSinkOperator rop = (ReduceSinkOperator) op;
+            ReduceSinkDesc rdesc = rop.getConf();
+            int tag = rdesc.getTag();
+
+            int index = -1;
+            for (int i = 0; i < order.length; i++)
+                if (order[i] == tag) {
+                    index = i;
+                    break;
+                }
+            lops[index] = parents.get(hiveParents.indexOf(op));
+            ops[index] = op;
+        }
+
+        parents.clear();
+        hiveParents.clear();
+
+        for (int i = 0; i < lops.length; i++) {
+            parents.add(lops[i]);
+            hiveParents.add(ops[i]);
+        }
+    }
+
+    /**
+     * translate a hive join operator to asterix join operator->assign
+     * operator->project operator
+     * 
+     * @param parentOperator
+     * @param operator
+     * @return
+     */
+    private ILogicalOperator translateJoinOperator(Operator operator, Mutable<ILogicalOperator> parentOperator,
+            Translator t) {
+
+        JoinDesc joinDesc = (JoinDesc) operator.getConf();
+
+        // get the projection expression (already re-written) from each source
+        // table
+        Map<Byte, List<ExprNodeDesc>> exprMap = joinDesc.getExprs();
+        reorder(joinDesc.getTagOrder(), operatorToAsterixParents.get(operator), operatorToHiveParents.get(operator));
+
+        // make an reduce join operator
+        ILogicalOperator currentOperator = generateJoinTree(joinDesc.getCondsList(),
+                operatorToAsterixParents.get(operator), operatorToHiveParents.get(operator), 0, t);
+        parentOperator = new MutableObject<ILogicalOperator>(currentOperator);
+
+        // add assign and project operator on top of a join
+        // output variables
+        ArrayList<LogicalVariable> variables = new ArrayList<LogicalVariable>();
+        Set<Entry<Byte, List<ExprNodeDesc>>> entries = exprMap.entrySet();
+        Iterator<Entry<Byte, List<ExprNodeDesc>>> iterator = entries.iterator();
+        while (iterator.hasNext()) {
+            List<ExprNodeDesc> outputExprs = iterator.next().getValue();
+            ILogicalOperator assignOperator = t.getAssignOperator(parentOperator, outputExprs, variables);
+
+            if (assignOperator != null) {
+                currentOperator = assignOperator;
+                parentOperator = new MutableObject<ILogicalOperator>(currentOperator);
+            }
+        }
+
+        ILogicalOperator po = new ProjectOperator(variables);
+        po.getInputs().add(parentOperator);
+        t.rewriteOperatorOutputSchema(variables, operator);
+        return po;
+    }
+
+    /**
+     * deal with reduce sink operator for the case of join
+     */
+    @Override
+    public Mutable<ILogicalOperator> visit(ReduceSinkOperator operator, Mutable<ILogicalOperator> parentOperator,
+            Translator t) {
+
+        Operator downStream = (Operator) operator.getChildOperators().get(0);
+        if (!(downStream instanceof JoinOperator))
+            return null;
+
+        ReduceSinkDesc desc = (ReduceSinkDesc) operator.getConf();
+        List<ExprNodeDesc> keys = desc.getKeyCols();
+        List<ExprNodeDesc> values = desc.getValueCols();
+        List<ExprNodeDesc> partitionCols = desc.getPartitionCols();
+
+        /**
+         * rewrite key, value, paritioncol expressions
+         */
+        for (ExprNodeDesc key : keys)
+            t.rewriteExpression(key);
+        for (ExprNodeDesc value : values)
+            t.rewriteExpression(value);
+        for (ExprNodeDesc col : partitionCols)
+            t.rewriteExpression(col);
+
+        ILogicalOperator currentOperator = null;
+
+        // add assign operator for keys if necessary
+        ArrayList<LogicalVariable> keyVariables = new ArrayList<LogicalVariable>();
+        ILogicalOperator assignOperator = t.getAssignOperator(parentOperator, keys, keyVariables);
+        if (assignOperator != null) {
+            currentOperator = assignOperator;
+            parentOperator = new MutableObject<ILogicalOperator>(currentOperator);
+        }
+
+        // add assign operator for values if necessary
+        ArrayList<LogicalVariable> variables = new ArrayList<LogicalVariable>();
+        assignOperator = t.getAssignOperator(parentOperator, values, variables);
+        if (assignOperator != null) {
+            currentOperator = assignOperator;
+            parentOperator = new MutableObject<ILogicalOperator>(currentOperator);
+        }
+
+        // unified schema: key, value
+        ArrayList<LogicalVariable> unifiedKeyValues = new ArrayList<LogicalVariable>();
+        unifiedKeyValues.addAll(keyVariables);
+        for (LogicalVariable value : variables)
+            if (keyVariables.indexOf(value) < 0)
+                unifiedKeyValues.add(value);
+
+        // insert projection operator, it is a *must*,
+        // in hive, reduce sink sometimes also do the projection operator's
+        // task
+        currentOperator = new ProjectOperator(unifiedKeyValues);
+        currentOperator.getInputs().add(parentOperator);
+        parentOperator = new MutableObject<ILogicalOperator>(currentOperator);
+
+        reduceSinkToKeyVariables.put(operator, keyVariables);
+        List<String> fieldNames = new ArrayList<String>();
+        List<TypeInfo> types = new ArrayList<TypeInfo>();
+        for (LogicalVariable var : unifiedKeyValues) {
+            fieldNames.add(var.toString());
+            types.add(t.getType(var));
+        }
+        reduceSinkToFieldNames.put(operator, fieldNames);
+        reduceSinkToTypes.put(operator, types);
+        t.rewriteOperatorOutputSchema(variables, operator);
+
+        latestAlgebricksOperator = currentOperator;
+        latestReduceSink = operator;
+        return new MutableObject<ILogicalOperator>(currentOperator);
+    }
+
+    /**
+     * partial rewrite a join operator
+     * 
+     * @param operator
+     * @param t
+     */
+    private void translateJoinOperatorPreprocess(Operator operator, Translator t) {
+        JoinDesc desc = (JoinDesc) operator.getConf();
+        ReduceSinkDesc reduceSinkDesc = (ReduceSinkDesc) latestReduceSink.getConf();
+        int tag = reduceSinkDesc.getTag();
+
+        Map<Byte, List<ExprNodeDesc>> exprMap = desc.getExprs();
+        List<ExprNodeDesc> exprs = exprMap.get(Byte.valueOf((byte) tag));
+
+        for (ExprNodeDesc expr : exprs)
+            t.rewriteExpression(expr);
+
+        List<Operator> parents = operatorToHiveParents.get(operator);
+        if (parents == null) {
+            parents = new ArrayList<Operator>();
+            operatorToHiveParents.put(operator, parents);
+        }
+        parents.add(latestReduceSink);
+
+        List<ILogicalOperator> asterixParents = operatorToAsterixParents.get(operator);
+        if (asterixParents == null) {
+            asterixParents = new ArrayList<ILogicalOperator>();
+            operatorToAsterixParents.put(operator, asterixParents);
+        }
+        asterixParents.add(latestAlgebricksOperator);
+    }
+
+    // generate a join tree from a list of exchange/reducesink operator
+    // both exchanges and reduce sinks have the same order
+    private ILogicalOperator generateJoinTree(List<JoinCondDesc> conds, List<ILogicalOperator> exchanges,
+            List<Operator> reduceSinks, int offset, Translator t) {
+        // get a list of reduce sink descs (input descs)
+        int inputSize = reduceSinks.size() - offset;
+
+        if (inputSize == 2) {
+            ILogicalOperator currentRoot;
+
+            List<ReduceSinkDesc> reduceSinkDescs = new ArrayList<ReduceSinkDesc>();
+            for (int i = reduceSinks.size() - 1; i >= offset; i--)
+                reduceSinkDescs.add((ReduceSinkDesc) reduceSinks.get(i).getConf());
+
+            // get the object inspector for the join
+            List<String> fieldNames = new ArrayList<String>();
+            List<TypeInfo> types = new ArrayList<TypeInfo>();
+            for (int i = reduceSinks.size() - 1; i >= offset; i--) {
+                fieldNames.addAll(reduceSinkToFieldNames.get(reduceSinks.get(i)));
+                types.addAll(reduceSinkToTypes.get(reduceSinks.get(i)));
+            }
+
+            // get number of equality conjunctions in the final join condition
+            int size = reduceSinkDescs.get(0).getKeyCols().size();
+
+            // make up the join conditon expression
+            List<ExprNodeDesc> joinConditionChildren = new ArrayList<ExprNodeDesc>();
+            for (int i = 0; i < size; i++) {
+                // create a join key pair
+                List<ExprNodeDesc> keyPair = new ArrayList<ExprNodeDesc>();
+                for (ReduceSinkDesc sink : reduceSinkDescs) {
+                    keyPair.add(sink.getKeyCols().get(i));
+                }
+                // create a hive equal condition
+                ExprNodeDesc equality = new ExprNodeGenericFuncDesc(TypeInfoFactory.booleanTypeInfo,
+                        new GenericUDFOPEqual(), keyPair);
+                // add the equal condition to the conjunction list
+                joinConditionChildren.add(equality);
+            }
+            // get final conjunction expression
+            ExprNodeDesc conjunct = null;
+
+            if (joinConditionChildren.size() > 1)
+                conjunct = new ExprNodeGenericFuncDesc(TypeInfoFactory.booleanTypeInfo, new GenericUDFOPAnd(),
+                        joinConditionChildren);
+            else if (joinConditionChildren.size() == 1)
+                conjunct = joinConditionChildren.get(0);
+            else {
+                // there is no join equality condition, equal-join
+                conjunct = new ExprNodeConstantDesc(TypeInfoFactory.booleanTypeInfo, new Boolean(true));
+            }
+            // get an ILogicalExpression from hive's expression
+            Mutable<ILogicalExpression> expression = t.translateScalarFucntion(conjunct);
+
+            Mutable<ILogicalOperator> leftBranch = new MutableObject<ILogicalOperator>(
+                    exchanges.get(exchanges.size() - 1));
+            Mutable<ILogicalOperator> rightBranch = new MutableObject<ILogicalOperator>(
+                    exchanges.get(exchanges.size() - 2));
+            // get the join operator
+            if (conds.get(offset).getType() == JoinDesc.LEFT_OUTER_JOIN) {
+                currentRoot = new LeftOuterJoinOperator(expression);
+                Mutable<ILogicalOperator> temp = leftBranch;
+                leftBranch = rightBranch;
+                rightBranch = temp;
+            } else if (conds.get(offset).getType() == JoinDesc.RIGHT_OUTER_JOIN) {
+                currentRoot = new LeftOuterJoinOperator(expression);
+            } else
+                currentRoot = new InnerJoinOperator(expression);
+
+            currentRoot.getInputs().add(leftBranch);
+            currentRoot.getInputs().add(rightBranch);
+
+            // rewriteOperatorOutputSchema(variables, operator);
+            return currentRoot;
+        } else {
+            // get the child join operator and insert and one-to-one exchange
+            ILogicalOperator joinSrcOne = generateJoinTree(conds, exchanges, reduceSinks, offset + 1, t);
+            // joinSrcOne.addInput(childJoin);
+
+            ILogicalOperator currentRoot;
+
+            List<ReduceSinkDesc> reduceSinkDescs = new ArrayList<ReduceSinkDesc>();
+            for (int i = offset; i < offset + 2; i++)
+                reduceSinkDescs.add((ReduceSinkDesc) reduceSinks.get(i).getConf());
+
+            // get the object inspector for the join
+            List<String> fieldNames = new ArrayList<String>();
+            List<TypeInfo> types = new ArrayList<TypeInfo>();
+            for (int i = offset; i < reduceSinks.size(); i++) {
+                fieldNames.addAll(reduceSinkToFieldNames.get(reduceSinks.get(i)));
+                types.addAll(reduceSinkToTypes.get(reduceSinks.get(i)));
+            }
+
+            // get number of equality conjunctions in the final join condition
+            int size = reduceSinkDescs.get(0).getKeyCols().size();
+
+            // make up the join condition expression
+            List<ExprNodeDesc> joinConditionChildren = new ArrayList<ExprNodeDesc>();
+            for (int i = 0; i < size; i++) {
+                // create a join key pair
+                List<ExprNodeDesc> keyPair = new ArrayList<ExprNodeDesc>();
+                for (ReduceSinkDesc sink : reduceSinkDescs) {
+                    keyPair.add(sink.getKeyCols().get(i));
+                }
+                // create a hive equal condition
+                ExprNodeDesc equality = new ExprNodeGenericFuncDesc(TypeInfoFactory.booleanTypeInfo,
+                        new GenericUDFOPEqual(), keyPair);
+                // add the equal condition to the conjunction list
+                joinConditionChildren.add(equality);
+            }
+            // get final conjunction expression
+            ExprNodeDesc conjunct = null;
+
+            if (joinConditionChildren.size() > 1)
+                conjunct = new ExprNodeGenericFuncDesc(TypeInfoFactory.booleanTypeInfo, new GenericUDFOPAnd(),
+                        joinConditionChildren);
+            else if (joinConditionChildren.size() == 1)
+                conjunct = joinConditionChildren.get(0);
+            else {
+                // there is no join equality condition, full outer join
+                conjunct = new ExprNodeConstantDesc(TypeInfoFactory.booleanTypeInfo, new Boolean(true));
+            }
+            // get an ILogicalExpression from hive's expression
+            Mutable<ILogicalExpression> expression = t.translateScalarFucntion(conjunct);
+
+            Mutable<ILogicalOperator> leftBranch = new MutableObject<ILogicalOperator>(joinSrcOne);
+            Mutable<ILogicalOperator> rightBranch = new MutableObject<ILogicalOperator>(exchanges.get(offset));
+
+            // get the join operator
+            if (conds.get(offset).getType() == JoinDesc.LEFT_OUTER_JOIN) {
+                currentRoot = new LeftOuterJoinOperator(expression);
+                Mutable<ILogicalOperator> temp = leftBranch;
+                leftBranch = rightBranch;
+                rightBranch = temp;
+            } else if (conds.get(offset).getType() == JoinDesc.RIGHT_OUTER_JOIN) {
+                currentRoot = new LeftOuterJoinOperator(expression);
+            } else
+                currentRoot = new InnerJoinOperator(expression);
+
+            // set the inputs from Algebricks join operator
+            // add the current table
+            currentRoot.getInputs().add(leftBranch);
+            currentRoot.getInputs().add(rightBranch);
+
+            return currentRoot;
+        }
+    }
+}
diff --git a/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/LateralViewJoinVisitor.java b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/LateralViewJoinVisitor.java
new file mode 100644
index 0000000..cc19364
--- /dev/null
+++ b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/LateralViewJoinVisitor.java
@@ -0,0 +1,110 @@
+package edu.uci.ics.hivesterix.logical.plan.visitor;
+
+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.hadoop.hive.ql.exec.LateralViewJoinOperator;
+import org.apache.hadoop.hive.ql.exec.Operator;
+import org.apache.hadoop.hive.ql.exec.UDTFOperator;
+import org.apache.hadoop.hive.ql.plan.UDTFDesc;
+import org.apache.hadoop.hive.serde2.typeinfo.TypeInfoFactory;
+
+import edu.uci.ics.hivesterix.logical.plan.visitor.base.DefaultVisitor;
+import edu.uci.ics.hivesterix.logical.plan.visitor.base.Translator;
+import edu.uci.ics.hivesterix.runtime.jobgen.Schema;
+import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalExpression;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalVariable;
+import edu.uci.ics.hyracks.algebricks.core.algebra.expressions.VariableReferenceExpression;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.UnnestOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.visitors.VariableUtilities;
+
+/**
+ * The lateral view join operator is used for FROM src LATERAL VIEW udtf()...
+ * This operator was implemented with the following operator DAG in mind.
+ * For a query such as
+ * SELECT pageid, adid.* FROM example_table LATERAL VIEW explode(adid_list) AS
+ * adid
+ * The top of the operator DAG will look similar to
+ * [Table Scan] | [Lateral View Forward] / \ [Select](*) [Select](adid_list) | |
+ * | [UDTF] (explode) \ / [Lateral View Join] | | [Select] (pageid, adid.*) |
+ * ....
+ * Rows from the table scan operator are first to a lateral view forward
+ * operator that just forwards the row and marks the start of a LV. The select
+ * operator on the left picks all the columns while the select operator on the
+ * right picks only the columns needed by the UDTF.
+ * The output of select in the left branch and output of the UDTF in the right
+ * branch are then sent to the lateral view join (LVJ). In most cases, the UDTF
+ * will generate > 1 row for every row received from the TS, while the left
+ * select operator will generate only one. For each row output from the TS, the
+ * LVJ outputs all possible rows that can be created by joining the row from the
+ * left select and one of the rows output from the UDTF.
+ * Additional lateral views can be supported by adding a similar DAG after the
+ * previous LVJ operator.
+ */
+
+@SuppressWarnings("rawtypes")
+public class LateralViewJoinVisitor extends DefaultVisitor {
+
+    private UDTFDesc udtf;
+
+    private List<Mutable<ILogicalOperator>> parents = new ArrayList<Mutable<ILogicalOperator>>();
+
+    @Override
+    public Mutable<ILogicalOperator> visit(LateralViewJoinOperator operator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) throws AlgebricksException {
+
+        parents.add(AlgebricksParentOperatorRef);
+        if (operator.getParentOperators().size() > parents.size()) {
+            return null;
+        }
+
+        Operator parent0 = operator.getParentOperators().get(0);
+        ILogicalOperator parentOperator;
+        ILogicalExpression unnestArg;
+        if (parent0 instanceof UDTFOperator) {
+            List<LogicalVariable> unnestVars = new ArrayList<LogicalVariable>();
+            VariableUtilities.getLiveVariables(parents.get(1).getValue(), unnestVars);
+            unnestArg = new VariableReferenceExpression(unnestVars.get(0));
+            parentOperator = parents.get(1).getValue();
+        } else {
+            List<LogicalVariable> unnestVars = new ArrayList<LogicalVariable>();
+            VariableUtilities.getLiveVariables(parents.get(0).getValue(), unnestVars);
+            unnestArg = new VariableReferenceExpression(unnestVars.get(0));
+            parentOperator = parents.get(0).getValue();
+        }
+
+        LogicalVariable var = t.getVariable(udtf.toString(), TypeInfoFactory.unknownTypeInfo);
+
+        Mutable<ILogicalExpression> unnestExpr = t.translateUnnestFunction(udtf, new MutableObject<ILogicalExpression>(
+                unnestArg));
+        ILogicalOperator currentOperator = new UnnestOperator(var, unnestExpr);
+
+        List<LogicalVariable> outputVars = new ArrayList<LogicalVariable>();
+        VariableUtilities.getLiveVariables(parentOperator, outputVars);
+        outputVars.add(var);
+        currentOperator.getInputs().add(new MutableObject<ILogicalOperator>(parentOperator));
+
+        parents.clear();
+        udtf = null;
+        t.rewriteOperatorOutputSchema(outputVars, operator);
+        return new MutableObject<ILogicalOperator>(currentOperator);
+    }
+
+    @Override
+    public Mutable<ILogicalOperator> visit(UDTFOperator operator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) {
+        Schema currentSchema = t.generateInputSchema(operator.getParentOperators().get(0));
+        udtf = (UDTFDesc) operator.getConf();
+
+        // populate the schema from upstream operator
+        operator.setSchema(operator.getParentOperators().get(0).getSchema());
+        List<LogicalVariable> latestOutputSchema = t.getVariablesFromSchema(currentSchema);
+        t.rewriteOperatorOutputSchema(latestOutputSchema, operator);
+        return null;
+    }
+
+}
diff --git a/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/LimitVisitor.java b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/LimitVisitor.java
new file mode 100644
index 0000000..cc10f8f
--- /dev/null
+++ b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/LimitVisitor.java
@@ -0,0 +1,41 @@
+package edu.uci.ics.hivesterix.logical.plan.visitor;
+
+import java.util.List;
+
+import org.apache.commons.lang3.mutable.Mutable;
+import org.apache.commons.lang3.mutable.MutableObject;
+import org.apache.hadoop.hive.ql.exec.LimitOperator;
+import org.apache.hadoop.hive.ql.plan.LimitDesc;
+
+import edu.uci.ics.hivesterix.logical.expression.HivesterixConstantValue;
+import edu.uci.ics.hivesterix.logical.plan.visitor.base.DefaultVisitor;
+import edu.uci.ics.hivesterix.logical.plan.visitor.base.Translator;
+import edu.uci.ics.hivesterix.runtime.jobgen.Schema;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalExpression;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalVariable;
+import edu.uci.ics.hyracks.algebricks.core.algebra.expressions.ConstantExpression;
+
+public class LimitVisitor extends DefaultVisitor {
+
+    @Override
+    public Mutable<ILogicalOperator> visit(LimitOperator operator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) {
+        Schema currentSchema = t.generateInputSchema(operator.getParentOperators().get(0));
+
+        LimitDesc desc = (LimitDesc) operator.getConf();
+        int limit = desc.getLimit();
+        Integer limitValue = new Integer(limit);
+
+        ILogicalExpression expr = new ConstantExpression(new HivesterixConstantValue(limitValue));
+        ILogicalOperator currentOperator = new edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.LimitOperator(
+                expr, true);
+        currentOperator.getInputs().add(AlgebricksParentOperatorRef);
+
+        operator.setSchema(operator.getParentOperators().get(0).getSchema());
+        List<LogicalVariable> latestOutputSchema = t.getVariablesFromSchema(currentSchema);
+        t.rewriteOperatorOutputSchema(latestOutputSchema, operator);
+        return new MutableObject<ILogicalOperator>(currentOperator);
+    }
+
+}
diff --git a/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/MapJoinVisitor.java b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/MapJoinVisitor.java
new file mode 100644
index 0000000..4aba6a4
--- /dev/null
+++ b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/MapJoinVisitor.java
@@ -0,0 +1,171 @@
+package edu.uci.ics.hivesterix.logical.plan.visitor;
+
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+
+import org.apache.commons.lang3.mutable.Mutable;
+import org.apache.commons.lang3.mutable.MutableObject;
+import org.apache.hadoop.hive.ql.exec.ColumnInfo;
+import org.apache.hadoop.hive.ql.exec.MapJoinOperator;
+import org.apache.hadoop.hive.ql.exec.Operator;
+import org.apache.hadoop.hive.ql.plan.ExprNodeConstantDesc;
+import org.apache.hadoop.hive.ql.plan.ExprNodeDesc;
+import org.apache.hadoop.hive.ql.plan.ExprNodeGenericFuncDesc;
+import org.apache.hadoop.hive.ql.plan.MapJoinDesc;
+import org.apache.hadoop.hive.ql.udf.generic.GenericUDFOPAnd;
+import org.apache.hadoop.hive.ql.udf.generic.GenericUDFOPEqual;
+import org.apache.hadoop.hive.serde2.typeinfo.TypeInfo;
+import org.apache.hadoop.hive.serde2.typeinfo.TypeInfoFactory;
+
+import edu.uci.ics.hivesterix.logical.plan.visitor.base.DefaultVisitor;
+import edu.uci.ics.hivesterix.logical.plan.visitor.base.Translator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalExpression;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalVariable;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.InnerJoinOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.ProjectOperator;
+
+@SuppressWarnings("rawtypes")
+public class MapJoinVisitor extends DefaultVisitor {
+
+    /**
+     * map a join operator (in hive) to its parent operators (in asterix)
+     */
+    private HashMap<Operator, List<Mutable<ILogicalOperator>>> opMap = new HashMap<Operator, List<Mutable<ILogicalOperator>>>();
+
+    @Override
+    public Mutable<ILogicalOperator> visit(MapJoinOperator operator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) {
+        List<Operator<? extends Serializable>> joinSrc = operator.getParentOperators();
+        List<Mutable<ILogicalOperator>> parents = opMap.get(operator);
+        if (parents == null) {
+            parents = new ArrayList<Mutable<ILogicalOperator>>();
+            opMap.put(operator, parents);
+        }
+        parents.add(AlgebricksParentOperatorRef);
+        if (joinSrc.size() != parents.size())
+            return null;
+
+        ILogicalOperator currentOperator;
+        // make an map join operator
+        // TODO: will have trouble for n-way joins
+        MapJoinDesc joinDesc = (MapJoinDesc) operator.getConf();
+
+        Map<Byte, List<ExprNodeDesc>> keyMap = joinDesc.getKeys();
+        // get the projection expression (already re-written) from each source
+        // table
+        Map<Byte, List<ExprNodeDesc>> exprMap = joinDesc.getExprs();
+
+        int inputSize = operator.getParentOperators().size();
+        // get a list of reduce sink descs (input descs)
+
+        // get the parent operator
+        List<Mutable<ILogicalOperator>> parentOps = parents;
+
+        List<String> fieldNames = new ArrayList<String>();
+        List<TypeInfo> types = new ArrayList<TypeInfo>();
+        for (Operator ts : joinSrc) {
+            List<ColumnInfo> columns = ts.getSchema().getSignature();
+            for (ColumnInfo col : columns) {
+                fieldNames.add(col.getInternalName());
+                types.add(col.getType());
+            }
+        }
+
+        // get number of equality conjunctions in the final join condition
+        Set<Entry<Byte, List<ExprNodeDesc>>> keyEntries = keyMap.entrySet();
+        Iterator<Entry<Byte, List<ExprNodeDesc>>> entry = keyEntries.iterator();
+
+        int size = 0;
+        if (entry.hasNext())
+            size = entry.next().getValue().size();
+
+        // make up the join conditon expression
+        List<ExprNodeDesc> joinConditionChildren = new ArrayList<ExprNodeDesc>();
+        for (int i = 0; i < size; i++) {
+            // create a join key pair
+            List<ExprNodeDesc> keyPair = new ArrayList<ExprNodeDesc>();
+            for (int j = 0; j < inputSize; j++) {
+                keyPair.add(keyMap.get(Byte.valueOf((byte) j)).get(i));
+            }
+            // create a hive equal condition
+            ExprNodeDesc equality = new ExprNodeGenericFuncDesc(TypeInfoFactory.booleanTypeInfo,
+                    new GenericUDFOPEqual(), keyPair);
+            // add the equal condition to the conjunction list
+            joinConditionChildren.add(equality);
+        }
+        // get final conjunction expression
+        ExprNodeDesc conjunct = null;
+
+        if (joinConditionChildren.size() > 1)
+            conjunct = new ExprNodeGenericFuncDesc(TypeInfoFactory.booleanTypeInfo, new GenericUDFOPAnd(),
+                    joinConditionChildren);
+        else if (joinConditionChildren.size() == 1)
+            conjunct = joinConditionChildren.get(0);
+        else {
+            // there is no join equality condition, full outer join
+            conjunct = new ExprNodeConstantDesc(TypeInfoFactory.booleanTypeInfo, new Boolean(true));
+        }
+        // get an ILogicalExpression from hive's expression
+        Mutable<ILogicalExpression> expression = t.translateScalarFucntion(conjunct);
+
+        ArrayList<LogicalVariable> left = new ArrayList<LogicalVariable>();
+        ArrayList<LogicalVariable> right = new ArrayList<LogicalVariable>();
+
+        Set<Entry<Byte, List<ExprNodeDesc>>> kentries = keyMap.entrySet();
+        Iterator<Entry<Byte, List<ExprNodeDesc>>> kiterator = kentries.iterator();
+        int iteration = 0;
+        ILogicalOperator assignOperator = null;
+        while (kiterator.hasNext()) {
+            List<ExprNodeDesc> outputExprs = kiterator.next().getValue();
+
+            if (iteration == 0)
+                assignOperator = t.getAssignOperator(AlgebricksParentOperatorRef, outputExprs, left);
+            else
+                assignOperator = t.getAssignOperator(AlgebricksParentOperatorRef, outputExprs, right);
+
+            if (assignOperator != null) {
+                currentOperator = assignOperator;
+                AlgebricksParentOperatorRef = new MutableObject<ILogicalOperator>(currentOperator);
+            }
+            iteration++;
+        }
+
+        List<Mutable<ILogicalOperator>> inputs = parentOps;
+
+        // get the join operator
+        currentOperator = new InnerJoinOperator(expression);
+
+        // set the inputs from asterix join operator
+        for (Mutable<ILogicalOperator> input : inputs)
+            currentOperator.getInputs().add(input);
+        AlgebricksParentOperatorRef = new MutableObject<ILogicalOperator>(currentOperator);
+
+        // add assign and project operator
+        // output variables
+        ArrayList<LogicalVariable> variables = new ArrayList<LogicalVariable>();
+        Set<Entry<Byte, List<ExprNodeDesc>>> entries = exprMap.entrySet();
+        Iterator<Entry<Byte, List<ExprNodeDesc>>> iterator = entries.iterator();
+        while (iterator.hasNext()) {
+            List<ExprNodeDesc> outputExprs = iterator.next().getValue();
+            assignOperator = t.getAssignOperator(AlgebricksParentOperatorRef, outputExprs, variables);
+
+            if (assignOperator != null) {
+                currentOperator = assignOperator;
+                AlgebricksParentOperatorRef = new MutableObject<ILogicalOperator>(currentOperator);
+            }
+        }
+
+        currentOperator = new ProjectOperator(variables);
+        currentOperator.getInputs().add(AlgebricksParentOperatorRef);
+        t.rewriteOperatorOutputSchema(variables, operator);
+        // opMap.clear();
+        return new MutableObject<ILogicalOperator>(currentOperator);
+    }
+}
diff --git a/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/ProjectVisitor.java b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/ProjectVisitor.java
new file mode 100644
index 0000000..eb0922f
--- /dev/null
+++ b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/ProjectVisitor.java
@@ -0,0 +1,56 @@
+package edu.uci.ics.hivesterix.logical.plan.visitor;
+
+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.hadoop.hive.ql.exec.SelectOperator;
+import org.apache.hadoop.hive.ql.plan.ExprNodeDesc;
+import org.apache.hadoop.hive.ql.plan.SelectDesc;
+
+import edu.uci.ics.hivesterix.logical.plan.visitor.base.DefaultVisitor;
+import edu.uci.ics.hivesterix.logical.plan.visitor.base.Translator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalVariable;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.ProjectOperator;
+
+public class ProjectVisitor extends DefaultVisitor {
+
+    /**
+     * translate project operator
+     */
+    @Override
+    public Mutable<ILogicalOperator> visit(SelectOperator operator, Mutable<ILogicalOperator> AlgebricksParentOperator,
+            Translator t) {
+
+        SelectDesc desc = (SelectDesc) operator.getConf();
+
+        if (desc == null)
+            return null;
+
+        List<ExprNodeDesc> cols = desc.getColList();
+
+        if (cols == null)
+            return null;
+
+        // insert assign operator if necessary
+        ArrayList<LogicalVariable> variables = new ArrayList<LogicalVariable>();
+
+        for (ExprNodeDesc expr : cols)
+            t.rewriteExpression(expr);
+
+        ILogicalOperator assignOp = t.getAssignOperator(AlgebricksParentOperator, cols, variables);
+        ILogicalOperator currentOperator = null;
+        if (assignOp != null) {
+            currentOperator = assignOp;
+            AlgebricksParentOperator = new MutableObject<ILogicalOperator>(currentOperator);
+        }
+
+        currentOperator = new ProjectOperator(variables);
+        currentOperator.getInputs().add(AlgebricksParentOperator);
+        t.rewriteOperatorOutputSchema(variables, operator);
+        return new MutableObject<ILogicalOperator>(currentOperator);
+    }
+
+}
diff --git a/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/SortVisitor.java b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/SortVisitor.java
new file mode 100644
index 0000000..325b632
--- /dev/null
+++ b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/SortVisitor.java
@@ -0,0 +1,113 @@
+package edu.uci.ics.hivesterix.logical.plan.visitor;
+
+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.hadoop.hive.ql.exec.ExtractOperator;
+import org.apache.hadoop.hive.ql.exec.Operator;
+import org.apache.hadoop.hive.ql.exec.ReduceSinkOperator;
+import org.apache.hadoop.hive.ql.plan.ExprNodeDesc;
+import org.apache.hadoop.hive.ql.plan.ReduceSinkDesc;
+
+import edu.uci.ics.hivesterix.logical.plan.visitor.base.DefaultVisitor;
+import edu.uci.ics.hivesterix.logical.plan.visitor.base.Translator;
+import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException;
+import edu.uci.ics.hyracks.algebricks.common.utils.Pair;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalExpression;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalVariable;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.OrderOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.OrderOperator.IOrder;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.ProjectOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.visitors.VariableUtilities;
+import edu.uci.ics.hyracks.algebricks.core.algebra.properties.OrderColumn;
+
+public class SortVisitor extends DefaultVisitor {
+
+    @SuppressWarnings("rawtypes")
+    @Override
+    public Mutable<ILogicalOperator> visit(ReduceSinkOperator operator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) throws AlgebricksException {
+        ReduceSinkDesc desc = (ReduceSinkDesc) operator.getConf();
+        Operator downStream = (Operator) operator.getChildOperators().get(0);
+        List<ExprNodeDesc> keys = desc.getKeyCols();
+        if (!(downStream instanceof ExtractOperator && desc.getNumReducers() == 1 && keys.size() > 0)) {
+            return null;
+        }
+
+        List<ExprNodeDesc> schema = new ArrayList<ExprNodeDesc>();
+        List<ExprNodeDesc> values = desc.getValueCols();
+        List<ExprNodeDesc> partitionCols = desc.getPartitionCols();
+        for (ExprNodeDesc key : keys) {
+            t.rewriteExpression(key);
+        }
+        for (ExprNodeDesc value : values) {
+            t.rewriteExpression(value);
+        }
+        for (ExprNodeDesc col : partitionCols) {
+            t.rewriteExpression(col);
+        }
+
+        // add a order-by operator and limit if any
+        List<Pair<IOrder, Mutable<ILogicalExpression>>> pairs = new ArrayList<Pair<IOrder, Mutable<ILogicalExpression>>>();
+        char[] orders = desc.getOrder().toCharArray();
+        int i = 0;
+        for (ExprNodeDesc key : keys) {
+            Mutable<ILogicalExpression> expr = t.translateScalarFucntion(key);
+            IOrder order = orders[i] == '+' ? OrderOperator.ASC_ORDER : OrderOperator.DESC_ORDER;
+
+            Pair<IOrder, Mutable<ILogicalExpression>> pair = new Pair<IOrder, Mutable<ILogicalExpression>>(order, expr);
+            pairs.add(pair);
+            i++;
+        }
+
+        // get input variables
+        ArrayList<LogicalVariable> inputVariables = new ArrayList<LogicalVariable>();
+        VariableUtilities.getProducedVariables(AlgebricksParentOperatorRef.getValue(), inputVariables);
+
+        ArrayList<LogicalVariable> keyVariables = new ArrayList<LogicalVariable>();
+        ILogicalOperator currentOperator;
+        ILogicalOperator assignOp = t.getAssignOperator(AlgebricksParentOperatorRef, keys, keyVariables);
+        if (assignOp != null) {
+            currentOperator = assignOp;
+            AlgebricksParentOperatorRef = new MutableObject<ILogicalOperator>(currentOperator);
+        }
+
+        OrderColumn[] keyColumns = new OrderColumn[keyVariables.size()];
+
+        for (int j = 0; j < keyColumns.length; j++)
+            keyColumns[j] = new OrderColumn(keyVariables.get(j), pairs.get(j).first.getKind());
+
+        // handle order operator
+        currentOperator = new OrderOperator(pairs);
+        currentOperator.getInputs().add(AlgebricksParentOperatorRef);
+        AlgebricksParentOperatorRef = new MutableObject<ILogicalOperator>(currentOperator);
+
+        // project back, remove generated sort-key columns if any
+        if (assignOp != null) {
+            currentOperator = new ProjectOperator(inputVariables);
+            currentOperator.getInputs().add(AlgebricksParentOperatorRef);
+            AlgebricksParentOperatorRef = new MutableObject<ILogicalOperator>(currentOperator);
+        }
+
+        /**
+         * a special rule for hive's order by output schema of reduce sink
+         * operator only contains the columns
+         */
+        for (ExprNodeDesc value : values) {
+            schema.add(value);
+        }
+
+        ArrayList<LogicalVariable> variables = new ArrayList<LogicalVariable>();
+        ILogicalOperator assignOperator = t.getAssignOperator(AlgebricksParentOperatorRef, schema, variables);
+        t.rewriteOperatorOutputSchema(variables, operator);
+
+        if (assignOperator != null) {
+            currentOperator = assignOperator;
+            AlgebricksParentOperatorRef = new MutableObject<ILogicalOperator>(currentOperator);
+        }
+        return new MutableObject<ILogicalOperator>(currentOperator);
+    }
+}
diff --git a/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/TableScanWriteVisitor.java b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/TableScanWriteVisitor.java
new file mode 100644
index 0000000..3af1832
--- /dev/null
+++ b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/TableScanWriteVisitor.java
@@ -0,0 +1,135 @@
+package edu.uci.ics.hivesterix.logical.plan.visitor;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+
+import org.apache.commons.lang3.mutable.Mutable;
+import org.apache.commons.lang3.mutable.MutableObject;
+import org.apache.hadoop.hive.ql.exec.ColumnInfo;
+import org.apache.hadoop.hive.ql.exec.FileSinkOperator;
+import org.apache.hadoop.hive.ql.exec.TableScanOperator;
+import org.apache.hadoop.hive.ql.plan.PartitionDesc;
+import org.apache.hadoop.hive.ql.plan.TableScanDesc;
+import org.apache.hadoop.hive.serde2.typeinfo.TypeInfo;
+
+import edu.uci.ics.hivesterix.logical.plan.visitor.base.DefaultVisitor;
+import edu.uci.ics.hivesterix.logical.plan.visitor.base.Translator;
+import edu.uci.ics.hivesterix.runtime.jobgen.HiveDataSink;
+import edu.uci.ics.hivesterix.runtime.jobgen.HiveDataSource;
+import edu.uci.ics.hivesterix.runtime.jobgen.HiveMetaDataProvider;
+import edu.uci.ics.hivesterix.runtime.jobgen.Schema;
+import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalExpression;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalVariable;
+import edu.uci.ics.hyracks.algebricks.core.algebra.expressions.VariableReferenceExpression;
+import edu.uci.ics.hyracks.algebricks.core.algebra.metadata.IDataSink;
+import edu.uci.ics.hyracks.algebricks.core.algebra.metadata.IDataSource;
+import edu.uci.ics.hyracks.algebricks.core.algebra.metadata.IMetadataProvider;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.DataSourceScanOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.EmptyTupleSourceOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.WriteOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.visitors.VariableUtilities;
+
+public class TableScanWriteVisitor extends DefaultVisitor {
+
+    /**
+     * map from alias to partition desc
+     */
+    private HashMap<String, PartitionDesc> aliasToPathMap;
+
+    /**
+     * map from partition desc to data source
+     */
+    private HashMap<PartitionDesc, IDataSource<PartitionDesc>> dataSourceMap = new HashMap<PartitionDesc, IDataSource<PartitionDesc>>();
+
+    /**
+     * constructor
+     * 
+     * @param aliasToPathMap
+     */
+    public TableScanWriteVisitor(HashMap<String, PartitionDesc> aliasToPathMap) {
+        this.aliasToPathMap = aliasToPathMap;
+    }
+
+    @Override
+    public Mutable<ILogicalOperator> visit(TableScanOperator operator,
+            Mutable<ILogicalOperator> AlgebricksParentOperator, Translator t) throws AlgebricksException {
+        TableScanDesc desc = (TableScanDesc) operator.getConf();
+        if (desc == null) {
+            List<LogicalVariable> schema = new ArrayList<LogicalVariable>();
+            VariableUtilities.getLiveVariables(AlgebricksParentOperator.getValue(), schema);
+            t.rewriteOperatorOutputSchema(schema, operator);
+            return null;
+        }
+
+        List<ColumnInfo> columns = operator.getSchema().getSignature();
+        for (int i = columns.size() - 1; i >= 0; i--)
+            if (columns.get(i).getIsVirtualCol() == true)
+                columns.remove(i);
+
+        // start with empty tuple operator
+        List<TypeInfo> types = new ArrayList<TypeInfo>();
+        ArrayList<LogicalVariable> variables = new ArrayList<LogicalVariable>();
+        List<String> names = new ArrayList<String>();
+        for (ColumnInfo column : columns) {
+            types.add(column.getType());
+
+            LogicalVariable var = t.getVariableFromFieldName(column.getTabAlias() + "." + column.getInternalName());
+            LogicalVariable varNew;
+
+            if (var != null) {
+                varNew = t.getVariable(column.getTabAlias() + "." + column.getInternalName() + operator.toString(),
+                        column.getType());
+                t.replaceVariable(var, varNew);
+                var = varNew;
+            } else
+                var = t.getNewVariable(column.getTabAlias() + "." + column.getInternalName(), column.getType());
+
+            variables.add(var);
+            names.add(column.getInternalName());
+        }
+        Schema currentSchema = new Schema(names, types);
+
+        String alias = desc.getAlias();
+        PartitionDesc partDesc = aliasToPathMap.get(alias);
+        IDataSource<PartitionDesc> dataSource = new HiveDataSource<PartitionDesc>(partDesc, currentSchema.getSchema());
+        ILogicalOperator currentOperator = new DataSourceScanOperator(variables, dataSource);
+
+        // set empty tuple source operator
+        ILogicalOperator ets = new EmptyTupleSourceOperator();
+        currentOperator.getInputs().add(new MutableObject<ILogicalOperator>(ets));
+
+        // setup data source
+        dataSourceMap.put(partDesc, dataSource);
+        t.rewriteOperatorOutputSchema(variables, operator);
+        return new MutableObject<ILogicalOperator>(currentOperator);
+    }
+
+    @Override
+    public Mutable<ILogicalOperator> visit(FileSinkOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperator, Translator t) {
+
+        if (hiveOperator.getChildOperators() != null && hiveOperator.getChildOperators().size() > 0)
+            return null;
+
+        Schema currentSchema = t.generateInputSchema(hiveOperator.getParentOperators().get(0));
+
+        IDataSink sink = new HiveDataSink(hiveOperator, currentSchema.getSchema());
+        List<Mutable<ILogicalExpression>> exprList = new ArrayList<Mutable<ILogicalExpression>>();
+        for (String column : currentSchema.getNames()) {
+            exprList.add(new MutableObject<ILogicalExpression>(new VariableReferenceExpression(t.getVariable(column))));
+        }
+
+        ILogicalOperator currentOperator = new WriteOperator(exprList, sink);
+        if (AlgebricksParentOperator != null) {
+            currentOperator.getInputs().add(AlgebricksParentOperator);
+        }
+
+        IMetadataProvider<PartitionDesc, Object> metaData = new HiveMetaDataProvider<PartitionDesc, Object>(
+                hiveOperator, currentSchema, dataSourceMap);
+        t.setMetadataProvider(metaData);
+        return new MutableObject<ILogicalOperator>(currentOperator);
+    }
+}
diff --git a/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/UnionVisitor.java b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/UnionVisitor.java
new file mode 100644
index 0000000..96b9463
--- /dev/null
+++ b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/UnionVisitor.java
@@ -0,0 +1,62 @@
+package edu.uci.ics.hivesterix.logical.plan.visitor;
+
+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.hadoop.hive.ql.exec.UnionOperator;
+import org.apache.hadoop.hive.serde2.typeinfo.TypeInfoFactory;
+
+import edu.uci.ics.hivesterix.logical.plan.visitor.base.DefaultVisitor;
+import edu.uci.ics.hivesterix.logical.plan.visitor.base.Translator;
+import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException;
+import edu.uci.ics.hyracks.algebricks.common.utils.Triple;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalVariable;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.visitors.VariableUtilities;
+
+public class UnionVisitor extends DefaultVisitor {
+
+    List<Mutable<ILogicalOperator>> parents = new ArrayList<Mutable<ILogicalOperator>>();
+
+    @Override
+    public Mutable<ILogicalOperator> visit(UnionOperator operator, Mutable<ILogicalOperator> AlgebricksParentOperator,
+            Translator t) throws AlgebricksException {
+
+        parents.add(AlgebricksParentOperator);
+        if (operator.getParentOperators().size() > parents.size()) {
+            return null;
+        }
+
+        List<LogicalVariable> leftVars = new ArrayList<LogicalVariable>();
+        List<LogicalVariable> rightVars = new ArrayList<LogicalVariable>();
+
+        VariableUtilities.getUsedVariables(parents.get(0).getValue(), leftVars);
+        VariableUtilities.getUsedVariables(parents.get(1).getValue(), rightVars);
+
+        List<Triple<LogicalVariable, LogicalVariable, LogicalVariable>> triples = new ArrayList<Triple<LogicalVariable, LogicalVariable, LogicalVariable>>();
+        List<LogicalVariable> unionVars = new ArrayList<LogicalVariable>();
+
+        for (int i = 0; i < leftVars.size(); i++) {
+            LogicalVariable unionVar = t.getVariable(
+                    leftVars.get(i).getId() + "union" + AlgebricksParentOperator.hashCode(),
+                    TypeInfoFactory.unknownTypeInfo);
+            unionVars.add(unionVar);
+            Triple<LogicalVariable, LogicalVariable, LogicalVariable> triple = new Triple<LogicalVariable, LogicalVariable, LogicalVariable>(
+                    leftVars.get(i), rightVars.get(i), unionVar);
+            t.replaceVariable(leftVars.get(i), unionVar);
+            t.replaceVariable(rightVars.get(i), unionVar);
+            triples.add(triple);
+        }
+        ILogicalOperator currentOperator = new edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.UnionAllOperator(
+                triples);
+        for (Mutable<ILogicalOperator> parent : parents)
+            currentOperator.getInputs().add(parent);
+
+        t.rewriteOperatorOutputSchema(unionVars, operator);
+        parents.clear();
+        return new MutableObject<ILogicalOperator>(currentOperator);
+    }
+
+}
diff --git a/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/base/DefaultVisitor.java b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/base/DefaultVisitor.java
new file mode 100644
index 0000000..d298553
--- /dev/null
+++ b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/base/DefaultVisitor.java
@@ -0,0 +1,145 @@
+package edu.uci.ics.hivesterix.logical.plan.visitor.base;
+
+import org.apache.commons.lang3.mutable.Mutable;
+import org.apache.hadoop.hive.ql.exec.CollectOperator;
+import org.apache.hadoop.hive.ql.exec.ExtractOperator;
+import org.apache.hadoop.hive.ql.exec.FileSinkOperator;
+import org.apache.hadoop.hive.ql.exec.FilterOperator;
+import org.apache.hadoop.hive.ql.exec.ForwardOperator;
+import org.apache.hadoop.hive.ql.exec.GroupByOperator;
+import org.apache.hadoop.hive.ql.exec.JoinOperator;
+import org.apache.hadoop.hive.ql.exec.LateralViewForwardOperator;
+import org.apache.hadoop.hive.ql.exec.LateralViewJoinOperator;
+import org.apache.hadoop.hive.ql.exec.LimitOperator;
+import org.apache.hadoop.hive.ql.exec.MapJoinOperator;
+import org.apache.hadoop.hive.ql.exec.MapOperator;
+import org.apache.hadoop.hive.ql.exec.ReduceSinkOperator;
+import org.apache.hadoop.hive.ql.exec.SMBMapJoinOperator;
+import org.apache.hadoop.hive.ql.exec.ScriptOperator;
+import org.apache.hadoop.hive.ql.exec.SelectOperator;
+import org.apache.hadoop.hive.ql.exec.TableScanOperator;
+import org.apache.hadoop.hive.ql.exec.UDTFOperator;
+import org.apache.hadoop.hive.ql.exec.UnionOperator;
+
+import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalOperator;
+
+/**
+ * a default empty implementation of visitor
+ * 
+ * @author yingyib
+ */
+public class DefaultVisitor implements Visitor {
+
+    @Override
+    public Mutable<ILogicalOperator> visit(CollectOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperator, Translator t) throws AlgebricksException {
+        return null;
+    }
+
+    @Override
+    public Mutable<ILogicalOperator> visit(JoinOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperator, Translator t) throws AlgebricksException {
+        return null;
+    }
+
+    @Override
+    public Mutable<ILogicalOperator> visit(ExtractOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperator, Translator t) throws AlgebricksException {
+        return null;
+    }
+
+    @Override
+    public Mutable<ILogicalOperator> visit(MapJoinOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperator, Translator t) throws AlgebricksException {
+        return null;
+    }
+
+    @Override
+    public Mutable<ILogicalOperator> visit(SMBMapJoinOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperator, Translator t) throws AlgebricksException {
+        return null;
+    }
+
+    public Mutable<ILogicalOperator> visit(FileSinkOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperator, Translator t) throws AlgebricksException {
+        return null;
+    }
+
+    public Mutable<ILogicalOperator> visit(ReduceSinkOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperator, Translator t) throws AlgebricksException {
+        return null;
+    }
+
+    @Override
+    public Mutable<ILogicalOperator> visit(FilterOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperator, Translator t) throws AlgebricksException {
+        return null;
+    }
+
+    @Override
+    public Mutable<ILogicalOperator> visit(ForwardOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperator, Translator t) throws AlgebricksException {
+        return null;
+    }
+
+    @Override
+    public Mutable<ILogicalOperator> visit(GroupByOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperator, Translator t) throws AlgebricksException {
+        return null;
+    }
+
+    @Override
+    public Mutable<ILogicalOperator> visit(LateralViewForwardOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperator, Translator t) throws AlgebricksException {
+        return null;
+    }
+
+    @Override
+    public Mutable<ILogicalOperator> visit(LateralViewJoinOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperator, Translator t) throws AlgebricksException {
+        return null;
+    }
+
+    @Override
+    public Mutable<ILogicalOperator> visit(LimitOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperator, Translator t) throws AlgebricksException {
+        return null;
+    }
+
+    @Override
+    public Mutable<ILogicalOperator> visit(MapOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperator, Translator t) throws AlgebricksException {
+        return null;
+    }
+
+    @Override
+    public Mutable<ILogicalOperator> visit(ScriptOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperator, Translator t) throws AlgebricksException {
+        return null;
+    }
+
+    @Override
+    public Mutable<ILogicalOperator> visit(SelectOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperator, Translator t) throws AlgebricksException {
+        return null;
+    }
+
+    @Override
+    public Mutable<ILogicalOperator> visit(TableScanOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperator, Translator t) throws AlgebricksException {
+        return null;
+    }
+
+    @Override
+    public Mutable<ILogicalOperator> visit(UDTFOperator operator, Mutable<ILogicalOperator> AlgebricksParentOperator,
+            Translator t) throws AlgebricksException {
+        return null;
+    }
+
+    @Override
+    public Mutable<ILogicalOperator> visit(UnionOperator operator, Mutable<ILogicalOperator> AlgebricksParentOperator,
+            Translator t) throws AlgebricksException {
+        return null;
+    }
+}
diff --git a/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/base/Translator.java b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/base/Translator.java
new file mode 100644
index 0000000..8aa139a
--- /dev/null
+++ b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/base/Translator.java
@@ -0,0 +1,170 @@
+package edu.uci.ics.hivesterix.logical.plan.visitor.base;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.commons.lang3.mutable.Mutable;
+import org.apache.hadoop.hive.ql.exec.Operator;
+import org.apache.hadoop.hive.ql.plan.AggregationDesc;
+import org.apache.hadoop.hive.ql.plan.ExprNodeDesc;
+import org.apache.hadoop.hive.ql.plan.PartitionDesc;
+import org.apache.hadoop.hive.ql.plan.UDTFDesc;
+import org.apache.hadoop.hive.serde2.typeinfo.TypeInfo;
+
+import edu.uci.ics.hivesterix.runtime.jobgen.Schema;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalExpression;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalVariable;
+import edu.uci.ics.hyracks.algebricks.core.algebra.metadata.IMetadataProvider;
+
+@SuppressWarnings("rawtypes")
+public interface Translator {
+
+    /**
+     * generate input schema
+     * 
+     * @param operator
+     * @return
+     */
+    public Schema generateInputSchema(Operator operator);
+
+    /**
+     * rewrite the names of output columns for feture expression evaluators to
+     * use
+     * 
+     * @param operator
+     */
+    public void rewriteOperatorOutputSchema(List<LogicalVariable> vars, Operator operator);
+
+    /**
+     * rewrite the names of output columns for feture expression evaluators to
+     * use
+     * 
+     * @param operator
+     */
+    public void rewriteOperatorOutputSchema(Operator operator);
+
+    /**
+     * rewrite an expression and substitute variables
+     * 
+     * @param expr
+     *            hive expression
+     */
+    public void rewriteExpression(ExprNodeDesc expr);
+
+    /**
+     * rewrite an expression and substitute variables
+     * 
+     * @param expr
+     *            hive expression
+     */
+    public void rewriteExpressionPartial(ExprNodeDesc expr);
+
+    /**
+     * get an assign operator as a child of parent
+     * 
+     * @param parent
+     * @param cols
+     * @param variables
+     * @return
+     */
+    public ILogicalOperator getAssignOperator(Mutable<ILogicalOperator> parent, List<ExprNodeDesc> cols,
+            ArrayList<LogicalVariable> variables);
+
+    /**
+     * get type for a logical variable
+     * 
+     * @param var
+     * @return type info
+     */
+    public TypeInfo getType(LogicalVariable var);
+
+    /**
+     * translate an expression from hive to Algebricks
+     * 
+     * @param desc
+     * @return
+     */
+    public Mutable<ILogicalExpression> translateScalarFucntion(ExprNodeDesc desc);
+
+    /**
+     * translate an aggregation from hive to Algebricks
+     * 
+     * @param aggregateDesc
+     * @return
+     */
+    public Mutable<ILogicalExpression> translateAggregation(AggregationDesc aggregateDesc);
+
+    /**
+     * translate unnesting (UDTF) function expression
+     * 
+     * @param aggregator
+     * @return
+     */
+    public Mutable<ILogicalExpression> translateUnnestFunction(UDTFDesc udtfDesc, Mutable<ILogicalExpression> argument);
+
+    /**
+     * get variable from a schema
+     * 
+     * @param schema
+     * @return
+     */
+    public List<LogicalVariable> getVariablesFromSchema(Schema schema);
+
+    /**
+     * get variable from name
+     * 
+     * @param name
+     * @return
+     */
+    public LogicalVariable getVariable(String name);
+
+    /**
+     * get variable from field name
+     * 
+     * @param name
+     * @return
+     */
+    public LogicalVariable getVariableFromFieldName(String name);
+
+    /**
+     * get variable from name, type
+     * 
+     * @param fieldName
+     * @param type
+     * @return
+     */
+    public LogicalVariable getVariable(String fieldName, TypeInfo type);
+
+    /**
+     * get new variable from name, type
+     * 
+     * @param fieldName
+     * @param type
+     * @return
+     */
+    public LogicalVariable getNewVariable(String fieldName, TypeInfo type);
+
+    /**
+     * set the metadata provider
+     * 
+     * @param metadata
+     */
+    public void setMetadataProvider(IMetadataProvider<PartitionDesc, Object> metadata);
+
+    /**
+     * get the metadata provider
+     * 
+     * @param metadata
+     */
+    public IMetadataProvider<PartitionDesc, Object> getMetadataProvider();
+
+    /**
+     * replace the variable
+     * 
+     * @param oldVar
+     * @param newVar
+     */
+    public void replaceVariable(LogicalVariable oldVar, LogicalVariable newVar);
+
+}
diff --git a/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/base/Visitor.java b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/base/Visitor.java
new file mode 100644
index 0000000..11ae357
--- /dev/null
+++ b/hivesterix/hivesterix-translator/src/main/java/edu/uci/ics/hivesterix/logical/plan/visitor/base/Visitor.java
@@ -0,0 +1,85 @@
+package edu.uci.ics.hivesterix.logical.plan.visitor.base;
+
+import org.apache.commons.lang3.mutable.Mutable;
+import org.apache.hadoop.hive.ql.exec.CollectOperator;
+import org.apache.hadoop.hive.ql.exec.ExtractOperator;
+import org.apache.hadoop.hive.ql.exec.FileSinkOperator;
+import org.apache.hadoop.hive.ql.exec.FilterOperator;
+import org.apache.hadoop.hive.ql.exec.ForwardOperator;
+import org.apache.hadoop.hive.ql.exec.GroupByOperator;
+import org.apache.hadoop.hive.ql.exec.JoinOperator;
+import org.apache.hadoop.hive.ql.exec.LateralViewForwardOperator;
+import org.apache.hadoop.hive.ql.exec.LateralViewJoinOperator;
+import org.apache.hadoop.hive.ql.exec.LimitOperator;
+import org.apache.hadoop.hive.ql.exec.MapJoinOperator;
+import org.apache.hadoop.hive.ql.exec.MapOperator;
+import org.apache.hadoop.hive.ql.exec.ReduceSinkOperator;
+import org.apache.hadoop.hive.ql.exec.SMBMapJoinOperator;
+import org.apache.hadoop.hive.ql.exec.ScriptOperator;
+import org.apache.hadoop.hive.ql.exec.SelectOperator;
+import org.apache.hadoop.hive.ql.exec.TableScanOperator;
+import org.apache.hadoop.hive.ql.exec.UDTFOperator;
+import org.apache.hadoop.hive.ql.exec.UnionOperator;
+
+import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalOperator;
+
+public interface Visitor {
+
+    public Mutable<ILogicalOperator> visit(CollectOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) throws AlgebricksException;
+
+    public Mutable<ILogicalOperator> visit(JoinOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) throws AlgebricksException;
+
+    public Mutable<ILogicalOperator> visit(ExtractOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) throws AlgebricksException;
+
+    public Mutable<ILogicalOperator> visit(MapJoinOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) throws AlgebricksException;
+
+    public Mutable<ILogicalOperator> visit(SMBMapJoinOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) throws AlgebricksException;
+
+    public Mutable<ILogicalOperator> visit(FilterOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) throws AlgebricksException;
+
+    public Mutable<ILogicalOperator> visit(ForwardOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) throws AlgebricksException;
+
+    public Mutable<ILogicalOperator> visit(GroupByOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) throws AlgebricksException;
+
+    public Mutable<ILogicalOperator> visit(LateralViewForwardOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) throws AlgebricksException;
+
+    public Mutable<ILogicalOperator> visit(LateralViewJoinOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) throws AlgebricksException;
+
+    public Mutable<ILogicalOperator> visit(LimitOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) throws AlgebricksException;
+
+    public Mutable<ILogicalOperator> visit(MapOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) throws AlgebricksException;
+
+    public Mutable<ILogicalOperator> visit(ScriptOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) throws AlgebricksException;
+
+    public Mutable<ILogicalOperator> visit(SelectOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) throws AlgebricksException;
+
+    public Mutable<ILogicalOperator> visit(TableScanOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) throws AlgebricksException;
+
+    public Mutable<ILogicalOperator> visit(FileSinkOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) throws AlgebricksException;
+
+    public Mutable<ILogicalOperator> visit(ReduceSinkOperator hiveOperator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) throws AlgebricksException;
+
+    public Mutable<ILogicalOperator> visit(UDTFOperator operator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) throws AlgebricksException;
+
+    public Mutable<ILogicalOperator> visit(UnionOperator operator,
+            Mutable<ILogicalOperator> AlgebricksParentOperatorRef, Translator t) throws AlgebricksException;
+}