I think start is userkey here!

[zgcbj]

https://github.com/tikv/rocksdb/blob/ce0ea61aecd53ac02a0e7da2b166961c7d98650a/db/compaction/compaction.cc#L549

ExtractUserKey(*start) will assert false!

same to ExtractUserKey(*end)

Am I right?

[tabokie]

Nice catch! Our unit tests didn't catch it because it will only be non-null when sub-compaction is involved.

The start is set here: https://github.com/tikv/rocksdb/blob/ce0ea61aecd53ac02a0e7da2b166961c7d98650a/db/compaction/compaction_job.cc#L542-L550

And the boundaries_ is set here:

https://github.com/tikv/rocksdb/blob/ce0ea61aecd53ac02a0e7da2b166961c7d98650a/db/compaction/compaction_job.cc#L691

You're welcome to send us a fix~