This reverts commit 37dc31c429. There is no
reason to suppose compacting different tables concurently on different shards
reduces space requirements, apart from non-deterministically pausing
random shards.
However, when data is badly distributed and there are many tables, it will
slow down major compaction considerably. Consider a case where there are
100 tables, each with a 2GB large partition on some shard. This extra
200GB will be compacted on just one shard. With compation rate of 40 MB/s,
this adds more than an hour to the process. With the existing code, these
compactions would overlap if the badly distributed data was not all in one
shard.
It is also counter to tablets, where data is not equally ditributed on
purpose.
Closes#10246
1feec08c2d