DESCRIPTION

Specifying autoIndexId : false while creating a capped collection from the JS mongo shell does not prevent creation of an index on _id.

STEPS TO REPRODUCE

$ mongo

> use test
> db.createCollection("mycoll",

{size:10000000, autoIndexId:false}

);

{ "ok" : 1 }

> db.mycoll.getIndexes()
[
{
"name" : "id",
"ns" : "test.mycoll",
"key" :

{ "_id" : 1 }

,
"v" : 0
}
]

> db._dbCommand(

{create:"mycoll2", size:10000000, autoIndexId:false}

)

{ "ok" : 1 }

> db.mycoll2.getIndexes()
[ ]

SUGGESTED RESOLUTION

The current createCollection JS function does not copy the autoIndexId parameter from the passed-in opt object. If the parameter is set in opt, also set it in the cmd object.

Current code:
> db.createCollection
function (name, opt) {
var options = opt || {};
var cmd =

{create:name, capped:options.capped, size:options.size, max:options.max}

;
var res = this._dbCommand(cmd);
return res;
}