You can use the CASENUM_FIND_GAPS stored procedure to get range of free case numbers from previously purged cases or sub-cases. 

Steps to run the CASENUM_FIND_GAPS

1) Shutdown TIBCO iProcess Engine 

2) Run the CASENUM_FIND_GAPS stored procedure.

exec swpro.casenum_find_gaps (1, 200000, 1000)

The above statement will look for gaps of 1000 from the range of 1 to 200000.

3) After running the stored procedure, restart TIBCO iProcess Engine.



NOTE: It is advisable for customers to keep purging cases or sub-cases at regular intervals in order to allow for case numbers to be reused.

You can find more information about CASENUM_FIND_GAPS in the following guides:
https://docs.tibco.com/pub/ipe-oracle/11.6.1/doc/pdf/TIB_ipe_sql_11.6_admin_guide.pdf
https://docs.tibco.com/pub/ipe-oracle/11.6.1/doc/pdf/TIB_ipe_oracle_11.6_admin_guide.pdf

When the case number limit reaches to 4294967295 or 4 gig limits then, iProcess will not create further cases or sub-cases and it will error out.

TIBCO iProcess Engine (SQL) TIBCO iProcess Engine (Oracle)

CASENUM_FIND_GAPS, CASENUM_GAPS, SEQUENCE, CNUM_SEQ_CACHE, REQID_SEQ_CACHE, 4294967295, Case Number