I’m using Kafka feeding a Storm Cluster with tranquility bolts (v 4.2) serving a 0.7.1.1 Druid Cluster.
During my ingestion, I index the count by minute using the count aggregator, but when I group my data by hour, I find a difference (~5 to 10%) between a raw count on my segments and a longSum using my count aggregation.
Since I also store my data on a Mysql server, it appears that the raw count seems to be the correct number.
Even weirder: if I group my data by minute, LongSum(computed_count) is different than a raw count and this time the right number according to Mysql seems to be LongSum(computed_count).
Any idea what could be the cause? Is there anything I’m missing here?