How to set bitmap type for Merge Tasks created by coordinator

Hi all!

We recently upgraded from Druid 0.8.2. to 0.9.2 and would like to use roaring bitmaps by default. Unfortunately the config option druid.processing.bitmap.type=roaring doesn’t work anymore, it was removed by

We can now use roaring bitmaps by configuring indexSpec in our Hadoop Index Tasks but the Merge Tasks created by the coordinator to merge small segments to larger ones use the default consise bitmaps. I don’t see an option to set another default value.

Any ideas?

Thanks for help,


This seems like a missing feature, there should be some way to specify an indexSpec when coordinator merging is on. Maybe providing it as a json object like druid.coordinator.merge.indexSpec={“bitmap”:{“type”:“roaring”}}.

Could you please raise a github issue about this? Or, a PR, if you have the time!