Designer deployment: Why is refresh() executed before drop projection?
Vertica community edition: Vertica Analytic Database v7.1.1-0
I ran admintools / designer on the VMART sample database.
The generated design deployment script starts out with 4 create projection statements for 4 tables in VMART, followed by select refresh(on those 4 tables) operation, select make_ahm_now() operation, then 4 drop projection statements for existing projections for those same 4 tables.
Thus, the design creates new projections for 4 tables, also finds and removes existing projections for those tables.
Question: Why is the designer deployment script executing a REFRESH() operation BEFORE the old/obsolete projections are dropped?
The Refresh operation is documented as follows:
"REFRESH - Performs a synchronous, optionally-targeted refresh of a specified table's projections."
Wouldn’t it make sense to drop and get rid of the obsolete projections before executing a refresh() operation?
What is the reason for executing a refresh() just prior to a drop projection