In aggregated tables, group by AGG_TIMESTAMP does not populate correct results

[Thidasala]

Description:

Aggregation:

define aggregation ApiErroranalysisAgg
from Request
select apiName, apiVersion, apiMethod, apiResourceTemplate, responseCode, apiContext, sum(backendLatency) as backendLatency, sum(otherLatency) as otherLatency, count() as totalRequestCount, applicationName, label
group by responseCode, apiResourceTemplate
aggregate by requestTimestamp every seconds...years;

Query:

from ApiErroranalysisAgg 
on (apiName == \"EmployeeApi\" and responseCode>200) 
within 1560938182969L, 1576749384340L 
per \"hour\" 
select apiName, count(responseCode) as count, AGG_TIMESTAMP 
group by AGG_TIMESTAMP

Affected Siddhi Version:
5.0.0- 5.1.12

[niveathika]

After the initial evaluation, it seems that the Siddhi Query selector does not recognise "group by AGG_TIMESTAMP"

[niveathika]

I was able to reproduce this only for Persistence table,
niveathika/siddhi-store-rdbms@1f1e4cd

Test case passes for in-memory tables: #1592

[niveathika]

It seems the group by "AGG_TIMESTAMP" is removed when processing optimisation queries