[GitHub] storm pull request #2295: STORM-2712: accept arbitrary number of rows per tu...

[morokosi <gi...@git.apache.org>]

GitHub user morokosi opened a pull request:

    https://github.com/apache/storm/pull/2295

    STORM-2712: accept arbitrary number of rows per tuple in storm-cassandra

    Current implementation in `TridentResultSetValuesMapper::map` restricts a SELECT query to return one row. In `StateQueryProcessor::finishBatch`, it checks the equality between the result size of `batchRetrieve` and input tuple size. When the number of result rows is less than 1 or greater than 1, it breaks the condition and an exception is thrown.
    
    We should accept arbitrary number of rows by adjusting List dimensions.

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

    $ git pull https://github.com/morokosi/storm cassandra-resultset-mapper

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

    https://github.com/apache/storm/pull/2295.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 #2295
    
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commit 58bd51ec88c8eff02d35904e106edd68ea45e6a4
Author: morokosi <mo...@gmail.com>
Date:   2017-08-28T13:59:14Z

    STORM-2712: accept arbitrary number of rows per tuple in storm-cassandra

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[GitHub] storm issue #2295: STORM-2712: accept arbitrary number of rows per tuple in ...

[morokosi <gi...@git.apache.org>]

Github user morokosi commented on the issue:

    https://github.com/apache/storm/pull/2295
  
    In a nutshell, the changeset makes utilize of inner list dimensions correctly when a cassandra query result has multiple rows.
    
    Assume we have a cassandra table like the following:
    
    ```sql
    CREATE TABLE t1 (pk int, ck int, data text, PRIMARY KEY (pk, ck)));
    ```
    
    | pk | ck | data |
    | -- | -- | -- |
    | 1 | 0 | a |
    | 1 | 1 | b |
    | 2 | 0 | c |
    | 3 | 0 | d |
    
    and we have a StateQuery as `SELECT data from t1 where pk = ?` with input tuples `1,2,3`.
    
    With current implementation, the return list of `TridentResultSetValuesMapper::map` is as follows:
    
    ```
    [
      [values(pk=1, ck=0)],
      [values(pk=1, ck=1)],
      [values(pk=2, ck=0)],
      [values(pk=3, ck=0)]
    ]
    ```
    
    This throws an exception because the list size differs from the input tuple size.
    
    On the other hand, one with the changeset results
    
    ```
    [
      [values(pk=1, ck=0), values(pk=1, ck=1)],
      [values(pk=2, ck=0)],
      [values(pk=3, ck=0)]  
    ]
    ```
    
    which the list size is same as the input tuple size.


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[GitHub] storm pull request #2295: STORM-2712: accept arbitrary number of rows per tu...

[HeartSaVioR <gi...@git.apache.org>]

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

    https://github.com/apache/storm/pull/2295#discussion_r139648054
  
    --- Diff: external/storm-cassandra/src/main/java/org/apache/storm/cassandra/trident/state/TridentResultSetValuesMapper.java ---
    @@ -44,6 +44,8 @@ public TridentResultSetValuesMapper(Fields outputDeclaredFields) {
         @Override
         public List<List<Values>> map(Session session, Statement statement, ITuple tuple) {
             List<List<Values>> list = new ArrayList<>();
    +        List<Values> innerList = new LinkedList<>();
    --- End diff --
    
    Could you explain that how different the changeset is? I don't get it and for me it looks like same.


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[GitHub] storm pull request #2295: STORM-2712: accept arbitrary number of rows per tu...

[asfgit <gi...@git.apache.org>]

Github user asfgit closed the pull request at:

    https://github.com/apache/storm/pull/2295


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[GitHub] storm issue #2295: STORM-2712: accept arbitrary number of rows per tuple in ...

[HeartSaVioR <gi...@git.apache.org>]

Github user HeartSaVioR commented on the issue:

    https://github.com/apache/storm/pull/2295
  
    Could you explain that how different the changeset is? I don't get it and for me it looks like same.


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[GitHub] storm issue #2295: STORM-2712: accept arbitrary number of rows per tuple in ...

[HeartSaVioR <gi...@git.apache.org>]

Github user HeartSaVioR commented on the issue:

    https://github.com/apache/storm/pull/2295
  
    Ah OK. I missed that difference while looking at the code, and now I realized the difference even in the code.
    Thanks for clarifying. +1


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