Yuan Tian created IOTDB-803:
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Summary: Improve the way of applying aggregate func to same series
in group by
Key: IOTDB-803
URL: https://issues.apache.org/jira/browse/IOTDB-803
Project: Apache IoTDB
Issue Type: Improvement
Components: Core/Engine
Reporter: Yuan Tian
Now, in group by, if we include more than one aggregate function for one
series, we will iterate the series data as many times as the number of the
aggregate functions.
For example,
select count(s1), sum(s1), avg(s1) from root.sg1.d1 group by([0, 100000), 10ms)
Suppose that the batch data we get from s1 ranges from 0 to 20
While calculating the count(s1), we will iterate the batch data from 0 to 10.
And then while calculating sum or avg, we will reset the cursor to 0, and
iterate the batch data again.
However, we can do count, sum and avg function simutaneously in one iteration
while will be also good for cpu cache hit ratio.
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