Can I solve this with an "performatic" view ????

Question

Friends, I would like to solve that select above with another solution. Can u help me ?
create view my_view as
select * from mp.tableA where pkb_test.fnb_get_user = 'MP'
UNION
select * from cf.tableA where pkb_test.fnb_get_user = 'CF'
The problem is: the tableA has about 1000000 each and you can imagine how much time it will expend to solve any query ....
Thanks,
Jone.

Answer 1

Without seeing what the procedure pkb_test.fnb_get_user does, it is a little hard to say. However, the follwoing points occur to me.
1. Since there is no apparent connection between your table and the result of pkb_test.fnb_get_user, you will get a full table scan of tablea in both halves of the UNION.
2. Since the two tables are in different schema's, you may be able to use UNION ALL instead of UNION. This will save a sort distinct.
3. You do realize that pkb_test.fnb_get_user is getting called once for every row in each of the tables.
Unless the return value of pkb_test.fnb_get_user is influenced in some way by the contents of each row of tableA (and I see no way it can be since you are not passing any parameters), then you can do away with the procedure call alltogether, and simply do:
SELECT * FROM mp.tablea
UNION ALL
SELECT * FROM cf.tableaunless you really do need distinct rows. In which case you will have to use UNION. This will still full scan both tables, but you will save 2,000,000 procedure calls.
Depending on what exactly you are trying to accomplish, there may be other, faster ways to do it.
TTFN
John