[GitHub] storm issue #1714: STORM-2125 Use Calcite's implementation of Rex Compiler

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

Github user HeartSaVioR commented on the issue:

    https://github.com/apache/storm/pull/1714
  
    There's an another issue: when to initialize DataContext.
    
    Calcite utilizes the variables in DataContext. and there're datetime related variables in DataContext.
    
    The thing is, SQL standard says that functions such as CURRENT_TIMESTAMP return the same value throughout the query. Since we're querying in stream, when to initialize DataContext defines the boundary to show same datetime across rows. With joining stream, the issue is more complicated.
    
    For now I just initialize DataContext at the query compilation phase and pass it to components, so that the value of current datetime is static (don't change) across workers in topology. If we would like to make it dynamic, we need to discuss.


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