Reducing the Cost of the query by indexing.

Question

Hello,
I have a query as under :
SELECT T1_WO.WO_ID, T1_RW_MSG.RMSG_FN_ID, T1_RW_MSG.RMSG_PROD_CD, T1_RW_MSG.RMSG_OPRN_CD, T1_WO.WO_ENTRY_DT, T1_RW_MSG.RMSG_OUR_REF_NUM, T1_WO.WO_CURR_QUEUE, T1_WO.WO_PRIORITY, T1_WO.WO_STATUS_CD, T1_RW_MSG.RMSG_TRANS_MD, T1_RW_MSG.RMSG_SRC_TYP, T1_WO.WO_TYP_FLG, T1_WO.WO_DEQUEUE_DT, T1_RW_MSG.RMSG_BTCH_ID, T1_RW_MSG.RMSG_SEQ_NUM_IN_BTCH, T1_WO.WO_FRM_QUEUE , T1_WO.WO_ORIG_ENTRY_DT,T1_WO.WO_SRC_TYP, T1_RW_MSG.RMSG_TILIS_PROC_LOC FROM T1_RW_MSG, T1_WO WHERE ( T1_RW_MSG.RMSG_FN_ID = T1_WO.RMSG_FN_ID ) AND ( T1_WO.WO_TYP_FLG = 'R') AND ( ( T1_WO.WO_ERR_FLG = 'F' ) AND ( T1_WO.WO_BSY_FLG = 'F' ) AND (T1_WO.WO_CURR_QUEUE IN ('MUMBAISAP','CCD19SAP') OR (T1_WO.WO_CURR_QUEUE IN ('') AND T1_WO.WO_FRM_ROLE_INSTANCE = 'CCD19SAP') OR (T1_WO.WO_CURR_QUEUE IN ('') AND T1_WO.WO_FRM_ROLE_INSTANCE <> 'CCD19SAP')) )
ORDER BY T1_WO.WO_PRIORITY DESC, T1_WO.WO_ENTRY_DT ASC;
This query has an ORDER BY clause wherein two columns
WO_PRIORITY DESC,WO_ENTRY_DT are used which are not indexed.
These columns are not indexed.Now I try to reduce the cost of these query by indexing these columns WO_PRIORITY DESC,WO_ENTRY_DT.Will this reduce the cost of the query.
Message was edited by:
UdayM

Answer 1

wrap your code in [code] and [/code] tags to preserve the formatting you will do to make it readable. You're unlikely to get much help if you make it hard to read.
an example of code formatting:
WITH t1_wo AS (SELECT 'a' wo_curr_queue from dual
               UNION
               SELECT to_char(null) from dual
               UNION
               SELECT '' from dual)
  SELECT *
  FROM t1_wo
  WHERE t1_wo.wo_curr_queue IN ('')Interestingly, that returns no rows, which makes me suspect that the sections of your query that include t1_wo.wo_curr_queue IN ('') will never work.