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Kazuaki Ishizaki fcb68e0f5d [SPARK-19786][SQL] Facilitate loop optimizations in a JIT compiler regarding range() 
## What changes were proposed in this pull request?

This PR improves performance of operations with `range()` by changing Java code generated by Catalyst. This PR is inspired by the [blog article](https://databricks.com/blog/2017/02/16/processing-trillion-rows-per-second-single-machine-can-nested-loop-joins-fast.html).

This PR changes generated code in the following two points.
1. Replace a while-loop with long instance variables a for-loop with int local varibles
2. Suppress generation of `shouldStop()` method if this method is unnecessary (e.g. `append()` is not generated).

These points facilitates compiler optimizations in a JIT compiler by feeding the simplified Java code into the JIT compiler. The performance is improved by 7.6x.

Benchmark program:
```java
val N = 1 << 29
val iters = 2
val benchmark = new Benchmark("range.count", N * iters)
benchmark.addCase(s"with this PR") { i =>
  var n = 0
  var len = 0
  while (n < iters) {
    len += sparkSession.range(N).selectExpr("count(id)").collect.length
    n += 1
  }
}
benchmark.run
```

Performance result 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
range.count:                             Best/Avg Time(ms)    Rate(M/s)   Per Row(ns)   Relative
------------------------------------------------------------------------------------------------
w/o this PR                                   1349 / 1356        796.2           1.3       1.0X
```

Performance result 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
range.count:                             Best/Avg Time(ms)    Rate(M/s)   Per Row(ns)   Relative
------------------------------------------------------------------------------------------------
with this PR                                   177 /  271       6065.3           0.2       1.0X
```

Here is a comparison between generated code w/o and with this PR. Only the method ```agg_doAggregateWithoutKey``` is changed.

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 boolean agg_initAgg;
/* 009 */   private boolean agg_bufIsNull;
/* 010 */   private long agg_bufValue;
/* 011 */   private org.apache.spark.sql.execution.metric.SQLMetric range_numOutputRows;
/* 012 */   private org.apache.spark.sql.execution.metric.SQLMetric range_numGeneratedRows;
/* 013 */   private boolean range_initRange;
/* 014 */   private long range_number;
/* 015 */   private TaskContext range_taskContext;
/* 016 */   private InputMetrics range_inputMetrics;
/* 017 */   private long range_batchEnd;
/* 018 */   private long range_numElementsTodo;
/* 019 */   private scala.collection.Iterator range_input;
/* 020 */   private UnsafeRow range_result;
/* 021 */   private org.apache.spark.sql.catalyst.expressions.codegen.BufferHolder range_holder;
/* 022 */   private org.apache.spark.sql.catalyst.expressions.codegen.UnsafeRowWriter range_rowWriter;
/* 023 */   private org.apache.spark.sql.execution.metric.SQLMetric agg_numOutputRows;
/* 024 */   private org.apache.spark.sql.execution.metric.SQLMetric agg_aggTime;
/* 025 */   private UnsafeRow agg_result;
/* 026 */   private org.apache.spark.sql.catalyst.expressions.codegen.BufferHolder agg_holder;
/* 027 */   private org.apache.spark.sql.catalyst.expressions.codegen.UnsafeRowWriter agg_rowWriter;
/* 028 */
/* 029 */   public GeneratedIterator(Object[] references) {
/* 030 */     this.references = references;
/* 031 */   }
/* 032 */
/* 033 */   public void init(int index, scala.collection.Iterator[] inputs) {
/* 034 */     partitionIndex = index;
/* 035 */     this.inputs = inputs;
/* 036 */     agg_initAgg = false;
/* 037 */
/* 038 */     this.range_numOutputRows = (org.apache.spark.sql.execution.metric.SQLMetric) references[0];
/* 039 */     this.range_numGeneratedRows = (org.apache.spark.sql.execution.metric.SQLMetric) references[1];
/* 040 */     range_initRange = false;
/* 041 */     range_number = 0L;
/* 042 */     range_taskContext = TaskContext.get();
/* 043 */     range_inputMetrics = range_taskContext.taskMetrics().inputMetrics();
/* 044 */     range_batchEnd = 0;
/* 045 */     range_numElementsTodo = 0L;
/* 046 */     range_input = inputs[0];
/* 047 */     range_result = new UnsafeRow(1);
/* 048 */     this.range_holder = new org.apache.spark.sql.catalyst.expressions.codegen.BufferHolder(range_result, 0);
/* 049 */     this.range_rowWriter = new org.apache.spark.sql.catalyst.expressions.codegen.UnsafeRowWriter(range_holder, 1);
/* 050 */     this.agg_numOutputRows = (org.apache.spark.sql.execution.metric.SQLMetric) references[2];
/* 051 */     this.agg_aggTime = (org.apache.spark.sql.execution.metric.SQLMetric) references[3];
/* 052 */     agg_result = new UnsafeRow(1);
/* 053 */     this.agg_holder = new org.apache.spark.sql.catalyst.expressions.codegen.BufferHolder(agg_result, 0);
/* 054 */     this.agg_rowWriter = new org.apache.spark.sql.catalyst.expressions.codegen.UnsafeRowWriter(agg_holder, 1);
/* 055 */
/* 056 */   }
/* 057 */
/* 058 */   private void agg_doAggregateWithoutKey() throws java.io.IOException {
/* 059 */     // initialize aggregation buffer
/* 060 */     agg_bufIsNull = false;
/* 061 */     agg_bufValue = 0L;
/* 062 */
/* 063 */     // initialize Range
/* 064 */     if (!range_initRange) {
/* 065 */       range_initRange = true;
/* 066 */       initRange(partitionIndex);
/* 067 */     }
/* 068 */
/* 069 */     while (true) {
/* 070 */       while (range_number != range_batchEnd) {
/* 071 */         long range_value = range_number;
/* 072 */         range_number += 1L;
/* 073 */
/* 074 */         // do aggregate
/* 075 */         // common sub-expressions
/* 076 */
/* 077 */         // evaluate aggregate function
/* 078 */         boolean agg_isNull1 = false;
/* 079 */
/* 080 */         long agg_value1 = -1L;
/* 081 */         agg_value1 = agg_bufValue + 1L;
/* 082 */         // update aggregation buffer
/* 083 */         agg_bufIsNull = false;
/* 084 */         agg_bufValue = agg_value1;
/* 085 */
/* 086 */         if (shouldStop()) return;
/* 087 */       }
/* 088 */
/* 089 */       if (range_taskContext.isInterrupted()) {
/* 090 */         throw new TaskKilledException();
/* 091 */       }
/* 092 */
/* 093 */       long range_nextBatchTodo;
/* 094 */       if (range_numElementsTodo > 1000L) {
/* 095 */         range_nextBatchTodo = 1000L;
/* 096 */         range_numElementsTodo -= 1000L;
/* 097 */       } else {
/* 098 */         range_nextBatchTodo = range_numElementsTodo;
/* 099 */         range_numElementsTodo = 0;
/* 100 */         if (range_nextBatchTodo == 0) break;
/* 101 */       }
/* 102 */       range_numOutputRows.add(range_nextBatchTodo);
/* 103 */       range_inputMetrics.incRecordsRead(range_nextBatchTodo);
/* 104 */
/* 105 */       range_batchEnd += range_nextBatchTodo * 1L;
/* 106 */     }
/* 107 */
/* 108 */   }
/* 109 */
/* 110 */   private void initRange(int idx) {
/* 111 */     java.math.BigInteger index = java.math.BigInteger.valueOf(idx);
/* 112 */     java.math.BigInteger numSlice = java.math.BigInteger.valueOf(2L);
/* 113 */     java.math.BigInteger numElement = java.math.BigInteger.valueOf(10000L);
/* 114 */     java.math.BigInteger step = java.math.BigInteger.valueOf(1L);
/* 115 */     java.math.BigInteger start = java.math.BigInteger.valueOf(0L);
/* 117 */
/* 118 */     java.math.BigInteger st = index.multiply(numElement).divide(numSlice).multiply(step).add(start);
/* 119 */     if (st.compareTo(java.math.BigInteger.valueOf(Long.MAX_VALUE)) > 0) {
/* 120 */       range_number = Long.MAX_VALUE;
/* 121 */     } else if (st.compareTo(java.math.BigInteger.valueOf(Long.MIN_VALUE)) < 0) {
/* 122 */       range_number = Long.MIN_VALUE;
/* 123 */     } else {
/* 124 */       range_number = st.longValue();
/* 125 */     }
/* 126 */     range_batchEnd = range_number;
/* 127 */
/* 128 */     java.math.BigInteger end = index.add(java.math.BigInteger.ONE).multiply(numElement).divide(numSlice)
/* 129 */     .multiply(step).add(start);
/* 130 */     if (end.compareTo(java.math.BigInteger.valueOf(Long.MAX_VALUE)) > 0) {
/* 131 */       partitionEnd = Long.MAX_VALUE;
/* 132 */     } else if (end.compareTo(java.math.BigInteger.valueOf(Long.MIN_VALUE)) < 0) {
/* 133 */       partitionEnd = Long.MIN_VALUE;
/* 134 */     } else {
/* 135 */       partitionEnd = end.longValue();
/* 136 */     }
/* 137 */
/* 138 */     java.math.BigInteger startToEnd = java.math.BigInteger.valueOf(partitionEnd).subtract(
/* 139 */       java.math.BigInteger.valueOf(range_number));
/* 140 */     range_numElementsTodo  = startToEnd.divide(step).longValue();
/* 141 */     if (range_numElementsTodo < 0) {
/* 142 */       range_numElementsTodo = 0;
/* 143 */     } else if (startToEnd.remainder(step).compareTo(java.math.BigInteger.valueOf(0L)) != 0) {
/* 144 */       range_numElementsTodo++;
/* 145 */     }
/* 146 */   }
/* 147 */
/* 148 */   protected void processNext() throws java.io.IOException {
/* 149 */     while (!agg_initAgg) {
/* 150 */       agg_initAgg = true;
/* 151 */       long agg_beforeAgg = System.nanoTime();
/* 152 */       agg_doAggregateWithoutKey();
/* 153 */       agg_aggTime.add((System.nanoTime() - agg_beforeAgg) / 1000000);
/* 154 */
/* 155 */       // output the result
/* 156 */
/* 157 */       agg_numOutputRows.add(1);
/* 158 */       agg_rowWriter.zeroOutNullBytes();
/* 159 */
/* 160 */       if (agg_bufIsNull) {
/* 161 */         agg_rowWriter.setNullAt(0);
/* 162 */       } else {
/* 163 */         agg_rowWriter.write(0, agg_bufValue);
/* 164 */       }
/* 165 */       append(agg_result);
/* 166 */     }
/* 167 */   }
/* 168 */ }
```

Generated code with 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 boolean agg_initAgg;
/* 009 */   private boolean agg_bufIsNull;
/* 010 */   private long agg_bufValue;
/* 011 */   private org.apache.spark.sql.execution.metric.SQLMetric range_numOutputRows;
/* 012 */   private org.apache.spark.sql.execution.metric.SQLMetric range_numGeneratedRows;
/* 013 */   private boolean range_initRange;
/* 014 */   private long range_number;
/* 015 */   private TaskContext range_taskContext;
/* 016 */   private InputMetrics range_inputMetrics;
/* 017 */   private long range_batchEnd;
/* 018 */   private long range_numElementsTodo;
/* 019 */   private scala.collection.Iterator range_input;
/* 020 */   private UnsafeRow range_result;
/* 021 */   private org.apache.spark.sql.catalyst.expressions.codegen.BufferHolder range_holder;
/* 022 */   private org.apache.spark.sql.catalyst.expressions.codegen.UnsafeRowWriter range_rowWriter;
/* 023 */   private org.apache.spark.sql.execution.metric.SQLMetric agg_numOutputRows;
/* 024 */   private org.apache.spark.sql.execution.metric.SQLMetric agg_aggTime;
/* 025 */   private UnsafeRow agg_result;
/* 026 */   private org.apache.spark.sql.catalyst.expressions.codegen.BufferHolder agg_holder;
/* 027 */   private org.apache.spark.sql.catalyst.expressions.codegen.UnsafeRowWriter agg_rowWriter;
/* 028 */
/* 029 */   public GeneratedIterator(Object[] references) {
/* 030 */     this.references = references;
/* 031 */   }
/* 032 */
/* 033 */   public void init(int index, scala.collection.Iterator[] inputs) {
/* 034 */     partitionIndex = index;
/* 035 */     this.inputs = inputs;
/* 036 */     agg_initAgg = false;
/* 037 */
/* 038 */     this.range_numOutputRows = (org.apache.spark.sql.execution.metric.SQLMetric) references[0];
/* 039 */     this.range_numGeneratedRows = (org.apache.spark.sql.execution.metric.SQLMetric) references[1];
/* 040 */     range_initRange = false;
/* 041 */     range_number = 0L;
/* 042 */     range_taskContext = TaskContext.get();
/* 043 */     range_inputMetrics = range_taskContext.taskMetrics().inputMetrics();
/* 044 */     range_batchEnd = 0;
/* 045 */     range_numElementsTodo = 0L;
/* 046 */     range_input = inputs[0];
/* 047 */     range_result = new UnsafeRow(1);
/* 048 */     this.range_holder = new org.apache.spark.sql.catalyst.expressions.codegen.BufferHolder(range_result, 0);
/* 049 */     this.range_rowWriter = new org.apache.spark.sql.catalyst.expressions.codegen.UnsafeRowWriter(range_holder, 1);
/* 050 */     this.agg_numOutputRows = (org.apache.spark.sql.execution.metric.SQLMetric) references[2];
/* 051 */     this.agg_aggTime = (org.apache.spark.sql.execution.metric.SQLMetric) references[3];
/* 052 */     agg_result = new UnsafeRow(1);
/* 053 */     this.agg_holder = new org.apache.spark.sql.catalyst.expressions.codegen.BufferHolder(agg_result, 0);
/* 054 */     this.agg_rowWriter = new org.apache.spark.sql.catalyst.expressions.codegen.UnsafeRowWriter(agg_holder, 1);
/* 055 */
/* 056 */   }
/* 057 */
/* 058 */   private void agg_doAggregateWithoutKey() throws java.io.IOException {
/* 059 */     // initialize aggregation buffer
/* 060 */     agg_bufIsNull = false;
/* 061 */     agg_bufValue = 0L;
/* 062 */
/* 063 */     // initialize Range
/* 064 */     if (!range_initRange) {
/* 065 */       range_initRange = true;
/* 066 */       initRange(partitionIndex);
/* 067 */     }
/* 068 */
/* 069 */     while (true) {
/* 070 */       long range_range = range_batchEnd - range_number;
/* 071 */       if (range_range != 0L) {
/* 072 */         int range_localEnd = (int)(range_range / 1L);
/* 073 */         for (int range_localIdx = 0; range_localIdx < range_localEnd; range_localIdx++) {
/* 074 */           long range_value = ((long)range_localIdx * 1L) + range_number;
/* 075 */
/* 076 */           // do aggregate
/* 077 */           // common sub-expressions
/* 078 */
/* 079 */           // evaluate aggregate function
/* 080 */           boolean agg_isNull1 = false;
/* 081 */
/* 082 */           long agg_value1 = -1L;
/* 083 */           agg_value1 = agg_bufValue + 1L;
/* 084 */           // update aggregation buffer
/* 085 */           agg_bufIsNull = false;
/* 086 */           agg_bufValue = agg_value1;
/* 087 */
/* 088 */           // shouldStop check is eliminated
/* 089 */         }
/* 090 */         range_number = range_batchEnd;
/* 091 */       }
/* 092 */
/* 093 */       if (range_taskContext.isInterrupted()) {
/* 094 */         throw new TaskKilledException();
/* 095 */       }
/* 096 */
/* 097 */       long range_nextBatchTodo;
/* 098 */       if (range_numElementsTodo > 1000L) {
/* 099 */         range_nextBatchTodo = 1000L;
/* 100 */         range_numElementsTodo -= 1000L;
/* 101 */       } else {
/* 102 */         range_nextBatchTodo = range_numElementsTodo;
/* 103 */         range_numElementsTodo = 0;
/* 104 */         if (range_nextBatchTodo == 0) break;
/* 105 */       }
/* 106 */       range_numOutputRows.add(range_nextBatchTodo);
/* 107 */       range_inputMetrics.incRecordsRead(range_nextBatchTodo);
/* 108 */
/* 109 */       range_batchEnd += range_nextBatchTodo * 1L;
/* 110 */     }
/* 111 */
/* 112 */   }
/* 113 */
/* 114 */   private void initRange(int idx) {
/* 115 */     java.math.BigInteger index = java.math.BigInteger.valueOf(idx);
/* 116 */     java.math.BigInteger numSlice = java.math.BigInteger.valueOf(2L);
/* 117 */     java.math.BigInteger numElement = java.math.BigInteger.valueOf(10000L);
/* 118 */     java.math.BigInteger step = java.math.BigInteger.valueOf(1L);
/* 119 */     java.math.BigInteger start = java.math.BigInteger.valueOf(0L);
/* 120 */     long partitionEnd;
/* 121 */
/* 122 */     java.math.BigInteger st = index.multiply(numElement).divide(numSlice).multiply(step).add(start);
/* 123 */     if (st.compareTo(java.math.BigInteger.valueOf(Long.MAX_VALUE)) > 0) {
/* 124 */       range_number = Long.MAX_VALUE;
/* 125 */     } else if (st.compareTo(java.math.BigInteger.valueOf(Long.MIN_VALUE)) < 0) {
/* 126 */       range_number = Long.MIN_VALUE;
/* 127 */     } else {
/* 128 */       range_number = st.longValue();
/* 129 */     }
/* 130 */     range_batchEnd = range_number;
/* 131 */
/* 132 */     java.math.BigInteger end = index.add(java.math.BigInteger.ONE).multiply(numElement).divide(numSlice)
/* 133 */     .multiply(step).add(start);
/* 134 */     if (end.compareTo(java.math.BigInteger.valueOf(Long.MAX_VALUE)) > 0) {
/* 135 */       partitionEnd = Long.MAX_VALUE;
/* 136 */     } else if (end.compareTo(java.math.BigInteger.valueOf(Long.MIN_VALUE)) < 0) {
/* 137 */       partitionEnd = Long.MIN_VALUE;
/* 138 */     } else {
/* 139 */       partitionEnd = end.longValue();
/* 140 */     }
/* 141 */
/* 142 */     java.math.BigInteger startToEnd = java.math.BigInteger.valueOf(partitionEnd).subtract(
/* 143 */       java.math.BigInteger.valueOf(range_number));
/* 144 */     range_numElementsTodo  = startToEnd.divide(step).longValue();
/* 145 */     if (range_numElementsTodo < 0) {
/* 146 */       range_numElementsTodo = 0;
/* 147 */     } else if (startToEnd.remainder(step).compareTo(java.math.BigInteger.valueOf(0L)) != 0) {
/* 148 */       range_numElementsTodo++;
/* 149 */     }
/* 150 */   }
/* 151 */
/* 152 */   protected void processNext() throws java.io.IOException {
/* 153 */     while (!agg_initAgg) {
/* 154 */       agg_initAgg = true;
/* 155 */       long agg_beforeAgg = System.nanoTime();
/* 156 */       agg_doAggregateWithoutKey();
/* 157 */       agg_aggTime.add((System.nanoTime() - agg_beforeAgg) / 1000000);
/* 158 */
/* 159 */       // output the result
/* 160 */
/* 161 */       agg_numOutputRows.add(1);
/* 162 */       agg_rowWriter.zeroOutNullBytes();
/* 163 */
/* 164 */       if (agg_bufIsNull) {
/* 165 */         agg_rowWriter.setNullAt(0);
/* 166 */       } else {
/* 167 */         agg_rowWriter.write(0, agg_bufValue);
/* 168 */       }
/* 169 */       append(agg_result);
/* 170 */     }
/* 171 */   }
/* 172 */ }
```

A part of suppressing `shouldStop()` was originally developed by inouehrs

## How was this patch tested?

Add new tests into `DataFrameRangeSuite`

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

Closes #17122 from kiszk/SPARK-19786.
2017-03-10 18:04:37 +01:00
.github [SPARK-18073][DOCS][WIP] Migrate wiki to spark.apache.org web site 2016-11-23 11:25:47 +00:00
assembly [SPARK-19550][BUILD][CORE][WIP] Remove Java 7 support 2017-02-16 12:32:45 +00:00
bin [SPARK-1267][SPARK-18129] Allow PySpark to be pip installed 2016-11-16 14:22:15 -08:00
build [SPARK-19550][BUILD][CORE][WIP] Remove Java 7 support 2017-02-16 12:32:45 +00:00
common [SPARK-19843][SQL][FOLLOWUP] Classdoc for IntWrapper and LongWrapper 2017-03-08 09:38:05 -08:00
conf [SPARK-11653][DEPLOY] Allow spark-daemon.sh to run in the foreground 2016-10-20 09:49:58 +01:00
core [SPARK-19793] Use clock.getTimeMillis when mark task as finished in TaskSetManager. 2017-03-09 10:56:19 -08:00
data [SPARK-16421][EXAMPLES][ML] Improve ML Example Outputs 2016-08-05 20:57:46 +01:00
dev [SPARK-19550] Follow-up: fixed a typo that fails the dev/make-distribution.sh script. 2017-02-18 14:08:59 +00:00
docs [SPARK-19715][STRUCTURED STREAMING] Option to Strip Paths in FileSource 2017-03-09 11:02:44 -08:00
examples [SPARK-19345][ML][DOC] Add doc for "coldStartStrategy" usage in ALS 2017-03-02 15:51:16 +02:00
external [SPARK-19886] Fix reportDataLoss if statement in SS KafkaSource 2017-03-09 17:42:10 -08:00
graphx [SPARK-14804][SPARK][GRAPHX] Fix checkpointing of VertexRDD/EdgeRDD 2017-01-25 17:17:34 -08:00
launcher [SPARK-19534][TESTS] Convert Java tests to use lambdas, Java 8 features 2017-02-19 09:42:50 -08:00
licenses [MINOR][BUILD] Add modernizr MIT license; specify "2014 and onwards" in license copyright 2016-06-04 21:41:27 +01:00
mllib [SPARK-16440][MLLIB] Ensure broadcasted variables are destroyed even in case of exception 2017-03-08 11:44:25 +00:00
mllib-local [SPARK-19402][DOCS] Support LaTex inline formula correctly and fix warnings in Scala/Java APIs generation 2017-02-01 13:26:16 +00:00
project [SPARK-19874][BUILD] Hide API docs for org.apache.spark.sql.internal 2017-03-08 23:15:52 -08:00
python [SPARK-12334][SQL][PYSPARK] Support read from multiple input paths for orc file in DataFrameReader.orc 2017-03-09 11:44:34 -08:00
R [SPARK-19601][SQL] Fix CollapseRepartition rule to preserve shuffle-enabled Repartition 2017-03-08 09:36:01 -08:00
repl [SPARK-18055][SQL] Use correct mirror in ExpresionEncoder 2017-03-08 01:32:42 -08:00
resource-managers [SPARK-19857][YARN] Correctly calculate next credential update time. 2017-03-07 16:21:18 -08:00
sbin [SPARK-19083] sbin/start-history-server.sh script use of $@ without quotes 2017-01-06 09:57:49 -08:00
sql [SPARK-19786][SQL] Facilitate loop optimizations in a JIT compiler regarding range() 2017-03-10 18:04:37 +01:00
streaming [SPARK-19822][TEST] CheckpointSuite.testCheckpointedOperation: should not filter checkpointFilesOfLatestTime with the PATH string. 2017-03-05 18:17:30 -08:00
tools [SPARK-18695] Bump master branch version to 2.2.0-SNAPSHOT 2016-12-02 21:09:37 -08:00
.gitattributes [SPARK-3870] EOL character enforcement 2014-10-31 12:39:52 -07:00
.gitignore [SPARK-19562][BUILD] Added exclude for dev/pr-deps to gitignore 2017-02-13 11:22:31 +00:00
.travis.yml [SPARK-19801][BUILD] Remove JDK7 from Travis CI 2017-03-03 12:00:54 +01:00
appveyor.yml [SPARK-19660][CORE][SQL] Replace the configuration property names that are deprecated in the version of Hadoop 2.6 2017-02-28 10:13:42 +00:00
CONTRIBUTING.md [SPARK-18073][DOCS][WIP] Migrate wiki to spark.apache.org web site 2016-11-23 11:25:47 +00:00
LICENSE [SPARK-17960][PYSPARK][UPGRADE TO PY4J 0.10.4] 2016-10-21 09:48:24 +01:00
NOTICE [SPARK-18262][BUILD][SQL] JSON.org license is now CatX 2016-11-10 10:20:03 -08:00
pom.xml [SPARK-19405][STREAMING] Support for cross-account Kinesis reads via STS 2017-02-22 11:32:36 -05:00
README.md [MINOR][DOCS] Remove Apache Spark Wiki address 2016-12-10 16:40:10 +00:00
scalastyle-config.xml [SPARK-13747][CORE] Fix potential ThreadLocal leaks in RPC when using ForkJoinPool 2016-12-13 09:53:22 -08:00

README.md

Apache Spark

Spark is a fast and general cluster computing system for Big Data. It provides high-level APIs in Scala, Java, Python, and R, and an optimized engine that supports general computation graphs for data analysis. It also supports a rich set of higher-level tools including Spark SQL for SQL and DataFrames, MLlib for machine learning, GraphX for graph processing, and Spark Streaming for stream processing.

http://spark.apache.org/

Online Documentation

You can find the latest Spark documentation, including a programming guide, on the project web page. This README file only contains basic setup instructions.

Building Spark

Spark is built using Apache Maven. To build Spark and its example programs, run:

build/mvn -DskipTests clean package

(You do not need to do this if you downloaded a pre-built package.)

You can build Spark using more than one thread by using the -T option with Maven, see "Parallel builds in Maven 3". More detailed documentation is available from the project site, at "Building Spark".

For general development tips, including info on developing Spark using an IDE, see "Useful Developer Tools".

Interactive Scala Shell

The easiest way to start using Spark is through the Scala shell:

./bin/spark-shell

Try the following command, which should return 1000:

scala> sc.parallelize(1 to 1000).count()

Interactive Python Shell

Alternatively, if you prefer Python, you can use the Python shell:

./bin/pyspark

And run the following command, which should also return 1000:

>>> sc.parallelize(range(1000)).count()

Example Programs

Spark also comes with several sample programs in the examples directory. To run one of them, use ./bin/run-example <class> [params]. For example:

./bin/run-example SparkPi

will run the Pi example locally.

You can set the MASTER environment variable when running examples to submit examples to a cluster. This can be a mesos:// or spark:// URL, "yarn" to run on YARN, and "local" to run locally with one thread, or "local[N]" to run locally with N threads. You can also use an abbreviated class name if the class is in the examples package. For instance:

MASTER=spark://host:7077 ./bin/run-example SparkPi

Many of the example programs print usage help if no params are given.

Running Tests

Testing first requires building Spark. Once Spark is built, tests can be run using:

./dev/run-tests

Please see the guidance on how to run tests for a module, or individual tests.

A Note About Hadoop Versions

Spark uses the Hadoop core library to talk to HDFS and other Hadoop-supported storage systems. Because the protocols have changed in different versions of Hadoop, you must build Spark against the same version that your cluster runs.

Please refer to the build documentation at "Specifying the Hadoop Version" for detailed guidance on building for a particular distribution of Hadoop, including building for particular Hive and Hive Thriftserver distributions.

Configuration

Please refer to the Configuration Guide in the online documentation for an overview on how to configure Spark.

## Contributing

Please review the Contribution to Spark guide for information on how to get started contributing to the project.