Operations: Server: How to Compact a Database

• The compaction operation removes empty gaps on the disk that still occupy space after deletes.

• You can choose what should be compacted: documents and/or listed indexes.

• The operation compacts on one node.
  If you wish to compact all nodes in the database group, the command must be sent to each node separately.

• From Client API: Use the CompactDatabaseOperation.
  To compact on more than one node, the command must be sent to each node by specifying ForNode(<nodeTag>).

• From Studio: Compaction can be triggered from the Storage Report view.
  The operation will compact the database only on the node being viewed (node info is in the Studio footer).

• In this page:
  • Syntax
  • Example I - Compact specific indexes
  • Example II - Compact all indexes
  • Example III - Compact a database that is external to the store
  • Compaction Triggers Documents Compression

Syntax

public CompactDatabaseOperation(CompactSettings compactSettings)

public class CompactSettings
{
    public string DatabaseName { get; set; }

    public bool Documents { get; set; }

    public string[] Indexes { get; set; }
}

DatabaseName is a mandatory parameter.
You must also specify Documents and/or Indexes.

Example I - Compact specific indexes

The following example shows how to compact only specific indexes. Documents are also set to be compacted.

CompactSettings settings = new CompactSettings
{
    DatabaseName = "Northwind",
    // If true, the documents will also be compacted.
    Documents = true,
    // Only the specified indexes will compact.
    Indexes = new[] { "Orders/Totals", "Orders/ByCompany" } 
};
// You can use 'ForNode(<nodeTag>)' to specify on which node to compact.
// If ForNode() is not used, RavenDB will operate by default on the preferred node.
Operation operation = store.Maintenance.Server.ForNode("A")
    .Send(new CompactDatabaseOperation(settings));
operation.WaitForCompletion();

// To compact on all nodes, the above command must be sent to each node separately.

Example II - Compact all indexes

The following example shows how to compact all of the indexes and documents in the database.

// Get all index names in the database.
string[] indexNames = store.Maintenance.Send(new GetIndexNamesOperation(0, int.MaxValue));

CompactSettings settings = new CompactSettings
{
    DatabaseName = "Northwind",
    // If true, documents will also be compacted.
    Documents = true,
    // 'indexNames' contains all of the index names.
    Indexes = indexNames
};
// You can use 'ForNode(<nodeTag>)' to specify on which node to compact.
// If ForNode() is not used, RavenDB will operate by default on the preferred node.
Operation operation = store.Maintenance.Server.ForNode("A")
    .Send(new CompactDatabaseOperation(settings));
operation.WaitForCompletion();

// To compact on all nodes, the above command must be sent to each node separately.

Example III - Compact a database that is external to the store

• CompactDatabaseOperation automatically runs on the store's database.
  If we try to compact a different database, the process will succeed only if the database resides on the cluster's first online node.
  Trying to compact a non-default database on a different node will fail with an error such as -
  "500 Internal Server Error : System.InvalidOperationException , Cannot compact database 'name' on node A, because it doesn't reside on this node."

• To solve this, we can explicitly identify the database we want to compact by providing its name to CompactDatabaseOperation as in the following example.
  

  // To compact a database other than the store's database, we need to explicitly provide 
  // its name to the store's Request Executor.  
  using (var store = new DocumentStore
  {
      Urls = new[] { "http://localhost:8080" },
      Database = "sampleDB" // the store's database
  }.Initialize())
  {
      store.GetRequestExecutor().GetPreferredNode().Wait();
  
      const string DBToCompact = "NonDefaultDB"; // the database we want to compact
      string[] indexNames = store.Maintenance.Send(new GetIndexNamesOperation(0, int.MaxValue));
  
      var compactOperation = new CompactDatabaseOperation(new Raven.Client.ServerWide.CompactSettings
      {
          DatabaseName = DBToCompact,
          Documents = true,
          Indexes = indexNames
      });
  
      // Get request executor for our DB
      var reqEx = store.GetRequestExecutor(DBToCompact);
  
      using (reqEx.ContextPool.AllocateOperationContext(out var context))
      {
          var compactCommand = compactOperation.GetCommand(store.Conventions, context);
          reqEx.Execute(compactCommand, context);
      }
  }