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Posted to dev@iotdb.apache.org by "Jialin Qiao (Jira)" <ji...@apache.org> on 2020/02/25 01:04:00 UTC
[jira] [Closed] (IOTDB-514) To support aggregation in the
distributed version
[ https://issues.apache.org/jira/browse/IOTDB-514?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Jialin Qiao closed IOTDB-514.
-----------------------------
Fix Version/s: 0.10.0-SNAPSHOT
Resolution: Fixed
> To support aggregation in the distributed version
> -------------------------------------------------
>
> Key: IOTDB-514
> URL: https://issues.apache.org/jira/browse/IOTDB-514
> Project: Apache IoTDB
> Issue Type: Improvement
> Reporter: Tian Jiang
> Assignee: Yuxin Zhang
> Priority: Major
> Labels: aggregation, distributed, pull-request-available, query
> Fix For: 0.10.0-SNAPSHOT, master branch
>
> Time Spent: 20m
> Remaining Estimate: 0h
>
> The current aggregation cannot satisfy the needs in the distributed version, to be specific, there are two points that should be satisfied:
> 1. The FirstValueAggrResult and LastValueAggrResult should also contain timestamp.
> Without a timestamp, the coordinator node cannot tell the result from which node is the true first/last.
> 2. An AggrResult should be able to merge with another. When we get AggrResults from all nodes that participate in the query, these results should be merged to generate a new result.
> To resolve the issue, you should:
> 1. Add a field `timestamp` in FirstValueAggrResult and LastValueAggrResult
> 2. Add an abstract method `merge(AggregateResult another)` in AggregateResult and implement it properly.
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