How to reduce execution time of this SQL?

Question

This SQL will output only 2 rows. I tried using hints (an index) but to no avail.
http://www.freeimagehosting.net/uploads/cf214afcf1.jpg
Or, is it NOT possible, limit of query optimization has reached?

Answer 1

Rakesh jayappa wrote:
Hi,
Run the sql tuning advisory.
Let me know recommendation.
Kind Regards,
Rakesh************************** Here is my tuning request **************************
1.) The following SQL statement has been identified to perform poorly. It currently takes up to 12 seconds to execute, but it's supposed to take a second at most.
This is the statement:
select DISTINCT trunc(c.sst_post_date) as post_date
from ac_t_sessn b , ac_t_ssntr c
where
       b.ses_status = 0
          and b.ses_profit_center = c.sst_profit_center
          and b.ses_acct_year = c.sst_acct_year
          and b.ses_acct_period = c.sst_acct_period
          and b.ses_sessn_no = c.sst_sessn_no
   AND
         C.sst_post_mtd||C.sst_post_TYPE IN
       (SELECT Y.pst_post_mtd||Y.pst_post_type
        FROM ac_r_post_functions Y
       WHERE Y.pst_post_status IN (0,'2'))
order by trunc(c.sst_post_date);It should return data from a table in a specific order.
2.) The version of the database is Oracle9i Enterprise Edition Release *9.2.0.6.0*
3.) These are the parameters relevant to the optimizer:
UAT_UML@umltest>show parameter optimizer
NAME                                 TYPE        VALUE
optimizer_dynamic_sampling           integer     1
optimizer_features_enable            string      9.2.0
optimizer_index_caching              integer     0
optimizer_index_cost_adj             integer     100
optimizer_max_permutations           integer     2000
optimizer_mode                       string      CHOOSE
UAT_UML@umltest>show parameter db_file_multi
NAME                                 TYPE        VALUE
db_file_multiblock_read_count        integer     16
UAT_UML@umltest>show parameter db_block_size
NAME                                 TYPE        VALUE
db_block_size                        integer     8192
UAT_UML@umltest>show parameter cursor_sharing
NAME                                 TYPE        VALUE
cursor_sharing                       string      EXACT
UAT_UML@umltest>column sname format a20
UAT_UML@umltest>column pname format a20
UAT_UML@umltest>column pval2 format a20
UAT_UML@umltest>select
  2             sname
  3           , pname
  4           , pval1
  5           , pval2
  6      from
  7           sys.aux_stats$;
no rows selected4.) Here is the output of EXPLAIN PLAN:
UAT_UML@umltest>select * from table(dbms_xplan.display);
PLAN_TABLE_OUTPUT
| Id  | Operation              |  Name                | Rows  | Bytes |TempSpc| Cost  |
|   0 | SELECT STATEMENT       |                      |   454 | 22700 |       |  5391 |
|   1 |  SORT UNIQUE           |                      |   454 | 22700 |       |  5072 |
|   2 |   HASH JOIN            |                      | 69384 |  3387K|  2592K|  4478 |
|   3 |    INDEX FAST FULL SCAN| INDX_AC_T_SESSN      |   110K|  1294K|       |   244 |
|   4 |    HASH JOIN           |                      |   416K|    15M|       |  3877 |
|   5 |     TABLE ACCESS FULL  | AC_R_POST_FUNCTIONS  |    23 |   253 |       |     2 |
|   6 |     TABLE ACCESS FULL  | AC_T_SSNTR           |  1790K|    46M|       |  3866 |
Note: cpu costing is off, PLAN_TABLE' is old version5.) Here is the output of SQL*Plus AUTOTRACE including the TIMING information:
UAT_UML@umltest>set autotrace traceonly arraysize 100
UAT_UML@umltest>
UAT_UML@umltest>select DISTINCT trunc(c.sst_post_date) as post_date
  2  from ac_t_sessn b , ac_t_ssntr c
  3  where
  4  b.ses_status = 0
  5  and b.ses_profit_center = c.sst_profit_center
  6  and b.ses_acct_year = c.sst_acct_year
  7  and b.ses_acct_period = c.sst_acct_period
  8  and b.ses_sessn_no = c.sst_sessn_no
  9  AND
10  C.sst_post_mtd||C.sst_post_TYPE IN (SELECT         Y.pst_post_mtd||Y.pst_post_type FROM ac_r_po
st_functions Y
11  WHERE Y.pst_post_status IN (0,'2'))
12  order by trunc(c.sst_post_date);
Execution Plan
   0      SELECT STATEMENT Optimizer=CHOOSE (Cost=5391 Card=454 Bytes=
          22700)
   1    0   SORT (UNIQUE) (Cost=5072 Card=454 Bytes=22700)
   2    1     HASH JOIN (Cost=4478 Card=69384 Bytes=3469200)
   3    2       INDEX (FAST FULL SCAN) OF 'INDX_AC_T_SESSN' (NON-UNIQU
          E) (Cost=244 Card=110433 Bytes=1325196)
   4    2       HASH JOIN (Cost=3877 Card=416304 Bytes=15819552)
   5    4         TABLE ACCESS (FULL) OF 'AC_R_POST_FUNCTIONS' (Cost=2
           Card=23 Bytes=253)
   6    4         TABLE ACCESS (FULL) OF 'AC_T_SSNTR' (Cost=3866 Card=
          1790555 Bytes=48344985)
Statistics
          0  recursive calls
          0  db block gets
      42741  consistent gets
        171  physical reads
          0  redo size
        425  bytes sent via SQL*Net to client
        507  bytes received via SQL*Net from client
          2  SQL*Net roundtrips to/from client
          1  sorts (memory)
          0  sorts (disk)
          2  rows processed
UAT_UML@umltest>DISCONNECT
Disconnected from Oracle9i Enterprise Edition Release 9.2.0.6.0 - Production
With the Partitioning, OLAP and Oracle Data Mining options
JServer Release 9.2.0.6.0 - Production6.) The TKPROF output snippet
TKPROF: Release 11.2.0.1.0 - Development on Wed Oct 27 12:47:35 2010
Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.
Trace file: umltest_ora_1604.trc
Sort options: prsela  exeela  fchela 
count    = number of times OCI procedure was executed
cpu      = cpu time in seconds executing
elapsed  = elapsed time in seconds executing
disk     = number of physical reads of buffers from disk
query    = number of buffers gotten for consistent read
current  = number of buffers gotten in current mode (usually for update)
rows     = number of rows processed by the fetch or execute call
select DISTINCT trunc(c.sst_post_date) as post_date
from ac_t_sessn b , ac_t_ssntr c
where
b.ses_status = 0
and b.ses_profit_center = c.sst_profit_center
and b.ses_acct_year = c.sst_acct_year
and b.ses_acct_period = c.sst_acct_period
and b.ses_sessn_no = c.sst_sessn_no
AND
C.sst_post_mtd||C.sst_post_TYPE IN (SELECT         Y.pst_post_mtd||Y.pst_post_type FROM ac_r_post_functions Y
WHERE Y.pst_post_status IN (0,'2'))
order by trunc(c.sst_post_date)
call     count       cpu    elapsed       disk      query    current        rows
Parse        1      0.01       0.00          0          0          0           0
Execute      1      0.00       0.00          0          0          0           0
Fetch        2      3.20       4.38        171      42741          0           2
total        4      3.21       4.39        171      42741          0           2
Misses in library cache during parse: 1
Optimizer mode: CHOOSE
Parsing user id: 445 
Rows     Row Source Operation
      2  SORT UNIQUE
     24   HASH JOIN 
     11    INDEX FAST FULL SCAN OBJ#(62817) (object id 62817)
2293715    HASH JOIN 
     31     TABLE ACCESS FULL OBJ#(67305)
1790555     TABLE ACCESS FULL OBJ#(62828)
alter session set sql_trace true
call     count       cpu    elapsed       disk      query    current        rows
Parse        0      0.00       0.00          0          0          0           0
Execute      1      0.00       0.00          0          0          0           0
Fetch        0      0.00       0.00          0          0          0           0
total        1      0.00       0.00          0          0          0           0
Misses in library cache during parse: 0
Misses in library cache during execute: 1
Optimizer mode: CHOOSE
Parsing user id: 445 
OVERALL TOTALS FOR ALL NON-RECURSIVE STATEMENTS
call     count       cpu    elapsed       disk      query    current        rows
Parse        1      0.01       0.00          0          0          0           0
Execute      2      0.00       0.00          0          0          0           0
Fetch        2      3.20       4.38        171      42741          0           2
total        5      3.21       4.39        171      42741          0           2
Misses in library cache during parse: 1
Misses in library cache during execute: 1
OVERALL TOTALS FOR ALL RECURSIVE STATEMENTS
call     count       cpu    elapsed       disk      query    current        rows
Parse        0      0.00       0.00          0          0          0           0
Execute      0      0.00       0.00          0          0          0           0
Fetch        0      0.00       0.00          0          0          0           0
total        0      0.00       0.00          0          0          0           0
Misses in library cache during parse: 0
    2  user  SQL statements in session.
    0  internal SQL statements in session.
    2  SQL statements in session.
Trace file: umltest_ora_1604.trc
Trace file compatibility: 9.02.00
Sort options: prsela  exeela  fchela 
       1  session in tracefile.
       2  user  SQL statements in trace file.
       0  internal SQL statements in trace file.
       2  SQL statements in trace file.
       2  unique SQL statements in trace file.
      51  lines in trace file.
      10  elapsed seconds in trace file. Any help would be greatly appreciated?