[jira] [Commented] (CALCITE-3780) SESSION Table-valued Function

[Vladimir Sitnikov (Jira)]

    [ 
https://issues.apache.org/jira/browse/CALCITE-3780?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17199099#comment-17199099
 ] 

Vladimir Sitnikov commented on CALCITE-3780:
--------------------------------------------

Thanks.
I've got a couple of more questions:

1) is {{org.apache.calcite.adapter.enumerable.EnumUtils.HopEnumerator#current}} 
always non-nullable?

It is not clear if always produces a non-null result since {{for}} loop look 
like it can be empty (however, it is not clear).


{code:java}
      } else {
        Object[] current = inputEnumerator.current();
        List<Pair> windows = 
hopWindows(SqlFunctions.toLong(current[indexOfWatermarkedColumn]),
            emitFrequency, windowSize, offset);
        for (Pair window : windows) {
          Object[] curWithWindow = new Object[current.length + 2];
          System.arraycopy(current, 0, curWithWindow, 0, current.length);
          curWithWindow[current.length] = window.left;
          curWithWindow[current.length + 1] = window.right;
          list.offer(curWithWindow);
        }
        return takeOne();
      }
{code}

2) Should {{org.apache.calcite.adapter.enumerable.EnumUtils#hopWindows}} use 
{{Math.floorDiv(sizeMillis, periodMillis)}} rather than 
{{Math.toIntExact(sizeMillis / periodMillis)}} ?

> SESSION Table-valued Function
> -----------------------------
>
>                 Key: CALCITE-3780
>                 URL: https://issues.apache.org/jira/browse/CALCITE-3780
>             Project: Calcite
>          Issue Type: Sub-task
>            Reporter: Rui Wang
>            Assignee: Rui Wang
>            Priority: Major
>             Fix For: 1.23.0
>
>
> We can create SESSION table-valued function to replace GROUP BY SESSION for 
> inactive gap session functionality:
> {code:sql}
> SELECT *
> FROM TABLE SESSION (
>   data => TABLE Bid ,
>   timecol => DESCRIPTOR ( bidtime ) ,
>   keycol => DESCRIPTOR(key),
>   inactive_gap => INTERVAL '10' MINUTES )
> {code}
>  
>  



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