I am attaching the latest 7.2.1 code for each platform for sppr_sys_reservequeueitem_b here. It's safe to replace the out of the box version of this stored procedure in any 6.x or 7.x release up to 7.2.1 with what I have attached.

To make the performance improvement, you also need the following 7.1.x OOTB indexes. These indexes are different depending on which database platform is in use.

Note: you need to properly schema qualify these statements with your prpc data schema name for both the indexes and stored procedures.

Oracle and DB2 version:

CREATE INDEX pr_sys_queues_index1
ON pr_sys_queues
(
    PYITEMSTATUS asc,
    PYAGENTNAME asc,
    PYMINIMUMDATETIMEFORPROCESSING asc,
    PZINSKEY asc
)
/

CREATE INDEX pr_sys_queues_index2
ON longj_admin_data.pr_sys_queues
(
    PYITEMID asc,
    PYITEMSTATUS asc,
    PXPROCESSINGNODEID asc
)
/

MSSQL version:

CREATE INDEX pr_sys_queues_index1
ON longj_d_admin_split.pr_sys_queues
(
    pyItemStatus asc,pyAgentName asc,pyMinimumDateTimeForProcessing asc,pzInsKey asc
)
go

CREATE INDEX pr_sys_queues_index2
ON longj_d_admin_split.pr_sys_queues
(
    pyItemId asc,pyItemStatus asc,pxProcessingNodeId asc
)
go

Postgres version:

CREATE INDEX pr_sys_queues_index1
ON longj_d_admin_split.pr_sys_queues
(
    pyitemstatus asc,
    pyagentname asc,
    pyminimumdatetimeforprocessing asc,
    pzinskey asc
)
;

CREATE INDEX pr_sys_queues_index2
ON longj_d_admin_split.pr_sys_queues
(
    pyitemid asc,
    pyitemstatus asc,
    pxprocessingnodeid asc
)
;