amaliujia commented on a change in pull request #1981:
URL: https://github.com/apache/calcite/pull/1981#discussion_r455212526
##########
File path: core/src/test/resources/sql/stream.iq
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@@ -64,6 +78,25 @@ SELECT * FROM TABLE(HOP(TABLE ORDERS, DESCRIPTOR(ROWTIME),
INTERVAL '5' MINUTE,
!ok
+SELECT * FROM TABLE(HOP(TABLE ORDERS, DESCRIPTOR(ROWTIME), INTERVAL '5'
MINUTE, INTERVAL '10' MINUTE, INTERVAL '2' MINUTE));
++---------------------+----+---------+-------+---------------------+---------------------+
+| ROWTIME | ID | PRODUCT | UNITS | window_start |
window_end |
++---------------------+----+---------+-------+---------------------+---------------------+
+| 2015-02-15 10:15:00 | 1 | paint | 10 | 2015-02-15 10:07:00 |
2015-02-15 10:17:00 |
+| 2015-02-15 10:15:00 | 1 | paint | 10 | 2015-02-15 10:12:00 |
2015-02-15 10:22:00 |
+| 2015-02-15 10:24:15 | 2 | paper | 5 | 2015-02-15 10:17:00 |
2015-02-15 10:27:00 |
+| 2015-02-15 10:24:15 | 2 | paper | 5 | 2015-02-15 10:22:00 |
2015-02-15 10:32:00 |
+| 2015-02-15 10:24:45 | 3 | brush | 12 | 2015-02-15 10:17:00 |
2015-02-15 10:27:00 |
+| 2015-02-15 10:24:45 | 3 | brush | 12 | 2015-02-15 10:22:00 |
2015-02-15 10:32:00 |
+| 2015-02-15 10:58:00 | 4 | paint | 3 | 2015-02-15 10:52:00 |
2015-02-15 11:02:00 |
+| 2015-02-15 10:58:00 | 4 | paint | 3 | 2015-02-15 10:57:00 |
2015-02-15 11:07:00 |
+| 2015-02-15 11:10:00 | 5 | paint | 3 | 2015-02-15 11:02:00 |
2015-02-15 11:12:00 |
Review comment:
I see. I would prefer to leave that work for another PR because Join
still has some areas that need a clarification.
Join windowed streams will need more thoughts. For example, can a TUMBLE
stream join HOP stream? It might make sense if there is a use case that intends
to do such join, but such case might be rare. So we could end up with
validating and rejecting some Join cases. And if we plan to add more
constraints, then multi-way join will also become a case that need special
handling because join reordering might lead to an illegal join plan (depends on
the rules of allowed windowed joins though).
I feel like it would be better to promote stream to the first class citizen
in Calcite then in rule matching we should consider different joins: table join
table, steam join table and stream join stream, and then join involves streams
might need to consider different optimization factors. e.g. estimated biggest
window size? number events per second? etc.
Anyway, what I want to say is Join is a big area that can be discussed and
implemented separately.
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