[FLINK-5654] Add processing time OVER RANGE BETWEEN x PRECEDING aggregation to SQL - ASF JIRA

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Details

Type: Sub-task
Status: Closed
Priority: Major
Resolution: Implemented
Affects Version/s: None
Fix Version/s: 1.3.0
Component/s: Table SQL / API
Labels:
None

Description

The goal of this issue is to add support for OVER RANGE aggregations on processing time streams to the SQL interface.

Queries similar to the following should be supported:

SELECT 
  a, 
  SUM(b) OVER (PARTITION BY c ORDER BY procTime() RANGE BETWEEN INTERVAL '1' HOUR PRECEDING AND CURRENT ROW) AS sumB,
  MIN(b) OVER (PARTITION BY c ORDER BY procTime() RANGE BETWEEN INTERVAL '1' HOUR PRECEDING AND CURRENT ROW) AS minB
FROM myStream

The following restrictions should initially apply:

All OVER clauses in the same SELECT clause must be exactly the same.
The PARTITION BY clause is optional (no partitioning results in single threaded execution).
The ORDER BY clause may only have procTime() as parameter. procTime() is a parameterless scalar function that just indicates processing time mode.
UNBOUNDED PRECEDING is not supported (see ~~FLINK-5657~~)
FOLLOWING is not supported.

The restrictions will be resolved in follow up issues. If we find that some of the restrictions are trivial to address, we can add the functionality in this issue as well.

This issue includes:

Design of the DataStream operator to compute OVER ROW aggregates
Translation from Calcite's RelNode representation (LogicalProject with RexOver expression).