I assume you are talking about the backend for the R80+ SMS. The best documents are linked in this thread:
https://community.checkpoint.com/t5/General-Management-Topics/R80-10-Architecture-Overview/td-p/3159
There is some additional content in the CCSM courseware that delves into the internal table structure of the postgres database and how to directly work with the database via the psql command that I haven't seen elsewhere, but that content is restricted and cannot be reposted here.
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