We are currently using v0.7.x, and going to upgrade to v0.8.2. Just like to know if there is any gain in query (especially GroupBy)?
Hi, 0.8.2 is quite an old release at this point.
There have been constant performance improvements along the way, but we are close to release Druid 0.9.2, which has a completely rewritten groupBy engine. Folks that have tested it have seen 5-10x performance improvement for groupBys.
We do plan to move to 0.9.x. Our testing showed that from 0.7 to 0.9 involves quite a bit changes, so we are doing incremental upgrading. We have to be careful for production deployment.