Class Cache

Namespace

RocksDbNet

Assembly

RocksDb.Net.dll

An LRU or HyperClock block/row cache. Maps to rocksdb_cache_t.

public sealed class Cache : RocksDbHandle, IDisposable

Inheritance

object

RocksDbHandle

Cache

Implements

IDisposable

Inherited Members

RocksDbHandle.Handle

RocksDbHandle.Owned

RocksDbHandle.IsDisposed

RocksDbHandle.ThrowIfDisposed()

RocksDbHandle.Dispose()

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.ReferenceEquals(object, object)

object.ToString()

Properties

Capacity

Gets or sets the cache capacity in bytes.

public ulong Capacity { get; set; }

Property Value

ulong

OccupancyCount

How many entries the cache currently holds.

public ulong OccupancyCount { get; }

Property Value

ulong

Remarks

Together with Usage this gives the average entry size, which is what EstimatedEntryCharge wants. Measuring it on a running database beats guessing.

PinnedUsage

Current pinned memory usage of the cache in bytes.

public ulong PinnedUsage { get; }

Property Value

ulong

TableAddressCount

How many slots the cache's hash table has.

public ulong TableAddressCount { get; }

Property Value

ulong

Remarks

Compare against OccupancyCount to see how full the table is. Chiefly of interest for a HyperClock cache, whose table is fixed at creation.

Usage

Current memory usage of the cache in bytes.

public ulong Usage { get; }

Property Value

ulong

Methods

CreateHyperClock(HyperClockCacheOptions)

Creates a HyperClock cache from options.

public static Cache CreateHyperClock(HyperClockCacheOptions options)

Parameters

options HyperClockCacheOptions

Returns

Cache

Remarks

Use this when the shard count matters. RocksDb copies the options, so they may be disposed straight afterwards.

CreateHyperClock(ulong, ulong)

Creates a HyperClock cache.

public static Cache CreateHyperClock(ulong capacityBytes, ulong estimatedEntryChargeBytes)

Parameters

capacityBytes ulong

Total capacity in bytes.

estimatedEntryChargeBytes ulong

Rough average entry size, or zero to let RocksDb adapt.

Returns

Cache

Remarks

HyperClock replaces the LRU cache's per-shard locking with a fixed-size table, which scales better under concurrent readers. In exchange it wants an estimate of the average entry size to size that table; passing zero lets RocksDb work it out.

CreateLru(LruCacheOptions)

Creates an LRU cache from options.

public static Cache CreateLru(LruCacheOptions options)

Parameters

options LruCacheOptions

Returns

Cache

Remarks

Use this when the shard count matters. RocksDb copies the options, so they may be disposed straight afterwards.

CreateLru(ulong)

Creates an LRU cache with the specified capacity (bytes).

public static Cache CreateLru(ulong capacityBytes)

Parameters

capacityBytes ulong

Returns

Cache

CreateLruWithStrictCapacityLimit(ulong)

Creates an LRU cache that enforces strict capacity limits.

public static Cache CreateLruWithStrictCapacityLimit(ulong capacityBytes)

Parameters

capacityBytes ulong

Returns

Cache

DisposeHandle()

Releases the native handle. Called during disposal.

protected override void DisposeHandle()

Remarks

Protected rather than public: it destroys the native object without marking this instance disposed or clearing the handle, so calling it from outside and then disposing normally would free the same pointer twice. It was the most Dispose-looking member on the type. Callers want Dispose().