Apache Druid

first check if the late data is either ignored on the ingestion task (there's a parameter for that) or that it's not put in the topic in the first place

also check if there's any auto-compaction enabled, because that could also try to compact the segments and uses a lock (it has lower priority than the indexing, but can lock out the batch ingestion)

instead of overwrite, you can also queue the old data, and insert into the topic once a day

an then let the auto-compation do the merging