* Fixed a bug where a snapshot taken during SST file ingestion would be unstable.
* Fixed a bug where a snapshot taken during SST file ingestion would be unstable.
* Fixed a bug for non-TransactionDB with avoid_flush_during_recovery = true and TransactionDB where in case of crash, min_log_number_to_keep may not change on recovery and persisting a new MANIFEST with advanced log_numbers for some column families, results in "column family inconsistency" error on second recovery. As a solution, RocksDB will persist the new MANIFEST after successfully syncing the new WAL. If a future recovery starts from the new MANIFEST, then it means the new WAL is successfully synced. Due to the sentinel empty write batch at the beginning, kPointInTimeRecovery of WAL is guaranteed to go after this point. If future recovery starts from the old MANIFEST, it means the writing the new MANIFEST failed. We won't have the "SST ahead of WAL" error.
* Fixed a bug where RocksDB DB::Open() may creates and writes to two new MANIFEST files even before recovery succeeds. Now writes to MANIFEST are persisted only after recovery is successful.
### Public API changes
### Public API changes
* Add new API GetUnixTime in Snapshot class which returns the unix time at which Snapshot is taken.
* Add new API GetUnixTime in Snapshot class which returns the unix time at which Snapshot is taken.
* Add transaction `get_pinned` and `multi_get` to C API.
* Add transaction `get_pinned` and `multi_get` to C API.