Using Channels

This is the manual for older MicroStream versions (Version < 5.0).

The new documentation (Version >= 5.0) is located at:

https://docs.microstream.one/

Channel Usage

Channels are the IO threads used by the MicroStream storage engine. A single channel represents the unity of a thread, a storage directory and cached data. Increasing the number of channels means to run more IO threads.

The channel count is an important configuration value that impacts to IO performance.

Channel Configuration

For the channel configuration the following configuration properties are available:

• Channel count

  The number of channels that MicroStream will use. Must be $2^n$

• Channel directory prefix

  The channel directory will be prefix+channelNumber e.g. "ch_0" if prefix is "ch_"

• Data file prefix default is "channel_"

• Data file suffix deflaut id ".dat"

Channel file size configuration is done by the the Storage Data File Evaluator.

They can be set By storage.embedded.configuration API:

Java

EmbeddedStorageManager storageManager = Configuration.Default()
	.setChannelCount(4)
	.setChannelDirectoryPrefix("channel_")
	.setDataFilePrefix("channel_")
	.setDataFileSuffix(".bin")
	.createEmbeddedStorageFoundation()
	.createEmbeddedStorageManager();

Xml

<properties>
	<property name="channelCount" value="4" />
	<property name="channelDirectoryPrefix" value="channel_" />
	<property name="dataFilePrefix value="channel_" />
	<property name="dataFileSuffix" value=".dat" />
</properties>

ini

channelCount = 4
channelDirectoryPrefix = prefix
dataFilePrefix = channel_
dataFileSuffix = .dat

See also: Configuration

Or by setting a StorageFileProvider using theEmbeddedStorageFoundationfactory

NioFileSystem          fileSystem = NioFileSystem.New();
EmbeddedStorageManager storage    = EmbeddedStorage.Foundation(
	Storage.ConfigurationBuilder()
		.setChannelCountProvider(Storage.ChannelCountProvider(4))
		.setStorageFileProvider(
			StorageLiveFileProvider.Builder()
				.setDirectory(fileSystem.ensureDirectoryPath("storage"))
				.createFileProvider()
		)
		.createConfiguration()
)
.start();