All Known Implementing Classes:: DBOptions, Options

public interface DBOptionsInterface<T extends DBOptionsInterface<T>>

Method Summary

All Methods Instance Methods Abstract Methods Deprecated Methods
Modifier and Type	Method	Description
`AccessHint`	`accessHintOnCompactionStart()`	Specify the file access pattern once a compaction is started.
`boolean`	`adviseRandomOnOpen()`	If set true, will hint the underlying file system that the file access pattern is random, when a sst file is opened.
`boolean`	`allow2pc()`	if set to false then recovery will fail when a prepared transaction is encountered in the WAL Default: false
`boolean`	`allowConcurrentMemtableWrite()`	If true, allow multi-writers to update mem tables in parallel.
`boolean`	`allowFAllocate()`	Whether fallocate calls are allowed
`boolean`	`allowIngestBehind()`	Returns true if ingest behind is allowed.
`boolean`	`allowMmapReads()`	Allow the OS to mmap file for reading sst tables.
`boolean`	`allowMmapWrites()`	Allow the OS to mmap file for writing.
`boolean`	`atomicFlush()`	Determine if atomic flush of multiple column families is enabled.
`boolean`	`avoidFlushDuringRecovery()`	By default RocksDB replay WAL logs and flush them on DB open, which may create very small SST files.
`boolean`	`avoidUnnecessaryBlockingIO()`	If true, working thread may avoid doing unnecessary and long-latency operation (such as deleting obsolete files directly or deleting memtable) and will instead schedule a background job to do it.
`boolean`	`bestEffortsRecovery()`	By default, RocksDB recovery fails if any table file referenced in MANIFEST are missing after scanning the MANIFEST.
`long`	`bgerrorResumeRetryInterval()`	If max_bgerror_resume_count is ≥ 2, db resume is called multiple times.
`boolean`	`createIfMissing()`	Return true if the create_if_missing flag is set to true.
`boolean`	`createMissingColumnFamilies()`	Return true if the create_missing_column_families flag is set to true.
`java.lang.String`	`dbLogDir()`	Returns the directory of info log.
`java.util.List<DbPath>`	`dbPaths()`	A list of paths where SST files can be put into, with its target size.
`long`	`dbWriteBufferSize()`	Amount of data to build up in memtables across all column families before writing to disk.
`long`	`deleteObsoleteFilesPeriodMicros()`	The periodicity when obsolete files get deleted.
`boolean`	`dumpMallocStats()`	If true, then print malloc stats together with rocksdb.stats when printing to LOG.
`boolean`	`enablePipelinedWrite()`	Returns true if pipelined writes are enabled.
`boolean`	`enableThreadTracking()`	If true, then the status of the threads involved in this DB will be tracked and available via GetThreadList() API.
`boolean`	`enableWriteThreadAdaptiveYield()`	If true, threads synchronizing with the write batch group leader will wait for up to `writeThreadMaxYieldUsec()` before blocking on a mutex.
`boolean`	`errorIfExists()`	If true, an error will be thrown during RocksDB.open() if the database already exists.
`boolean`	`failIfOptionsFileError()`	If true, then DB::Open / CreateColumnFamily / DropColumnFamily / SetOptions will fail if options file is not detected or properly persisted.
`Env`	`getEnv()`	Returns the set RocksEnv instance.
`InfoLogLevel`	`infoLogLevel()`	Returns currently set log level.
`boolean`	`isFdCloseOnExec()`	Disable child process inherit open files.
`long`	`keepLogFileNum()`	Returns the maximum number of info log files to be kept.
`java.util.List<AbstractEventListener>`	`listeners()`	Sets the `EventListener`s whose callback functions will be called when specific RocksDB event happens.
`long`	`logFileTimeToRoll()`	Returns the time interval for the info log file to roll (in seconds).
`long`	`logReadaheadSize()`	The number of bytes to prefetch when reading the log.
`long`	`manifestPreallocationSize()`	Number of bytes to preallocate (via fallocate) the manifest files.
`boolean`	`manualWalFlush()`	Returns true if automatic WAL flushing is disabled.
`int`	`maxBackgroundFlushes()`	Deprecated.
`int`	`maxBgerrorResumeCount()`	It defines how many times db resume is called by a separate thread when background retryable IO Error happens.
`int`	`maxFileOpeningThreads()`	If `MutableDBOptionsInterface.maxOpenFiles()` is -1, DB will open all files on DB::Open().
`long`	`maxLogFileSize()`	Returns the maximum size of a info log file.
`long`	`maxManifestFileSize()`	Manifest file is rolled over on reaching this limit.
`int`	`maxSubcompactions()`	This value represents the maximum number of threads that will concurrently perform a compaction job by breaking it into multiple, smaller ones that are run simultaneously.
`long`	`maxWriteBatchGroupSizeBytes()`	The maximum limit of number of bytes that are written in a single batch of WAL or memtable write.
`boolean`	`newTableReaderForCompactionInputs()`	If true, always create a new file descriptor and new table reader for compaction inputs.
`T`	`optimizeForSmallDb()`	Use this if your DB is very small (like under 1GB) and you don't want to spend lots of memory for memtables.
`boolean`	`paranoidChecks()`	If true, the implementation will do aggressive checking of the data it is processing and will stop early if it detects any errors.
`boolean`	`persistStatsToDisk()`	If true, automatically persist stats to a hidden column family (column family name: ___rocksdb_stats_history___) every stats_persist_period_sec seconds; otherwise, write to an in-memory struct.
`boolean`	`preserveDeletes()`	Returns true if deletes are preserved.
`long`	`randomAccessMaxBufferSize()`	This is a maximum buffer size that is used by WinMmapReadableFile in unbuffered disk I/O mode.
`long`	`recycleLogFileNum()`	Recycle log files.
`Cache`	`rowCache()`	A global cache for table-level rows.
`T`	`setAccessHintOnCompactionStart(AccessHint accessHint)`	Specify the file access pattern once a compaction is started.
`T`	`setAdviseRandomOnOpen(boolean adviseRandomOnOpen)`	If set true, will hint the underlying file system that the file access pattern is random, when a sst file is opened.
`T`	`setAllow2pc(boolean allow2pc)`	if set to false then recovery will fail when a prepared transaction is encountered in the WAL Default: false
`T`	`setAllowConcurrentMemtableWrite(boolean allowConcurrentMemtableWrite)`	If true, allow multi-writers to update mem tables in parallel.
`T`	`setAllowFAllocate(boolean allowFAllocate)`	Whether fallocate calls are allowed
`T`	`setAllowIngestBehind(boolean allowIngestBehind)`	Set this option to true during creation of database if you want to be able to ingest behind (call IngestExternalFile() skipping keys that already exist, rather than overwriting matching keys).
`T`	`setAllowMmapReads(boolean allowMmapReads)`	Allow the OS to mmap file for reading sst tables.
`T`	`setAllowMmapWrites(boolean allowMmapWrites)`	Allow the OS to mmap file for writing.
`T`	`setAtomicFlush(boolean atomicFlush)`	If true, RocksDB supports flushing multiple column families and committing their results atomically to MANIFEST.
`T`	`setAvoidFlushDuringRecovery(boolean avoidFlushDuringRecovery)`	By default RocksDB replay WAL logs and flush them on DB open, which may create very small SST files.
`T`	`setAvoidUnnecessaryBlockingIO(boolean avoidUnnecessaryBlockingIO)`	If true, working thread may avoid doing unnecessary and long-latency operation (such as deleting obsolete files directly or deleting memtable) and will instead schedule a background job to do it.
`T`	`setBestEffortsRecovery(boolean bestEffortsRecovery)`	By default, RocksDB recovery fails if any table file referenced in MANIFEST are missing after scanning the MANIFEST.
`T`	`setBgerrorResumeRetryInterval(long bgerrorResumeRetryInterval)`	If max_bgerror_resume_count is ≥ 2, db resume is called multiple times.
`T`	`setCreateIfMissing(boolean flag)`	If this value is set to true, then the database will be created if it is missing during `RocksDB.open()`.
`T`	`setCreateMissingColumnFamilies(boolean flag)`	If true, missing column families will be automatically created
`T`	`setDbLogDir(java.lang.String dbLogDir)`	This specifies the info LOG dir.
`T`	`setDbPaths(java.util.Collection<DbPath> dbPaths)`	A list of paths where SST files can be put into, with its target size.
`T`	`setDbWriteBufferSize(long dbWriteBufferSize)`	Amount of data to build up in memtables across all column families before writing to disk.
`T`	`setDeleteObsoleteFilesPeriodMicros(long micros)`	The periodicity when obsolete files get deleted.
`T`	`setDumpMallocStats(boolean dumpMallocStats)`	If true, then print malloc stats together with rocksdb.stats when printing to LOG.
`T`	`setEnablePipelinedWrite(boolean enablePipelinedWrite)`	By default, a single write thread queue is maintained.
`T`	`setEnableThreadTracking(boolean enableThreadTracking)`	If true, then the status of the threads involved in this DB will be tracked and available via GetThreadList() API.
`T`	`setEnableWriteThreadAdaptiveYield(boolean enableWriteThreadAdaptiveYield)`	If true, threads synchronizing with the write batch group leader will wait for up to `writeThreadMaxYieldUsec()` before blocking on a mutex.
`T`	`setEnv(Env env)`	Use the specified object to interact with the environment, e.g.
`T`	`setErrorIfExists(boolean errorIfExists)`	If true, an error will be thrown during RocksDB.open() if the database already exists.
`T`	`setFailIfOptionsFileError(boolean failIfOptionsFileError)`	If true, then DB::Open / CreateColumnFamily / DropColumnFamily / SetOptions will fail if options file is not detected or properly persisted.
`T`	`setIncreaseParallelism(int totalThreads)`	By default, RocksDB uses only one background thread for flush and compaction.
`T`	`setInfoLogLevel(InfoLogLevel infoLogLevel)`	Sets the RocksDB log level.
`T`	`setIsFdCloseOnExec(boolean isFdCloseOnExec)`	Disable child process inherit open files.
`T`	`setKeepLogFileNum(long keepLogFileNum)`	Specifies the maximum number of info log files to be kept.
`T`	`setListeners(java.util.List<AbstractEventListener> listeners)`	Sets the `EventListener`s whose callback functions will be called when specific RocksDB event happens.
`T`	`setLogFileTimeToRoll(long logFileTimeToRoll)`	Specifies the time interval for the info log file to roll (in seconds).
`T`	`setLogger(Logger logger)`	Any internal progress/error information generated by the db will be written to the Logger if it is non-nullptr, or to a file stored in the same directory as the DB contents if info_log is nullptr.
`T`	`setLogReadaheadSize(long logReadaheadSize)`	The number of bytes to prefetch when reading the log.
`T`	`setManifestPreallocationSize(long size)`	Number of bytes to preallocate (via fallocate) the manifest files.
`T`	`setManualWalFlush(boolean manualWalFlush)`	If true WAL is not flushed automatically after each write.
`T`	`setMaxBackgroundFlushes(int maxBackgroundFlushes)`	Deprecated. Use `MutableDBOptionsInterface.setMaxBackgroundJobs(int)`
`T`	`setMaxBgErrorResumeCount(int maxBgerrorResumeCount)`	It defines how many times db resume is called by a separate thread when background retryable IO Error happens.
`T`	`setMaxFileOpeningThreads(int maxFileOpeningThreads)`	If `MutableDBOptionsInterface.maxOpenFiles()` is -1, DB will open all files on DB::Open().
`T`	`setMaxLogFileSize(long maxLogFileSize)`	Specifies the maximum size of a info log file.
`T`	`setMaxManifestFileSize(long maxManifestFileSize)`	Manifest file is rolled over on reaching this limit.
`T`	`setMaxSubcompactions(int maxSubcompactions)`	This value represents the maximum number of threads that will concurrently perform a compaction job by breaking it into multiple, smaller ones that are run simultaneously.
`T`	`setMaxWriteBatchGroupSizeBytes(long maxWriteBatchGroupSizeBytes)`	The maximum limit of number of bytes that are written in a single batch of WAL or memtable write.
`T`	`setNewTableReaderForCompactionInputs(boolean newTableReaderForCompactionInputs)`	If true, always create a new file descriptor and new table reader for compaction inputs.
`T`	`setParanoidChecks(boolean paranoidChecks)`	If true, the implementation will do aggressive checking of the data it is processing and will stop early if it detects any errors.
`T`	`setPersistStatsToDisk(boolean persistStatsToDisk)`	If true, automatically persist stats to a hidden column family (column family name: ___rocksdb_stats_history___) every stats_persist_period_sec seconds; otherwise, write to an in-memory struct.
`T`	`setPreserveDeletes(boolean preserveDeletes)`	Needed to support differential snapshots.
`T`	`setRandomAccessMaxBufferSize(long randomAccessMaxBufferSize)`	This is a maximum buffer size that is used by WinMmapReadableFile in unbuffered disk I/O mode.
`T`	`setRateLimiter(RateLimiter rateLimiter)`	Use to control write rate of flush and compaction.
`T`	`setRecycleLogFileNum(long recycleLogFileNum)`	Recycle log files.
`T`	`setRowCache(Cache rowCache)`	A global cache for table-level rows.
`T`	`setSkipCheckingSstFileSizesOnDbOpen(boolean skipCheckingSstFileSizesOnDbOpen)`	If true, then `RocksDB.open(String)` will not fetch and check sizes of all sst files.
`T`	`setSkipStatsUpdateOnDbOpen(boolean skipStatsUpdateOnDbOpen)`	If true, then DB::Open() will not update the statistics used to optimize compaction decision by loading table properties from many files.
`T`	`setSstFileManager(SstFileManager sstFileManager)`	Use to track SST files and control their file deletion rate.
`T`	`setStatistics(Statistics statistics)`	Sets the statistics object which collects metrics about database operations.
`T`	`setTableCacheNumshardbits(int tableCacheNumshardbits)`	Number of shards used for table cache.
`T`	`setTwoWriteQueues(boolean twoWriteQueues)`	If enabled it uses two queues for writes, one for the ones with disable_memtable and one for the ones that also write to memtable.
`T`	`setUnorderedWrite(boolean unorderedWrite)`	Setting `unorderedWrite()` to true trades higher write throughput with relaxing the immutability guarantee of snapshots.
`T`	`setUseAdaptiveMutex(boolean useAdaptiveMutex)`	Use adaptive mutex, which spins in the user space before resorting to kernel.
`T`	`setUseDirectIoForFlushAndCompaction(boolean useDirectIoForFlushAndCompaction)`	Enable the OS to use direct reads and writes in flush and compaction Default: false
`T`	`setUseDirectReads(boolean useDirectReads)`	Enable the OS to use direct I/O for reading sst tables.
`T`	`setUseFsync(boolean useFsync)`	If true, then every store to stable storage will issue a fsync.
`T`	`setWalDir(java.lang.String walDir)`	This specifies the absolute dir path for write-ahead logs (WAL).
`T`	`setWalFilter(AbstractWalFilter walFilter)`	A filter object supplied to be invoked while processing write-ahead-logs (WALs) during recovery.
`T`	`setWalRecoveryMode(WALRecoveryMode walRecoveryMode)`	Recovery mode to control the consistency while replaying WAL Default: `WALRecoveryMode.PointInTimeRecovery`
`T`	`setWalSizeLimitMB(long sizeLimitMB)`	WalTtlSeconds() and walSizeLimitMB() affect how archived logs will be deleted.
`T`	`setWalTtlSeconds(long walTtlSeconds)`	`walTtlSeconds()` and `walSizeLimitMB()` affect how archived logs will be deleted.
`T`	`setWriteBufferManager(WriteBufferManager writeBufferManager)`	Use passed `WriteBufferManager` to control memory usage across multiple column families and/or DB instances.
`T`	`setWriteDbidToManifest(boolean writeDbidToManifest)`	Historically DB ID has always been stored in Identity File in DB folder.
`T`	`setWriteThreadMaxYieldUsec(long writeThreadMaxYieldUsec)`	The maximum number of microseconds that a write operation will use a yielding spin loop to coordinate with other write threads before blocking on a mutex.
`T`	`setWriteThreadSlowYieldUsec(long writeThreadSlowYieldUsec)`	The latency in microseconds after which a std::this_thread::yield call (sched_yield on Linux) is considered to be a signal that other processes or threads would like to use the current core.
`boolean`	`skipCheckingSstFileSizesOnDbOpen()`	If true, then `RocksDB.open(String)` will not fetch and check sizes of all sst files.
`boolean`	`skipStatsUpdateOnDbOpen()`	If true, then DB::Open() will not update the statistics used to optimize compaction decision by loading table properties from many files.
`Statistics`	`statistics()`	Returns statistics object.
`int`	`tableCacheNumshardbits()`	Number of shards used for table cache.
`boolean`	`twoWriteQueues()`	Returns true if two write queues are enabled.
`boolean`	`unorderedWrite()`	Returns true if unordered write are enabled.
`boolean`	`useAdaptiveMutex()`	Use adaptive mutex, which spins in the user space before resorting to kernel.
`boolean`	`useDirectIoForFlushAndCompaction()`	Enable the OS to use direct reads and writes in flush and compaction
`boolean`	`useDirectReads()`	Enable the OS to use direct I/O for reading sst tables.
`boolean`	`useFsync()`	If true, then every store to stable storage will issue a fsync.
`java.lang.String`	`walDir()`	Returns the path to the write-ahead-logs (WAL) directory.
`WalFilter`	`walFilter()`	Get's the filter for processing WALs during recovery.
`WALRecoveryMode`	`walRecoveryMode()`	Recovery mode to control the consistency while replaying WAL Default: `WALRecoveryMode.PointInTimeRecovery`
`long`	`walSizeLimitMB()`	`walTtlSeconds()` and `#walSizeLimitMB()` affect how archived logs will be deleted.
`long`	`walTtlSeconds()`	WalTtlSeconds() and walSizeLimitMB() affect how archived logs will be deleted.
`WriteBufferManager`	`writeBufferManager()`	Reference to `WriteBufferManager` used by it.
`boolean`	`writeDbidToManifest()`	Historically DB ID has always been stored in Identity File in DB folder.
`long`	`writeThreadMaxYieldUsec()`	The maximum number of microseconds that a write operation will use a yielding spin loop to coordinate with other write threads before blocking on a mutex.
`long`	`writeThreadSlowYieldUsec()`	The latency in microseconds after which a std::this_thread::yield call (sched_yield on Linux) is considered to be a signal that other processes or threads would like to use the current core.

- Method Detail
  - optimizeForSmallDb
```
T optimizeForSmallDb()
```
    Use this if your DB is very small (like under 1GB) and you don't want to spend lots of memory for memtables.
    
    Returns:
    
    the instance of the current object.
  - setEnv
```
T setEnv(Env env)
```
    Use the specified object to interact with the environment, e.g. to read/write files, schedule background work, etc. Default: Env.getDefault()
    
    Parameters:
    
    env - Env instance.
    
    Returns:
    
    the instance of the current Options.
  - getEnv
```
Env getEnv()
```
    Returns the set RocksEnv instance.
    
    Returns:
    
    RocksEnv instance set in the options.
  - setIncreaseParallelism
```
T setIncreaseParallelism(int totalThreads)
```
    By default, RocksDB uses only one background thread for flush and compaction. Calling this function will set it up such that total of `total_threads` is used.
    
    You almost definitely want to call this function if your system is bottlenecked by RocksDB.
    
    Parameters:
    
    totalThreads - The total number of threads to be used by RocksDB. A good value is the number of cores.
    
    Returns:
    
    the instance of the current Options
  - setCreateIfMissing
```
T setCreateIfMissing(boolean flag)
```
    If this value is set to true, then the database will be created if it is missing during RocksDB.open(). Default: false
    
    Parameters:
    
    flag - a flag indicating whether to create a database the specified database in RocksDB.open(org.rocksdb.Options, String) operation is missing.
    
    Returns:
    
    the instance of the current Options
    
    See Also:
    
    RocksDB.open(org.rocksdb.Options, String)
  - createIfMissing
```
boolean createIfMissing()
```
    Return true if the create_if_missing flag is set to true. If true, the database will be created if it is missing.
    
    Returns:
    
    true if the createIfMissing option is set to true.
    
    See Also:
    
    setCreateIfMissing(boolean)
  - setCreateMissingColumnFamilies
```
T setCreateMissingColumnFamilies(boolean flag)
```
    If true, missing column families will be automatically created
    
    Default: false
    
    Parameters:
    
    flag - a flag indicating if missing column families shall be created automatically.
    
    Returns:
    
    true if missing column families shall be created automatically on open.
  - createMissingColumnFamilies
```
boolean createMissingColumnFamilies()
```
    Return true if the create_missing_column_families flag is set to true. If true column families be created if missing.
    
    Returns:
    
    true if the createMissingColumnFamilies is set to true.
    
    See Also:
    
    setCreateMissingColumnFamilies(boolean)
  - setErrorIfExists
```
T setErrorIfExists(boolean errorIfExists)
```
    If true, an error will be thrown during RocksDB.open() if the database already exists. Default: false
    
    Parameters:
    
    errorIfExists - if true, an exception will be thrown during RocksDB.open() if the database already exists.
    
    Returns:
    
    the reference to the current option.
    
    See Also:
    
    RocksDB.open(org.rocksdb.Options, String)
  - errorIfExists
```
boolean errorIfExists()
```
    If true, an error will be thrown during RocksDB.open() if the database already exists.
    
    Returns:
    
    if true, an error is raised when the specified database already exists before open.
  - setParanoidChecks
```
T setParanoidChecks(boolean paranoidChecks)
```
    If true, the implementation will do aggressive checking of the data it is processing and will stop early if it detects any errors. This may have unforeseen ramifications: for example, a corruption of one DB entry may cause a large number of entries to become unreadable or for the entire DB to become unopenable. If any of the writes to the database fails (Put, Delete, Merge, Write), the database will switch to read-only mode and fail all other Write operations. Default: true
    
    Parameters:
    
    paranoidChecks - a flag to indicate whether paranoid-check is on.
    
    Returns:
    
    the reference to the current option.
  - paranoidChecks
```
boolean paranoidChecks()
```
    If true, the implementation will do aggressive checking of the data it is processing and will stop early if it detects any errors. This may have unforeseen ramifications: for example, a corruption of one DB entry may cause a large number of entries to become unreadable or for the entire DB to become unopenable. If any of the writes to the database fails (Put, Delete, Merge, Write), the database will switch to read-only mode and fail all other Write operations.
    
    Returns:
    
    a boolean indicating whether paranoid-check is on.
  - setRateLimiter
```
T setRateLimiter(RateLimiter rateLimiter)
```
    Use to control write rate of flush and compaction. Flush has higher priority than compaction. Rate limiting is disabled if nullptr. Default: nullptr
    
    Parameters:
    
    rateLimiter - RateLimiter instance.
    
    Returns:
    
    the instance of the current object.
    
    Since:
    
    3.10.0
  - setSstFileManager
```
T setSstFileManager(SstFileManager sstFileManager)
```
    Use to track SST files and control their file deletion rate. Features: - Throttle the deletion rate of the SST files. - Keep track the total size of all SST files. - Set a maximum allowed space limit for SST files that when reached the DB wont do any further flushes or compactions and will set the background error. - Can be shared between multiple dbs. Limitations: - Only track and throttle deletes of SST files in first db_path (db_name if db_paths is empty).
    
    Parameters:
    
    sstFileManager - The SST File Manager for the db.
    
    Returns:
    
    the instance of the current object.
  - setLogger
```
T setLogger(Logger logger)
```
    Any internal progress/error information generated by the db will be written to the Logger if it is non-nullptr, or to a file stored in the same directory as the DB contents if info_log is nullptr.
    
    Default: nullptr
    
    Parameters:
    
    logger - Logger instance.
    
    Returns:
    
    the instance of the current object.
  - setInfoLogLevel
```
T setInfoLogLevel(InfoLogLevel infoLogLevel)
```
    Sets the RocksDB log level. Default level is INFO
    
    Parameters:
    
    infoLogLevel - log level to set.
    
    Returns:
    
    the instance of the current object.
  - infoLogLevel
```
InfoLogLevel infoLogLevel()
```
    Returns currently set log level.
    
    Returns:
    
    InfoLogLevel instance.
  - setMaxFileOpeningThreads
```
T setMaxFileOpeningThreads(int maxFileOpeningThreads)
```
    If MutableDBOptionsInterface.maxOpenFiles() is -1, DB will open all files on DB::Open(). You can use this option to increase the number of threads used to open the files. Default: 16
    
    Parameters:
    
    maxFileOpeningThreads - the maximum number of threads to use to open files
    
    Returns:
    
    the reference to the current options.
  - maxFileOpeningThreads
```
int maxFileOpeningThreads()
```
    If MutableDBOptionsInterface.maxOpenFiles() is -1, DB will open all files on DB::Open(). You can use this option to increase the number of threads used to open the files. Default: 16
    
    Returns:
    
    the maximum number of threads to use to open files
  - setStatistics
```
T setStatistics(Statistics statistics)
```
    Sets the statistics object which collects metrics about database operations. Statistics objects should not be shared between DB instances as it does not use any locks to prevent concurrent updates.
    
    Parameters:
    
    statistics - The statistics to set
    
    Returns:
    
    the instance of the current object.
    
    See Also:
    
    RocksDB.open(org.rocksdb.Options, String)
  - statistics
```
Statistics statistics()
```
    Returns statistics object.
    
    Returns:
    
    the instance of the statistics object or null if there is no statistics object.
    
    See Also:
    
    setStatistics(Statistics)
  - setUseFsync
```
T setUseFsync(boolean useFsync)
```
    If true, then every store to stable storage will issue a fsync.
    
    If false, then every store to stable storage will issue a fdatasync. This parameter should be set to true while storing data to filesystem like ext3 that can lose files after a reboot.
    
    Default: false
    
    Parameters:
    
    useFsync - a boolean flag to specify whether to use fsync
    
    Returns:
    
    the instance of the current object.
  - useFsync
```
boolean useFsync()
```
    If true, then every store to stable storage will issue a fsync.
    
    If false, then every store to stable storage will issue a fdatasync. This parameter should be set to true while storing data to filesystem like ext3 that can lose files after a reboot.
    
    Returns:
    
    boolean value indicating if fsync is used.
  - setDbPaths
```
T setDbPaths(java.util.Collection<DbPath> dbPaths)
```
    A list of paths where SST files can be put into, with its target size. Newer data is placed into paths specified earlier in the vector while older data gradually moves to paths specified later in the vector. For example, you have a flash device with 10GB allocated for the DB, as well as a hard drive of 2TB, you should config it to be: [{"/flash_path", 10GB}, {"/hard_drive", 2TB}] The system will try to guarantee data under each path is close to but not larger than the target size. But current and future file sizes used by determining where to place a file are based on best-effort estimation, which means there is a chance that the actual size under the directory is slightly more than target size under some workloads. User should give some buffer room for those cases. If none of the paths has sufficient room to place a file, the file will be placed to the last path anyway, despite to the target size. Placing newer data to earlier paths is also best-efforts. User should expect user files to be placed in higher levels in some extreme cases. If left empty, only one path will be used, which is db_name passed when opening the DB. Default: empty
    
    Parameters:
    
    dbPaths - the paths and target sizes
    
    Returns:
    
    the reference to the current options
  - dbPaths
```
java.util.List<DbPath> dbPaths()
```
    A list of paths where SST files can be put into, with its target size. Newer data is placed into paths specified earlier in the vector while older data gradually moves to paths specified later in the vector. For example, you have a flash device with 10GB allocated for the DB, as well as a hard drive of 2TB, you should config it to be: [{"/flash_path", 10GB}, {"/hard_drive", 2TB}] The system will try to guarantee data under each path is close to but not larger than the target size. But current and future file sizes used by determining where to place a file are based on best-effort estimation, which means there is a chance that the actual size under the directory is slightly more than target size under some workloads. User should give some buffer room for those cases. If none of the paths has sufficient room to place a file, the file will be placed to the last path anyway, despite to the target size. Placing newer data to earlier paths is also best-efforts. User should expect user files to be placed in higher levels in some extreme cases. If left empty, only one path will be used, which is db_name passed when opening the DB. Default: Collections.emptyList()
    
    Returns:
    
    dbPaths the paths and target sizes
  - setDbLogDir
```
T setDbLogDir(java.lang.String dbLogDir)
```
    This specifies the info LOG dir. If it is empty, the log files will be in the same dir as data. If it is non empty, the log files will be in the specified dir, and the db data dir's absolute path will be used as the log file name's prefix.
    
    Parameters:
    
    dbLogDir - the path to the info log directory
    
    Returns:
    
    the instance of the current object.
  - dbLogDir
```
java.lang.String dbLogDir()
```
    Returns the directory of info log. If it is empty, the log files will be in the same dir as data. If it is non empty, the log files will be in the specified dir, and the db data dir's absolute path will be used as the log file name's prefix.
    
    Returns:
    
    the path to the info log directory
  - setWalDir
```
T setWalDir(java.lang.String walDir)
```
    This specifies the absolute dir path for write-ahead logs (WAL). If it is empty, the log files will be in the same dir as data, dbname is used as the data dir by default If it is non empty, the log files will be in kept the specified dir. When destroying the db, all log files in wal_dir and the dir itself is deleted
    
    Parameters:
    
    walDir - the path to the write-ahead-log directory.
    
    Returns:
    
    the instance of the current object.
  - walDir
```
java.lang.String walDir()
```
    Returns the path to the write-ahead-logs (WAL) directory. If it is empty, the log files will be in the same dir as data, dbname is used as the data dir by default If it is non empty, the log files will be in kept the specified dir. When destroying the db, all log files in wal_dir and the dir itself is deleted
    
    Returns:
    
    the path to the write-ahead-logs (WAL) directory.
  - setDeleteObsoleteFilesPeriodMicros
```
T setDeleteObsoleteFilesPeriodMicros(long micros)
```
    The periodicity when obsolete files get deleted. The default value is 6 hours. The files that get out of scope by compaction process will still get automatically delete on every compaction, regardless of this setting
    
    Parameters:
    
    micros - the time interval in micros
    
    Returns:
    
    the instance of the current object.
  - deleteObsoleteFilesPeriodMicros
```
long deleteObsoleteFilesPeriodMicros()
```
    The periodicity when obsolete files get deleted. The default value is 6 hours. The files that get out of scope by compaction process will still get automatically delete on every compaction, regardless of this setting
    
    Returns:
    
    the time interval in micros when obsolete files will be deleted.
  - setMaxSubcompactions
```
T setMaxSubcompactions(int maxSubcompactions)
```
    This value represents the maximum number of threads that will concurrently perform a compaction job by breaking it into multiple, smaller ones that are run simultaneously. Default: 1 (i.e. no subcompactions)
    
    Parameters:
    
    maxSubcompactions - The maximum number of threads that will concurrently perform a compaction job
    
    Returns:
    
    the instance of the current object.
  - maxSubcompactions
```
int maxSubcompactions()
```
    This value represents the maximum number of threads that will concurrently perform a compaction job by breaking it into multiple, smaller ones that are run simultaneously. Default: 1 (i.e. no subcompactions)
    
    Returns:
    
    The maximum number of threads that will concurrently perform a compaction job
  - setMaxBackgroundFlushes
```
@Deprecated
T setMaxBackgroundFlushes(int maxBackgroundFlushes)
```
    Deprecated.
    Use MutableDBOptionsInterface.setMaxBackgroundJobs(int)
    
    NOT SUPPORTED ANYMORE: RocksDB automatically decides this based on the value of max_background_jobs. For backwards compatibility we will set `max_background_jobs = max_background_compactions + max_background_flushes` in the case where user sets at least one of `max_background_compactions` or `max_background_flushes`. Specifies the maximum number of concurrent background flush jobs. If you're increasing this, also consider increasing number of threads in HIGH priority thread pool. For more information, see Default: -1
    
    Parameters:
    
    maxBackgroundFlushes - number of max concurrent flush jobs
    
    Returns:
    
    the instance of the current object.
    
    See Also:
    
    Env.setBackgroundThreads(int), Env.setBackgroundThreads(int, Priority), MutableDBOptionsInterface.maxBackgroundCompactions()
  - maxBackgroundFlushes
```
@Deprecated
int maxBackgroundFlushes()
```
    Deprecated.
    
    NOT SUPPORTED ANYMORE: RocksDB automatically decides this based on the value of max_background_jobs. For backwards compatibility we will set `max_background_jobs = max_background_compactions + max_background_flushes` in the case where user sets at least one of `max_background_compactions` or `max_background_flushes`. Returns the maximum number of concurrent background flush jobs. If you're increasing this, also consider increasing number of threads in HIGH priority thread pool. For more information, see Default: -1
    
    Returns:
    
    the maximum number of concurrent background flush jobs.
    
    See Also:
    
    Env.setBackgroundThreads(int), Env.setBackgroundThreads(int, Priority)
  - setMaxLogFileSize
```
T setMaxLogFileSize(long maxLogFileSize)
```
    Specifies the maximum size of a info log file. If the current log file is larger than `max_log_file_size`, a new info log file will be created. If 0, all logs will be written to one log file.
    
    Parameters:
    
    maxLogFileSize - the maximum size of a info log file.
    
    Returns:
    
    the instance of the current object.
    
    Throws:
    
    java.lang.IllegalArgumentException - thrown on 32-Bit platforms while overflowing the underlying platform specific value.
  - maxLogFileSize
```
long maxLogFileSize()
```
    Returns the maximum size of a info log file. If the current log file is larger than this size, a new info log file will be created. If 0, all logs will be written to one log file.
    
    Returns:
    
    the maximum size of the info log file.
  - setLogFileTimeToRoll
```
T setLogFileTimeToRoll(long logFileTimeToRoll)
```
    Specifies the time interval for the info log file to roll (in seconds). If specified with non-zero value, log file will be rolled if it has been active longer than `log_file_time_to_roll`. Default: 0 (disabled)
    
    Parameters:
    
    logFileTimeToRoll - the time interval in seconds.
    
    Returns:
    
    the instance of the current object.
    
    Throws:
    
    java.lang.IllegalArgumentException - thrown on 32-Bit platforms while overflowing the underlying platform specific value.
  - logFileTimeToRoll
```
long logFileTimeToRoll()
```
    Returns the time interval for the info log file to roll (in seconds). If specified with non-zero value, log file will be rolled if it has been active longer than `log_file_time_to_roll`. Default: 0 (disabled)
    
    Returns:
    
    the time interval in seconds.
  - setKeepLogFileNum
```
T setKeepLogFileNum(long keepLogFileNum)
```
    Specifies the maximum number of info log files to be kept. Default: 1000
    
    Parameters:
    
    keepLogFileNum - the maximum number of info log files to be kept.
    
    Returns:
    
    the instance of the current object.
    
    Throws:
    
    java.lang.IllegalArgumentException - thrown on 32-Bit platforms while overflowing the underlying platform specific value.
  - keepLogFileNum
```
long keepLogFileNum()
```
    Returns the maximum number of info log files to be kept. Default: 1000
    
    Returns:
    
    the maximum number of info log files to be kept.
  - setRecycleLogFileNum
```
T setRecycleLogFileNum(long recycleLogFileNum)
```
    Recycle log files. If non-zero, we will reuse previously written log files for new logs, overwriting the old data. The value indicates how many such files we will keep around at any point in time for later use. This is more efficient because the blocks are already allocated and fdatasync does not need to update the inode after each write. Default: 0
    
    Parameters:
    
    recycleLogFileNum - the number of log files to keep for recycling
    
    Returns:
    
    the reference to the current options
  - recycleLogFileNum
```
long recycleLogFileNum()
```
    Recycle log files. If non-zero, we will reuse previously written log files for new logs, overwriting the old data. The value indicates how many such files we will keep around at any point in time for later use. This is more efficient because the blocks are already allocated and fdatasync does not need to update the inode after each write. Default: 0
    
    Returns:
    
    the number of log files kept for recycling
  - setMaxManifestFileSize
```
T setMaxManifestFileSize(long maxManifestFileSize)
```
    Manifest file is rolled over on reaching this limit. The older manifest file be deleted. The default value is 1GB so that the manifest file can grow, but not reach the limit of storage capacity.
    
    Parameters:
    
    maxManifestFileSize - the size limit of a manifest file.
    
    Returns:
    
    the instance of the current object.
  - maxManifestFileSize
```
long maxManifestFileSize()
```
    Manifest file is rolled over on reaching this limit. The older manifest file be deleted. The default value is 1GB so that the manifest file can grow, but not reach the limit of storage capacity.
    
    Returns:
    
    the size limit of a manifest file.
  - setTableCacheNumshardbits
```
T setTableCacheNumshardbits(int tableCacheNumshardbits)
```
    Number of shards used for table cache.
    
    Parameters:
    
    tableCacheNumshardbits - the number of chards
    
    Returns:
    
    the instance of the current object.
  - tableCacheNumshardbits
```
int tableCacheNumshardbits()
```
    Number of shards used for table cache.
    
    Returns:
    
    the number of shards used for table cache.
  - setWalTtlSeconds
```
T setWalTtlSeconds(long walTtlSeconds)
```
    walTtlSeconds() and walSizeLimitMB() affect how archived logs will be deleted.
    
    If both set to 0, logs will be deleted asap and will not get into the archive.
    
    If WAL_ttl_seconds is 0 and WAL_size_limit_MB is not 0, WAL files will be checked every 10 min and if total size is greater then WAL_size_limit_MB, they will be deleted starting with the earliest until size_limit is met. All empty files will be deleted.
    
    If WAL_ttl_seconds is not 0 and WAL_size_limit_MB is 0, then WAL files will be checked every WAL_ttl_seconds / 2 and those that are older than WAL_ttl_seconds will be deleted.
    
    If both are not 0, WAL files will be checked every 10 min and both checks will be performed with ttl being first.
    Parameters:
    
    walTtlSeconds - the ttl seconds
    
    Returns:
    
    the instance of the current object.
    
    See Also:
    
    setWalSizeLimitMB(long)
  - walTtlSeconds
```
long walTtlSeconds()
```
    WalTtlSeconds() and walSizeLimitMB() affect how archived logs will be deleted.
    
    If both set to 0, logs will be deleted asap and will not get into the archive.
    
    If WAL_ttl_seconds is 0 and WAL_size_limit_MB is not 0, WAL files will be checked every 10 min and if total size is greater then WAL_size_limit_MB, they will be deleted starting with the earliest until size_limit is met. All empty files will be deleted.
    
    If WAL_ttl_seconds is not 0 and WAL_size_limit_MB is 0, then WAL files will be checked every WAL_ttl_seconds / 2 and those that are older than WAL_ttl_seconds will be deleted.
    
    If both are not 0, WAL files will be checked every 10 min and both checks will be performed with ttl being first.
    Returns:
    
    the wal-ttl seconds
    
    See Also:
    
    walSizeLimitMB()
  - setWalSizeLimitMB
```
T setWalSizeLimitMB(long sizeLimitMB)
```
    WalTtlSeconds() and walSizeLimitMB() affect how archived logs will be deleted.
    
    If both set to 0, logs will be deleted asap and will not get into the archive.
    
    If WAL_ttl_seconds is 0 and WAL_size_limit_MB is not 0, WAL files will be checked every 10 min and if total size is greater then WAL_size_limit_MB, they will be deleted starting with the earliest until size_limit is met. All empty files will be deleted.
    
    If WAL_ttl_seconds is not 0 and WAL_size_limit_MB is 0, then WAL files will be checked every WAL_ttl_secondsi / 2 and those that are older than WAL_ttl_seconds will be deleted.
    
    If both are not 0, WAL files will be checked every 10 min and both checks will be performed with ttl being first.
    Parameters:
    
    sizeLimitMB - size limit in mega-bytes.
    
    Returns:
    
    the instance of the current object.
    
    See Also:
    
    setWalSizeLimitMB(long)
  - walSizeLimitMB
```
long walSizeLimitMB()
```
    walTtlSeconds() and #walSizeLimitMB() affect how archived logs will be deleted.
    
    If both set to 0, logs will be deleted asap and will not get into the archive.
    
    If WAL_ttl_seconds is 0 and WAL_size_limit_MB is not 0, WAL files will be checked every 10 min and if total size is greater then WAL_size_limit_MB, they will be deleted starting with the earliest until size_limit is met. All empty files will be deleted.
    
    If WAL_ttl_seconds is not 0 and WAL_size_limit_MB is 0, then WAL files will be checked every WAL_ttl_seconds i / 2 and those that are older than WAL_ttl_seconds will be deleted.
    
    If both are not 0, WAL files will be checked every 10 min and both checks will be performed with ttl being first.
    Returns:
    
    size limit in mega-bytes.
    
    See Also:
    
    walSizeLimitMB()
  - setMaxWriteBatchGroupSizeBytes
```
T setMaxWriteBatchGroupSizeBytes(long maxWriteBatchGroupSizeBytes)
```
    The maximum limit of number of bytes that are written in a single batch of WAL or memtable write. It is followed when the leader write size is larger than 1/8 of this limit. Default: 1 MB
    
    Parameters:
    
    maxWriteBatchGroupSizeBytes - the maximum limit of number of bytes, see description.
    
    Returns:
    
    the instance of the current object.
  - maxWriteBatchGroupSizeBytes
```
long maxWriteBatchGroupSizeBytes()
```
    The maximum limit of number of bytes that are written in a single batch of WAL or memtable write. It is followed when the leader write size is larger than 1/8 of this limit. Default: 1 MB
    
    Returns:
    
    the maximum limit of number of bytes, see description.
  - setManifestPreallocationSize
```
T setManifestPreallocationSize(long size)
```
    Number of bytes to preallocate (via fallocate) the manifest files. Default is 4mb, which is reasonable to reduce random IO as well as prevent overallocation for mounts that preallocate large amounts of data (such as xfs's allocsize option).
    
    Parameters:
    
    size - the size in byte
    
    Returns:
    
    the instance of the current object.
    
    Throws:
    
    java.lang.IllegalArgumentException - thrown on 32-Bit platforms while overflowing the underlying platform specific value.
  - manifestPreallocationSize
```
long manifestPreallocationSize()
```
    Number of bytes to preallocate (via fallocate) the manifest files. Default is 4mb, which is reasonable to reduce random IO as well as prevent overallocation for mounts that preallocate large amounts of data (such as xfs's allocsize option).
    
    Returns:
    
    size in bytes.
  - setUseDirectReads
```
T setUseDirectReads(boolean useDirectReads)
```
    Enable the OS to use direct I/O for reading sst tables. Default: false
    
    Parameters:
    
    useDirectReads - if true, then direct read is enabled
    
    Returns:
    
    the instance of the current object.
  - useDirectReads
```
boolean useDirectReads()
```
    Enable the OS to use direct I/O for reading sst tables. Default: false
    
    Returns:
    
    if true, then direct reads are enabled
  - setUseDirectIoForFlushAndCompaction
```
T setUseDirectIoForFlushAndCompaction(boolean useDirectIoForFlushAndCompaction)
```
    Enable the OS to use direct reads and writes in flush and compaction Default: false
    
    Parameters:
    
    useDirectIoForFlushAndCompaction - if true, then direct I/O will be enabled for background flush and compactions
    
    Returns:
    
    the instance of the current object.
  - useDirectIoForFlushAndCompaction
```
boolean useDirectIoForFlushAndCompaction()
```
    Enable the OS to use direct reads and writes in flush and compaction
    
    Returns:
    
    if true, then direct I/O is enabled for flush and compaction
  - setAllowFAllocate
```
T setAllowFAllocate(boolean allowFAllocate)
```
    Whether fallocate calls are allowed
    
    Parameters:
    
    allowFAllocate - false if fallocate() calls are bypassed
    
    Returns:
    
    the reference to the current options.
  - allowFAllocate
```
boolean allowFAllocate()
```
    Whether fallocate calls are allowed
    
    Returns:
    
    false if fallocate() calls are bypassed
  - setAllowMmapReads
```
T setAllowMmapReads(boolean allowMmapReads)
```
    Allow the OS to mmap file for reading sst tables. Default: false
    
    Parameters:
    
    allowMmapReads - true if mmap reads are allowed.
    
    Returns:
    
    the instance of the current object.
  - allowMmapReads
```
boolean allowMmapReads()
```
    Allow the OS to mmap file for reading sst tables. Default: false
    
    Returns:
    
    true if mmap reads are allowed.
  - setAllowMmapWrites
```
T setAllowMmapWrites(boolean allowMmapWrites)
```
    Allow the OS to mmap file for writing. Default: false
    
    Parameters:
    
    allowMmapWrites - true if mmap writes are allowd.
    
    Returns:
    
    the instance of the current object.
  - allowMmapWrites
```
boolean allowMmapWrites()
```
    Allow the OS to mmap file for writing. Default: false
    
    Returns:
    
    true if mmap writes are allowed.
  - setIsFdCloseOnExec
```
T setIsFdCloseOnExec(boolean isFdCloseOnExec)
```
    Disable child process inherit open files. Default: true
    
    Parameters:
    
    isFdCloseOnExec - true if child process inheriting open files is disabled.
    
    Returns:
    
    the instance of the current object.
  - isFdCloseOnExec
```
boolean isFdCloseOnExec()
```
    Disable child process inherit open files. Default: true
    
    Returns:
    
    true if child process inheriting open files is disabled.
  - setAdviseRandomOnOpen
```
T setAdviseRandomOnOpen(boolean adviseRandomOnOpen)
```
    If set true, will hint the underlying file system that the file access pattern is random, when a sst file is opened. Default: true
    
    Parameters:
    
    adviseRandomOnOpen - true if hinting random access is on.
    
    Returns:
    
    the instance of the current object.
  - adviseRandomOnOpen
```
boolean adviseRandomOnOpen()
```
    If set true, will hint the underlying file system that the file access pattern is random, when a sst file is opened. Default: true
    
    Returns:
    
    true if hinting random access is on.
  - setDbWriteBufferSize
```
T setDbWriteBufferSize(long dbWriteBufferSize)
```
    Amount of data to build up in memtables across all column families before writing to disk. This is distinct from ColumnFamilyOptions.writeBufferSize(), which enforces a limit for a single memtable. This feature is disabled by default. Specify a non-zero value to enable it. Default: 0 (disabled)
    
    Parameters:
    
    dbWriteBufferSize - the size of the write buffer
    
    Returns:
    
    the reference to the current options.
  - setWriteBufferManager
```
T setWriteBufferManager(WriteBufferManager writeBufferManager)
```
    Use passed WriteBufferManager to control memory usage across multiple column families and/or DB instances. Check https://github.com/facebook/rocksdb/wiki/Write-Buffer-Manager for more details on when to use it
    
    Parameters:
    
    writeBufferManager - The WriteBufferManager to use
    
    Returns:
    
    the reference of the current options.
  - writeBufferManager
```
WriteBufferManager writeBufferManager()
```
    Reference to WriteBufferManager used by it.
    Default: null (Disabled)
    
    Returns:
    
    a reference to WriteBufferManager
  - dbWriteBufferSize
```
long dbWriteBufferSize()
```
    Amount of data to build up in memtables across all column families before writing to disk. This is distinct from ColumnFamilyOptions.writeBufferSize(), which enforces a limit for a single memtable. This feature is disabled by default. Specify a non-zero value to enable it. Default: 0 (disabled)
    
    Returns:
    
    the size of the write buffer
  - setAccessHintOnCompactionStart
```
T setAccessHintOnCompactionStart(AccessHint accessHint)
```
    Specify the file access pattern once a compaction is started. It will be applied to all input files of a compaction. Default: AccessHint.NORMAL
    
    Parameters:
    
    accessHint - The access hint
    
    Returns:
    
    the reference to the current options.
  - accessHintOnCompactionStart
```
AccessHint accessHintOnCompactionStart()
```
    Specify the file access pattern once a compaction is started. It will be applied to all input files of a compaction. Default: AccessHint.NORMAL
    
    Returns:
    
    The access hint
  - setNewTableReaderForCompactionInputs
```
T setNewTableReaderForCompactionInputs(boolean newTableReaderForCompactionInputs)
```
    If true, always create a new file descriptor and new table reader for compaction inputs. Turn this parameter on may introduce extra memory usage in the table reader, if it allocates extra memory for indexes. This will allow file descriptor prefetch options to be set for compaction input files and not to impact file descriptors for the same file used by user queries. Suggest to enable BlockBasedTableConfig.cacheIndexAndFilterBlocks() for this mode if using block-based table. Default: false
    
    Parameters:
    
    newTableReaderForCompactionInputs - true if a new file descriptor and table reader should be created for compaction inputs
    
    Returns:
    
    the reference to the current options.
  - newTableReaderForCompactionInputs
```
boolean newTableReaderForCompactionInputs()
```
    If true, always create a new file descriptor and new table reader for compaction inputs. Turn this parameter on may introduce extra memory usage in the table reader, if it allocates extra memory for indexes. This will allow file descriptor prefetch options to be set for compaction input files and not to impact file descriptors for the same file used by user queries. Suggest to enable BlockBasedTableConfig.cacheIndexAndFilterBlocks() for this mode if using block-based table. Default: false
    
    Returns:
    
    true if a new file descriptor and table reader are created for compaction inputs
  - setRandomAccessMaxBufferSize
```
T setRandomAccessMaxBufferSize(long randomAccessMaxBufferSize)
```
    This is a maximum buffer size that is used by WinMmapReadableFile in unbuffered disk I/O mode. We need to maintain an aligned buffer for reads. We allow the buffer to grow until the specified value and then for bigger requests allocate one shot buffers. In unbuffered mode we always bypass read-ahead buffer at ReadaheadRandomAccessFile When read-ahead is required we then make use of MutableDBOptionsInterface.compactionReadaheadSize() value and always try to read ahead. With read-ahead we always pre-allocate buffer to the size instead of growing it up to a limit. This option is currently honored only on Windows Default: 1 Mb Special value: 0 - means do not maintain per instance buffer. Allocate per request buffer and avoid locking.
    
    Parameters:
    
    randomAccessMaxBufferSize - the maximum size of the random access buffer
    
    Returns:
    
    the reference to the current options.
  - randomAccessMaxBufferSize
```
long randomAccessMaxBufferSize()
```
    This is a maximum buffer size that is used by WinMmapReadableFile in unbuffered disk I/O mode. We need to maintain an aligned buffer for reads. We allow the buffer to grow until the specified value and then for bigger requests allocate one shot buffers. In unbuffered mode we always bypass read-ahead buffer at ReadaheadRandomAccessFile When read-ahead is required we then make use of MutableDBOptionsInterface.compactionReadaheadSize() value and always try to read ahead. With read-ahead we always pre-allocate buffer to the size instead of growing it up to a limit. This option is currently honored only on Windows Default: 1 Mb Special value: 0 - means do not maintain per instance buffer. Allocate per request buffer and avoid locking.
    
    Returns:
    
    the maximum size of the random access buffer
  - setUseAdaptiveMutex
```
T setUseAdaptiveMutex(boolean useAdaptiveMutex)
```
    Use adaptive mutex, which spins in the user space before resorting to kernel. This could reduce context switch when the mutex is not heavily contended. However, if the mutex is hot, we could end up wasting spin time. Default: false
    
    Parameters:
    
    useAdaptiveMutex - true if adaptive mutex is used.
    
    Returns:
    
    the instance of the current object.
  - useAdaptiveMutex
```
boolean useAdaptiveMutex()
```
    Use adaptive mutex, which spins in the user space before resorting to kernel. This could reduce context switch when the mutex is not heavily contended. However, if the mutex is hot, we could end up wasting spin time. Default: false
    
    Returns:
    
    true if adaptive mutex is used.
  - setListeners
```
T setListeners(java.util.List<AbstractEventListener> listeners)
```
    Sets the EventListeners whose callback functions will be called when specific RocksDB event happens. Note: the RocksJava API currently only supports EventListeners implemented in Java. It could be extended in future to also support adding/removing EventListeners implemented in C++.
    
    Parameters:
    
    listeners - the listeners who should be notified on various events.
    
    Returns:
    
    the instance of the current object.
  - listeners
```
java.util.List<AbstractEventListener> listeners()
```
    Sets the EventListeners whose callback functions will be called when specific RocksDB event happens. Note: the RocksJava API currently only supports EventListeners implemented in Java. It could be extended in future to also support adding/removing EventListeners implemented in C++.
    
    Returns:
    
    the instance of the current object.
  - setEnableThreadTracking
```
T setEnableThreadTracking(boolean enableThreadTracking)
```
    If true, then the status of the threads involved in this DB will be tracked and available via GetThreadList() API. Default: false
    
    Parameters:
    
    enableThreadTracking - true to enable tracking
    
    Returns:
    
    the reference to the current options.
  - enableThreadTracking
```
boolean enableThreadTracking()
```
    If true, then the status of the threads involved in this DB will be tracked and available via GetThreadList() API. Default: false
    
    Returns:
    
    true if tracking is enabled
  - setEnablePipelinedWrite
```
T setEnablePipelinedWrite(boolean enablePipelinedWrite)
```
    By default, a single write thread queue is maintained. The thread gets to the head of the queue becomes write batch group leader and responsible for writing to WAL and memtable for the batch group. If enablePipelinedWrite() is true, separate write thread queue is maintained for WAL write and memtable write. A write thread first enter WAL writer queue and then memtable writer queue. Pending thread on the WAL writer queue thus only have to wait for previous writers to finish their WAL writing but not the memtable writing. Enabling the feature may improve write throughput and reduce latency of the prepare phase of two-phase commit. Default: false
    
    Parameters:
    
    enablePipelinedWrite - true to enabled pipelined writes
    
    Returns:
    
    the reference to the current options.
  - enablePipelinedWrite
```
boolean enablePipelinedWrite()
```
    Returns true if pipelined writes are enabled. See setEnablePipelinedWrite(boolean).
    
    Returns:
    
    true if pipelined writes are enabled, false otherwise.
  - setUnorderedWrite
```
T setUnorderedWrite(boolean unorderedWrite)
```
    Setting unorderedWrite() to true trades higher write throughput with relaxing the immutability guarantee of snapshots. This violates the repeatability one expects from ::Get from a snapshot, as well as ::MultiGet and Iterator's consistent-point-in-time view property. If the application cannot tolerate the relaxed guarantees, it can implement its own mechanisms to work around that and yet benefit from the higher throughput. Using TransactionDB with WRITE_PREPARED write policy and twoWriteQueues() true is one way to achieve immutable snapshots despite unordered_write. By default, i.e., when it is false, rocksdb does not advance the sequence number for new snapshots unless all the writes with lower sequence numbers are already finished. This provides the immutability that we except from snapshots. Moreover, since Iterator and MultiGet internally depend on snapshots, the snapshot immutability results into Iterator and MultiGet offering consistent-point-in-time view. If set to true, although Read-Your-Own-Write property is still provided, the snapshot immutability property is relaxed: the writes issued after the snapshot is obtained (with larger sequence numbers) will be still not visible to the reads from that snapshot, however, there still might be pending writes (with lower sequence number) that will change the state visible to the snapshot after they are landed to the memtable.
    
    Parameters:
    
    unorderedWrite - true to enabled unordered write
    
    Returns:
    
    the reference to the current options.
  - unorderedWrite
```
boolean unorderedWrite()
```
    Returns true if unordered write are enabled. See setUnorderedWrite(boolean).
    
    Returns:
    
    true if unordered write are enabled, false otherwise.
  - setAllowConcurrentMemtableWrite
```
T setAllowConcurrentMemtableWrite(boolean allowConcurrentMemtableWrite)
```
    If true, allow multi-writers to update mem tables in parallel. Only some memtable factorys support concurrent writes; currently it is implemented only for SkipListFactory. Concurrent memtable writes are not compatible with inplace_update_support or filter_deletes. It is strongly recommended to set setEnableWriteThreadAdaptiveYield(boolean) if you are going to use this feature. Default: true
    
    Parameters:
    
    allowConcurrentMemtableWrite - true to enable concurrent writes for the memtable
    
    Returns:
    
    the reference to the current options.
  - allowConcurrentMemtableWrite
```
boolean allowConcurrentMemtableWrite()
```
    If true, allow multi-writers to update mem tables in parallel. Only some memtable factorys support concurrent writes; currently it is implemented only for SkipListFactory. Concurrent memtable writes are not compatible with inplace_update_support or filter_deletes. It is strongly recommended to set setEnableWriteThreadAdaptiveYield(boolean) if you are going to use this feature. Default: true
    
    Returns:
    
    true if concurrent writes are enabled for the memtable
  - setEnableWriteThreadAdaptiveYield
```
T setEnableWriteThreadAdaptiveYield(boolean enableWriteThreadAdaptiveYield)
```
    If true, threads synchronizing with the write batch group leader will wait for up to writeThreadMaxYieldUsec() before blocking on a mutex. This can substantially improve throughput for concurrent workloads, regardless of whether allowConcurrentMemtableWrite() is enabled. Default: true
    
    Parameters:
    
    enableWriteThreadAdaptiveYield - true to enable adaptive yield for the write threads
    
    Returns:
    
    the reference to the current options.
  - enableWriteThreadAdaptiveYield
```
boolean enableWriteThreadAdaptiveYield()
```
    If true, threads synchronizing with the write batch group leader will wait for up to writeThreadMaxYieldUsec() before blocking on a mutex. This can substantially improve throughput for concurrent workloads, regardless of whether allowConcurrentMemtableWrite() is enabled. Default: true
    
    Returns:
    
    true if adaptive yield is enabled for the writing threads
  - setWriteThreadMaxYieldUsec
```
T setWriteThreadMaxYieldUsec(long writeThreadMaxYieldUsec)
```
    The maximum number of microseconds that a write operation will use a yielding spin loop to coordinate with other write threads before blocking on a mutex. (Assuming writeThreadSlowYieldUsec() is set properly) increasing this value is likely to increase RocksDB throughput at the expense of increased CPU usage. Default: 100
    
    Parameters:
    
    writeThreadMaxYieldUsec - maximum number of microseconds
    
    Returns:
    
    the reference to the current options.
  - writeThreadMaxYieldUsec
```
long writeThreadMaxYieldUsec()
```
    The maximum number of microseconds that a write operation will use a yielding spin loop to coordinate with other write threads before blocking on a mutex. (Assuming writeThreadSlowYieldUsec() is set properly) increasing this value is likely to increase RocksDB throughput at the expense of increased CPU usage. Default: 100
    
    Returns:
    
    the maximum number of microseconds
  - setWriteThreadSlowYieldUsec
```
T setWriteThreadSlowYieldUsec(long writeThreadSlowYieldUsec)
```
    The latency in microseconds after which a std::this_thread::yield call (sched_yield on Linux) is considered to be a signal that other processes or threads would like to use the current core. Increasing this makes writer threads more likely to take CPU by spinning, which will show up as an increase in the number of involuntary context switches. Default: 3
    
    Parameters:
    
    writeThreadSlowYieldUsec - the latency in microseconds
    
    Returns:
    
    the reference to the current options.
  - writeThreadSlowYieldUsec
```
long writeThreadSlowYieldUsec()
```
    The latency in microseconds after which a std::this_thread::yield call (sched_yield on Linux) is considered to be a signal that other processes or threads would like to use the current core. Increasing this makes writer threads more likely to take CPU by spinning, which will show up as an increase in the number of involuntary context switches. Default: 3
    
    Returns:
    
    writeThreadSlowYieldUsec the latency in microseconds
  - setSkipStatsUpdateOnDbOpen
```
T setSkipStatsUpdateOnDbOpen(boolean skipStatsUpdateOnDbOpen)
```
    If true, then DB::Open() will not update the statistics used to optimize compaction decision by loading table properties from many files. Turning off this feature will improve DBOpen time especially in disk environment. Default: false
    
    Parameters:
    
    skipStatsUpdateOnDbOpen - true if updating stats will be skipped
    
    Returns:
    
    the reference to the current options.
  - skipStatsUpdateOnDbOpen
```
boolean skipStatsUpdateOnDbOpen()
```
    If true, then DB::Open() will not update the statistics used to optimize compaction decision by loading table properties from many files. Turning off this feature will improve DBOpen time especially in disk environment. Default: false
    
    Returns:
    
    true if updating stats will be skipped
  - setSkipCheckingSstFileSizesOnDbOpen
```
T setSkipCheckingSstFileSizesOnDbOpen(boolean skipCheckingSstFileSizesOnDbOpen)
```
    If true, then RocksDB.open(String) will not fetch and check sizes of all sst files. This may significantly speed up startup if there are many sst files, especially when using non-default Env with expensive GetFileSize(). We'll still check that all required sst files exist. If paranoid_checks is false, this option is ignored, and sst files are not checked at all. Default: false
    
    Parameters:
    
    skipCheckingSstFileSizesOnDbOpen - if true, then SST file sizes will not be checked when calling RocksDB.open(String).
    
    Returns:
    
    the reference to the current options.
  - skipCheckingSstFileSizesOnDbOpen
```
boolean skipCheckingSstFileSizesOnDbOpen()
```
    If true, then RocksDB.open(String) will not fetch and check sizes of all sst files. This may significantly speed up startup if there are many sst files, especially when using non-default Env with expensive GetFileSize(). We'll still check that all required sst files exist. If paranoid_checks is false, this option is ignored, and sst files are not checked at all. Default: false
    
    Returns:
    
    true, if file sizes will not be checked when calling RocksDB.open(String).
  - setWalRecoveryMode
```
T setWalRecoveryMode(WALRecoveryMode walRecoveryMode)
```
    Recovery mode to control the consistency while replaying WAL Default: WALRecoveryMode.PointInTimeRecovery
    
    Parameters:
    
    walRecoveryMode - The WAL recover mode
    
    Returns:
    
    the reference to the current options.
  - walRecoveryMode
```
WALRecoveryMode walRecoveryMode()
```
    Recovery mode to control the consistency while replaying WAL Default: WALRecoveryMode.PointInTimeRecovery
    
    Returns:
    
    The WAL recover mode
  - setAllow2pc
```
T setAllow2pc(boolean allow2pc)
```
    if set to false then recovery will fail when a prepared transaction is encountered in the WAL Default: false
    
    Parameters:
    
    allow2pc - true if two-phase-commit is enabled
    
    Returns:
    
    the reference to the current options.
  - allow2pc
```
boolean allow2pc()
```
    if set to false then recovery will fail when a prepared transaction is encountered in the WAL Default: false
    
    Returns:
    
    true if two-phase-commit is enabled
  - setRowCache
```
T setRowCache(Cache rowCache)
```
    A global cache for table-level rows. Default: null (disabled)
    
    Parameters:
    
    rowCache - The global row cache
    
    Returns:
    
    the reference to the current options.
  - rowCache
```
Cache rowCache()
```
    A global cache for table-level rows. Default: null (disabled)
    
    Returns:
    
    The global row cache
  - setWalFilter
```
T setWalFilter(AbstractWalFilter walFilter)
```
    A filter object supplied to be invoked while processing write-ahead-logs (WALs) during recovery. The filter provides a way to inspect log records, ignoring a particular record or skipping replay. The filter is invoked at startup and is invoked from a single-thread currently.
    
    Parameters:
    
    walFilter - the filter for processing WALs during recovery.
    
    Returns:
    
    the reference to the current options.
  - walFilter
```
WalFilter walFilter()
```
    Get's the filter for processing WALs during recovery. See setWalFilter(AbstractWalFilter).
    
    Returns:
    
    the filter used for processing WALs during recovery.
  - setFailIfOptionsFileError
```
T setFailIfOptionsFileError(boolean failIfOptionsFileError)
```
    If true, then DB::Open / CreateColumnFamily / DropColumnFamily / SetOptions will fail if options file is not detected or properly persisted. DEFAULT: false
    
    Parameters:
    
    failIfOptionsFileError - true if we should fail if there is an error in the options file
    
    Returns:
    
    the reference to the current options.
  - failIfOptionsFileError
```
boolean failIfOptionsFileError()
```
    If true, then DB::Open / CreateColumnFamily / DropColumnFamily / SetOptions will fail if options file is not detected or properly persisted. DEFAULT: false
    
    Returns:
    
    true if we should fail if there is an error in the options file
  - setDumpMallocStats
```
T setDumpMallocStats(boolean dumpMallocStats)
```
    If true, then print malloc stats together with rocksdb.stats when printing to LOG. DEFAULT: false
    
    Parameters:
    
    dumpMallocStats - true if malloc stats should be printed to LOG
    
    Returns:
    
    the reference to the current options.
  - dumpMallocStats
```
boolean dumpMallocStats()
```
    If true, then print malloc stats together with rocksdb.stats when printing to LOG. DEFAULT: false
    
    Returns:
    
    true if malloc stats should be printed to LOG
  - setAvoidFlushDuringRecovery
```
T setAvoidFlushDuringRecovery(boolean avoidFlushDuringRecovery)
```
    By default RocksDB replay WAL logs and flush them on DB open, which may create very small SST files. If this option is enabled, RocksDB will try to avoid (but not guarantee not to) flush during recovery. Also, existing WAL logs will be kept, so that if crash happened before flush, we still have logs to recover from. DEFAULT: false
    
    Parameters:
    
    avoidFlushDuringRecovery - true to try to avoid (but not guarantee not to) flush during recovery
    
    Returns:
    
    the reference to the current options.
  - avoidFlushDuringRecovery
```
boolean avoidFlushDuringRecovery()
```
    By default RocksDB replay WAL logs and flush them on DB open, which may create very small SST files. If this option is enabled, RocksDB will try to avoid (but not guarantee not to) flush during recovery. Also, existing WAL logs will be kept, so that if crash happened before flush, we still have logs to recover from. DEFAULT: false
    
    Returns:
    
    true to try to avoid (but not guarantee not to) flush during recovery
  - setAllowIngestBehind
```
T setAllowIngestBehind(boolean allowIngestBehind)
```
    Set this option to true during creation of database if you want to be able to ingest behind (call IngestExternalFile() skipping keys that already exist, rather than overwriting matching keys). Setting this option to true will affect 2 things: 1) Disable some internal optimizations around SST file compression 2) Reserve bottom-most level for ingested files only. 3) Note that num_levels should be >= 3 if this option is turned on. DEFAULT: false
    
    Parameters:
    
    allowIngestBehind - true to allow ingest behind, false to disallow.
    
    Returns:
    
    the reference to the current options.
  - allowIngestBehind
```
boolean allowIngestBehind()
```
    Returns true if ingest behind is allowed. See setAllowIngestBehind(boolean).
    
    Returns:
    
    true if ingest behind is allowed, false otherwise.
  - setPreserveDeletes
```
T setPreserveDeletes(boolean preserveDeletes)
```
    Needed to support differential snapshots. If set to true then DB will only process deletes with sequence number less than what was set by SetPreserveDeletesSequenceNumber(uint64_t ts). Clients are responsible to periodically call this method to advance the cutoff time. If this method is never called and preserve_deletes is set to true NO deletes will ever be processed. At the moment this only keeps normal deletes, SingleDeletes will not be preserved. DEFAULT: false
    
    Parameters:
    
    preserveDeletes - true to preserve deletes.
    
    Returns:
    
    the reference to the current options.
  - preserveDeletes
```
boolean preserveDeletes()
```
    Returns true if deletes are preserved. See setPreserveDeletes(boolean).
    
    Returns:
    
    true if deletes are preserved, false otherwise.
  - setTwoWriteQueues
```
T setTwoWriteQueues(boolean twoWriteQueues)
```
    If enabled it uses two queues for writes, one for the ones with disable_memtable and one for the ones that also write to memtable. This allows the memtable writes not to lag behind other writes. It can be used to optimize MySQL 2PC in which only the commits, which are serial, write to memtable. DEFAULT: false
    
    Parameters:
    
    twoWriteQueues - true to enable two write queues, false otherwise.
    
    Returns:
    
    the reference to the current options.
  - twoWriteQueues
```
boolean twoWriteQueues()
```
    Returns true if two write queues are enabled.
    
    Returns:
    
    true if two write queues are enabled, false otherwise.
  - setManualWalFlush
```
T setManualWalFlush(boolean manualWalFlush)
```
    If true WAL is not flushed automatically after each write. Instead it relies on manual invocation of FlushWAL to write the WAL buffer to its file. DEFAULT: false
    
    Parameters:
    
    manualWalFlush - true to set disable automatic WAL flushing, false otherwise.
    
    Returns:
    
    the reference to the current options.
  - manualWalFlush
```
boolean manualWalFlush()
```
    Returns true if automatic WAL flushing is disabled. See setManualWalFlush(boolean).
    
    Returns:
    
    true if automatic WAL flushing is disabled, false otherwise.
  - setAtomicFlush
```
T setAtomicFlush(boolean atomicFlush)
```
    If true, RocksDB supports flushing multiple column families and committing their results atomically to MANIFEST. Note that it is not necessary to set atomic_flush to true if WAL is always enabled since WAL allows the database to be restored to the last persistent state in WAL. This option is useful when there are column families with writes NOT protected by WAL. For manual flush, application has to specify which column families to flush atomically in RocksDB.flush(FlushOptions, List). For auto-triggered flush, RocksDB atomically flushes ALL column families. Currently, any WAL-enabled writes after atomic flush may be replayed independently if the process crashes later and tries to recover.
    
    Parameters:
    
    atomicFlush - true to enable atomic flush of multiple column families.
    
    Returns:
    
    the reference to the current options.
  - atomicFlush
```
boolean atomicFlush()
```
    Determine if atomic flush of multiple column families is enabled. See setAtomicFlush(boolean).
    
    Returns:
    
    true if atomic flush is enabled.
  - setAvoidUnnecessaryBlockingIO
```
T setAvoidUnnecessaryBlockingIO(boolean avoidUnnecessaryBlockingIO)
```
    If true, working thread may avoid doing unnecessary and long-latency operation (such as deleting obsolete files directly or deleting memtable) and will instead schedule a background job to do it. Use it if you're latency-sensitive. If set to true, takes precedence over ReadOptions.setBackgroundPurgeOnIteratorCleanup(boolean).
    
    Parameters:
    
    avoidUnnecessaryBlockingIO - If true, working thread may avoid doing unnecessary operation.
    
    Returns:
    
    the reference to the current options.
  - avoidUnnecessaryBlockingIO
```
boolean avoidUnnecessaryBlockingIO()
```
    If true, working thread may avoid doing unnecessary and long-latency operation (such as deleting obsolete files directly or deleting memtable) and will instead schedule a background job to do it. Use it if you're latency-sensitive. If set to true, takes precedence over ReadOptions.setBackgroundPurgeOnIteratorCleanup(boolean).
    
    Returns:
    
    true, if working thread may avoid doing unnecessary operation.
  - setPersistStatsToDisk
```
T setPersistStatsToDisk(boolean persistStatsToDisk)
```
    If true, automatically persist stats to a hidden column family (column family name: ___rocksdb_stats_history___) every stats_persist_period_sec seconds; otherwise, write to an in-memory struct. User can query through `GetStatsHistory` API. If user attempts to create a column family with the same name on a DB which have previously set persist_stats_to_disk to true, the column family creation will fail, but the hidden column family will survive, as well as the previously persisted statistics. When peristing stats to disk, the stat name will be limited at 100 bytes. Default: false
    
    Parameters:
    
    persistStatsToDisk - true if stats should be persisted to hidden column family.
    
    Returns:
    
    the instance of the current object.
  - persistStatsToDisk
```
boolean persistStatsToDisk()
```
    If true, automatically persist stats to a hidden column family (column family name: ___rocksdb_stats_history___) every stats_persist_period_sec seconds; otherwise, write to an in-memory struct. User can query through `GetStatsHistory` API. If user attempts to create a column family with the same name on a DB which have previously set persist_stats_to_disk to true, the column family creation will fail, but the hidden column family will survive, as well as the previously persisted statistics. When peristing stats to disk, the stat name will be limited at 100 bytes. Default: false
    
    Returns:
    
    true if stats should be persisted to hidden column family.
  - setWriteDbidToManifest
```
T setWriteDbidToManifest(boolean writeDbidToManifest)
```
    Historically DB ID has always been stored in Identity File in DB folder. If this flag is true, the DB ID is written to Manifest file in addition to the Identity file. By doing this 2 problems are solved 1. We don't checksum the Identity file where as Manifest file is. 2. Since the source of truth for DB is Manifest file DB ID will sit with the source of truth. Previously the Identity file could be copied independent of Manifest and that can result in wrong DB ID. We recommend setting this flag to true. Default: false
    
    Parameters:
    
    writeDbidToManifest - if true, then DB ID will be written to Manifest file.
    
    Returns:
    
    the instance of the current object.
  - writeDbidToManifest
```
boolean writeDbidToManifest()
```
    Historically DB ID has always been stored in Identity File in DB folder. If this flag is true, the DB ID is written to Manifest file in addition to the Identity file. By doing this 2 problems are solved 1. We don't checksum the Identity file where as Manifest file is. 2. Since the source of truth for DB is Manifest file DB ID will sit with the source of truth. Previously the Identity file could be copied independent of Manifest and that can result in wrong DB ID. We recommend setting this flag to true. Default: false
    
    Returns:
    
    true, if DB ID will be written to Manifest file.
  - setLogReadaheadSize
```
T setLogReadaheadSize(long logReadaheadSize)
```
    The number of bytes to prefetch when reading the log. This is mostly useful for reading a remotely located log, as it can save the number of round-trips. If 0, then the prefetching is disabled. Default: 0
    
    Parameters:
    
    logReadaheadSize - the number of bytes to prefetch when reading the log.
    
    Returns:
    
    the instance of the current object.
  - logReadaheadSize
```
long logReadaheadSize()
```
    The number of bytes to prefetch when reading the log. This is mostly useful for reading a remotely located log, as it can save the number of round-trips. If 0, then the prefetching is disabled. Default: 0
    
    Returns:
    
    the number of bytes to prefetch when reading the log.
  - setBestEffortsRecovery
```
T setBestEffortsRecovery(boolean bestEffortsRecovery)
```
    By default, RocksDB recovery fails if any table file referenced in MANIFEST are missing after scanning the MANIFEST. Best-efforts recovery is another recovery mode that tries to restore the database to the most recent point in time without missing file. Currently not compatible with atomic flush. Furthermore, WAL files will not be used for recovery if best_efforts_recovery is true. Default: false
    
    Parameters:
    
    bestEffortsRecovery - if true, RocksDB will use best-efforts mode when recovering.
    
    Returns:
    
    the instance of the current object.
  - bestEffortsRecovery
```
boolean bestEffortsRecovery()
```
    By default, RocksDB recovery fails if any table file referenced in MANIFEST are missing after scanning the MANIFEST. Best-efforts recovery is another recovery mode that tries to restore the database to the most recent point in time without missing file. Currently not compatible with atomic flush. Furthermore, WAL files will not be used for recovery if best_efforts_recovery is true. Default: false
    
    Returns:
    
    true, if RocksDB uses best-efforts mode when recovering.
  - setMaxBgErrorResumeCount
```
T setMaxBgErrorResumeCount(int maxBgerrorResumeCount)
```
    It defines how many times db resume is called by a separate thread when background retryable IO Error happens. When background retryable IO Error happens, SetBGError is called to deal with the error. If the error can be auto-recovered (e.g., retryable IO Error during Flush or WAL write), then db resume is called in background to recover from the error. If this value is 0 or negative, db resume will not be called. Default: INT_MAX
    
    Parameters:
    
    maxBgerrorResumeCount - maximum number of times db resume should be called when IO Error happens.
    
    Returns:
    
    the instance of the current object.
  - maxBgerrorResumeCount
```
int maxBgerrorResumeCount()
```
    It defines how many times db resume is called by a separate thread when background retryable IO Error happens. When background retryable IO Error happens, SetBGError is called to deal with the error. If the error can be auto-recovered (e.g., retryable IO Error during Flush or WAL write), then db resume is called in background to recover from the error. If this value is 0 or negative, db resume will not be called. Default: INT_MAX
    
    Returns:
    
    maximum number of times db resume should be called when IO Error happens.
  - setBgerrorResumeRetryInterval
```
T setBgerrorResumeRetryInterval(long bgerrorResumeRetryInterval)
```
    If max_bgerror_resume_count is ≥ 2, db resume is called multiple times. This option decides how long to wait to retry the next resume if the previous resume fails and satisfy redo resume conditions. Default: 1000000 (microseconds).
    
    Parameters:
    
    bgerrorResumeRetryInterval - how many microseconds to wait between DB resume attempts.
    
    Returns:
    
    the instance of the current object.
  - bgerrorResumeRetryInterval
```
long bgerrorResumeRetryInterval()
```
    If max_bgerror_resume_count is ≥ 2, db resume is called multiple times. This option decides how long to wait to retry the next resume if the previous resume fails and satisfy redo resume conditions. Default: 1000000 (microseconds).
    
    Returns:
    
    the instance of the current object.

Interface DBOptionsInterface<T extends DBOptionsInterface<T>>

Method Summary

Method Detail

optimizeForSmallDb

setEnv

getEnv

setIncreaseParallelism

setCreateIfMissing

createIfMissing

setCreateMissingColumnFamilies

createMissingColumnFamilies

setErrorIfExists

errorIfExists

setParanoidChecks

paranoidChecks

setRateLimiter

setSstFileManager

setLogger

setInfoLogLevel

infoLogLevel

setMaxFileOpeningThreads

maxFileOpeningThreads

setStatistics

statistics

setUseFsync

useFsync

setDbPaths

dbPaths

setDbLogDir

dbLogDir

setWalDir

walDir

setDeleteObsoleteFilesPeriodMicros

deleteObsoleteFilesPeriodMicros

setMaxSubcompactions

maxSubcompactions

setMaxBackgroundFlushes

maxBackgroundFlushes

setMaxLogFileSize

maxLogFileSize

setLogFileTimeToRoll

logFileTimeToRoll

setKeepLogFileNum

keepLogFileNum

setRecycleLogFileNum

recycleLogFileNum

setMaxManifestFileSize

maxManifestFileSize

setTableCacheNumshardbits

tableCacheNumshardbits

setWalTtlSeconds

walTtlSeconds

setWalSizeLimitMB

walSizeLimitMB

setMaxWriteBatchGroupSizeBytes

maxWriteBatchGroupSizeBytes

setManifestPreallocationSize

manifestPreallocationSize

setUseDirectReads

useDirectReads

setUseDirectIoForFlushAndCompaction

useDirectIoForFlushAndCompaction

setAllowFAllocate

allowFAllocate

setAllowMmapReads

allowMmapReads

setAllowMmapWrites

allowMmapWrites

setIsFdCloseOnExec

isFdCloseOnExec

setAdviseRandomOnOpen

adviseRandomOnOpen

setDbWriteBufferSize

setWriteBufferManager

writeBufferManager

dbWriteBufferSize

setAccessHintOnCompactionStart

accessHintOnCompactionStart

setNewTableReaderForCompactionInputs

newTableReaderForCompactionInputs