Use the -b command line argument to start kdb in read only mode, or start up with a negative port number.

one can verify the read-only mode by examining the return value of function \_

$ q -b
KDB+ 2.7 2011.02.16 Copyright (C) 1993-2011 Kx Systems

No. Multithreaded q code cannot have side effects, so the functions called by peach must be side-effect free. You will receive the error ‘mq if you try otherwise.

See also: kdb error code table