[GitHub] carbondata pull request #1240: [CARBONDATA-1365] add RLE codec implemen

[qiuchenjian-2]

GitHub user jackylk opened a pull request:

    https://github.com/apache/carbondata/pull/1240

    [CARBONDATA-1365] add RLE codec implemen

    Be sure to do all of the following to help us incorporate your contribution
    quickly and easily:
   
     - [ ] Make sure the PR title is formatted like:
       `[CARBONDATA-<Jira issue #>] Description of pull request`
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           [Individual Contributor License Agreement](https://www.apache.org/licenses/icla.txt).
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            Please provide details on
            - Whether new unit test cases have been added or why no new tests are required?
            - What manual testing you have done?
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    ---


You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/jackylk/incubator-carbondata int_rle

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/carbondata/pull/1240.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

    This closes #1240
   
----
commit 924c43bb8856560350722e47aa60a3a64634fecf
Author: Jacky Li <[hidden email]>
Date:   2017-08-06T16:02:13Z

    add RLE codec

----


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[qiuchenjian-2]

Github user CarbonDataQA commented on the issue:

    https://github.com/apache/carbondata/pull/1240
 
    Build Failed with Spark 1.6, Please check CI http://144.76.159.231:8080/job/ApacheCarbonPRBuilder/799/



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[qiuchenjian-2]

Github user CarbonDataQA commented on the issue:

    https://github.com/apache/carbondata/pull/1240
 
    Build Failed  with Spark 2.1.0, Please check CI http://136.243.101.176:8080/job/ApacheCarbonPRBuilder/3397/



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[qiuchenjian-2]

Github user CarbonDataQA commented on the issue:

    https://github.com/apache/carbondata/pull/1240
 
    SDV Build Success with Spark 2.1, Please check CI http://144.76.159.231:8080/job/ApacheSDVTests/126/



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[qiuchenjian-2]

Github user CarbonDataQA commented on the issue:

    https://github.com/apache/carbondata/pull/1240
 
    Build Success with Spark 2.1.0, Please check CI http://136.243.101.176:8080/job/ApacheCarbonPRBuilder/3398/



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[qiuchenjian-2]

Github user CarbonDataQA commented on the issue:

    https://github.com/apache/carbondata/pull/1240
 
    SDV Build Failed with Spark 2.1, Please check CI http://144.76.159.231:8080/job/ApacheSDVTests/127/



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[qiuchenjian-2]

Github user CarbonDataQA commented on the issue:

    https://github.com/apache/carbondata/pull/1240
 
    Build Success with Spark 1.6, Please check CI http://144.76.159.231:8080/job/ApacheCarbonPRBuilder/800/



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[qiuchenjian-2]

Github user ravipesala commented on the issue:

    https://github.com/apache/carbondata/pull/1240
 
    Build Success with Spark 2.1.0, Please check CI http://136.243.101.176:8080/job/ApacheCarbonPRBuilder/3401/



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[qiuchenjian-2]

Github user ravipesala commented on the issue:

    https://github.com/apache/carbondata/pull/1240
 
    Build Success with Spark 1.6, Please check CI http://144.76.159.231:8080/job/ApacheCarbonPRBuilder/803/



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[qiuchenjian-2]

Github user ravipesala commented on the issue:

    https://github.com/apache/carbondata/pull/1240
 
    SDV Build Success with Spark 2.1, Please check CI http://144.76.159.231:8080/job/ApacheSDVTests/130/



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[qiuchenjian-2]

Github user ravipesala commented on a diff in the pull request:

    https://github.com/apache/carbondata/pull/1240#discussion_r132898313
 
    --- Diff: core/src/main/java/org/apache/carbondata/core/datastore/page/encoding/RLECodec.java ---
    @@ -0,0 +1,417 @@
    +/*
    + * 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.carbondata.core.datastore.page.encoding;
    +
    +import java.io.ByteArrayInputStream;
    +import java.io.ByteArrayOutputStream;
    +import java.io.DataInputStream;
    +import java.io.DataOutputStream;
    +import java.io.IOException;
    +import java.util.ArrayList;
    +import java.util.List;
    +
    +import org.apache.carbondata.core.datastore.page.ColumnPage;
    +import org.apache.carbondata.core.datastore.page.ComplexColumnPage;
    +import org.apache.carbondata.core.datastore.page.statistics.SimpleStatsResult;
    +import org.apache.carbondata.core.memory.MemoryException;
    +import org.apache.carbondata.core.metadata.CodecMetaFactory;
    +import org.apache.carbondata.core.metadata.datatype.DataType;
    +
    +/**
    + * RLE encoding implementation for integral column page.
    + * This encoding keeps track of repeated-run and non-repeated-run, and make use
    + * of the highest bit of the length field to indicate the type of run.
    + * The length field is encoded as 32bits value.
    + *
    + * For example: input data {5, 5, 1, 2, 3, 3, 3, 3, 3} will be encoded to
    + * {0x00, 0x00, 0x00, 0x02, 0x05,             (repeated-run, 2 values of 5)
    + *  0x80, 0x00, 0x00, 0x03, 0x01, 0x02, 0x03, (non-repeated-run, 3 values: 1, 2, 3)
    + *  0x00, 0x00, 0x00, 0x04, 0x03}             (repeated-run, 4 values of 3)
    + */
    +public class RLECodec implements ColumnPageCodec {
    +
    +  enum RUN_STATE { INIT, START, REPEATED_RUN, NONREPEATED_RUN }
    +
    +  private DataType dataType;
    +  private int pageSize;
    +
    +  /**
    +   * New RLECodec
    +   * @param dataType data type of the raw column page before encode
    +   * @param pageSize page size of the raw column page before encode
    +   */
    +  RLECodec(DataType dataType, int pageSize) {
    +    this.dataType = dataType;
    +    this.pageSize = pageSize;
    +  }
    +
    +  @Override
    +  public String getName() {
    +    return "RLECodec";
    +  }
    +
    +  @Override
    +  public EncodedColumnPage encode(ColumnPage input) throws MemoryException, IOException {
    +    Encoder encoder = new Encoder();
    +    return encoder.encode(input);
    +  }
    +
    +  @Override
    +  public EncodedColumnPage[] encodeComplexColumn(ComplexColumnPage input) {
    +    throw new UnsupportedOperationException("complex column does not support RLE encoding");
    +  }
    +
    +  @Override
    +  public ColumnPage decode(byte[] input, int offset, int length) throws MemoryException,
    +      IOException {
    +    Decoder decoder = new Decoder(dataType, pageSize);
    +    return decoder.decode(input, offset, length);
    +  }
    +
    +  // This codec supports integral type only
    +  private void validateDataType(DataType dataType) {
    +    switch (dataType) {
    +      case BYTE:
    +      case SHORT:
    +      case INT:
    +      case LONG:
    +        break;
    +      default:
    +        throw new UnsupportedOperationException(dataType + " is not supported for RLE");
    +    }
    +  }
    +
    +  private class Encoder {
    +    // While encoding RLE, this class internally work as a state machine
    +    // INIT state is the initial state before any value comes
    +    // START state is the start for each run
    +    // REPEATED_RUN state means it is collecting repeated values (`lastValue`)
    +    // NONREPEATED_RUN state means it is collecting non-repeated values (`nonRepeatValues`)
    +    private RUN_STATE runState;
    +
    +    // count for each run, either REPEATED_RUN or NONREPEATED_RUN
    +    private int valueCount;
    +
    +    // collected value for REPEATED_RUN
    +    private Object lastValue;
    +
    +    // collected value for NONREPEATED_RUN
    +    private List<Object> nonRepeatValues;
    +
    +    // data type of input page
    +    private DataType dataType;
    +
    +    // output stream for encoded data
    +    private ByteArrayOutputStream bao;
    +    private DataOutputStream stream;
    +
    +    private Encoder() {
    +      this.runState = RUN_STATE.INIT;
    +      this.valueCount = 0;
    +      this.nonRepeatValues = new ArrayList<>();
    +      this.bao = new ByteArrayOutputStream();
    +      this.stream = new DataOutputStream(bao);
    +    }
    +
    +    private EncodedColumnPage encode(ColumnPage input) throws MemoryException, IOException {
    +      validateDataType(input.getDataType());
    +      this.dataType = input.getDataType();
    +      switch (dataType) {
    +        case BYTE:
    +          byte[] bytePage = input.getBytePage();
    +          for (int i = 0; i < bytePage.length; i++) {
    +            putValue(bytePage[i]);
    +          }
    +          break;
    +        case SHORT:
    +          short[] shortPage = input.getShortPage();
    +          for (int i = 0; i < shortPage.length; i++) {
    +            putValue(shortPage[i]);
    +          }
    +          break;
    +        case INT:
    +          int[] intPage = input.getIntPage();
    +          for (int i = 0; i < intPage.length; i++) {
    +            putValue(intPage[i]);
    +          }
    +          break;
    +        case LONG:
    +          long[] longPage = input.getLongPage();
    +          for (int i = 0; i < longPage.length; i++) {
    +            putValue(longPage[i]);
    +          }
    +          break;
    +        default:
    +          throw new UnsupportedOperationException(input.getDataType() +
    +              " does not support RLE encoding");
    +      }
    +      byte[] encoded = collectResult();
    +      SimpleStatsResult stats = (SimpleStatsResult) input.getStatistics();
    +      return new EncodedMeasurePage(
    +          input.getPageSize(),
    +          encoded,
    +          CodecMetaFactory.createMeta(stats, input.getDataType()),
    +          stats.getNullBits());
    +    }
    +
    +    private void putValue(Object value) throws IOException {
    +      if (runState == RUN_STATE.INIT) {
    +        startNewRun(value);
    +      } else {
    +        if (lastValue.equals(value)) {
    +          putRepeatValue(value);
    +        } else {
    +          putNonRepeatValue(value);
    +        }
    +      }
    +    }
    +
    +    // when last row is reached, write out all collected data
    +    private byte[] collectResult() throws IOException {
    +      switch (runState) {
    +        case REPEATED_RUN:
    +          writeRunLength(valueCount);
    +          writeRunValue(lastValue);
    +          break;
    +        case NONREPEATED_RUN:
    +          writeRunLength(valueCount | 0x80000000);
    --- End diff --
   
    I think writing short is enough as of now. Because we are restricting page size in short only


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[qiuchenjian-2]

Github user ravipesala commented on a diff in the pull request:

    https://github.com/apache/carbondata/pull/1240#discussion_r132899540
 
    --- Diff: core/src/main/java/org/apache/carbondata/core/datastore/page/encoding/RLECodec.java ---
    @@ -0,0 +1,417 @@
    +/*
    + * 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.carbondata.core.datastore.page.encoding;
    +
    +import java.io.ByteArrayInputStream;
    +import java.io.ByteArrayOutputStream;
    +import java.io.DataInputStream;
    +import java.io.DataOutputStream;
    +import java.io.IOException;
    +import java.util.ArrayList;
    +import java.util.List;
    +
    +import org.apache.carbondata.core.datastore.page.ColumnPage;
    +import org.apache.carbondata.core.datastore.page.ComplexColumnPage;
    +import org.apache.carbondata.core.datastore.page.statistics.SimpleStatsResult;
    +import org.apache.carbondata.core.memory.MemoryException;
    +import org.apache.carbondata.core.metadata.CodecMetaFactory;
    +import org.apache.carbondata.core.metadata.datatype.DataType;
    +
    +/**
    + * RLE encoding implementation for integral column page.
    + * This encoding keeps track of repeated-run and non-repeated-run, and make use
    + * of the highest bit of the length field to indicate the type of run.
    + * The length field is encoded as 32bits value.
    + *
    + * For example: input data {5, 5, 1, 2, 3, 3, 3, 3, 3} will be encoded to
    + * {0x00, 0x00, 0x00, 0x02, 0x05,             (repeated-run, 2 values of 5)
    + *  0x80, 0x00, 0x00, 0x03, 0x01, 0x02, 0x03, (non-repeated-run, 3 values: 1, 2, 3)
    + *  0x00, 0x00, 0x00, 0x04, 0x03}             (repeated-run, 4 values of 3)
    + */
    +public class RLECodec implements ColumnPageCodec {
    +
    +  enum RUN_STATE { INIT, START, REPEATED_RUN, NONREPEATED_RUN }
    +
    +  private DataType dataType;
    +  private int pageSize;
    +
    +  /**
    +   * New RLECodec
    +   * @param dataType data type of the raw column page before encode
    +   * @param pageSize page size of the raw column page before encode
    +   */
    +  RLECodec(DataType dataType, int pageSize) {
    +    this.dataType = dataType;
    +    this.pageSize = pageSize;
    +  }
    +
    +  @Override
    +  public String getName() {
    +    return "RLECodec";
    +  }
    +
    +  @Override
    +  public EncodedColumnPage encode(ColumnPage input) throws MemoryException, IOException {
    +    Encoder encoder = new Encoder();
    +    return encoder.encode(input);
    +  }
    +
    +  @Override
    +  public EncodedColumnPage[] encodeComplexColumn(ComplexColumnPage input) {
    +    throw new UnsupportedOperationException("complex column does not support RLE encoding");
    +  }
    +
    +  @Override
    +  public ColumnPage decode(byte[] input, int offset, int length) throws MemoryException,
    +      IOException {
    +    Decoder decoder = new Decoder(dataType, pageSize);
    +    return decoder.decode(input, offset, length);
    +  }
    +
    +  // This codec supports integral type only
    +  private void validateDataType(DataType dataType) {
    +    switch (dataType) {
    +      case BYTE:
    +      case SHORT:
    +      case INT:
    +      case LONG:
    --- End diff --
   
    ideally double and decimal also can be supported right with this encoding, why those are not supported


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[qiuchenjian-2]

Github user jackylk commented on a diff in the pull request:

    https://github.com/apache/carbondata/pull/1240#discussion_r133606239
 
    --- Diff: core/src/main/java/org/apache/carbondata/core/datastore/page/encoding/RLECodec.java ---
    @@ -0,0 +1,417 @@
    +/*
    + * 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.carbondata.core.datastore.page.encoding;
    +
    +import java.io.ByteArrayInputStream;
    +import java.io.ByteArrayOutputStream;
    +import java.io.DataInputStream;
    +import java.io.DataOutputStream;
    +import java.io.IOException;
    +import java.util.ArrayList;
    +import java.util.List;
    +
    +import org.apache.carbondata.core.datastore.page.ColumnPage;
    +import org.apache.carbondata.core.datastore.page.ComplexColumnPage;
    +import org.apache.carbondata.core.datastore.page.statistics.SimpleStatsResult;
    +import org.apache.carbondata.core.memory.MemoryException;
    +import org.apache.carbondata.core.metadata.CodecMetaFactory;
    +import org.apache.carbondata.core.metadata.datatype.DataType;
    +
    +/**
    + * RLE encoding implementation for integral column page.
    + * This encoding keeps track of repeated-run and non-repeated-run, and make use
    + * of the highest bit of the length field to indicate the type of run.
    + * The length field is encoded as 32bits value.
    + *
    + * For example: input data {5, 5, 1, 2, 3, 3, 3, 3, 3} will be encoded to
    + * {0x00, 0x00, 0x00, 0x02, 0x05,             (repeated-run, 2 values of 5)
    + *  0x80, 0x00, 0x00, 0x03, 0x01, 0x02, 0x03, (non-repeated-run, 3 values: 1, 2, 3)
    + *  0x00, 0x00, 0x00, 0x04, 0x03}             (repeated-run, 4 values of 3)
    + */
    +public class RLECodec implements ColumnPageCodec {
    +
    +  enum RUN_STATE { INIT, START, REPEATED_RUN, NONREPEATED_RUN }
    +
    +  private DataType dataType;
    +  private int pageSize;
    +
    +  /**
    +   * New RLECodec
    +   * @param dataType data type of the raw column page before encode
    +   * @param pageSize page size of the raw column page before encode
    +   */
    +  RLECodec(DataType dataType, int pageSize) {
    +    this.dataType = dataType;
    +    this.pageSize = pageSize;
    +  }
    +
    +  @Override
    +  public String getName() {
    +    return "RLECodec";
    +  }
    +
    +  @Override
    +  public EncodedColumnPage encode(ColumnPage input) throws MemoryException, IOException {
    +    Encoder encoder = new Encoder();
    +    return encoder.encode(input);
    +  }
    +
    +  @Override
    +  public EncodedColumnPage[] encodeComplexColumn(ComplexColumnPage input) {
    +    throw new UnsupportedOperationException("complex column does not support RLE encoding");
    +  }
    +
    +  @Override
    +  public ColumnPage decode(byte[] input, int offset, int length) throws MemoryException,
    +      IOException {
    +    Decoder decoder = new Decoder(dataType, pageSize);
    +    return decoder.decode(input, offset, length);
    +  }
    +
    +  // This codec supports integral type only
    +  private void validateDataType(DataType dataType) {
    +    switch (dataType) {
    +      case BYTE:
    +      case SHORT:
    +      case INT:
    +      case LONG:
    +        break;
    +      default:
    +        throw new UnsupportedOperationException(dataType + " is not supported for RLE");
    +    }
    +  }
    +
    +  private class Encoder {
    +    // While encoding RLE, this class internally work as a state machine
    +    // INIT state is the initial state before any value comes
    +    // START state is the start for each run
    +    // REPEATED_RUN state means it is collecting repeated values (`lastValue`)
    +    // NONREPEATED_RUN state means it is collecting non-repeated values (`nonRepeatValues`)
    +    private RUN_STATE runState;
    +
    +    // count for each run, either REPEATED_RUN or NONREPEATED_RUN
    +    private int valueCount;
    +
    +    // collected value for REPEATED_RUN
    +    private Object lastValue;
    +
    +    // collected value for NONREPEATED_RUN
    +    private List<Object> nonRepeatValues;
    +
    +    // data type of input page
    +    private DataType dataType;
    +
    +    // output stream for encoded data
    +    private ByteArrayOutputStream bao;
    +    private DataOutputStream stream;
    +
    +    private Encoder() {
    +      this.runState = RUN_STATE.INIT;
    +      this.valueCount = 0;
    +      this.nonRepeatValues = new ArrayList<>();
    +      this.bao = new ByteArrayOutputStream();
    +      this.stream = new DataOutputStream(bao);
    +    }
    +
    +    private EncodedColumnPage encode(ColumnPage input) throws MemoryException, IOException {
    +      validateDataType(input.getDataType());
    +      this.dataType = input.getDataType();
    +      switch (dataType) {
    +        case BYTE:
    +          byte[] bytePage = input.getBytePage();
    +          for (int i = 0; i < bytePage.length; i++) {
    +            putValue(bytePage[i]);
    +          }
    +          break;
    +        case SHORT:
    +          short[] shortPage = input.getShortPage();
    +          for (int i = 0; i < shortPage.length; i++) {
    +            putValue(shortPage[i]);
    +          }
    +          break;
    +        case INT:
    +          int[] intPage = input.getIntPage();
    +          for (int i = 0; i < intPage.length; i++) {
    +            putValue(intPage[i]);
    +          }
    +          break;
    +        case LONG:
    +          long[] longPage = input.getLongPage();
    +          for (int i = 0; i < longPage.length; i++) {
    +            putValue(longPage[i]);
    +          }
    +          break;
    +        default:
    +          throw new UnsupportedOperationException(input.getDataType() +
    +              " does not support RLE encoding");
    +      }
    +      byte[] encoded = collectResult();
    +      SimpleStatsResult stats = (SimpleStatsResult) input.getStatistics();
    +      return new EncodedMeasurePage(
    +          input.getPageSize(),
    +          encoded,
    +          CodecMetaFactory.createMeta(stats, input.getDataType()),
    +          stats.getNullBits());
    +    }
    +
    +    private void putValue(Object value) throws IOException {
    +      if (runState == RUN_STATE.INIT) {
    +        startNewRun(value);
    +      } else {
    +        if (lastValue.equals(value)) {
    +          putRepeatValue(value);
    +        } else {
    +          putNonRepeatValue(value);
    +        }
    +      }
    +    }
    +
    +    // when last row is reached, write out all collected data
    +    private byte[] collectResult() throws IOException {
    +      switch (runState) {
    +        case REPEATED_RUN:
    +          writeRunLength(valueCount);
    +          writeRunValue(lastValue);
    +          break;
    +        case NONREPEATED_RUN:
    +          writeRunLength(valueCount | 0x80000000);
    --- End diff --
   
    Ok, I will change to short now. Later we need to change to support page more than 32000 rows, like array<int>.


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[qiuchenjian-2]

Github user jackylk commented on a diff in the pull request:

    https://github.com/apache/carbondata/pull/1240#discussion_r133606402
 
    --- Diff: core/src/main/java/org/apache/carbondata/core/datastore/page/encoding/RLECodec.java ---
    @@ -0,0 +1,417 @@
    +/*
    + * 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.carbondata.core.datastore.page.encoding;
    +
    +import java.io.ByteArrayInputStream;
    +import java.io.ByteArrayOutputStream;
    +import java.io.DataInputStream;
    +import java.io.DataOutputStream;
    +import java.io.IOException;
    +import java.util.ArrayList;
    +import java.util.List;
    +
    +import org.apache.carbondata.core.datastore.page.ColumnPage;
    +import org.apache.carbondata.core.datastore.page.ComplexColumnPage;
    +import org.apache.carbondata.core.datastore.page.statistics.SimpleStatsResult;
    +import org.apache.carbondata.core.memory.MemoryException;
    +import org.apache.carbondata.core.metadata.CodecMetaFactory;
    +import org.apache.carbondata.core.metadata.datatype.DataType;
    +
    +/**
    + * RLE encoding implementation for integral column page.
    + * This encoding keeps track of repeated-run and non-repeated-run, and make use
    + * of the highest bit of the length field to indicate the type of run.
    + * The length field is encoded as 32bits value.
    + *
    + * For example: input data {5, 5, 1, 2, 3, 3, 3, 3, 3} will be encoded to
    + * {0x00, 0x00, 0x00, 0x02, 0x05,             (repeated-run, 2 values of 5)
    + *  0x80, 0x00, 0x00, 0x03, 0x01, 0x02, 0x03, (non-repeated-run, 3 values: 1, 2, 3)
    + *  0x00, 0x00, 0x00, 0x04, 0x03}             (repeated-run, 4 values of 3)
    + */
    +public class RLECodec implements ColumnPageCodec {
    +
    +  enum RUN_STATE { INIT, START, REPEATED_RUN, NONREPEATED_RUN }
    +
    +  private DataType dataType;
    +  private int pageSize;
    +
    +  /**
    +   * New RLECodec
    +   * @param dataType data type of the raw column page before encode
    +   * @param pageSize page size of the raw column page before encode
    +   */
    +  RLECodec(DataType dataType, int pageSize) {
    +    this.dataType = dataType;
    +    this.pageSize = pageSize;
    +  }
    +
    +  @Override
    +  public String getName() {
    +    return "RLECodec";
    +  }
    +
    +  @Override
    +  public EncodedColumnPage encode(ColumnPage input) throws MemoryException, IOException {
    +    Encoder encoder = new Encoder();
    +    return encoder.encode(input);
    +  }
    +
    +  @Override
    +  public EncodedColumnPage[] encodeComplexColumn(ComplexColumnPage input) {
    +    throw new UnsupportedOperationException("complex column does not support RLE encoding");
    +  }
    +
    +  @Override
    +  public ColumnPage decode(byte[] input, int offset, int length) throws MemoryException,
    +      IOException {
    +    Decoder decoder = new Decoder(dataType, pageSize);
    +    return decoder.decode(input, offset, length);
    +  }
    +
    +  // This codec supports integral type only
    +  private void validateDataType(DataType dataType) {
    +    switch (dataType) {
    +      case BYTE:
    +      case SHORT:
    +      case INT:
    +      case LONG:
    --- End diff --
   
    I think we better make it for integral value only. For double and decimal, their distinct value are more in most of the case.
    Anyway, we can add it in future if it is required in future PR.


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[qiuchenjian-2]

Github user ravipesala commented on the issue:

    https://github.com/apache/carbondata/pull/1240
 
    SDV Build Success with Spark 2.1, Please check CI http://144.76.159.231:8080/job/ApacheSDVTests/204/



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[qiuchenjian-2]

Github user ravipesala commented on the issue:

    https://github.com/apache/carbondata/pull/1240
 
    LGTM


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[qiuchenjian-2]

Github user asfgit closed the pull request at:

    https://github.com/apache/carbondata/pull/1240


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