defaultMaxTimeMS

Definition

defaultMaxTimeMS

New in version 8.0.

Available for both mongod and mongos.

Specifies a default time limit in milliseconds for individual read operations to complete. If a query specifies a maxTimeMS() option, that value overrides the defaultMaxTimeMS value.

defaultMaxTimeMS applies to the following read operations:

• aggregate (except $merge and $out stages)

• count

• dbHash

• distinct

• find

Access Control

To modify cluster parameters, you must authenticate as a user that has one of the following roles:

• clusterAdmin

• clusterMonitor

Syntax

To set defaultMaxTimeMS for your deployment, run the following command on the admin database:

db.adminCommand(
   {
      setClusterParameter: {
         defaultMaxTimeMS: { readOperations: <value> }
      }
   }
)

To view the current value for defaultMaxTimeMS, run the following command on the admin database:

db.adminCommand( { getClusterParameter: "defaultMaxTimeMS" } )

Behavior

By default, defaultMaxTimeMS.readOperations is 0, meaning no default query timeout is set. If there is no default query timeout, the query runs until it either returns a result or fails.

If a query specifies a maxTimeMS() option, that value overrides the defaultMaxTimeMS value.

Example

The following command sets the default query timeout 5000 milliseconds:

db.runCommand( {
   setClusterParameter: {
      defaultMaxTimeMS: { readOperations: 5000 }
   }
} )

To check the value of defaultMaxTimeMS, run the following command:

db.adminCommand( { getClusterParameter: "defaultMaxTimeMS" } )

{
   "clusterParameters" : [
      {
         "_id" : "defaultMaxTimeMS",
         "clusterParameterTime" : Timestamp(1711564868, 17),
         "readOperations" : NumberLong(5000)
      }
   ],
   "ok" : 1,
   "$clusterTime" : {
      "clusterTime" : Timestamp(1712161244, 1),
      "signature" : {
         "hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
         "keyId" : NumberLong(0)
      }
   },
   "operationTime" : Timestamp(1712161244, 1)
}

db.test.find( { name: "Carol" } )
db.test.find( { name: "Carol" } ).maxTimeMS( 8000 )