[jira] [Updated] (HIVE-21313) Use faster function to prevent copying immutable byte array twice

["ZhangXin (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HIVE-21313?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

ZhangXin updated HIVE-21313:
----------------------------
    Description: 
In file ql/src/java/org/apache/hadoop/hive/ql/exec/vector/VectorAssignRow.java

We may find code like this:

```

Text text = (Text) convertTargetWritable;
if (text == null) {
    text = new Text();
}
text.set(string);
((BytesColumnVector) columnVector).setVal(
    batchIndex, text.getBytes(), 0, text.getLength());

```

 

Using `setVal` method can copy the bytes array generated by `text.getBytes()`. This is totally unnecessary at all. Since the bytes array is immutable, we can just use `setRef` method to point to the specific  byte array, which will also lower the memory usage.

 

 

 
        Summary: Use faster function to prevent copying immutable byte array twice  (was: Use faster function to revent)

> Use faster function to prevent copying immutable byte array twice
> -----------------------------------------------------------------
>
>                 Key: HIVE-21313
>                 URL: https://issues.apache.org/jira/browse/HIVE-21313
>             Project: Hive
>          Issue Type: Improvement
>            Reporter: ZhangXin
>            Priority: Major
>
> In file ql/src/java/org/apache/hadoop/hive/ql/exec/vector/VectorAssignRow.java
> We may find code like this:
> ```
> Text text = (Text) convertTargetWritable;
> if (text == null) {
>     text = new Text();
> }
> text.set(string);
> ((BytesColumnVector) columnVector).setVal(
>     batchIndex, text.getBytes(), 0, text.getLength());
> ```
>  
> Using `setVal` method can copy the bytes array generated by `text.getBytes()`. This is totally unnecessary at all. Since the bytes array is immutable, we can just use `setRef` method to point to the specific  byte array, which will also lower the memory usage.
>  
>  
>  



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