[jira] [Commented] (ORC-168) Documentation Writer Example: batch.size++ has a wrong possition

["ASF GitHub Bot (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/ORC-168?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15963133#comment-15963133 ] 

ASF GitHub Bot commented on ORC-168:
------------------------------------

GitHub user Citrullin opened a pull request:

    https://github.com/apache/orc/pull/104

    Core documentation fixes

    There's an issue with the size count and the MapColumnVector is named ListColumnVector
    Also wrote a jira ticket for it:
    https://issues.apache.org/jira/browse/ORC-168

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

    $ git pull https://github.com/Citrullin/orc master

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

    https://github.com/apache/orc/pull/104.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 #104
    
----
commit c1083247a917f18289761bcf13f902555b5cbda8
Author: Philipp Blum <ph...@webtrekk.com>
Date:   2017-04-10T16:26:06Z

    fix wrong batch.size counter

commit b4c75761115d3fc48f53ebed51bb64a6e8a204c8
Author: Philipp Blum <ph...@webtrekk.com>
Date:   2017-04-10T16:29:06Z

    Rename ListColumnVector to MapColumnVector

----


> Documentation Writer Example: batch.size++ has a wrong possition
> ----------------------------------------------------------------
>
>                 Key: ORC-168
>                 URL: https://issues.apache.org/jira/browse/ORC-168
>             Project: ORC
>          Issue Type: Improvement
>          Components: documentation, Java
>            Reporter: Philipp Blum
>            Priority: Critical
>
> There's one little mistake in the Java Core Example. The for loops starts with a batch.size++:
> for(int r=0; r < 10000; ++r) {
>   int row = batch.size++;
>   x.vector[row] = r;
>   y.vector[row] = r * 3;
>   // If the batch is full, write it out and start over.
>   if (batch.size == batch.getMaxSize()) {
>     writer.addRowBatch(batch);
>     batch.reset();
>   }
> }
> If you start with a batch.size++ the first index will be 1, so the first entry in the orc file will be empty.
> Correct is:
> for(int r=0; r < 10000; ++r) {
>   int row = batch.size;
>   x.vector[row] = r;
>   y.vector[row] = r * 3;
>   // If the batch is full, write it out and start over.
>   if (batch.size == batch.getMaxSize()) {
>     writer.addRowBatch(batch);
>     batch.reset();
>   }
>  batch.size++;
> }
> Already tested it in scala.



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