optimize-performance.md

title	description	ms.date	ms.reviewer	ms.topic	author	ms.subservice	ms.author	search.audienceType	contributors
Optimize performance using QueryExpression	Learn how to optimize performance when you retrieve data from Microsoft Dataverse using QueryExpression.	05/12/2024	jdaly	how-to	pnghub	dataverse-developer	gned	developer	JimDaly

Optimize performance using QueryExpression

This article describes ways you can optimize performance when retrieving data using QueryExpression.

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Query Hints

Important

Only apply these options when recommended by Microsoft technical support. Incorrect use of these options can damage the performance of a query.

Microsoft SQL Server supports many query hints to optimize queries. QueryExpression supports query hints and can pass these query options to SQL Server using the QueryExpression.QueryHints property.

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No lock

In earlier versions, the QueryExpression.NoLock property used to prevent shared locks on records. It's no longer necessary to include this property

Union Hint

You can improve performance when adding a FilterExpression that sets the ConditionExpression for columns in different tables by setting the FilterExpression.FilterHint property to union. But there are some restrictions:

• The FilterExpression.FilterOperator must use LogicalOperator.Or.
• Each query can contain only one union hint.
• If a FilterExpression with union hint isn't at top level filter, Dataverse transforms the query and move the filter with a union hint to root filter.
• If a union hint is more than three levels deep, it's ignored.

The following example sets a filter with the union hint on the telephone1 column for both the account and contact tables.

QueryExpression query = new("email")
{
   ColumnSet = new ColumnSet("activityid", "subject"),
   Criteria = new FilterExpression(LogicalOperator.And)
   {
      Conditions = {
         {
            new ConditionExpression(
               attributeName:"subject",
               conditionOperator:ConditionOperator.Like,
               value: "Alert:%")
         },
         {
            new ConditionExpression(
               attributeName:"statecode",
               conditionOperator:ConditionOperator.Equal,
               value: 0)
         }
      },
      Filters = {
         {
            new FilterExpression(LogicalOperator.Or){
               FilterHint = "union",
               Conditions = {
                  {
                     new ConditionExpression(
                        attributeName:"telephone1",
                        conditionOperator:ConditionOperator.Equal,
                        value: "555-123-4567"){
                           EntityName = "ac"
                        }
                  },
                  {
                     new ConditionExpression(
                        attributeName:"telephone1",
                        conditionOperator:ConditionOperator.Equal,
                        value: "555-123-4567"){
                           EntityName = "co"
                        }
                  }
               }
            }
         }
      }
   }
};        

LinkEntity linkToAccount = query.AddLink(
      linkToEntityName: "account",
      linkFromAttributeName: "regardingobjectid",
      linkToAttributeName: "accountid",
      joinOperator: JoinOperator.LeftOuter);
linkToAccount.EntityAlias = "ac";

LinkEntity linkToContact = query.AddLink(
      linkToEntityName: "contact",
      linkFromAttributeName: "regardingobjectid",
      linkToAttributeName: "contactid",
      joinOperator: JoinOperator.LeftOuter);
linkToContact.EntityAlias = "co";

See also

Query data using QueryExpression
Select columns using QueryExpression
Join tables using QueryExpression
Order rows using QueryExpression
Filter rows using QueryExpression
Page results using QueryExpression
Aggregate data using QueryExpression
Count rows using QueryExpression

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