org.rocksdb

Interface DBOptionsInterface

All Known Implementing Classes:

DBOptions, Options

public interface DBOptionsInterface

Method Summary

Modifier and Type	Method and Description
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	allowMmapReads() Allow the OS to mmap file for reading sst tables.
boolean	allowMmapWrites() Allow the OS to mmap file for writing.
boolean	allowOsBuffer() Data being read from file storage may be buffered in the OS Default: true
long	bytesPerSync() Allows OS to incrementally sync files to disk while they are being written, asynchronously, in the background.
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.Object	createStatistics() Creates statistics object which collects metrics about database operations.
java.lang.String	dbLogDir() Returns the directory of info log.
long	deleteObsoleteFilesPeriodMicros() The periodicity when obsolete files get deleted.
boolean	disableDataSync() If true, then the contents of data files are not synced to stable storage.
boolean	errorIfExists() If true, an error will be thrown during RocksDB.open() if the database already exists.
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.
long	logFileTimeToRoll() Returns the time interval for the info log file to roll (in seconds).
long	manifestPreallocationSize() Number of bytes to preallocate (via fallocate) the manifest files.
int	maxBackgroundCompactions() Returns the maximum number of concurrent background compaction jobs, submitted to the default LOW priority thread pool.
int	maxBackgroundFlushes() Returns the maximum number of concurrent background flush jobs.
long	maxLogFileSize() Returns the maximum size of a info log file.
long	maxManifestFileSize() Manifest file is rolled over on reaching this limit.
int	maxOpenFiles() Number of open files that can be used by the DB.
long	maxTotalWalSize() Returns the max total wal size.
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.
java.lang.Object	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.
java.lang.Object	setAllowMmapReads(boolean allowMmapReads) Allow the OS to mmap file for reading sst tables.
java.lang.Object	setAllowMmapWrites(boolean allowMmapWrites) Allow the OS to mmap file for writing.
java.lang.Object	setAllowOsBuffer(boolean allowOsBuffer) Data being read from file storage may be buffered in the OS Default: true
java.lang.Object	setBytesPerSync(long bytesPerSync) Allows OS to incrementally sync files to disk while they are being written, asynchronously, in the background.
java.lang.Object	setCreateIfMissing(boolean flag) If this value is set to true, then the database will be created if it is missing during RocksDB.open().
java.lang.Object	setCreateMissingColumnFamilies(boolean flag) If true, missing column families will be automatically created
java.lang.Object	setDbLogDir(java.lang.String dbLogDir) This specifies the info LOG dir.
java.lang.Object	setDeleteObsoleteFilesPeriodMicros(long micros) The periodicity when obsolete files get deleted.
java.lang.Object	setDisableDataSync(boolean disableDataSync) If true, then the contents of manifest and data files are not synced to stable storage.
java.lang.Object	setErrorIfExists(boolean errorIfExists) If true, an error will be thrown during RocksDB.open() if the database already exists.
java.lang.Object	setInfoLogLevel(InfoLogLevel infoLogLevel) Sets the RocksDB log level.
java.lang.Object	setIsFdCloseOnExec(boolean isFdCloseOnExec) Disable child process inherit open files.
java.lang.Object	setKeepLogFileNum(long keepLogFileNum) Specifies the maximum number of info log files to be kept.
java.lang.Object	setLogFileTimeToRoll(long logFileTimeToRoll) Specifies the time interval for the info log file to roll (in seconds).
java.lang.Object	setManifestPreallocationSize(long size) Number of bytes to preallocate (via fallocate) the manifest files.
java.lang.Object	setMaxBackgroundCompactions(int maxBackgroundCompactions) Specifies the maximum number of concurrent background compaction jobs, submitted to the default LOW priority thread pool.
java.lang.Object	setMaxBackgroundFlushes(int maxBackgroundFlushes) Specifies the maximum number of concurrent background flush jobs.
java.lang.Object	setMaxLogFileSize(long maxLogFileSize) Specifies the maximum size of a info log file.
java.lang.Object	setMaxManifestFileSize(long maxManifestFileSize) Manifest file is rolled over on reaching this limit.
java.lang.Object	setMaxOpenFiles(int maxOpenFiles) Number of open files that can be used by the DB.
java.lang.Object	setMaxTotalWalSize(long maxTotalWalSize) Once write-ahead logs exceed this size, we will start forcing the flush of column families whose memtables are backed by the oldest live WAL file (i.e.
java.lang.Object	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.
java.lang.Object	setRateLimiterConfig(RateLimiterConfig config) Use to control write rate of flush and compaction.
java.lang.Object	setSkipLogErrorOnRecovery(boolean skip) Skip log corruption error on recovery (If client is ok with losing most recent changes) Default: false
java.lang.Object	setStatsDumpPeriodSec(int statsDumpPeriodSec) if not zero, dump rocksdb.stats to LOG every stats_dump_period_sec Default: 3600 (1 hour)
java.lang.Object	setTableCacheNumshardbits(int tableCacheNumshardbits) Number of shards used for table cache.
java.lang.Object	setTableCacheRemoveScanCountLimit(int limit) During data eviction of table's LRU cache, it would be inefficient to strictly follow LRU because this piece of memory will not really be released unless its refcount falls to zero.
java.lang.Object	setUseAdaptiveMutex(boolean useAdaptiveMutex) Use adaptive mutex, which spins in the user space before resorting to kernel.
java.lang.Object	setUseFsync(boolean useFsync) If true, then every store to stable storage will issue a fsync.
java.lang.Object	setWalDir(java.lang.String walDir) This specifies the absolute dir path for write-ahead logs (WAL).
java.lang.Object	setWalSizeLimitMB(long sizeLimitMB) WalTtlSeconds() and walSizeLimitMB() affect how archived logs will be deleted.
java.lang.Object	setWalTtlSeconds(long walTtlSeconds) walTtlSeconds() and walSizeLimitMB() affect how archived logs will be deleted.
boolean	skipLogErrorOnRecovery() Skip log corruption error on recovery (If client is ok with losing most recent changes) Default: false
Statistics	statisticsPtr() Returns statistics object.
int	statsDumpPeriodSec() If not zero, dump rocksdb.stats to LOG every stats_dump_period_sec Default: 3600 (1 hour)
int	tableCacheNumshardbits() Number of shards used for table cache.
int	tableCacheRemoveScanCountLimit() During data eviction of table's LRU cache, it would be inefficient to strictly follow LRU because this piece of memory will not really be released unless its refcount falls to zero.
boolean	useAdaptiveMutex() Use adaptive mutex, which spins in the user space before resorting to kernel.
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.
long	walSizeLimitMB() walTtlSeconds() and #walSizeLimitMB() affect how archived logs will be deleted.
long	walTtlSeconds() WalTtlSeconds() and walSizeLimitMB() affect how archived logs will be deleted.

Method Detail

setCreateIfMissing

java.lang.Object 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

java.lang.Object 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

java.lang.Object 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

java.lang.Object 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.

setRateLimiterConfig

java.lang.Object setRateLimiterConfig(RateLimiterConfig config)

Use to control write rate of flush and compaction. Flush has higher priority than compaction. Rate limiting is disabled if nullptr. Default: nullptr

Parameters:

config - rate limiter config.

Returns:

the instance of the current Object.

setInfoLogLevel

java.lang.Object 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.

setMaxOpenFiles

java.lang.Object setMaxOpenFiles(int maxOpenFiles)

Number of open files that can be used by the DB. You may need to increase this if your database has a large working set. Value -1 means files opened are always kept open. You can estimate number of files based on target_file_size_base and target_file_size_multiplier for level-based compaction. For universal-style compaction, you can usually set it to -1. Default: 5000

Parameters:

maxOpenFiles - the maximum number of open files.

Returns:

the instance of the current Object.

maxOpenFiles

int maxOpenFiles()

Number of open files that can be used by the DB. You may need to increase this if your database has a large working set. Value -1 means files opened are always kept open. You can estimate number of files based on target_file_size_base and target_file_size_multiplier for level-based compaction. For universal-style compaction, you can usually set it to -1.

Returns:

the maximum number of open files.

setMaxTotalWalSize

java.lang.Object setMaxTotalWalSize(long maxTotalWalSize)

Once write-ahead logs exceed this size, we will start forcing the flush of column families whose memtables are backed by the oldest live WAL file (i.e. the ones that are causing all the space amplification).

If set to 0 (default), we will dynamically choose the WAL size limit to be [sum of all write_buffer_size * max_write_buffer_number] * 2

Default: 0

Parameters:

maxTotalWalSize - max total wal size.

Returns:

the instance of the current Object.

maxTotalWalSize

long maxTotalWalSize()

Returns the max total wal size. Once write-ahead logs exceed this size, we will start forcing the flush of column families whose memtables are backed by the oldest live WAL file (i.e. the ones that are causing all the space amplification).

If set to 0 (default), we will dynamically choose the WAL size limit to be [sum of all write_buffer_size * max_write_buffer_number] * 2

Returns:

max total wal size

createStatistics

java.lang.Object createStatistics()

Creates 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.

Returns:

the instance of the current Object.

See Also:

RocksDB.open(org.rocksdb.Options, String)

statisticsPtr

Statistics statisticsPtr()

Returns statistics object. Calls createStatistics() if C++ returns nullptr for statistics.

Returns:

the instance of the statistics object.

See Also:

createStatistics()

setDisableDataSync

java.lang.Object setDisableDataSync(boolean disableDataSync)

If true, then the contents of manifest and data files are not synced to stable storage. Their contents remain in the OS buffers till theOS decides to flush them.

This option is good for bulk-loading of data.

Once the bulk-loading is complete, please issue a sync to the OS to flush all dirty buffers to stable storage.

Default: false

Parameters:

disableDataSync - a boolean flag to specify whether to disable data sync.

Returns:

the instance of the current Object.

disableDataSync

boolean disableDataSync()

If true, then the contents of data files are not synced to stable storage. Their contents remain in the OS buffers till the OS decides to flush them. This option is good for bulk-loading of data. Once the bulk-loading is complete, please issue a sync to the OS to flush all dirty buffers to stable storage.

Returns:

if true, then data-sync is disabled.

setUseFsync

java.lang.Object 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.

setDbLogDir

java.lang.Object 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

java.lang.Object 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

java.lang.Object 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.

setMaxBackgroundCompactions

java.lang.Object setMaxBackgroundCompactions(int maxBackgroundCompactions)

Specifies the maximum number of concurrent background compaction jobs, submitted to the default LOW priority thread pool. If you're increasing this, also consider increasing number of threads in LOW priority thread pool. For more information, see Default: 1

Parameters:

maxBackgroundCompactions - the maximum number of background compaction jobs.

Returns:

the instance of the current Object.

See Also:

RocksEnv.setBackgroundThreads(int), RocksEnv.setBackgroundThreads(int, int), maxBackgroundFlushes()

maxBackgroundCompactions

int maxBackgroundCompactions()

Returns the maximum number of concurrent background compaction jobs, submitted to the default LOW priority thread pool. When increasing this number, we may also want to consider increasing number of threads in LOW priority thread pool. Default: 1

Returns:

the maximum number of concurrent background compaction jobs.

See Also:

RocksEnv.setBackgroundThreads(int), RocksEnv.setBackgroundThreads(int, int)

setMaxBackgroundFlushes

java.lang.Object setMaxBackgroundFlushes(int maxBackgroundFlushes)

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:

RocksEnv.setBackgroundThreads(int), RocksEnv.setBackgroundThreads(int, int), maxBackgroundCompactions()

maxBackgroundFlushes

int maxBackgroundFlushes()

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:

RocksEnv.setBackgroundThreads(int), RocksEnv.setBackgroundThreads(int, int)

setMaxLogFileSize

java.lang.Object setMaxLogFileSize(long maxLogFileSize)
                            throws RocksDBException

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:

RocksDBException - 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

java.lang.Object setLogFileTimeToRoll(long logFileTimeToRoll)
                               throws RocksDBException

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:

RocksDBException - 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

java.lang.Object setKeepLogFileNum(long keepLogFileNum)
                            throws RocksDBException

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:

RocksDBException - 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.

setMaxManifestFileSize

java.lang.Object setMaxManifestFileSize(long maxManifestFileSize)

Manifest file is rolled over on reaching this limit. The older manifest file be deleted. The default value is MAX_INT so that roll-over does not take place.

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 MAX_INT so that roll-over does not take place.

Returns:

the size limit of a manifest file.

setTableCacheNumshardbits

java.lang.Object 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.

setTableCacheRemoveScanCountLimit

java.lang.Object setTableCacheRemoveScanCountLimit(int limit)

During data eviction of table's LRU cache, it would be inefficient to strictly follow LRU because this piece of memory will not really be released unless its refcount falls to zero. Instead, make two passes: the first pass will release items with refcount = 1, and if not enough space releases after scanning the number of elements specified by this parameter, we will remove items in LRU order.

Parameters:

limit - scan count limit

Returns:

the instance of the current Object.

tableCacheRemoveScanCountLimit

int tableCacheRemoveScanCountLimit()

During data eviction of table's LRU cache, it would be inefficient to strictly follow LRU because this piece of memory will not really be released unless its refcount falls to zero. Instead, make two passes: the first pass will release items with refcount = 1, and if not enough space releases after scanning the number of elements specified by this parameter, we will remove items in LRU order.

Returns:

scan count limit

setWalTtlSeconds

java.lang.Object setWalTtlSeconds(long walTtlSeconds)

walTtlSeconds() and walSizeLimitMB() affect how archived logs will be deleted.

1. If both set to 0, logs will be deleted asap and will not get into the archive.
2. 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.
3. 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.
4. 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.

1. If both set to 0, logs will be deleted asap and will not get into the archive.
2. 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.
3. 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.
4. 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

java.lang.Object setWalSizeLimitMB(long sizeLimitMB)

WalTtlSeconds() and walSizeLimitMB() affect how archived logs will be deleted.

1. If both set to 0, logs will be deleted asap and will not get into the archive.
2. 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.
3. 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.
4. 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.

1. If both set to 0, logs will be deleted asap and will not get into the archive.
2. 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.
3. 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.
4. 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()

setManifestPreallocationSize

java.lang.Object setManifestPreallocationSize(long size)
                                       throws RocksDBException

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:

RocksDBException - 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.

setAllowOsBuffer

java.lang.Object setAllowOsBuffer(boolean allowOsBuffer)

Data being read from file storage may be buffered in the OS Default: true

Parameters:

allowOsBuffer - if true, then OS buffering is allowed.

Returns:

the instance of the current Object.

allowOsBuffer

boolean allowOsBuffer()

Data being read from file storage may be buffered in the OS Default: true

Returns:

if true, then OS buffering is allowed.

setAllowMmapReads

java.lang.Object 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

java.lang.Object 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

java.lang.Object 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.

setSkipLogErrorOnRecovery

java.lang.Object setSkipLogErrorOnRecovery(boolean skip)

Skip log corruption error on recovery (If client is ok with losing most recent changes) Default: false

Parameters:

skip - true if log corruption errors are skipped during recovery.

Returns:

the instance of the current Object.

skipLogErrorOnRecovery

boolean skipLogErrorOnRecovery()

Skip log corruption error on recovery (If client is ok with losing most recent changes) Default: false

Returns:

true if log corruption errors are skipped during recovery.

setStatsDumpPeriodSec

java.lang.Object setStatsDumpPeriodSec(int statsDumpPeriodSec)

if not zero, dump rocksdb.stats to LOG every stats_dump_period_sec Default: 3600 (1 hour)

Parameters:

statsDumpPeriodSec - time interval in seconds.

Returns:

the instance of the current Object.

statsDumpPeriodSec

int statsDumpPeriodSec()

If not zero, dump rocksdb.stats to LOG every stats_dump_period_sec Default: 3600 (1 hour)

Returns:

time interval in seconds.

setAdviseRandomOnOpen

java.lang.Object 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.

setUseAdaptiveMutex

java.lang.Object 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.

setBytesPerSync

java.lang.Object setBytesPerSync(long bytesPerSync)

Allows OS to incrementally sync files to disk while they are being written, asynchronously, in the background. Issue one request for every bytes_per_sync written. 0 turns it off. Default: 0

Parameters:

bytesPerSync - size in bytes

Returns:

the instance of the current Object.

bytesPerSync

long bytesPerSync()

Allows OS to incrementally sync files to disk while they are being written, asynchronously, in the background. Issue one request for every bytes_per_sync written. 0 turns it off. Default: 0

Returns:

size in bytes