HELP! Index Debate!

From: Smith, Ron L. <rlsmith_at_kmg.com>
Date: Thu, 31 Jul 2003 05:54:29 -0800
Message-ID: <F001.005C7FA1.20030731055429@fatcity.com>

Please help resolve this dispute.
We have a query that runs over 5 hours. Sections of the query are listed below.

The table QOH_DAY_FACT table had only on index and that was on the TIME_ID column. I propose adding an index with PROD_ID, WHS_ID, LOT_ID, WHS_LOC, TIME_ID and QUALITY_ID. My test shows the runtime was reduced to about 1.5 hours.

The developer said all the columns in the index except PROD_ID were being ignored. He says there should be six separate indexes, one for each column before Oracle will use them.

Also, does the order of the columns in the index have to match the order of the columns in the WHERE CLAUS or is it more important to match the WHERE CLAUS to the data content (least number of rows first)?

I will be running more tests, but I would like some input on this if anyone has an opinion.

Thanks!
Ron

select T1."COUNTRY_NAME" "c1"
, T2."PRODTN_PROC_NAME" "c2"
, T2."PLANT_NAME" "c3"
, T1."WHS_NAME" "c4"
, T1."WHS_CMPLX_NAME" "c5"
, T3."WHS_LOC_NAME" "c6"
, T4."GRADE_DESC" "c7"
, T4."PACK_DESC" "c8"
, T5."FULL_DT" "c9"
, T6."QOH_MT" "c10".......

....from "DWMART"."DISTRIB_FCLTY_DIM" T1
, "DWMART"."MFG_FCLTY_DIM" T2
, "DWMART"."DISTRIB_LOC_DIM" T3
, "DWMART"."TIME_DIM" T5
, "DWMART"."QUALITY_DIM" T7
, "DWMART"."QOH_DAY_FACT" T6
, "DWMART"."PROD_DIM" T4

where T6."PROD_ID"=T4."PROD_ID"(+)
   and T6."WHS_ID"=T1."WHS_ID"
   and T6."LOT_ID"=T2."LOT_ID"
   and T6."WHS_LOC_ID"=T3."WHS_LOC_ID"

   and T6."TIME_ID"=T5."TIME_ID"
   and T6."QUALITY_ID"=T7."QUALITY_ID"
order by "c9" asc

-- 
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-- 
Author: Smith, Ron L.
  INET: rlsmith_at_kmg.com

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Received on Thu Jul 31 2003 - 08:54:29 CDT