Is it latch contention?

Question

I ran a query and was monitoring it. I found high values for db_sequential_reads and later high values for latch free. I was monitoring using V$SESSION_WAIT. how confirm if there was any latch contention. Initial investigation pushing me to understand that there should be something wrong with a table and associated index. It may be a case of 'hot blocks' which are getting repeatedly touched by the query. The suggested fix is adding more FREELISTS. But the question is my tbale properties show an empty entry against FREELISTS for the table/indexes and I am on 9.2.0.7.Do the suggestions suit my case and are my interpretions correct?

Answer 1

Execution Plan
   0      SELECT STATEMENT Optimizer=CHOOSE (Cost=114 Card=1 Bytes=186
   1    0   SORT (GROUP BY) (Cost=93 Card=1 Bytes=186)
   2    1     FILTER
   3    2       NESTED LOOPS (Cost=89 Card=1 Bytes=186)
   4    3         HASH JOIN (Cost=88 Card=1 Bytes=162)
   5    4           MERGE JOIN (CARTESIAN) (Cost=73 Card=1 Bytes=135)
   6    5             MERGE JOIN (CARTESIAN) (Cost=35 Card=1 Bytes=122
   7    6               TABLE ACCESS (BY INDEX ROWID) OF 'PSNVSBOOKREQ
          UST' (Cost=3 Card=1 Bytes=46)
   8    7                 NESTED LOOPS (Cost=34 Card=1 Bytes=103)
   9    8                   HASH JOIN (Cost=31 Card=1 Bytes=57)
  10    9                     TABLE ACCESS (FULL) OF 'PS_YYXX_GL_ME_TB
          L' (Cost=14 Card=1 Bytes=23)
  11    9                     VIEW OF 'PS_CSXX_XLATTABLE' (Cost=17 Car
          d=2 Bytes=68)
  12   11                       SORT (UNIQUE) (Cost=17 Card=2 Bytes=13
          3)
  13   12                         UNION-ALL
  14   13                           FILTER
  15   14                             TABLE ACCESS (BY INDEX ROWID) OF
           'PSXLATITEM' (Cost=2 Card=1 Bytes=51)
  16   15                               INDEX (RANGE SCAN) OF 'PSAPSXL
          ATITEM' (NON-UNIQUE) (Cost=1 Card=21)
  17   14                             SORT (AGGREGATE)
  18   17                               FILTER
  19   18                                 INDEX (RANGE SCAN) OF 'PS_PS
          XLATITEM' (UNIQUE) (Cost=2 Card=1 Bytes=26)
  20   13                           FILTER
  21   20                             NESTED LOOPS (Cost=3 Card=1 Byte
          s=82)
  22   21                               TABLE ACCESS (BY INDEX ROWID)
          OF 'PSXLATITEMLANG' (Cost=2 Card=1 Bytes=54)
  23   22                                 INDEX (RANGE SCAN) OF 'PS_PS
          XLATITEMLANG' (UNIQUE) (Cost=2 Card=1)
  24   21                               TABLE ACCESS (BY INDEX ROWID)
          OF 'PSXLATITEM' (Cost=1 Card=1 Bytes=28)
  25   24                                 INDEX (UNIQUE SCAN) OF 'PS_P
          SXLATITEM' (UNIQUE)
  26   20                             SORT (AGGREGATE)
  27   26                               FILTER
  28   27                                 INDEX (RANGE SCAN) OF 'PS_PS
          XLATITEM' (UNIQUE) (Cost=2 Card=1 Bytes=26)
  29    8                   INLIST ITERATOR
  30   29                     INDEX (RANGE SCAN) OF 'PS_PSNVSBOOKREQUS
          T' (UNIQUE) (Cost=5 Card=43)
  31    6               BUFFER (SORT) (Cost=32 Card=1 Bytes=19)
  32   31                 TABLE ACCESS (BY INDEX ROWID) OF 'PS_YYXX_BC
          TRL_TBL' (Cost=1 Card=1 Bytes=19)
  33   32                   INDEX (RANGE SCAN) OF 'PS0YYXX_BCTRL_TBL'
          (NON-UNIQUE) (Cost=1 Card=4)
  34    5             BUFFER (SORT) (Cost=72 Card=564 Bytes=7332)
  35   34               TABLE ACCESS (FULL) OF 'PS_SET_CNTRL_GROUP' (C
          ost=38 Card=564 Bytes=7332)
  36    4           TABLE ACCESS (FULL) OF 'PS_NVS_SCOPE_FIELD' (Cost=
          14 Card=3606 Bytes=97362)
  37    3         TABLE ACCESS (BY INDEX ROWID) OF 'PS_NVS_REPORT' (Co
          st=1 Card=1 Bytes=24)
  38   37           INDEX (UNIQUE SCAN) OF 'PS_NVS_REPORT' (UNIQUE)
  39    2       SORT (AGGREGATE)
  40   39         VIEW OF 'PS_YYXX_XLATTABLE' (Cost=17 Card=2 Bytes=54
  41   40           SORT (UNIQUE) (Cost=17 Card=2 Bytes=133)
  42   41             UNION-ALL
  43   42               FILTER
  44   43                 FILTER
  45   44                   TABLE ACCESS (BY INDEX ROWID) OF 'PSXLATIT
          EM' (Cost=2 Card=1 Bytes=51)
  46   45                     INDEX (RANGE SCAN) OF 'PS_PSXLATITEM' (U
          NIQUE) (Cost=2 Card=1)
  47   43                 SORT (AGGREGATE)
  48   47                   FILTER
  49   48                     INDEX (RANGE SCAN) OF 'PS_PSXLATITEM' (U
          NIQUE) (Cost=2 Card=1 Bytes=26)
  50   42               FILTER
  51   50                 NESTED LOOPS (Cost=3 Card=1 Bytes=82)
  52   51                   TABLE ACCESS (BY INDEX ROWID) OF 'PSXLATIT
          EMLANG' (Cost=2 Card=1 Bytes=54)
  53   52                     INDEX (RANGE SCAN) OF 'PS_PSXLATITEMLANG
          ' (UNIQUE) (Cost=2 Card=1)
  54   51                   TABLE ACCESS (BY INDEX ROWID) OF 'PSXLATIT
          EM' (Cost=1 Card=1 Bytes=28)
  55   54                     INDEX (UNIQUE SCAN) OF 'PS_PSXLATITEM' (
          UNIQUE)
  56   50                 SORT (AGGREGATE)
  57   56                   FILTER
  58   57                     INDEX (RANGE SCAN) OF 'PS_PSXLATITEM' (U
          NIQUE) (Cost=2 Card=1 Bytes=26)
  59    2       SORT (AGGREGATE)
  60   59         TABLE ACCESS (BY INDEX ROWID) OF 'PS_YYXX_GL_ME_TBL'
           (Cost=4 Card=1 Bytes=29)
  61   60           INDEX (RANGE SCAN) OF 'PS_YYXX_GL_ME_TBL' (UNIQUE)
           (Cost=2 Card=5)
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Message was edited by:
        Elvis
Message was edited by:
        Elvis