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Kazuaki Ishizaki 5949e6c447 [SPARK-19008][SQL] Improve performance of Dataset.map by eliminating boxing/unboxing 
## What changes were proposed in this pull request?

This PR improve performance of Dataset.map() for primitive types by removing boxing/unbox operations. This is based on [the discussion](https://github.com/apache/spark/pull/16391#discussion_r93788919) with cloud-fan.

Current Catalyst generates a method call to a `apply()` method of an anonymous function written in Scala. The types of an argument and return value are `java.lang.Object`. As a result, each method call for a primitive value involves a pair of unboxing and boxing for calling this `apply()` method and a pair of boxing and unboxing for returning from this `apply()` method.

This PR directly calls a specialized version of a `apply()` method without boxing and unboxing. For example, if types of an arguments ant return value is `int`, this PR generates a method call to `apply$mcII$sp`. This PR supports any combination of `Int`, `Long`, `Float`, and `Double`.

The following is a benchmark result using [this program](https://github.com/apache/spark/pull/16391/files) with 4.7x. Here is a Dataset part of this program.

Without this PR
```
OpenJDK 64-Bit Server VM 1.8.0_111-8u111-b14-2ubuntu0.16.04.2-b14 on Linux 4.4.0-47-generic
Intel(R) Xeon(R) CPU E5-2667 v3  3.20GHz
back-to-back map:                        Best/Avg Time(ms)    Rate(M/s)   Per Row(ns)   Relative
------------------------------------------------------------------------------------------------
RDD                                           1923 / 1952         52.0          19.2       1.0X
DataFrame                                      526 /  548        190.2           5.3       3.7X
Dataset                                       3094 / 3154         32.3          30.9       0.6X
```

With this PR
```
OpenJDK 64-Bit Server VM 1.8.0_111-8u111-b14-2ubuntu0.16.04.2-b14 on Linux 4.4.0-47-generic
Intel(R) Xeon(R) CPU E5-2667 v3  3.20GHz
back-to-back map:                        Best/Avg Time(ms)    Rate(M/s)   Per Row(ns)   Relative
------------------------------------------------------------------------------------------------
RDD                                           1883 / 1892         53.1          18.8       1.0X
DataFrame                                      502 /  642        199.1           5.0       3.7X
Dataset                                        657 /  784        152.2           6.6       2.9X
```

```java
  def backToBackMap(spark: SparkSession, numRows: Long, numChains: Int): Benchmark = {
    import spark.implicits._
    val rdd = spark.sparkContext.range(0, numRows)
    val ds = spark.range(0, numRows)
    val func = (l: Long) => l + 1
    val benchmark = new Benchmark("back-to-back map", numRows)
...
    benchmark.addCase("Dataset") { iter =>
      var res = ds.as[Long]
      var i = 0
      while (i < numChains) {
        res = res.map(func)
        i += 1
      }
      res.queryExecution.toRdd.foreach(_ => Unit)
    }
    benchmark
  }
```

A motivating example
```java
Seq(1, 2, 3).toDS.map(i => i * 7).show
```

Generated code without this PR
```java
/* 005 */ final class GeneratedIterator extends org.apache.spark.sql.execution.BufferedRowIterator {
/* 006 */   private Object[] references;
/* 007 */   private scala.collection.Iterator[] inputs;
/* 008 */   private scala.collection.Iterator inputadapter_input;
/* 009 */   private UnsafeRow deserializetoobject_result;
/* 010 */   private org.apache.spark.sql.catalyst.expressions.codegen.BufferHolder deserializetoobject_holder;
/* 011 */   private org.apache.spark.sql.catalyst.expressions.codegen.UnsafeRowWriter deserializetoobject_rowWriter;
/* 012 */   private int mapelements_argValue;
/* 013 */   private UnsafeRow mapelements_result;
/* 014 */   private org.apache.spark.sql.catalyst.expressions.codegen.BufferHolder mapelements_holder;
/* 015 */   private org.apache.spark.sql.catalyst.expressions.codegen.UnsafeRowWriter mapelements_rowWriter;
/* 016 */   private UnsafeRow serializefromobject_result;
/* 017 */   private org.apache.spark.sql.catalyst.expressions.codegen.BufferHolder serializefromobject_holder;
/* 018 */   private org.apache.spark.sql.catalyst.expressions.codegen.UnsafeRowWriter serializefromobject_rowWriter;
/* 019 */
/* 020 */   public GeneratedIterator(Object[] references) {
/* 021 */     this.references = references;
/* 022 */   }
/* 023 */
/* 024 */   public void init(int index, scala.collection.Iterator[] inputs) {
/* 025 */     partitionIndex = index;
/* 026 */     this.inputs = inputs;
/* 027 */     inputadapter_input = inputs[0];
/* 028 */     deserializetoobject_result = new UnsafeRow(1);
/* 029 */     this.deserializetoobject_holder = new org.apache.spark.sql.catalyst.expressions.codegen.BufferHolder(deserializetoobject_result, 0);
/* 030 */     this.deserializetoobject_rowWriter = new org.apache.spark.sql.catalyst.expressions.codegen.UnsafeRowWriter(deserializetoobject_holder, 1);
/* 031 */
/* 032 */     mapelements_result = new UnsafeRow(1);
/* 033 */     this.mapelements_holder = new org.apache.spark.sql.catalyst.expressions.codegen.BufferHolder(mapelements_result, 0);
/* 034 */     this.mapelements_rowWriter = new org.apache.spark.sql.catalyst.expressions.codegen.UnsafeRowWriter(mapelements_holder, 1);
/* 035 */     serializefromobject_result = new UnsafeRow(1);
/* 036 */     this.serializefromobject_holder = new org.apache.spark.sql.catalyst.expressions.codegen.BufferHolder(serializefromobject_result, 0);
/* 037 */     this.serializefromobject_rowWriter = new org.apache.spark.sql.catalyst.expressions.codegen.UnsafeRowWriter(serializefromobject_holder, 1);
/* 038 */
/* 039 */   }
/* 040 */
/* 041 */   protected void processNext() throws java.io.IOException {
/* 042 */     while (inputadapter_input.hasNext() && !stopEarly()) {
/* 043 */       InternalRow inputadapter_row = (InternalRow) inputadapter_input.next();
/* 044 */       int inputadapter_value = inputadapter_row.getInt(0);
/* 045 */
/* 046 */       boolean mapelements_isNull = true;
/* 047 */       int mapelements_value = -1;
/* 048 */       if (!false) {
/* 049 */         mapelements_argValue = inputadapter_value;
/* 050 */
/* 051 */         mapelements_isNull = false;
/* 052 */         if (!mapelements_isNull) {
/* 053 */           Object mapelements_funcResult = null;
/* 054 */           mapelements_funcResult = ((scala.Function1) references[0]).apply(mapelements_argValue);
/* 055 */           if (mapelements_funcResult == null) {
/* 056 */             mapelements_isNull = true;
/* 057 */           } else {
/* 058 */             mapelements_value = (Integer) mapelements_funcResult;
/* 059 */           }
/* 060 */
/* 061 */         }
/* 062 */
/* 063 */       }
/* 064 */
/* 065 */       serializefromobject_rowWriter.zeroOutNullBytes();
/* 066 */
/* 067 */       if (mapelements_isNull) {
/* 068 */         serializefromobject_rowWriter.setNullAt(0);
/* 069 */       } else {
/* 070 */         serializefromobject_rowWriter.write(0, mapelements_value);
/* 071 */       }
/* 072 */       append(serializefromobject_result);
/* 073 */       if (shouldStop()) return;
/* 074 */     }
/* 075 */   }
/* 076 */ }
```

Generated code with this PR (lines 48-56 are changed)
```java
/* 005 */ final class GeneratedIterator extends org.apache.spark.sql.execution.BufferedRowIterator {
/* 006 */   private Object[] references;
/* 007 */   private scala.collection.Iterator[] inputs;
/* 008 */   private scala.collection.Iterator inputadapter_input;
/* 009 */   private UnsafeRow deserializetoobject_result;
/* 010 */   private org.apache.spark.sql.catalyst.expressions.codegen.BufferHolder deserializetoobject_holder;
/* 011 */   private org.apache.spark.sql.catalyst.expressions.codegen.UnsafeRowWriter deserializetoobject_rowWriter;
/* 012 */   private int mapelements_argValue;
/* 013 */   private UnsafeRow mapelements_result;
/* 014 */   private org.apache.spark.sql.catalyst.expressions.codegen.BufferHolder mapelements_holder;
/* 015 */   private org.apache.spark.sql.catalyst.expressions.codegen.UnsafeRowWriter mapelements_rowWriter;
/* 016 */   private UnsafeRow serializefromobject_result;
/* 017 */   private org.apache.spark.sql.catalyst.expressions.codegen.BufferHolder serializefromobject_holder;
/* 018 */   private org.apache.spark.sql.catalyst.expressions.codegen.UnsafeRowWriter serializefromobject_rowWriter;
/* 019 */
/* 020 */   public GeneratedIterator(Object[] references) {
/* 021 */     this.references = references;
/* 022 */   }
/* 023 */
/* 024 */   public void init(int index, scala.collection.Iterator[] inputs) {
/* 025 */     partitionIndex = index;
/* 026 */     this.inputs = inputs;
/* 027 */     inputadapter_input = inputs[0];
/* 028 */     deserializetoobject_result = new UnsafeRow(1);
/* 029 */     this.deserializetoobject_holder = new org.apache.spark.sql.catalyst.expressions.codegen.BufferHolder(deserializetoobject_result, 0);
/* 030 */     this.deserializetoobject_rowWriter = new org.apache.spark.sql.catalyst.expressions.codegen.UnsafeRowWriter(deserializetoobject_holder, 1);
/* 031 */
/* 032 */     mapelements_result = new UnsafeRow(1);
/* 033 */     this.mapelements_holder = new org.apache.spark.sql.catalyst.expressions.codegen.BufferHolder(mapelements_result, 0);
/* 034 */     this.mapelements_rowWriter = new org.apache.spark.sql.catalyst.expressions.codegen.UnsafeRowWriter(mapelements_holder, 1);
/* 035 */     serializefromobject_result = new UnsafeRow(1);
/* 036 */     this.serializefromobject_holder = new org.apache.spark.sql.catalyst.expressions.codegen.BufferHolder(serializefromobject_result, 0);
/* 037 */     this.serializefromobject_rowWriter = new org.apache.spark.sql.catalyst.expressions.codegen.UnsafeRowWriter(serializefromobject_holder, 1);
/* 038 */
/* 039 */   }
/* 040 */
/* 041 */   protected void processNext() throws java.io.IOException {
/* 042 */     while (inputadapter_input.hasNext() && !stopEarly()) {
/* 043 */       InternalRow inputadapter_row = (InternalRow) inputadapter_input.next();
/* 044 */       int inputadapter_value = inputadapter_row.getInt(0);
/* 045 */
/* 046 */       boolean mapelements_isNull = true;
/* 047 */       int mapelements_value = -1;
/* 048 */       if (!false) {
/* 049 */         mapelements_argValue = inputadapter_value;
/* 050 */
/* 051 */         mapelements_isNull = false;
/* 052 */         if (!mapelements_isNull) {
/* 053 */           mapelements_value = ((scala.Function1) references[0]).apply$mcII$sp(mapelements_argValue);
/* 054 */         }
/* 055 */
/* 056 */       }
/* 057 */
/* 058 */       serializefromobject_rowWriter.zeroOutNullBytes();
/* 059 */
/* 060 */       if (mapelements_isNull) {
/* 061 */         serializefromobject_rowWriter.setNullAt(0);
/* 062 */       } else {
/* 063 */         serializefromobject_rowWriter.write(0, mapelements_value);
/* 064 */       }
/* 065 */       append(serializefromobject_result);
/* 066 */       if (shouldStop()) return;
/* 067 */     }
/* 068 */   }
/* 069 */ }
```

Java bytecode for methods for `i => i * 7`
```java
$ javap -c Test\$\$anonfun\$5\$\$anonfun\$apply\$mcV\$sp\$1.class
Compiled from "Test.scala"
public final class org.apache.spark.sql.Test$$anonfun$5$$anonfun$apply$mcV$sp$1 extends scala.runtime.AbstractFunction1$mcII$sp implements scala.Serializable {
  public static final long serialVersionUID;

  public final int apply(int);
    Code:
       0: aload_0
       1: iload_1
       2: invokevirtual #18                 // Method apply$mcII$sp:(I)I
       5: ireturn

  public int apply$mcII$sp(int);
    Code:
       0: iload_1
       1: bipush        7
       3: imul
       4: ireturn

  public final java.lang.Object apply(java.lang.Object);
    Code:
       0: aload_0
       1: aload_1
       2: invokestatic  #29                 // Method scala/runtime/BoxesRunTime.unboxToInt:(Ljava/lang/Object;)I
       5: invokevirtual #31                 // Method apply:(I)I
       8: invokestatic  #35                 // Method scala/runtime/BoxesRunTime.boxToInteger:(I)Ljava/lang/Integer;
      11: areturn

  public org.apache.spark.sql.Test$$anonfun$5$$anonfun$apply$mcV$sp$1(org.apache.spark.sql.Test$$anonfun$5);
    Code:
       0: aload_0
       1: invokespecial #42                 // Method scala/runtime/AbstractFunction1$mcII$sp."<init>":()V
       4: return
}
```
## How was this patch tested?

Added new test suites to `DatasetPrimitiveSuite`.

Author: Kazuaki Ishizaki <ishizaki@jp.ibm.com>

Closes #17172 from kiszk/SPARK-19008.
2017-03-09 22:58:52 -08:00
..
catalyst [SPARK-19008][SQL] Improve performance of Dataset.map by eliminating boxing/unboxing 2017-03-09 22:58:52 -08:00
core [SPARK-19008][SQL] Improve performance of Dataset.map by eliminating boxing/unboxing 2017-03-09 22:58:52 -08:00
hive [SPARK-19611][SQL] Introduce configurable table schema inference 2017-03-09 12:55:33 -08:00
hive-thriftserver [SPARK-19673][SQL] "ThriftServer default app name is changed wrong" 2017-02-25 21:47:02 +00:00
README.md [SPARK-16557][SQL] Remove stale doc in sql/README.md 2016-07-14 19:24:42 -07:00

README.md

Spark SQL

This module provides support for executing relational queries expressed in either SQL or the DataFrame/Dataset API.

Spark SQL is broken up into four subprojects:

  • Catalyst (sql/catalyst) - An implementation-agnostic framework for manipulating trees of relational operators and expressions.
  • Execution (sql/core) - A query planner / execution engine for translating Catalyst's logical query plans into Spark RDDs. This component also includes a new public interface, SQLContext, that allows users to execute SQL or LINQ statements against existing RDDs and Parquet files.
  • Hive Support (sql/hive) - Includes an extension of SQLContext called HiveContext that allows users to write queries using a subset of HiveQL and access data from a Hive Metastore using Hive SerDes. There are also wrappers that allows users to run queries that include Hive UDFs, UDAFs, and UDTFs.
  • HiveServer and CLI support (sql/hive-thriftserver) - Includes support for the SQL CLI (bin/spark-sql) and a HiveServer2 (for JDBC/ODBC) compatible server.