Sql query tunning, need help!

Question

below is the sql that runs very very slow:
SELECT h.STAT_HIST_ID, h.WF_ACTN, h.USR_ACTN,
      h.WF_CHNG_DATA, h.USR_CHNG_DATA, h.PRCSG_TM, h.UPD_LOGIN, h.UPD_DT,
      RTRIM(c.LAST_NM || ', ' || c.FIRST_NM || ' ' || c.MIDDLE_INITIAL)
      FROM WF_STAT_HIST h, CSE_USER_DATA_VW c WHERE h.WRK_ITM_ID = 'GT1MPTG01ATBZP'
      AND h.UPD_LOGIN = c.USER_NM (+) ORDER BY h.UPD_DT ;Here is its index:
all_indexes:
SCGDBA     WF_STAT_HIST_INDX_ARCH     NORMAL     SCGDBA     WF_STAT_HIST     TABLE     NONUNIQUE     DISABLED          IMS_I
SCGDBA     PK_WF_STAT_HIST     NORMAL     SCGDBA     WF_STAT_HIST     TABLE     UNIQUE     DISABLED          SCG_I
SCGDBA     WF_STAT_HIST_IDX1     NORMAL     SCGDBA     WF_STAT_HIST     TABLE     NONUNIQUE     DISABLED          SCG_I
all_ind_columns:
SCGDBA     WF_STAT_HIST_INDX_ARCH     SCGDBA     WF_STAT_HIST     ARCHIVEDT     1     7     0     ASC
SCGDBA     PK_WF_STAT_HIST     SCGDBA     WF_STAT_HIST     STAT_HIST_ID     1     22     0     ASC
SCGDBA     WF_STAT_HIST_IDX1     SCGDBA     WF_STAT_HIST     WF_ACTN     1     50     50     ASC
SCGDBA     WF_STAT_HIST_IDX1     SCGDBA     WF_STAT_HIST     USR_ACTN     2     50     50     ASCHere is its explain plan:
Plan hash value: 479056202
| Id  | Operation           | Name             | Rows  | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT    |                  |   216 | 30456 | 70864   (2)| 00:14:11 |
|   1 |  SORT ORDER BY      |                  |   216 | 30456 | 70864   (2)| 00:14:11 |
|*  2 |   HASH JOIN OUTER   |                  |   216 | 30456 | 70863   (2)| 00:14:11 |
|*  3 |    TABLE ACCESS FULL| WF_STAT_HIST     |   216 | 24840 | 70857   (2)| 00:14:11 |
|   4 |    TABLE ACCESS FULL| CSE_USER_DATA_VW |  1013 | 26338 |     6   (0)| 00:00:01 |
Predicate Information (identified by operation id):
   2 - access("H"."UPD_LOGIN"="C"."USER_NM"(+))
   3 - filter("H"."WRK_ITM_ID"='GT1MPTG01ATBZP')Could you guys take a look and tell me what the problem might be?
I can`t give you TKPROF, because I got no access to that trace files!
Any thoughts would be appreciated:-)
Edited by: PhoenixBai on Sep 27, 2009 3:13 PM

Answer 1

Pl post the output of the following
select count(*) from wf_stat_hist;
select count (distinct wrk_itm_id) from wf_stat_hist;
select count (distinct upd_login) from wf_stat_hist;Your code is performing poorly because your WHERE clause is searching on a column on WF_STAT_HIST that is not indexed. Hopefully the output of the above code will determine which column (WRK_ITM_ID or UPD_LOGIN) is a better candidate to be indexed on. If neither of these columns is a good candidate, you may have to change the WHERE clause to be more selective rather than do a full table scan as the plan indicates.
HTH
Srini