[
https://issues.apache.org/jira/browse/CALCITE-2648?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16734520#comment-16734520
]
Hongze Zhang commented on CALCITE-2648:
---------------------------------------
[~vladimirsitnikov],
I didn't take a very detailed look at all the comments (sorry, I am a little
busy on some other things now), but I think I like the idea that leveraging the
order inside a over (partition by x order by x), and the idea generating more
than one LogicalWindow rels.
I have no objection to decline PR #897 and start from the better concept.
{quote}Would you like to implement "TL;DR:" above?
{quote}
If any other people have no plan on implementing this I think I could try help,
maybe start after some days.
I have a naive question here, If we can "have multiple LogicalWindow entities
in case input's collation satisfies window's collation", is there a
possibility to make each Window rel only include the window group information,
and use a Sort rel as input to handle the order by part? (maybe Window rels
should no longer care about order) Something like:
Window(partition by x order by x)
Input()
->
Window(partition by x)
Sort(order by x)
Input()
So that if the Input() is already sorted on x, the Sort(order by x) can be
automatically removed by rules.
> Output collation of EnumerableWindow is not consistent with its implementation
> ------------------------------------------------------------------------------
>
> Key: CALCITE-2648
> URL: https://issues.apache.org/jira/browse/CALCITE-2648
> Project: Calcite
> Issue Type: Bug
> Affects Versions: 1.17.0
> Reporter: Hongze Zhang
> Assignee: Julian Hyde
> Priority: Major
>
> Here is a case:
> {code:sql}
> select x, COUNT(*) OVER (PARTITION BY x) from (values (20), (35)) as t(x)
> ORDER BY x
> {code}
> Final plan:
> {code:java}
> EnumerableWindow(window#0=[window(partition {0} order by [] range between
> UNBOUNDED PRECEDING and UNBOUNDED FOLLOWING aggs [COUNT()])])
> EnumerableValues(tuples=[[{ 20 }, { 35 }]])
> {code}
> Output rows:
> {code:java}
> X |EXPR$1 |
> ---|-------|
> 35 |1 |
> 20 |1 |
> {code}
> EnumerableWindow is supposed to preserve input collations, as a result
> EnumerableSort is ignored. However the implementation of EnumerableWindow
> generates non-ordered output (when PARTITION BY clause is used).
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
