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cursor.comment()

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  • Definition
  • Compatibility
  • Behavior
  • Example
  • Output Examples
cursor.comment()

Important

mongosh Method

This page documents a mongosh method. This is not the documentation for a language-specific driver, such as Node.js.

For MongoDB API drivers, refer to the language-specific MongoDB driver documentation.

Adds a comment field to the query.

cursor.comment() has the following syntax:

cursor.comment( <string> )

comment() has the following parameter:

Parameter
Type
Description
comment
string
The comment to apply to the query.

This method is available in deployments hosted in the following environments:

  • MongoDB Atlas: The fully managed service for MongoDB deployments in the cloud

Note

This command is supported in all MongoDB Atlas clusters. For information on Atlas support for all commands, see Unsupported Commands.

  • MongoDB Enterprise: The subscription-based, self-managed version of MongoDB

  • MongoDB Community: The source-available, free-to-use, and self-managed version of MongoDB

comment() associates a comment string with the find operation. This can make it easier to track a particular query in the following diagnostic outputs:

See configure log verbosity for the mongod log, the Database Profiler tutorial, or the db.currentOp() command.

The following operation attaches a comment to a query on the restaurants collection:

db.restaurants.find(
{ "borough" : "Manhattan" }
).comment( "Find all Manhattan restaurants" )

The following is an excerpt from the system.profile:

{
"op" : "query",
"ns" : "guidebook.restaurant",
"query" : {
"find" : "restaurant",
"filter" : {
"borough" : "Manhattan"
},
"comment" : "Find all Manhattan restaurants"
},
...
}

The following is an excerpt from the mongod log. It has been formatted for readability.

Important

The verbosity level for QUERY must be greater than 0. See Configure Log Verbosity Levels

2015-11-23T13:09:16.202-05:00 I COMMAND [conn1]
command guidebook.restaurant command: find {
find: "restaurant",
filter: { "borough" : "Manhattan" },
comment: "Find all Manhattan restaurants"
}
...

Suppose the following operation is currently running on a mongod instance:

db.restaurants.find(
{ "borough" : "Manhattan" }
).comment("Find all Manhattan restaurants")

Running the db.currentOp() command returns the following:

{
"inprog" : [
{
"host" : "198.51.100.1:27017",
"desc" : "conn3",
"connectionId" : 3,
...
"op" : "query",
"ns" : "test.$cmd",
"command" : {
"find" : "restaurants",
"filter" : {
"borough" : "Manhattan"
},
"comment" : "Find all Manhattan restaurants",
"$db" : "test"
},
"numYields" : 0,
...
}
],
"ok" : 1
}

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