Hi all,
New to the group.
Does anyone knows any reason for redundante composite indexes (multiple-columns) by just changing the field's order ?
Like partitioning and whatever or legacy reasons on older versions of informix ?
The reason is I came across this situation on a frequently accessed table we have in ERP database:
CREATE INDEX i_2 ON table (company, store, item, start_date);
CREATE INDEX i_3 ON table (item, store, company, start_date);
CREATE INDEX i_4 ON table (start_date, company, store,item);
CREATE INDEX i_5 ON table (item, start_date, store, company);
CREATE INDEX i_6 ON table (store, company, start_date, item);
And according to Lester Knutsen
here on pages 39-40, he does not mention any reason that will justify that.
I suggested removing redundancy, but someone raised this was justified.
Thanks in advance
Really wanted to optimize this indexing because the table has a lot of updates and the I/O propagating to all indexes is a huge overhead.
G.
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Gilberto Pe-Curto
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