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https://issues.apache.org/jira/browse/CALCITE-5240?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17584502#comment-17584502
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Julian Hyde commented on CALCITE-5240:
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{quote} It would help if we had better abstraction for time units.{quote}
Now would be a good time to design that abstraction (since you've just gone
through the pain). Would you mind sketching something out?
I think the abstraction should be capable of representing, say, a quarter of an
hour (15 minutes), and would not require someone to modify any enums or switch
statements in order to add a new time unit.
> Enhance MaterializedViewRule so that it applies to rollup view for queries
> that contain a predicate on the rollup column
> ------------------------------------------------------------------------------------------------------------------------
>
> Key: CALCITE-5240
> URL: https://issues.apache.org/jira/browse/CALCITE-5240
> Project: Calcite
> Issue Type: Improvement
> Reporter: Thomas D'Silva
> Assignee: Thomas D'Silva
> Priority: Major
> Labels: pull-request-available
> Time Spent: 10m
> Remaining Estimate: 0h
>
> {{MaterializedViewRule}} is not applied when a view does not have a view
> predicate but the query contains a predicate. For eg. for the following
> materialized view
> {code:java}
> SELECT eventid, floor(ts to minute), count(*) as cnt
> FROM events
> GROUP BY eventid, floor(ts TO minute)
> {code}
> If we have the following query the view is not used.
> {code:java}
> SELECT floor(ts to minute), count(*)
> FROM events
> WHERE ts > timestamp'2018-01-01 00:02:30' AND ts <= timestamp'2018-01-01
> 00:05:30'
> GROUP BY eventid, floor(ts TO minute)
> {code}
> If {{MaterializedViewRule}} is modified to automatically add the predicate
> {{ts > timestamp'2018-01-01 00:03:00' AND ts < timestamp'2018-01-01
> 00:05:00'}} to the view then the following plan can be generated that uses
> the union rewriting feature to query both the table and the view efficiently.
> {code:java}
> EnumerableAggregate(group=[{0, 1}], EXPR$2=[$SUM0($2)])
> EnumerableUnion(all=[true])
> EnumerableAggregate(group=[{0, 1}], EXPR$2=[COUNT()])
> EnumerableCalc(expr#0..1=[{inputs}], expr#2=[FLAG(MINUTE)],
> expr#3=[FLOOR($t1, $t2)], expr#4=[Sarg[(2018-01-01 00:02:30..2018-01-01
> 00:03:00), [2018-01-01 00:05:00..2018-01-01 00:05:30]]], expr#5=[SEARCH($t1,
> $t4)], eventid=[$t0], $f1=[$t3], $condition=[$t5])
> EnumerableTableScan(table=[[hr, events]])
> EnumerableCalc(expr#0..2=[{inputs}], expr#3=[Sarg[[2018-01-01
> 00:03:00..2018-01-01 00:05:00)]], expr#4=[SEARCH($t1, $t3)],
> proj#0..2=[{exprs}], $condition=[$t4])
> EnumerableTableScan(table=[[hr, MV0]])
> {code}
> The mailing list has a discussion related to this
> [https://lists.apache.org/thread/c7v85fccpbobz44y1o4z7hklomrcl299]
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