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// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
package org.rocksdb;
public interface MutableDBOptionsInterface> {
/**
* Specifies the maximum number of concurrent background jobs (both flushes
* and compactions combined).
* Default: 2
*
* @param maxBackgroundJobs number of max concurrent background jobs
* @return the instance of the current object.
*/
T setMaxBackgroundJobs(int maxBackgroundJobs);
/**
* Returns the maximum number of concurrent background jobs (both flushes
* and compactions combined).
* Default: 2
*
* @return the maximum number of concurrent background jobs.
*/
int maxBackgroundJobs();
/**
* 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` (we replace -1 by 1 in case one option is unset).
*
* 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
*
* @param maxBackgroundCompactions the maximum number of background
* compaction jobs.
* @return the instance of the current object.
*
* @see RocksEnv#setBackgroundThreads(int)
* @see RocksEnv#setBackgroundThreads(int, Priority)
* @see DBOptionsInterface#maxBackgroundFlushes()
* @deprecated Use {@link #setMaxBackgroundJobs(int)}
*/
@Deprecated
T setMaxBackgroundCompactions(int maxBackgroundCompactions);
/**
* 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` (we replace -1 by 1 in case one option is unset).
*
* 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
*
* @return the maximum number of concurrent background compaction jobs.
* @see RocksEnv#setBackgroundThreads(int)
* @see RocksEnv#setBackgroundThreads(int, Priority)
*
* @deprecated Use {@link #setMaxBackgroundJobs(int)}
*/
@Deprecated
int maxBackgroundCompactions();
/**
* By default RocksDB will flush all memtables on DB close if there are
* unpersisted data (i.e. with WAL disabled) The flush can be skip to speedup
* DB close. Unpersisted data WILL BE LOST.
*
* DEFAULT: false
*
* Dynamically changeable through
* {@link RocksDB#setOptions(ColumnFamilyHandle, MutableColumnFamilyOptions)}
* API.
*
* @param avoidFlushDuringShutdown true if we should avoid flush during
* shutdown
*
* @return the reference to the current options.
*/
T setAvoidFlushDuringShutdown(boolean avoidFlushDuringShutdown);
/**
* By default RocksDB will flush all memtables on DB close if there are
* unpersisted data (i.e. with WAL disabled) The flush can be skip to speedup
* DB close. Unpersisted data WILL BE LOST.
*
* DEFAULT: false
*
* Dynamically changeable through
* {@link RocksDB#setOptions(ColumnFamilyHandle, MutableColumnFamilyOptions)}
* API.
*
* @return true if we should avoid flush during shutdown
*/
boolean avoidFlushDuringShutdown();
/**
* This is the maximum buffer size that is used by WritableFileWriter.
* On Windows, we need to maintain an aligned buffer for writes.
* We allow the buffer to grow until it's size hits the limit.
*
* Default: 1024 * 1024 (1 MB)
*
* @param writableFileMaxBufferSize the maximum buffer size
*
* @return the reference to the current options.
*/
T setWritableFileMaxBufferSize(long writableFileMaxBufferSize);
/**
* This is the maximum buffer size that is used by WritableFileWriter.
* On Windows, we need to maintain an aligned buffer for writes.
* We allow the buffer to grow until it's size hits the limit.
*
* Default: 1024 * 1024 (1 MB)
*
* @return the maximum buffer size
*/
long writableFileMaxBufferSize();
/**
* The limited write rate to DB if
* {@link ColumnFamilyOptions#softPendingCompactionBytesLimit()} or
* {@link ColumnFamilyOptions#level0SlowdownWritesTrigger()} is triggered,
* or we are writing to the last mem table allowed and we allow more than 3
* mem tables. It is calculated using size of user write requests before
* compression. RocksDB may decide to slow down more if the compaction still
* gets behind further.
* If the value is 0, we will infer a value from `rater_limiter` value
* if it is not empty, or 16MB if `rater_limiter` is empty. Note that
* if users change the rate in `rate_limiter` after DB is opened,
* `delayed_write_rate` won't be adjusted.
*
* Unit: bytes per second.
*
* Default: 0
*
* Dynamically changeable through {@link RocksDB#setDBOptions(MutableDBOptions)}.
*
* @param delayedWriteRate the rate in bytes per second
*
* @return the reference to the current options.
*/
T setDelayedWriteRate(long delayedWriteRate);
/**
* The limited write rate to DB if
* {@link ColumnFamilyOptions#softPendingCompactionBytesLimit()} or
* {@link ColumnFamilyOptions#level0SlowdownWritesTrigger()} is triggered,
* or we are writing to the last mem table allowed and we allow more than 3
* mem tables. It is calculated using size of user write requests before
* compression. RocksDB may decide to slow down more if the compaction still
* gets behind further.
* If the value is 0, we will infer a value from `rater_limiter` value
* if it is not empty, or 16MB if `rater_limiter` is empty. Note that
* if users change the rate in `rate_limiter` after DB is opened,
* `delayed_write_rate` won't be adjusted.
*
* Unit: bytes per second.
*
* Default: 0
*
* Dynamically changeable through {@link RocksDB#setDBOptions(MutableDBOptions)}.
*
* @return the rate in bytes per second
*/
long delayedWriteRate();
/**
* Set the max total write-ahead log 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
*
* The oldest WAL files are the ones that are causing all the space amplification.
*
* For example, with 15 column families, each with
* write_buffer_size = 128 MB
* max_write_buffer_number = 6
* max_total_wal_size will be calculated to be [15 * 128MB * 6] * 4 =
* 45GB
*
* The RocksDB wiki has some discussion about how the WAL interacts
* with memtables and flushing of column families, at
* ...
*
* 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] * 4
* This option takes effect only when there are more than one column family as
* otherwise the wal size is dictated by the write_buffer_size.
* Default: 0
*
* @param maxTotalWalSize max total wal size.
* @return the instance of the current object.
*/
T setMaxTotalWalSize(long maxTotalWalSize);
/**
* Returns the max total write-ahead log 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.
* The oldest WAL files are the ones that are causing all the space amplification.
*
* For example, with 15 column families, each with
* write_buffer_size = 128 MB
* max_write_buffer_number = 6
* max_total_wal_size will be calculated to be [15 * 128MB * 6] * 4 =
* 45GB
*
* The RocksDB wiki has some discussion about how the WAL interacts
* with memtables and flushing of column families, at
* ...
*
* 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] * 4
* This option takes effect only when there are more than one column family as
* otherwise the wal size is dictated by the write_buffer_size.
* Default: 0
*
*
* 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] * 4
*
*
* @return max total wal size
*/
long maxTotalWalSize();
/**
* 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
*
* @param micros the time interval in micros
* @return the instance of the current object.
*/
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
*
* @return the time interval in micros when obsolete files will be deleted.
*/
long deleteObsoleteFilesPeriodMicros();
/**
* if not zero, dump rocksdb.stats to LOG every stats_dump_period_sec
* Default: 600 (10 minutes)
*
* @param statsDumpPeriodSec time interval in seconds.
* @return the instance of the current object.
*/
T setStatsDumpPeriodSec(int statsDumpPeriodSec);
/**
* If not zero, dump rocksdb.stats to LOG every stats_dump_period_sec
* Default: 600 (10 minutes)
*
* @return time interval in seconds.
*/
int statsDumpPeriodSec();
/**
* If not zero, dump rocksdb.stats to RocksDB every
* {@code statsPersistPeriodSec}
*
* Default: 600
*
* @param statsPersistPeriodSec time interval in seconds.
* @return the instance of the current object.
*/
T setStatsPersistPeriodSec(int statsPersistPeriodSec);
/**
* If not zero, dump rocksdb.stats to RocksDB every
* {@code statsPersistPeriodSec}
*
* @return time interval in seconds.
*/
int statsPersistPeriodSec();
/**
* If not zero, periodically take stats snapshots and store in memory, the
* memory size for stats snapshots is capped at {@code statsHistoryBufferSize}
*
* Default: 1MB
*
* @param statsHistoryBufferSize the size of the buffer.
* @return the instance of the current object.
*/
T setStatsHistoryBufferSize(long statsHistoryBufferSize);
/**
* If not zero, periodically take stats snapshots and store in memory, the
* memory size for stats snapshots is capped at {@code statsHistoryBufferSize}
*
* @return the size of the buffer.
*/
long statsHistoryBufferSize();
/**
* 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 {@code target_file_size_base} and {@code target_file_size_multiplier}
* for level-based compaction. For universal-style compaction, you can usually
* set it to -1.
* Default: -1
*
* @param maxOpenFiles the maximum number of open files.
* @return the instance of the current object.
*/
T 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 {@code target_file_size_base} and {@code target_file_size_multiplier}
* for level-based compaction. For universal-style compaction, you can usually
* set it to -1.
* Default: -1
*
* @return the maximum number of open files.
*/
int maxOpenFiles();
/**
* 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
*
* @param bytesPerSync size in bytes
* @return the instance of the current object.
*/
T 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
*
* @return size in bytes
*/
long bytesPerSync();
/**
* Same as {@link #setBytesPerSync(long)} , but applies to WAL files
*
* Default: 0, turned off
*
* @param walBytesPerSync size in bytes
* @return the instance of the current object.
*/
T setWalBytesPerSync(long walBytesPerSync);
/**
* Same as {@link #bytesPerSync()} , but applies to WAL files
*
* Default: 0, turned off
*
* @return size in bytes
*/
long walBytesPerSync();
/**
* When true, guarantees WAL files have at most {@link #walBytesPerSync()}
* bytes submitted for writeback at any given time, and SST files have at most
* {@link #bytesPerSync()} bytes pending writeback at any given time. This
* can be used to handle cases where processing speed exceeds I/O speed
* during file generation, which can lead to a huge sync when the file is
* finished, even with {@link #bytesPerSync()} / {@link #walBytesPerSync()}
* properly configured.
*
* - If `sync_file_range` is supported it achieves this by waiting for any
* prior `sync_file_range`s to finish before proceeding. In this way,
* processing (compression, etc.) can proceed uninhibited in the gap
* between `sync_file_range`s, and we block only when I/O falls
* behind.
* - Otherwise the `WritableFile::Sync` method is used. Note this mechanism
* always blocks, thus preventing the interleaving of I/O and processing.
*
* Note: Enabling this option does not provide any additional persistence
* guarantees, as it may use `sync_file_range`, which does not write out
* metadata.
*
* Default: false
*
* @param strictBytesPerSync the bytes per sync
* @return the instance of the current object.
*/
T setStrictBytesPerSync(boolean strictBytesPerSync);
/**
* Return the strict byte limit per sync.
*
* See {@link #setStrictBytesPerSync(boolean)}
*
* @return the limit in bytes.
*/
boolean strictBytesPerSync();
/**
* If non-zero, we perform bigger reads when doing compaction. If you're
* running RocksDB on spinning disks, you should set this to at least 2MB.
*
* That way RocksDB's compaction is doing sequential instead of random reads.
*
* Default: 0
*
* @param compactionReadaheadSize The compaction read-ahead size
*
* @return the reference to the current options.
*/
T setCompactionReadaheadSize(final long compactionReadaheadSize);
/**
* If non-zero, we perform bigger reads when doing compaction. If you're
* running RocksDB on spinning disks, you should set this to at least 2MB.
*
* That way RocksDB's compaction is doing sequential instead of random reads.
*
* Default: 0
*
* @return The compaction read-ahead size
*/
long compactionReadaheadSize();
}