Summary:
I had a TODO to complete `CompactionOptions`'s compression API but never did it: d610e14f93/db/compaction/compaction_picker.cc (L371-L373)
Without solving that TODO, the API remains incomplete and unsafe. Now, however, I don't think it's worthwhile to complete it. I think we should instead delete the API entirely. This PR deprecates it in preparation for deletion in a future major release. The `ColumnFamilyOptions` settings for compression should be good enough for `CompactFiles()` since they are apparently good enough for every other compaction, including `CompactRange()`.
In the meantime, I also changed the default `CompressionType`. Having callers of `CompactFiles()` use Snappy compression by default does not make sense when the default could be to simply use the same compression type that is used for every other compaction. As a bonus, this change makes the default `CompressionType` consistent with the `CompressionOptions` that will be used.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/12587
Reviewed By: hx235
Differential Revision: D56619273
Pulled By: ajkr
fbshipit-source-id: 1477de49f14b06c72d6f0045616a8ce91d97e66e
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