I have an internal test harness setup that I am using for testing version upgrade from Druid 0.10.1 to 0.12.2. As part of the testing, I noticed that executing the same query against the same data sources(on different druid clusters) gives slightly different results for 0.10.1 and 0.12.2. I have seen this happen for search, group by, top n, select query types. The common part in all such queries is that they have a paging spec with descending set to false.
"pagingSpec": {"pagingIdentifiers": {}, "threshold": 5000} "desceding": false My guess is that data distribution is slightly differently within the two clusters which combined with paging spec is causing this mismatch. Is my guess correct? If so, is there a way to make such kind of testing deterministic. The other thing that I observed is that with doubleSum aggregation type, 0.10.1 is returning values with lower precision (ex - 616346.0) as opposed to 0.12.1 (ex - 616346.0208094628). Did something change to cause this change in precision?