Optimize performance using QueryExpression

For guidance about general things to avoid when composing Dataverse queries, see Query anti-patterns. The following sections are specific to QueryExpression.

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.

Query option	SQL Server hint
ForceOrder	Force Order
DisableRowGoal	Hint: DISABLE_OPTIMIZER_ROWGOAL
EnableOptimizerHotfixes	Hint: ENABLE_QUERY_OPTIMIZER_HOTFIXES
LoopJoin	Loop Join
MergeJoin	Merge Join
HashJoin	Hash Join
NO_PERFORMANCE_SPOOL	NO_PERFORMANCE_SPOOL
ENABLE_HIST_AMENDMENT_FOR_ASC_KEYS	Hint: ENABLE_HIST_AMENDMENT_FOR_ASC_KEYS

More information: Hints (Transact-SQL) - Query

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
Query anti-patterns