Summary:
https://github.com/facebook/rocksdb/pull/6807 extends the logic that
identifies and purges obsolete files to blob files handled by RocksDB
itself. In order to prevent that from interfering with the current BlobDB code,
we need to make sure that `BlobDBOptions::blob_dir` is different from
the storage directories used by the base DB. (Note: this is true by default.)
The patch adds a check that explicitly disallows this configuration and
returns `Status::NotSupported` from `BlobDB::Open` in such cases.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6810
Test Plan: Tested using the BlobDB mode of `db_bench`.
Reviewed By: riversand963
Differential Revision: D21412676
Pulled By: ltamasi
fbshipit-source-id: 6630cc7481e48c8bf55d59423b25f14d52ffe681