There are many differences between resharding and compaction that are
artificial, arising more from the way we ended up implementing it than
necessity. This patch attempts to pass the creator and replacer functions
through the compaction_descriptor.
There is a difference between the creator function for resharding and
regular compaction: resharding has to pass the shard number on behalf
of which the SSTable is created. However regular compactions can just
ignore this. No need to have a special path just for this.
After this is done, the constructor for the compaction object can be
greatly simplified. In further patches I intend to simplify it a bit
further, but some more cleanup has to happen first.
To make that happen we have to construct a compaction_descriptor object
inside the resharding function. This is temporary: resharding currently
works with a descriptor, but at some point that descriptor is lost and
broken into pieces to be passed to this function. The overarching goal
of this work is exactly to be able to keep that descriptor for as long
as possible, which should simplify things a lot.
Callers are patched, but there are plenty for sstable_datafile_test.cc.
For their benefit, a helper function is provided to keep the previous
signature (test only).
Signed-off-by: Glauber Costa <glauber@scylladb.com>
(cherry picked from commit e8801cd77b)
fc79da5912