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https://issues.apache.org/jira/browse/CALCITE-1429?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Julian Hyde updated CALCITE-1429:
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Summary: Druid adapter must send "fromNext" when requesting rows from Druid
(was: Error of fetching data in select query for Druid)
> Druid adapter must send "fromNext" when requesting rows from Druid
> ------------------------------------------------------------------
>
> Key: CALCITE-1429
> URL: https://issues.apache.org/jira/browse/CALCITE-1429
> Project: Calcite
> Issue Type: Bug
> Components: druid
> Reporter: Jiarong Wei
> Assignee: Julian Hyde
>
> As mentioned in [Druid
> documentation|http://druid.io/docs/0.9.1.1/querying/select-query.html],
> {quote}
> Note that in the second query, an offset is specified and that it is 1
> greater than the largest offset found in the initial results. To return the
> next "page", this offset must be incremented by 1 (should be decremented by 1
> for descending query), with each new query, but with option {{fromNext}}
> enabled, this operation is not needed. When an empty results set is received,
> the very last page has been returned.
> {quote}
> I think Druid adapter
> [presumes|https://github.com/apache/calcite/blob/master/druid/src/main/java/org/apache/calcite/adapter/druid/DruidQuery.java#L935]
> this feature is turned on but it's not set in
> [code|https://github.com/apache/calcite/blob/master/druid/src/main/java/org/apache/calcite/adapter/druid/DruidQuery.java#L627].
> Also, {{previousOffset}} may not be reasonable, see
> [DruidQuery|https://github.com/apache/calcite/blob/master/druid/src/main/java/org/apache/calcite/adapter/druid/DruidQuery.java#L940].
> I think whether we have already fetched all data is decided by the next
> request. If we don't have any data returned on next request, that means
> fetching is done.
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