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https://issues.apache.org/jira/browse/PARQUET-2190?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17696658#comment-17696658
 ] 

ASF GitHub Bot commented on PARQUET-2190:
-----------------------------------------

jiangjiguang closed pull request #1006: PARQUET-2190 byte array has better 
performance than ByteBuffer
URL: https://github.com/apache/parquet-mr/pull/1006




> byte array has better performance than  ByteBuffer
> --------------------------------------------------
>
>                 Key: PARQUET-2190
>                 URL: https://issues.apache.org/jira/browse/PARQUET-2190
>             Project: Parquet
>          Issue Type: Improvement
>            Reporter: jiangjiguang0719
>            Priority: Major
>
> The BytePacker should add the following method
> public abstract void unpack8Values(final byte[] input, final int inPos, final 
> int[] output, final int outPos);
> to replace method  
> @Deprecated
> public void unpack8Values(final byte[] input, final int inPos, final int[] 
> output, final int outPos) {
>     unpack8Values(ByteBuffer.wrap(input), inPos, output, outPos);
> }
>  
> Tested by me byte array has better performance than  ByteBuffer,
> The test result is:
> [Unpack8ValuesByteArray spent time] 80 ms
> [Unpack8ValuesByteBuffer spent time] 133 ms
>  
> The test code is:
> package org.apache.parquet.column.values.bitpacking;
> import java.nio.ByteBuffer;
> public class ByteBufferTest {
>   private static final BytePacker bytePacker = 
> Packer.LITTLE_ENDIAN.newBytePacker(7);
>   private static final int COUNT = 100000;
>   public static void main(String[] args) {
>     byte  [] in  = new byte[1008];
>     int [] out = new int[1152];
>     int [] out1 = new int[1152];
>     int [] out2 = new int[1152];
>     int res = 0;
>     for(int i = 0; i < in.length; i++) {
>       in[i] = (byte) i;
>     }
>     for(int i = 0; i < COUNT; i++) {
>       res += unpack8ValuesBytes(in, out, i % out.length);
>     }
>     res = 0;
>     long t1 = System.currentTimeMillis();
>     for(int i = 0; i < COUNT; i++) {
>       res += unpack8ValuesBytes(in, out1, i % out.length);
>     }
>     long t2 = System.currentTimeMillis();
>     System.out.println("[Unpack8ValuesByteArray spent time] " + (t2-t1) + " 
> ms");
>     ByteBuffer byteBuffer = ByteBuffer.wrap(in);
>     for(int i = 0; i < COUNT; i++) {
>       res += unpack8ValuesByteBuffer(byteBuffer, out, i % out.length);
>     }
>     res = 0;
>     long t3 = System.currentTimeMillis();
>     for(int i = 0; i < COUNT; i++) {
>       res += unpack8ValuesByteBuffer(byteBuffer, out2, i % out.length);
>     }
>     long t4 = System.currentTimeMillis();
>     System.out.println("[Unpack8ValuesByteBuffer spent time] " + (t4-t3) + " 
> ms");
>     for (int i=0; i<out1.length; i++) {
>       if(out1[i] != out2[i]) {
>         System.out.println("diff: " + out1[i] + " " + out2[i]);
>       }
>     }
>   }
>   private static int unpack8ValuesBytes(byte [] in, int [] out, int ctr) {
>     for(int i = 0, j = 0; i < in.length; i+=7, j+=8) {
>       bytePacker.unpack8Values(in, i, out, j);
>     }
>     return out[ctr];
>   }
>   private static int unpack8ValuesByteBuffer(ByteBuffer in, int [] out, int 
> ctr) {
>     for(int i = 0, j = 0; i < in.capacity(); i+=7, j+=8) {
>       bytePacker.unpack8Values(in, i, out, j);
>     }
>     return out[ctr];
>   }
> }



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