Table Of Contents

6.2. Streams


Streams are available starting with quasardb 2.0.0.

6.2.1. Features

A stream is an entry type that supports efficient storage and retrieval of large binary entries.

It is possible to randomly seek within, append, and truncate a stream and there is no practical limit to the size of a stream.

6.2.2. Design

Streams are split in chunks of one megabyte blobs. The streaming API takes care of maintaining consistence accross the blobs as you write to the stream. A separate metadata entry holds the size of the stream and various upkeeping information that enable the API to seek efficiently. The metadata information has a constant size, regardless of the stream size.

Since it is based on blobs, streams chunks are replicated and migrated like regular blobs.

6.2.3. When to use

You should consider streams when:

  • The entry size represents more than 5% of the total RAM available on the cluster.
  • You need to efficiently read from/write to the cluster in chunks
  • You want the content of your entry to be spread over the cluster

6.2.4. When not to use

Streams should not be used when the total size of the entry will never exceed one megabyte.

6.2.5. Performance

The larger the stream, the better the performance compared to a single blob.

6.1. Common principles
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6.3. Time series