WriteBatch Class

Definition

public class WriteBatch : IDisposable

WriteBatch groups any number of Put, Merge, Delete, and DeleteRange operations into a single atomic write. The batch buffers operations in memory until handed to RocksDb.Write.

Remarks

Either every operation in the batch lands or none do. Batches are also faster than individual writes because they amortise the WAL fsync and MemTable insertion overhead. Every overload accepts an optional ColumnFamilyHandle, so a single batch can write across multiple column families atomically. The mutating methods are fluent and return the batch for chaining.

ToBytes serializes the batch in the same format RocksDB writes to the WAL, which makes it the basis for replication and persistence. See Write batches.

Constructors

WriteBatch

public WriteBatch()

Creates a new empty write batch.

WriteBatch (bytes)

public WriteBatch(byte[] rep)

Reconstructs a batch from the bytes produced by ToBytes — used to replay a batch on another instance.

Methods

Put

public WriteBatch Put(string key, string value, ColumnFamilyHandle cf = null)

Queues an insert or overwrite. Span overloads (net6+) are supported.

Merge

public WriteBatch Merge(string key, string value, ColumnFamilyHandle cf = null)

Queues a merge operand for the configured merge operator.

Delete

public WriteBatch Delete(string key, ColumnFamilyHandle cf = null)

Queues a tombstone for the key.

DeleteRange

public WriteBatch DeleteRange(byte[] startKey, ulong sklen, byte[] endKey, ulong eklen, ColumnFamilyHandle cf = null)

Tombstones every key in the half-open range [startKey, endKey) in a single record — far cheaper than many individual deletes.

PutLogData

public WriteBatch PutLogData(byte[] blob, ulong len)

Adds metadata that travels in the WAL but isn't applied to the MemTable.

Clear

public WriteBatch Clear()

Resets the batch so it can be reused.

Count

public int Count()

Returns the number of operations queued in the batch.

SetSavePoint

public void SetSavePoint()

Marks the current position so the tail of the batch can be rolled back.

RollbackToSavePoint

public void RollbackToSavePoint()

Drops every operation queued since the last SetSavePoint.

ToBytes

public byte[] ToBytes()

Returns the serialized batch — exactly the WAL record format — so it can be shipped across the wire and replayed elsewhere.

Iterate

public void Iterate(IntPtr state, PutDelegate put, DeletedDelegate deleted)

Walks every operation in the batch via callbacks, useful for inspection or selective replay.

Applies to