Archives of the TeradataForum
Message Posted: Fri, 25 Nov 2011 @ 09:07:57 GMT
Subj: | | Re: Performance issue after splitting the big table |
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From: | | Jinesh P V |
Hi, One possible solutions is:
if you had created 6 parts from the original table based on values of a specific column, for example department, you can use that in the view
as below.
replace view v_large_table as
select 1 as department, a.* from large_table_department1 a union all select 2 as
department, a.* from large_table_department2 a union all select 3 as department, a.* from
large_table_department3 a union all .....
.....
.....
select 6 as department, a.* from large_table_department6 a ;
And then, if you use the column department in all queries, Teradata will scan only the specific table based on the satisfiability. (Otherwise
it will have scan all 6 tables and do the 'union all' as it may be happening now.)
explain select * from v_large_table
where department = 2
;
Thanks
Jinesh
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