Set Index Priority Operation

• In RavenDB, each index has its own dedicated thread for all indexing work.
  By default, RavenDB prioritizes processing requests over indexing,
  so indexing threads start with a lower priority than request-processing threads.

• Use SetIndexesPriorityOperation to increase or lower the index thread priority.

• Indexes scope:
  Index priority can be set for both static and auto indexes.

• Nodes scope:
  The priority will be updated on all nodes in the database group.

• Setting the priority can also be done from the indexes list view in the Studio.

• In this page:

  • Index priority
  • Set priority - single index
  • Set priority - multiple indexes
  • Syntax

Index priority

Setting the priority will affect the indexing thread priority at the operating system level:

Priority value	Indexing thread priority at OS level
Low	Lowest	<ul><li>Having the Lowest priority at the OS level, indexes will run only when there's a capacity for them, when the system is not occupied with higher-priority tasks.</li><li>Requests to the database will complete faster. Use when querying the server is more important to you than indexing.</li></ul>
Normal (default)	Below normal	<ul><li>Requests to the database are still preferred over the indexing process.</li><li>The indexing thread priority at the OS level is Below normal while Requests processes have a Normal priority.</li></ul>
High	Normal	<ul><li>Requests and Indexing will have the same priority at the OS level.</li></ul>

Set priority - single index

• Sync
• Async

// Define the set priority operation
// Pass index name & priority
var setPriorityOp = new SetIndexesPriorityOperation("Orders/Totals", IndexPriority.High);

// Execute the operation by passing it to Maintenance.Send
// An exception will be thrown if index does not exist
store.Maintenance.Send(setPriorityOp);

// Define the set priority operation
// Pass index name & priority
var setPriorityOp = new SetIndexesPriorityOperation("Orders/Totals", IndexPriority.High);
              
// Execute the operation by passing it to Maintenance.SendAsync
// An exception will be thrown if index does not exist
await store.Maintenance.SendAsync(setPriorityOp);

Set priority - multiple indexes

• Sync
• Async

// Define the index list and the new priority:
var parameters = new SetIndexesPriorityOperation.Parameters
{
  IndexNames = new[] {"Orders/Totals", "Orders/ByCompany"},
  Priority = IndexPriority.Low
};

// Define the set priority operation, pass the parameters
var setPriorityOp = new SetIndexesPriorityOperation(parameters);

// Execute the operation by passing it to Maintenance.Send
// An exception will be thrown if any of the specified indexes do not exist
store.Maintenance.Send(setPriorityOp);

// Define the index list and the new priority:
var parameters = new SetIndexesPriorityOperation.Parameters 
{
  IndexNames = new[] {"Orders/Totals", "Orders/ByCompany"}, 
  Priority = IndexPriority.Low
};
              
// Define the set priority operation, pass the parameters
var setPriorityOp = new SetIndexesPriorityOperation(parameters);

// Execute the operation by passing it to Maintenance.SendAsync
// An exception will be thrown if any of the specified indexes do not exist
await store.Maintenance.SendAsync(setPriorityOp);

Syntax

// Available overloads:
public SetIndexesPriorityOperation(string indexName, IndexPriority priority);
public SetIndexesPriorityOperation(Parameters parameters);

Parameters
indexName	string	Index name for which to change priority
priority	IndexingPriority	Priority to set
parameters	SetIndexesPriorityOperation.Parameters	List of indexes + Priority to set. An exception is thrown if any of the specified indexes do not exist.

public enum IndexPriority
{
  Low,
  Normal,
  High
}

public class Parameters
{
  public string[] IndexNames { get; set; }
  public IndexPriority Priority { get; set; }
}