Assume the following default settings: min_compaction_threshold = 4, max_compaction_threshold = 32.
When I start a bulk insert in Cassandra, I see minor compactions work: all similar sized files are compacted when there are four of them. However, when files gets larger, Cassandra waits with minor compactions. For example: four files are compacted to a 1GB file. There were already 3 other 1GB files. However, Cassandra does not immediately compact the four 1GB files. What makes Cassandra decide to wait with this minor compaction?