[GitHub] [incubator-pinot] Jackie-Jiang commented on a change in pull request #6053: Add support for Decimal with Precision Sum aggregation

[GitBox <gi...@apache.org>]

Jackie-Jiang commented on a change in pull request #6053:
URL: https://github.com/apache/incubator-pinot/pull/6053#discussion_r497201010



##########
File path: pinot-common/src/main/java/org/apache/pinot/common/function/scalar/DataTypeConversionFunctions.java
##########
@@ -0,0 +1,92 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.pinot.common.function.scalar;
+
+import java.math.BigDecimal;
+import java.math.BigInteger;
+import java.util.Base64;
+import org.apache.pinot.spi.annotations.ScalarFunction;
+
+
+public class DataTypeConversionFunctions {
+  private DataTypeConversionFunctions() {
+
+  }
+
+  @ScalarFunction
+  public static byte[] bigDecimalToBytes(BigDecimal number) {
+    int scale = number.scale();
+    BigInteger unscaled = number.unscaledValue();
+    byte[] value = unscaled.toByteArray();
+    byte[] bigDecimalBytesArray = new byte[value.length + 4];
+    for (int i = 0; i < 4; i++) {
+      bigDecimalBytesArray[i] = (byte) (scale >>> (8 * (3 - i)));
+    }
+    System.arraycopy(value, 0, bigDecimalBytesArray, 4, value.length);
+    return bigDecimalBytesArray;
+  }
+
+  @ScalarFunction
+  public static String bytesToBigDecimal(byte[] bytes) {
+    int scale = 0;
+    for (int i = 0; i < 4; i++) {

Review comment:
       Similarly here

##########
File path: pinot-common/src/main/java/org/apache/pinot/common/function/scalar/DataTypeConversionFunctions.java
##########
@@ -0,0 +1,92 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.pinot.common.function.scalar;
+
+import java.math.BigDecimal;
+import java.math.BigInteger;
+import java.util.Base64;
+import org.apache.pinot.spi.annotations.ScalarFunction;
+
+
+public class DataTypeConversionFunctions {
+  private DataTypeConversionFunctions() {
+
+  }
+
+  @ScalarFunction
+  public static byte[] bigDecimalToBytes(BigDecimal number) {
+    int scale = number.scale();
+    BigInteger unscaled = number.unscaledValue();
+    byte[] value = unscaled.toByteArray();
+    byte[] bigDecimalBytesArray = new byte[value.length + 4];
+    for (int i = 0; i < 4; i++) {
+      bigDecimalBytesArray[i] = (byte) (scale >>> (8 * (3 - i)));
+    }

Review comment:
       For better performance, avoid the for loop
   ```suggestion
       bigDecimalBytesArray[0] = (byte) scale >>> 24;
       bigDecimalBytesArray[1] = (byte) scale >>> 16;
       bigDecimalBytesArray[2] = (byte) scale >>> 8;
       bigDecimalBytesArray[3] = (byte) scale;
   ```

##########
File path: pinot-common/src/main/java/org/apache/pinot/common/function/scalar/DataTypeConversionFunctions.java
##########
@@ -0,0 +1,92 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.pinot.common.function.scalar;
+
+import java.math.BigDecimal;
+import java.math.BigInteger;
+import java.util.Base64;
+import org.apache.pinot.spi.annotations.ScalarFunction;
+
+
+public class DataTypeConversionFunctions {
+  private DataTypeConversionFunctions() {
+
+  }
+
+  @ScalarFunction
+  public static byte[] bigDecimalToBytes(BigDecimal number) {
+    int scale = number.scale();
+    BigInteger unscaled = number.unscaledValue();
+    byte[] value = unscaled.toByteArray();
+    byte[] bigDecimalBytesArray = new byte[value.length + 4];
+    for (int i = 0; i < 4; i++) {
+      bigDecimalBytesArray[i] = (byte) (scale >>> (8 * (3 - i)));
+    }
+    System.arraycopy(value, 0, bigDecimalBytesArray, 4, value.length);
+    return bigDecimalBytesArray;
+  }
+
+  @ScalarFunction
+  public static String bytesToBigDecimal(byte[] bytes) {
+    int scale = 0;
+    for (int i = 0; i < 4; i++) {
+      scale += (((int) bytes[i]) << (8 * (3 - i)));
+    }
+    byte[] vals = new byte[bytes.length - 4];
+    System.arraycopy(bytes, 4, vals, 0, vals.length);
+    BigInteger unscaled = new BigInteger(vals);
+    BigDecimal number = new BigDecimal(unscaled, scale);
+    return number.toString();
+  }
+
+  @ScalarFunction
+  public static byte[] bigDecimalFromString(String bigDecimal) {
+    return bigDecimalToBytes(new BigDecimal(bigDecimal));
+  }
+
+  @ScalarFunction
+  public static byte[] hexToBytes(String hex) {
+    int len = hex.length();

Review comment:
       You may use `BytesUtils.toBytes(hex)`

##########
File path: pinot-common/src/main/java/org/apache/pinot/common/function/scalar/DataTypeConversionFunctions.java
##########
@@ -0,0 +1,92 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.pinot.common.function.scalar;
+
+import java.math.BigDecimal;
+import java.math.BigInteger;
+import java.util.Base64;
+import org.apache.pinot.spi.annotations.ScalarFunction;
+
+
+public class DataTypeConversionFunctions {
+  private DataTypeConversionFunctions() {
+
+  }
+
+  @ScalarFunction
+  public static byte[] bigDecimalToBytes(BigDecimal number) {
+    int scale = number.scale();
+    BigInteger unscaled = number.unscaledValue();
+    byte[] value = unscaled.toByteArray();
+    byte[] bigDecimalBytesArray = new byte[value.length + 4];
+    for (int i = 0; i < 4; i++) {
+      bigDecimalBytesArray[i] = (byte) (scale >>> (8 * (3 - i)));
+    }
+    System.arraycopy(value, 0, bigDecimalBytesArray, 4, value.length);
+    return bigDecimalBytesArray;
+  }
+
+  @ScalarFunction
+  public static String bytesToBigDecimal(byte[] bytes) {
+    int scale = 0;
+    for (int i = 0; i < 4; i++) {
+      scale += (((int) bytes[i]) << (8 * (3 - i)));
+    }
+    byte[] vals = new byte[bytes.length - 4];
+    System.arraycopy(bytes, 4, vals, 0, vals.length);
+    BigInteger unscaled = new BigInteger(vals);
+    BigDecimal number = new BigDecimal(unscaled, scale);
+    return number.toString();
+  }
+
+  @ScalarFunction
+  public static byte[] bigDecimalFromString(String bigDecimal) {
+    return bigDecimalToBytes(new BigDecimal(bigDecimal));
+  }
+
+  @ScalarFunction
+  public static byte[] hexToBytes(String hex) {
+    int len = hex.length();
+    byte[] data = new byte[len / 2];
+    for (int i = 0; i < len; i += 2) {
+      data[i / 2] = (byte) ((Character.digit(hex.charAt(i), 16) << 4) + Character.digit(hex.charAt(i + 1), 16));
+    }
+    return data;
+  }
+
+  @ScalarFunction
+  public static String bytesToHex(byte[] bytes) {
+    StringBuilder sb = new StringBuilder();

Review comment:
       `BytesUtils.toHexString(bytes)`

##########
File path: pinot-core/src/main/java/org/apache/pinot/core/query/aggregation/function/SumWithPrecisionAggregationFunction.java
##########
@@ -0,0 +1,174 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.pinot.core.query.aggregation.function;
+
+import java.math.BigDecimal;
+import java.math.MathContext;
+import java.util.List;
+import java.util.Map;
+import org.apache.pinot.common.function.AggregationFunctionType;
+import org.apache.pinot.common.function.scalar.DataTypeConversionFunctions;
+import org.apache.pinot.common.utils.DataSchema;
+import org.apache.pinot.core.common.BlockValSet;
+import org.apache.pinot.core.query.aggregation.AggregationResultHolder;
+import org.apache.pinot.core.query.aggregation.ObjectAggregationResultHolder;
+import org.apache.pinot.core.query.aggregation.groupby.GroupByResultHolder;
+import org.apache.pinot.core.query.aggregation.groupby.ObjectGroupByResultHolder;
+import org.apache.pinot.core.query.request.context.ExpressionContext;
+
+
+public class SumWithPrecisionAggregationFunction extends BaseSingleInputAggregationFunction<BigDecimal, BigDecimal> {
+  MathContext _mathContext = new MathContext(0);
+  Integer _scale = null;
+
+  public SumWithPrecisionAggregationFunction(ExpressionContext expression, List<ExpressionContext> arguments) {
+    super(expression);
+    int numArguments = arguments.size();
+
+    if (numArguments == 3) {
+      Integer precision = Integer.parseInt(arguments.get(1).getLiteral());
+      _scale = Integer.parseInt(arguments.get(2).getLiteral());
+      _mathContext = new MathContext(precision);
+    } else if (numArguments == 2) {
+      Integer precision = Integer.parseInt(arguments.get(1).getLiteral());
+      _mathContext = new MathContext(precision);
+    }
+  }
+
+  @Override
+  public AggregationFunctionType getType() {
+    return AggregationFunctionType.SUMPRECISION;
+  }
+
+  @Override
+  public AggregationResultHolder createAggregationResultHolder() {
+    return new ObjectAggregationResultHolder();
+  }
+
+  @Override
+  public GroupByResultHolder createGroupByResultHolder(int initialCapacity, int maxCapacity) {
+    return new ObjectGroupByResultHolder(initialCapacity, maxCapacity);
+  }
+
+  @Override
+  public void aggregate(int length, AggregationResultHolder aggregationResultHolder,
+      Map<ExpressionContext, BlockValSet> blockValSetMap) {
+    byte[][] valueArray = blockValSetMap.get(_expression).getBytesValuesSV();

Review comment:
       We might also want to support string type as the BigDecimal values?

##########
File path: pinot-core/src/main/java/org/apache/pinot/core/query/aggregation/function/SumWithPrecisionAggregationFunction.java
##########
@@ -0,0 +1,174 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.pinot.core.query.aggregation.function;
+
+import java.math.BigDecimal;
+import java.math.MathContext;
+import java.util.List;
+import java.util.Map;
+import org.apache.pinot.common.function.AggregationFunctionType;
+import org.apache.pinot.common.function.scalar.DataTypeConversionFunctions;
+import org.apache.pinot.common.utils.DataSchema;
+import org.apache.pinot.core.common.BlockValSet;
+import org.apache.pinot.core.query.aggregation.AggregationResultHolder;
+import org.apache.pinot.core.query.aggregation.ObjectAggregationResultHolder;
+import org.apache.pinot.core.query.aggregation.groupby.GroupByResultHolder;
+import org.apache.pinot.core.query.aggregation.groupby.ObjectGroupByResultHolder;
+import org.apache.pinot.core.query.request.context.ExpressionContext;
+
+
+public class SumWithPrecisionAggregationFunction extends BaseSingleInputAggregationFunction<BigDecimal, BigDecimal> {
+  MathContext _mathContext = new MathContext(0);
+  Integer _scale = null;
+
+  public SumWithPrecisionAggregationFunction(ExpressionContext expression, List<ExpressionContext> arguments) {
+    super(expression);
+    int numArguments = arguments.size();
+
+    if (numArguments == 3) {
+      Integer precision = Integer.parseInt(arguments.get(1).getLiteral());
+      _scale = Integer.parseInt(arguments.get(2).getLiteral());
+      _mathContext = new MathContext(precision);
+    } else if (numArguments == 2) {
+      Integer precision = Integer.parseInt(arguments.get(1).getLiteral());
+      _mathContext = new MathContext(precision);
+    }
+  }
+
+  @Override
+  public AggregationFunctionType getType() {
+    return AggregationFunctionType.SUMPRECISION;
+  }
+
+  @Override
+  public AggregationResultHolder createAggregationResultHolder() {
+    return new ObjectAggregationResultHolder();
+  }
+
+  @Override
+  public GroupByResultHolder createGroupByResultHolder(int initialCapacity, int maxCapacity) {
+    return new ObjectGroupByResultHolder(initialCapacity, maxCapacity);
+  }
+
+  @Override
+  public void aggregate(int length, AggregationResultHolder aggregationResultHolder,
+      Map<ExpressionContext, BlockValSet> blockValSetMap) {
+    byte[][] valueArray = blockValSetMap.get(_expression).getBytesValuesSV();
+    BigDecimal sumValue = getDefaultResult(aggregationResultHolder);
+    for (int i = 0; i < length; i++) {
+      BigDecimal value = new BigDecimal(DataTypeConversionFunctions.bytesToBigDecimal(valueArray[i]));
+      sumValue = sumValue.add(value, _mathContext);
+    }
+    aggregationResultHolder.setValue(setScale(sumValue));

Review comment:
       To get the consistent result, we should either set the scale at the end (in `extractFinalResult`) or for each value. I think setting it in `extractFinalResult` should give better performance.

##########
File path: pinot-common/src/main/java/org/apache/pinot/common/function/scalar/DataTypeConversionFunctions.java
##########
@@ -0,0 +1,92 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.pinot.common.function.scalar;
+
+import java.math.BigDecimal;
+import java.math.BigInteger;
+import java.util.Base64;
+import org.apache.pinot.spi.annotations.ScalarFunction;
+
+
+public class DataTypeConversionFunctions {
+  private DataTypeConversionFunctions() {
+
+  }
+
+  @ScalarFunction
+  public static byte[] bigDecimalToBytes(BigDecimal number) {
+    int scale = number.scale();
+    BigInteger unscaled = number.unscaledValue();
+    byte[] value = unscaled.toByteArray();
+    byte[] bigDecimalBytesArray = new byte[value.length + 4];
+    for (int i = 0; i < 4; i++) {
+      bigDecimalBytesArray[i] = (byte) (scale >>> (8 * (3 - i)));
+    }
+    System.arraycopy(value, 0, bigDecimalBytesArray, 4, value.length);
+    return bigDecimalBytesArray;
+  }
+
+  @ScalarFunction
+  public static String bytesToBigDecimal(byte[] bytes) {
+    int scale = 0;
+    for (int i = 0; i < 4; i++) {
+      scale += (((int) bytes[i]) << (8 * (3 - i)));
+    }
+    byte[] vals = new byte[bytes.length - 4];
+    System.arraycopy(bytes, 4, vals, 0, vals.length);
+    BigInteger unscaled = new BigInteger(vals);
+    BigDecimal number = new BigDecimal(unscaled, scale);
+    return number.toString();
+  }
+
+  @ScalarFunction
+  public static byte[] bigDecimalFromString(String bigDecimal) {
+    return bigDecimalToBytes(new BigDecimal(bigDecimal));
+  }
+
+  @ScalarFunction
+  public static byte[] hexToBytes(String hex) {
+    int len = hex.length();
+    byte[] data = new byte[len / 2];
+    for (int i = 0; i < len; i += 2) {
+      data[i / 2] = (byte) ((Character.digit(hex.charAt(i), 16) << 4) + Character.digit(hex.charAt(i + 1), 16));
+    }
+    return data;
+  }
+
+  @ScalarFunction
+  public static String bytesToHex(byte[] bytes) {
+    StringBuilder sb = new StringBuilder();
+    for (byte b : bytes) {
+      sb.append(String.format("%02X ", b));
+    }
+
+    return sb.toString();
+  }
+
+  @ScalarFunction
+  public static String base64Encode(String input) {
+    return Base64.getEncoder().encodeToString(input.getBytes());
+  }
+
+  @ScalarFunction
+  public static String base64Decode(String input) {
+    return new String(Base64.getDecoder().decode(input.getBytes()));
+  }

Review comment:
       ```suggestion
     public static byte[] base64Decode(String input) {
       return Base64.getDecoder().decode(input);
     }
   ```

##########
File path: pinot-common/src/main/java/org/apache/pinot/common/function/scalar/DataTypeConversionFunctions.java
##########
@@ -0,0 +1,92 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.pinot.common.function.scalar;
+
+import java.math.BigDecimal;
+import java.math.BigInteger;
+import java.util.Base64;
+import org.apache.pinot.spi.annotations.ScalarFunction;
+
+
+public class DataTypeConversionFunctions {
+  private DataTypeConversionFunctions() {
+
+  }
+
+  @ScalarFunction
+  public static byte[] bigDecimalToBytes(BigDecimal number) {

Review comment:
       Recommend passing in `String` instead of `BigDecimal` for symmetry with `bytesToBigDecimal()`. Also, scaler transform function won't work on `BigDecimal` objects.

##########
File path: pinot-common/src/main/java/org/apache/pinot/common/function/scalar/DataTypeConversionFunctions.java
##########
@@ -0,0 +1,92 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.pinot.common.function.scalar;
+
+import java.math.BigDecimal;
+import java.math.BigInteger;
+import java.util.Base64;
+import org.apache.pinot.spi.annotations.ScalarFunction;
+
+
+public class DataTypeConversionFunctions {
+  private DataTypeConversionFunctions() {
+
+  }
+
+  @ScalarFunction
+  public static byte[] bigDecimalToBytes(BigDecimal number) {
+    int scale = number.scale();
+    BigInteger unscaled = number.unscaledValue();
+    byte[] value = unscaled.toByteArray();
+    byte[] bigDecimalBytesArray = new byte[value.length + 4];
+    for (int i = 0; i < 4; i++) {
+      bigDecimalBytesArray[i] = (byte) (scale >>> (8 * (3 - i)));
+    }
+    System.arraycopy(value, 0, bigDecimalBytesArray, 4, value.length);
+    return bigDecimalBytesArray;
+  }
+
+  @ScalarFunction
+  public static String bytesToBigDecimal(byte[] bytes) {
+    int scale = 0;
+    for (int i = 0; i < 4; i++) {
+      scale += (((int) bytes[i]) << (8 * (3 - i)));
+    }
+    byte[] vals = new byte[bytes.length - 4];
+    System.arraycopy(bytes, 4, vals, 0, vals.length);
+    BigInteger unscaled = new BigInteger(vals);
+    BigDecimal number = new BigDecimal(unscaled, scale);
+    return number.toString();
+  }
+
+  @ScalarFunction
+  public static byte[] bigDecimalFromString(String bigDecimal) {
+    return bigDecimalToBytes(new BigDecimal(bigDecimal));
+  }
+
+  @ScalarFunction
+  public static byte[] hexToBytes(String hex) {
+    int len = hex.length();
+    byte[] data = new byte[len / 2];
+    for (int i = 0; i < len; i += 2) {
+      data[i / 2] = (byte) ((Character.digit(hex.charAt(i), 16) << 4) + Character.digit(hex.charAt(i + 1), 16));
+    }
+    return data;
+  }
+
+  @ScalarFunction
+  public static String bytesToHex(byte[] bytes) {
+    StringBuilder sb = new StringBuilder();
+    for (byte b : bytes) {
+      sb.append(String.format("%02X ", b));
+    }
+
+    return sb.toString();
+  }
+
+  @ScalarFunction
+  public static String base64Encode(String input) {
+    return Base64.getEncoder().encodeToString(input.getBytes());
+  }

Review comment:
       ```suggestion
     public static byte[] base64Encode(byte[] bytes) {
       return Base64.getEncoder().encodeToString(bytes);
     }
   ```

##########
File path: pinot-core/src/main/java/org/apache/pinot/core/query/aggregation/function/SumWithPrecisionAggregationFunction.java
##########
@@ -0,0 +1,174 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.pinot.core.query.aggregation.function;
+
+import java.math.BigDecimal;
+import java.math.MathContext;
+import java.util.List;
+import java.util.Map;
+import org.apache.pinot.common.function.AggregationFunctionType;
+import org.apache.pinot.common.function.scalar.DataTypeConversionFunctions;
+import org.apache.pinot.common.utils.DataSchema;
+import org.apache.pinot.core.common.BlockValSet;
+import org.apache.pinot.core.query.aggregation.AggregationResultHolder;
+import org.apache.pinot.core.query.aggregation.ObjectAggregationResultHolder;
+import org.apache.pinot.core.query.aggregation.groupby.GroupByResultHolder;
+import org.apache.pinot.core.query.aggregation.groupby.ObjectGroupByResultHolder;
+import org.apache.pinot.core.query.request.context.ExpressionContext;
+
+
+public class SumWithPrecisionAggregationFunction extends BaseSingleInputAggregationFunction<BigDecimal, BigDecimal> {
+  MathContext _mathContext = new MathContext(0);
+  Integer _scale = null;
+
+  public SumWithPrecisionAggregationFunction(ExpressionContext expression, List<ExpressionContext> arguments) {
+    super(expression);
+    int numArguments = arguments.size();
+
+    if (numArguments == 3) {
+      Integer precision = Integer.parseInt(arguments.get(1).getLiteral());
+      _scale = Integer.parseInt(arguments.get(2).getLiteral());
+      _mathContext = new MathContext(precision);
+    } else if (numArguments == 2) {
+      Integer precision = Integer.parseInt(arguments.get(1).getLiteral());
+      _mathContext = new MathContext(precision);
+    }
+  }
+
+  @Override
+  public AggregationFunctionType getType() {
+    return AggregationFunctionType.SUMPRECISION;
+  }
+
+  @Override
+  public AggregationResultHolder createAggregationResultHolder() {
+    return new ObjectAggregationResultHolder();
+  }
+
+  @Override
+  public GroupByResultHolder createGroupByResultHolder(int initialCapacity, int maxCapacity) {
+    return new ObjectGroupByResultHolder(initialCapacity, maxCapacity);
+  }
+
+  @Override
+  public void aggregate(int length, AggregationResultHolder aggregationResultHolder,
+      Map<ExpressionContext, BlockValSet> blockValSetMap) {
+    byte[][] valueArray = blockValSetMap.get(_expression).getBytesValuesSV();
+    BigDecimal sumValue = getDefaultResult(aggregationResultHolder);
+    for (int i = 0; i < length; i++) {
+      BigDecimal value = new BigDecimal(DataTypeConversionFunctions.bytesToBigDecimal(valueArray[i]));

Review comment:
       Suggest adding a util class for `BigDecimal` (the scalar function can also call the util class). Here we should avoid converting `BigDecimal` to `String` and back again

##########
File path: pinot-core/src/main/java/org/apache/pinot/core/query/aggregation/function/SumWithPrecisionAggregationFunction.java
##########
@@ -0,0 +1,174 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.pinot.core.query.aggregation.function;
+
+import java.math.BigDecimal;
+import java.math.MathContext;
+import java.util.List;
+import java.util.Map;
+import org.apache.pinot.common.function.AggregationFunctionType;
+import org.apache.pinot.common.function.scalar.DataTypeConversionFunctions;
+import org.apache.pinot.common.utils.DataSchema;
+import org.apache.pinot.core.common.BlockValSet;
+import org.apache.pinot.core.query.aggregation.AggregationResultHolder;
+import org.apache.pinot.core.query.aggregation.ObjectAggregationResultHolder;
+import org.apache.pinot.core.query.aggregation.groupby.GroupByResultHolder;
+import org.apache.pinot.core.query.aggregation.groupby.ObjectGroupByResultHolder;
+import org.apache.pinot.core.query.request.context.ExpressionContext;
+
+
+public class SumWithPrecisionAggregationFunction extends BaseSingleInputAggregationFunction<BigDecimal, BigDecimal> {

Review comment:
       Please add some javadoc on the arguments expected for the function.
   Also recommend renaming it to `SumPrecisionAggregationFunction` to match the function name

##########
File path: pinot-core/src/main/java/org/apache/pinot/core/query/aggregation/function/SumWithPrecisionAggregationFunction.java
##########
@@ -0,0 +1,174 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.pinot.core.query.aggregation.function;
+
+import java.math.BigDecimal;
+import java.math.MathContext;
+import java.util.List;
+import java.util.Map;
+import org.apache.pinot.common.function.AggregationFunctionType;
+import org.apache.pinot.common.function.scalar.DataTypeConversionFunctions;
+import org.apache.pinot.common.utils.DataSchema;
+import org.apache.pinot.core.common.BlockValSet;
+import org.apache.pinot.core.query.aggregation.AggregationResultHolder;
+import org.apache.pinot.core.query.aggregation.ObjectAggregationResultHolder;
+import org.apache.pinot.core.query.aggregation.groupby.GroupByResultHolder;
+import org.apache.pinot.core.query.aggregation.groupby.ObjectGroupByResultHolder;
+import org.apache.pinot.core.query.request.context.ExpressionContext;
+
+
+public class SumWithPrecisionAggregationFunction extends BaseSingleInputAggregationFunction<BigDecimal, BigDecimal> {
+  MathContext _mathContext = new MathContext(0);

Review comment:
       Make these 2 variables `private final` because the aggregation function can be shared among multiple segments, and needs to be stateless.

##########
File path: pinot-common/src/main/java/org/apache/pinot/common/function/scalar/DataTypeConversionFunctions.java
##########
@@ -0,0 +1,92 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.pinot.common.function.scalar;
+
+import java.math.BigDecimal;
+import java.math.BigInteger;
+import java.util.Base64;
+import org.apache.pinot.spi.annotations.ScalarFunction;
+
+
+public class DataTypeConversionFunctions {
+  private DataTypeConversionFunctions() {
+
+  }
+
+  @ScalarFunction
+  public static byte[] bigDecimalToBytes(BigDecimal number) {
+    int scale = number.scale();
+    BigInteger unscaled = number.unscaledValue();
+    byte[] value = unscaled.toByteArray();
+    byte[] bigDecimalBytesArray = new byte[value.length + 4];
+    for (int i = 0; i < 4; i++) {
+      bigDecimalBytesArray[i] = (byte) (scale >>> (8 * (3 - i)));
+    }

Review comment:
       Actually, after another thought, I don't think we need to use 4 bytes for the scale. Scale larger than 256 doesn't make lots of sense.

##########
File path: pinot-core/src/main/java/org/apache/pinot/core/query/aggregation/function/SumWithPrecisionAggregationFunction.java
##########
@@ -0,0 +1,174 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.pinot.core.query.aggregation.function;
+
+import java.math.BigDecimal;
+import java.math.MathContext;
+import java.util.List;
+import java.util.Map;
+import org.apache.pinot.common.function.AggregationFunctionType;
+import org.apache.pinot.common.function.scalar.DataTypeConversionFunctions;
+import org.apache.pinot.common.utils.DataSchema;
+import org.apache.pinot.core.common.BlockValSet;
+import org.apache.pinot.core.query.aggregation.AggregationResultHolder;
+import org.apache.pinot.core.query.aggregation.ObjectAggregationResultHolder;
+import org.apache.pinot.core.query.aggregation.groupby.GroupByResultHolder;
+import org.apache.pinot.core.query.aggregation.groupby.ObjectGroupByResultHolder;
+import org.apache.pinot.core.query.request.context.ExpressionContext;
+
+
+public class SumWithPrecisionAggregationFunction extends BaseSingleInputAggregationFunction<BigDecimal, BigDecimal> {
+  MathContext _mathContext = new MathContext(0);
+  Integer _scale = null;
+
+  public SumWithPrecisionAggregationFunction(ExpressionContext expression, List<ExpressionContext> arguments) {
+    super(expression);

Review comment:
       ```suggestion
     public SumWithPrecisionAggregationFunction(List<ExpressionContext> arguments) {
       super(arguments.get(0));
   ```




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