Documents Compression

Despite the many benefits of the schema-less nature of document databases, one drawback is that it requires us to manage the structure of our data on a per-document basis. In extreme cases, the majority of the data you store is the documents' structure.

Documents Compression uses the top of the line Zstd compression algorithm to learn your data model and create dictionaries that represent the redundant structural data across documents. Compression is applied at the collection rather than the document level, to eliminate these cross-document duplications. RavenDB continuously inspects your documents as they change to retrain the algorithm and maintain the most efficient compression model. In many datasets, this can reduce the storage space by more than 50%.

The Zstd algorithm is trained by each compression operation and continuously improves its compression ratio.

Reading and querying compressed large datasets is usually at least as fast as reading and querying their uncompressed versions because the compressed data is loaded much faster. Compression and decompression is fully transparent to the user.

Documents compression is configured using the DocumentsCompressionConfiguration option in the DatabaseRecord.

public class DocumentsCompressionConfiguration
{
    public string[] Collections { get; set; }
    public bool CompressRevisions { get; set; }
    public bool CompressAllCollections { get; set; }
}

In this example, we configure compression to be active on the collection Orders and on the revisions of all collections:

using (var store = new DocumentStore())
{
    // Retrieve database record
    var record = store.Maintenance.Server.Send(new GetDatabaseRecordOperation(store.Database));

    // Enable compression on collection Orders
    // Enable compression of revisions on all 
    // collections
    record.DocumentsCompression = new DocumentsCompressionConfiguration(compressRevisions: true, "Orders");
    
    // Update the server
    store.Maintenance.Server.Send(new UpdateDatabaseOperation(record, record.Etag));
}