kdb q Access Error

An access error is due to a permissions/security error.
It can be caused by:

Failed Login due to Access Error

Attempting to connect to a remote process with the invalid username or password can cause an access error.

Server q -p 5000 >q -p 5000 KDB+ 3.4 Copyright (C) q)/ check password is pass q).z.pw:{x;y~"pass"}

Client q)h:hopen 5000 'access q)h:hopen `:localhost:5000:me:myPassWord 'access q)h:hopen `:localhost:5000:me:pass q)

System Command causes Access Error

Starting kdb with some variations of -u make kdb refuse to run system commands remotely. As you can see, local system commands work but remote ones do not, including attempts to exit.

Server q -p 5000 -u 1 >q -p 5000 -u 1 KDB+ 3.4 Copyright (C) q)system "echo 1" "1 "

Client q)h:hopen `:localhost:5000 q)h "til 11" 0 1 2 3 4 5 6 7 8 9 10 q)h (system;"echo 1") 'access q)h "\\\\" 'access q)

Accessing Files/Folders causes Access Error

If kdb has been started with -u and you try to access a file on the server above the current directory you will receive an access error like so:

Server q -p 5000 -u 1 >q -p 5000 -u 1 KDB+ 3.4 Copyright (C) q)read0 `:hello.txt "hello world" q)read0 `:../hello.txt "hello world"

Client q)h "read0 `:hello.txt" "hello world" q)h "read0 `:../hello.txt" 'access q)