mongodb/mongoid · error · Mongoid::Errors::InvalidSessionNesting

A session was started while another session was being used o

Error message

A session was started while another session was being used on this client.

What it means

Error "A session was started while another session was being used on this client." thrown in mongodb/mongoid.

Source

Thrown at lib/mongoid/clients/sessions.rb:39

        # @example Execute some operations in the context of a session.
        #   Band.with_session(causal_consistency: true) do
        #     band = Band.create
        #     band.records << Record.new
        #     band.save
        #     band.reload.records
        #   end
        #
        # @param [ Hash ] options The session options. Please see the driver
        #   documentation for the available session options.
        #
        # @raise [ Errors::InvalidSessionUse ] If an operation is attempted on a model using another
        #   client from which the session was started or if sessions are nested.
        #
        # @return [ Object ] The result of calling the block.
        #
        # @yieldparam [ Mongo::Session ] The session being used for the block.
        def with_session(options = {})
          raise Mongoid::Errors::InvalidSessionNesting.new if Threaded.get_session(client: persistence_context.client)

          session = persistence_context.client.start_session(options)
          Threaded.set_session(session, client: persistence_context.client)
          yield(session)
        rescue Mongo::Error::InvalidSession => e
          raise Mongoid::Errors::SessionsNotSupported.new if e.is_a?(Mongo::Error::SessionsNotSupported)

          raise e
        rescue Mongo::Error::OperationFailure => e
          if (e.code == 40_415 && e.server_message =~ /startTransaction/) ||
             (e.code == 20 && e.server_message =~ /Transaction/)
            raise Mongoid::Errors::TransactionsNotSupported.new
          else
            raise e
          end
        rescue *transactions_not_supported_exceptions
          raise Mongoid::Errors::TransactionsNotSupported
        ensure

View on GitHub (pinned to 0da0e23d71)

When it happens

Trigger: Thrown at lib/mongoid/clients/sessions.rb:39 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of mongodb/mongoid@0da0e23d71 (2026-08-23). Data as JSON: /api/errors/6e8b5b70b02b4ce6. Report an issue: GitHub.