rdisp/vb_key_comp is a SAP Parameter attribute which is used to control Verbuchungskey: Reihenfolge der Key-Komponenten information. This is available within R/3 SAP systems depending on the version and release level.
Below is the standard documentation available and a few details of the attributes values .
Using the parameter rdisp/vb_key_comp it is possible to changes the
update key in its construction if the parameter dynp/trans_id_format was
previously defined with the format 2. In this case the update key is
made up of the following components:
HOST IP address of the host (in HEX notation)
SYSNR System number of the application server
WPNR Work process number
DATE Date
TIME Time
STMP Stamp
rdisp/vb_key_comp now describes the sequence in which the components
appear in the update key.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.