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Compare Exchange Metadata

  • RavenDB 5.0 added metadata to compare exchange values.

  • In this page:

Syntax​

A compare exchange value's metadata is very similar to a document's metadata.

The metadata can be used to set compare exchange expiration.

The metadata is accessible as a root property of the compare exchange value object:

using (IAsyncDocumentSession session = store.OpenAsyncSession(
                                     new SessionOptions { 
                                         TransactionMode = TransactionMode.ClusterWide 
                                     }))
{
  // Create a new compare exchange value
  var cmpxchgValue = session.Advanced.ClusterTransaction.CreateCompareExchangeValue("key", "value");

  // Add a field to the metadata
  // with a value of type string
  cmpxchgValue.Metadata["Field name"] = "some value";

  // Retrieve metadata as a dictionary
  IDictionary<string, object> cmpxchgMetadata = cmpxchgValue.Metadata;
}

You can send it as a parameter of the Put Compare Exchange Value operation:

// Create some metadata
var cmpxchgMetadata = new MetadataAsDictionary {
                        ["Year"] = "2020" 
                    };

// Create/update the compare exchange value "best"
await documentStore.Operations.SendAsync(
  new PutCompareExchangeValueOperation<User>(
      "best", 
      new User { Name = "Alice" }, 
      0, 
      cmpxchgMetadata));