Question

just wondering is there a way to List all objects in database which have not been Queried.
i know you can see the last_ddl_time and Created Time through sys.dba_Objects. But i am More interested in Total_reads on Objects specially Indexes and tables.And Who has Used it.(Not the Owner)

thanks

Answer 1

You can probably use the V$SEGMENT_STATISTICS view to get the information you’re after. For example, if you wanted to see how many logical reads had been done on each segment in the SCOTT schema since the last database restart

SQL> select owner, object_name, value
  2    from v$segment_statistics
  3   where statistic_name = 'logical reads'
  4     and owner = 'SCOTT';

OWNER                          OBJECT_NAME                         VALUE
------------------------------ ------------------------------ ----------
SCOTT                          STATS_TEST                            448
SCOTT                          BIN$bQrMO1+dTOOh9S8K9O+z+Q==$0          0
SCOTT                          COUNTER_TEST                         1760
SCOTT                          BIN$763dsleISbi+AfEp20EN7A==$0         80
SCOTT                          TEST_TABLE                           5424
SCOTT                          BIN$5QAh3TmjRWqeMKof7tY93g==$0        144
SCOTT                          BIN$1i4uV7CbQL2Pl0tANHsJQw==$0         80
SCOTT                          BIN$8ydZ/jHySAeudojTmTtByQ==$0         48
SCOTT                          FOO_TEMP                              112
SCOTT                          ERR$_FOO                               64
SCOTT                          EVENT                                  32
SCOTT                          FOO                                    32
SCOTT                          T1                                    176
SCOTT                          T2                                     80
SCOTT                          EMP                                    32
SCOTT                          GRAD_STUDENT_TB                       240
SCOTT                          SYS_C0024557                           64
SCOTT                          PK_EMP                                  0

18 rows selected.

If you are licensed to use the AWR and your AWR retention is long enough and you can make due with fewer available statistics, and you are only interested in the most used segments, you may also be able to use the DBA_HIST_SEG_STAT table.

SQL> ed
Wrote file afiedt.buf

  1  select snap.begin_interval_time,
  2         stat.logical_reads_delta,
  3         obj.object_name
  4    from dba_hist_seg_stat stat
  5         join dba_hist_snapshot snap using (snap_id)
  6         join dba_objects obj on (obj.object_id = stat.obj#)
  7*  where obj.owner = 'SCOTT'
SQL> /

BEGIN_INTERVAL_TIME            LOGICAL_READS_DELTA OBJECT_NAME
------------------------------ ------------------- --------------------
16-AUG-11 04.00.11.428 PM                      160 T1
18-AUG-11 12.00.13.856 PM                      144 GRAD_STUDENT_TB
18-AUG-11 12.00.13.856 PM                       48 SYS_C0024557
20-AUG-11 03.00.59.376 PM                      144 LOAN_TXN

If you are trying to find out whether a particular object is lightly used, however, the AWR is probably not the right solution since it might not show up as one of the top segments in any snapshot window despite being used occasionally.

Alternately, you could write your own process to capture the data from V$SEGMENT_STATISTICS periodically and compute the deltas by subtracting the statistic values from different snapshots.