Key | Default | Type | Description
--- | --- | --- | ---
##### state.backend.rocksdb.checkpoint.transfer.thread.num | 4 | Integer | The number of threads (per stateful operator) used to transfer (download and upload) files in RocksDBStateBackend.If negative, the common (TM) IO thread pool is used (see cluster.io-pool.size)
##### state.backend.rocksdb.localdir | (none) | String | The local directory (on the TaskManager) where RocksDB puts its files. Per default, it will be <WORKING_DIR>/tmp. See `process.taskmanager.working-dir` for more details.
##### state.backend.rocksdb.options-factory | (none) | String | The options factory class for users to add customized options in DBOptions and ColumnFamilyOptions for RocksDB. If set, the RocksDB state backend will load the class and apply configs to DBOptions and ColumnFamilyOptions after loading ones from 'RocksDBConfigurableOptions' and pre-defined options.
##### state.backend.rocksdb.predefined-options | "DEFAULT" | String | The predefined settings for RocksDB DBOptions and ColumnFamilyOptions by Flink community. Current supported candidate predefined-options are DEFAULT, SPINNING_DISK_OPTIMIZED, SPINNING_DISK_OPTIMIZED_HIGH_MEM or FLASH_SSD_OPTIMIZED. Note that user customized options and options from the RocksDBOptionsFactory are applied on top of these predefined ones.