gp_resource_manager is reserved for later use to switch resource control stratagy from resource queue to an under-developing resource statagy named resource group. Eg:

gpconfig -c gp_resource_manager -v 'group'
gpconfig -c  gp_resource_manager -v 'queue'

To make it work, a restart of cluster is needed.

There was only one caller left, and it was quite superfluous. I don't see
a need to explicitly not use an index here. Also, there were no quals on
the query, so you couldn't possibly use an an index for it.

and 42cab821, since new PANIC
issues are found related to them.

failure fixed)

In some error cases, the resource queue lock is not released, hence
leading to lock leak and inconsistent resource queue status; this commit
overhauls the resource queue locking code to complete the cleanups if error
or signal happens during acquiring resource queue lock; meanwhile, some
unnecessary code blocks are removed and unreasonable code are fixed to make
it easier for reading and understanding;

This reverts commit b46f781f.

In some error cases, the resource queue lock is not released, hence
leading to lock leak and inconsistent resource queue status; this commit
overhauls the resource queue locking code to complete the cleanups if error
or signal happens during acquiring resource queue lock; meanwhile, some
unnecessary code blocks are removed and unreasonable code are fixed to make
it easier for reading and understanding;

Upstream doesn't have them, and they are just plain setter/getter
functions. Having functions like this woldn't be a bad idea per se, but
will cause merge conflicts.