In versions 6.1.x, to ensure better resource management, the MDEX Engine always runs in a multithreaded mode with the default number of threads equal to 1. In addition, starting with version 6.1.2, the --threads 0 value is ignored and interpreted as --threads 1.

Multithreaded mode is the only supported mode for the MDEX Engine and it cannot be disabled.

If you set the --threads 0 value, the Dgraph issues a warning and continues to run with one thread used for processing client requests (queries and partial updates).

As in previous releases, Oracle recommends that you experimentally increase the number of processing threads to improve performance. In addition to threads controlled by the threading pool (with the --threads flag), the MDEX Engine by default uses a pool of background threads (that you cannot control) .