Prior to Pega 7.1.7 the 'PR_SYS_QUEUES_BIX' , 'PR_EXTRACT_TIME’ table was created during the installation of core Pega. Starting in 7.1.7 it needs to be created as part of the installation of BIX. Since the core Pega upgrade no longer needs these tables and are getting dropped.
Prior to running the upgrade scripts, remove the dropping of these table scripts from the generated ddl before applying it.
If this issue is identified after the upgrade and the tables are alredy been dropped, recreate these tables as part of the installation of BIX 7.1.7. For the existing content of these tables, need to use database tools to copy the old table content to your new rules schema.
The Readme file in the AdditionalProducts/BIX directory has a following note telling to create these tables if they are not present.
Please apply DDL scripts manually to create the tables pr_extract_time and pr_sys_queues_bix if not already present in PegaRULES schema