org.rocksdb

类 WriteBatchWithIndex

java.lang.Object

org.rocksdb.AbstractNativeReference

org.rocksdb.AbstractImmutableNativeReference

org.rocksdb.RocksObject

org.rocksdb.AbstractWriteBatch

org.rocksdb.WriteBatchWithIndex

所有已实现的接口:

java.lang.AutoCloseable, WriteBatchInterface

public class WriteBatchWithIndex
extends AbstractWriteBatch

Similar to WriteBatch but with a binary searchable index built for all the keys inserted.

Calling put, merge, remove or putLogData calls the same function as with WriteBatch whilst also building an index.

A user can call newIterator() to create an iterator over the write batch or newIteratorWithBase(org.rocksdb.RocksIterator) to get an iterator for the database with Read-Your-Own-Writes like capability

字段概要

从类继承的字段 org.rocksdb.RocksObject

nativeHandle_

从类继承的字段 org.rocksdb.AbstractImmutableNativeReference

owningHandle_

构造器概要

构造器

构造器和说明
WriteBatchWithIndex() Creates a WriteBatchWithIndex where no bytes are reserved up-front, byte wise comparison is used for fallback key comparisons, and duplicate keys operations are retained
WriteBatchWithIndex(AbstractComparator fallbackIndexComparator, int reservedBytes, boolean overwriteKey) Creates a WriteBatchWithIndex
WriteBatchWithIndex(boolean overwriteKey) Creates a WriteBatchWithIndex where no bytes are reserved up-front, byte wise comparison is used for fallback key comparisons, and duplicate key assignment is determined by the constructor argument

方法概要

限定符和类型	方法和说明
protected void	disposeInternal(long handle)
byte[]	getFromBatch(ColumnFamilyHandle columnFamilyHandle, DBOptions options, byte[] key) Similar to RocksDB.get(ColumnFamilyHandle, byte[]) but will only read the key from this batch.
byte[]	getFromBatch(DBOptions options, byte[] key) Similar to RocksDB.get(byte[]) but will only read the key from this batch.
byte[]	getFromBatchAndDB(RocksDB db, ColumnFamilyHandle columnFamilyHandle, ReadOptions options, byte[] key) Similar to RocksDB.get(ColumnFamilyHandle, byte[]) but will also read writes from this batch.
byte[]	getFromBatchAndDB(RocksDB db, ReadOptions options, byte[] key) Similar to RocksDB.get(byte[]) but will also read writes from this batch.
WBWIRocksIterator	newIterator() Create an iterator of the default column family.
WBWIRocksIterator	newIterator(ColumnFamilyHandle columnFamilyHandle) Create an iterator of a column family.
RocksIterator	newIteratorWithBase(ColumnFamilyHandle columnFamilyHandle, RocksIterator baseIterator) Provides Read-Your-Own-Writes like functionality by creating a new Iterator that will use WBWIRocksIterator as a delta and baseIterator as a base Updating write batch with the current key of the iterator is not safe.
RocksIterator	newIteratorWithBase(ColumnFamilyHandle columnFamilyHandle, RocksIterator baseIterator, ReadOptions readOptions) Provides Read-Your-Own-Writes like functionality by creating a new Iterator that will use WBWIRocksIterator as a delta and baseIterator as a base Updating write batch with the current key of the iterator is not safe.
RocksIterator	newIteratorWithBase(RocksIterator baseIterator) Provides Read-Your-Own-Writes like functionality by creating a new Iterator that will use WBWIRocksIterator as a delta and baseIterator as a base.
RocksIterator	newIteratorWithBase(RocksIterator baseIterator, ReadOptions readOptions) Provides Read-Your-Own-Writes like functionality by creating a new Iterator that will use WBWIRocksIterator as a delta and baseIterator as a base.

从类继承的方法 org.rocksdb.AbstractWriteBatch

clear, count, delete, delete, delete, delete, deleteRange, deleteRange, getWriteBatch, merge, merge, popSavePoint, put, put, put, put, putLogData, rollbackToSavePoint, setMaxBytes, setSavePoint, singleDelete, singleDelete

从类继承的方法 org.rocksdb.RocksObject

disposeInternal, getNativeHandle

从类继承的方法 org.rocksdb.AbstractImmutableNativeReference

close, disOwnNativeHandle, isOwningHandle

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

构造器详细资料

WriteBatchWithIndex

public WriteBatchWithIndex()

Creates a WriteBatchWithIndex where no bytes are reserved up-front, byte wise comparison is used for fallback key comparisons, and duplicate keys operations are retained

WriteBatchWithIndex

public WriteBatchWithIndex(boolean overwriteKey)

Creates a WriteBatchWithIndex where no bytes are reserved up-front, byte wise comparison is used for fallback key comparisons, and duplicate key assignment is determined by the constructor argument

参数:

overwriteKey - if true, overwrite the key in the index when inserting a duplicate key, in this way an iterator will never show two entries with the same key.

WriteBatchWithIndex

public WriteBatchWithIndex(AbstractComparator fallbackIndexComparator,
                           int reservedBytes,
                           boolean overwriteKey)

Creates a WriteBatchWithIndex

参数:

fallbackIndexComparator - We fall back to this comparator to compare keys within a column family if we cannot determine the column family and so look up its comparator.

reservedBytes - reserved bytes in underlying WriteBatch

overwriteKey - if true, overwrite the key in the index when inserting a duplicate key, in this way an iterator will never show two entries with the same key.

方法详细资料

newIterator

public WBWIRocksIterator newIterator(ColumnFamilyHandle columnFamilyHandle)

Create an iterator of a column family. User can call RocksIteratorInterface.seek(byte[]) to search to the next entry of or after a key. Keys will be iterated in the order given by index_comparator. For multiple updates on the same key, each update will be returned as a separate entry, in the order of update time.

参数:

columnFamilyHandle - The column family to iterate over

返回:

An iterator for the Write Batch contents, restricted to the column family

newIterator

public WBWIRocksIterator newIterator()

Create an iterator of the default column family. User can call RocksIteratorInterface.seek(byte[]) to search to the next entry of or after a key. Keys will be iterated in the order given by index_comparator. For multiple updates on the same key, each update will be returned as a separate entry, in the order of update time.

返回:

An iterator for the Write Batch contents

newIteratorWithBase

public RocksIterator newIteratorWithBase(ColumnFamilyHandle columnFamilyHandle,
                                         RocksIterator baseIterator)

Provides Read-Your-Own-Writes like functionality by creating a new Iterator that will use WBWIRocksIterator as a delta and baseIterator as a base

Updating write batch with the current key of the iterator is not safe. We strongly recommend users not to do it. It will invalidate the current key() and value() of the iterator. This invalidation happens even before the write batch update finishes. The state may recover after Next() is called.

参数:

columnFamilyHandle - The column family to iterate over

baseIterator - The base iterator, e.g. RocksDB.newIterator()

返回:

An iterator which shows a view comprised of both the database point-in-time from baseIterator and modifications made in this write batch.

newIteratorWithBase

public RocksIterator newIteratorWithBase(ColumnFamilyHandle columnFamilyHandle,
                                         RocksIterator baseIterator,
                                         ReadOptions readOptions)

Provides Read-Your-Own-Writes like functionality by creating a new Iterator that will use WBWIRocksIterator as a delta and baseIterator as a base

Updating write batch with the current key of the iterator is not safe. We strongly recommend users not to do it. It will invalidate the current key() and value() of the iterator. This invalidation happens even before the write batch update finishes. The state may recover after Next() is called.

参数:

columnFamilyHandle - The column family to iterate over

baseIterator - The base iterator, e.g. RocksDB.newIterator()

readOptions - the read options, or null

返回:

An iterator which shows a view comprised of both the database point-in-time from baseIterator and modifications made in this write batch.

newIteratorWithBase

public RocksIterator newIteratorWithBase(RocksIterator baseIterator)

Provides Read-Your-Own-Writes like functionality by creating a new Iterator that will use WBWIRocksIterator as a delta and baseIterator as a base. Operates on the default column family.

参数:

baseIterator - The base iterator, e.g. RocksDB.newIterator()

返回:

An iterator which shows a view comprised of both the database point-in-time from baseIterator and modifications made in this write batch.

newIteratorWithBase

public RocksIterator newIteratorWithBase(RocksIterator baseIterator,
                                         ReadOptions readOptions)

Provides Read-Your-Own-Writes like functionality by creating a new Iterator that will use WBWIRocksIterator as a delta and baseIterator as a base. Operates on the default column family.

参数:

baseIterator - The base iterator, e.g. RocksDB.newIterator()

readOptions - the read options, or null

返回:

An iterator which shows a view comprised of both the database point-in-time from baseIterator and modifications made in this write batch.

getFromBatch

public byte[] getFromBatch(ColumnFamilyHandle columnFamilyHandle,
                           DBOptions options,
                           byte[] key)
                    throws RocksDBException

Similar to RocksDB.get(ColumnFamilyHandle, byte[]) but will only read the key from this batch.

参数:

columnFamilyHandle - The column family to retrieve the value from

options - The database options to use

key - The key to read the value for

返回:

a byte array storing the value associated with the input key if any. null if it does not find the specified key.

抛出:

RocksDBException - if the batch does not have enough data to resolve Merge operations, MergeInProgress status may be returned.

getFromBatch

public byte[] getFromBatch(DBOptions options,
                           byte[] key)
                    throws RocksDBException

Similar to RocksDB.get(byte[]) but will only read the key from this batch.

参数:

options - The database options to use

key - The key to read the value for

返回:

a byte array storing the value associated with the input key if any. null if it does not find the specified key.

抛出:

RocksDBException - if the batch does not have enough data to resolve Merge operations, MergeInProgress status may be returned.

getFromBatchAndDB

public byte[] getFromBatchAndDB(RocksDB db,
                                ColumnFamilyHandle columnFamilyHandle,
                                ReadOptions options,
                                byte[] key)
                         throws RocksDBException

Similar to RocksDB.get(ColumnFamilyHandle, byte[]) but will also read writes from this batch.

This function will query both this batch and the DB and then merge the results using the DB's merge operator (if the batch contains any merge requests).

Setting ReadOptions.setSnapshot(Snapshot) will affect what is read from the DB but will NOT change which keys are read from the batch (the keys in this batch do not yet belong to any snapshot and will be fetched regardless).

参数:

db - The Rocks database

columnFamilyHandle - The column family to retrieve the value from

options - The read options to use

key - The key to read the value for

返回:

a byte array storing the value associated with the input key if any. null if it does not find the specified key.

抛出:

RocksDBException - if the value for the key cannot be read

getFromBatchAndDB

public byte[] getFromBatchAndDB(RocksDB db,
                                ReadOptions options,
                                byte[] key)
                         throws RocksDBException

Similar to RocksDB.get(byte[]) but will also read writes from this batch.

This function will query both this batch and the DB and then merge the results using the DB's merge operator (if the batch contains any merge requests).

Setting ReadOptions.setSnapshot(Snapshot) will affect what is read from the DB but will NOT change which keys are read from the batch (the keys in this batch do not yet belong to any snapshot and will be fetched regardless).

参数:

db - The Rocks database

options - The read options to use

key - The key to read the value for

返回:

a byte array storing the value associated with the input key if any. null if it does not find the specified key.

抛出:

RocksDBException - if the value for the key cannot be read

disposeInternal

protected final void disposeInternal(long handle)

指定者:

disposeInternal 在类中 RocksObject