Details
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Improvement
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Status: Closed
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Major
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Resolution: Fixed
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None
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None
Description
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.
