During startup recovery after an unclean shutdown (i.e. it can't be resumed), we drop any incomplete-built indexes and rebuild them. When we drop these tables, we queue them for deletion, but we only run the reaper when the minimum of the oldest and checkpoint timestamps are advanced.

At this point in startup, we have not initialized replication, so we are not advancing the oldest or stable timestamps. We have started the checkpoint thread, but this also only runs every minute.

This can be problematic after an unclean shutdown due to running out of disk space during an index build. Because the table isn't dropped immediately, we end up with potentially very large files that can't be dropped until the next index build completes.