Hi Edward, There are a couple of ways to do transactional updates to Druid today:
1) When using streaming ingestion with the "parseBatch" feature (see io.druid.data.input.impl.InputRowParser), rows in the batch are inserted transactionally. 2) When using batch ingestion in overwrite mode (the default), all operations are transactional. Of course, you must be willing to overwrite an entire time interval in this mode. With (1) scans are not transactionally consistent. With (2) scans of a particular interval _are_ transactionally consistent, due to the nature of how we handle overwrite-style ingestion (the new segment set has a higher version number, and queries will use either the older or newer version). However Druid never offers read-your-writes consistency. There is always some delay (however small) between when you trigger an insert and when that insert is actually readable. On Tue, May 29, 2018 at 4:38 PM, Edward Bortnikov <ebort...@oath.com.invalid > wrote: > Hi, Community, > Do we have any existing or perceived use cases of transactional > (multi-row) updates to Druid? Same about transactionally consistent scans? > Thanks, Edward
