admonitions-eval.rst

Write Lock

For long running |object| operation, consider using either the :command:`eval` command with nolock: true or using :doc:`other server side code execution options </core/server-side-javascript>`.

Sharded Data

You can not use |object| with :term:`sharded <sharding>` collections. In general, you should avoid using |object| in :term:`sharded clusters <sharded cluster>`; nevertheless, it is possible to use |object| with non-sharded collections and databases stored in a :term:`sharded cluster`.

Access Control

.. versionchanged:: 2.6

JavaScript Engine

.. versionchanged:: 2.4

The V8 JavaScript engine, which became the default in 2.4, allows multiple JavaScript operations to execute at the same time. Prior to 2.4, |object| executed in a single thread.