changed the value to 4 days as it will purge every 31 days
exec dbms_stats.alter_stats_history_retention(4);
You can query DBA_AUTOTASK_CLIENT_HISTORY
DBA_AUTOTASK_CLIENT_HISTORY displays a per-window history of job execution counts for each automated maintenance task. In the history, you can see if the job has run successfully in the past and when it stopped running succesfully.
SQL> SELECT client_name, window_name, jobs_created, jobs_started, jobs_completed, window_start_time,window_end_time FROM dba_autotask_client_history WHERE client_name like '%stats%';
How long old stats are kept
select dbms_stats.get_stats_history_retention from dual;
Set retention of old stats to 10 days
exec dbms_stats.alter_stats_history_retention(10);
Purge stats older than 10 days (best to do this in stages if there is a lot of data (sysdate-30,sydate-25 etc)
exec DBMS_STATS.PURGE_STATS(SYSDATE-10);
Show available stats that have not been purged
select dbms_stats.get_stats_history_availability from dual;
Show how big the tables are and rebuild after stats have been purged
col Mb form 9,999,999
col SEGMENT_NAME form a40
col SEGMENT_TYPE form a6
set lines 120
select sum(bytes/1024/1024) Mb, segment_name,segment_type from dba_segments
where tablespace_name = 'SYSAUX'
and segment_name like 'WRI$_OPTSTAT%'
and segment_type='TABLE'
group by segment_name,segment_type order by 1 asc
MB SEGMENT_NAME SEGMEN
---------- ---------------------------------------- ------
0 WRI$_OPTSTAT_OPR TABLE
0 WRI$_OPTSTAT_AUX_HISTORY TABLE
88 WRI$_OPTSTAT_TAB_HISTORY TABLE
126 WRI$_OPTSTAT_IND_HISTORY TABLE
158 WRI$_OPTSTAT_HISTGRM_HISTORY TABLE
4,482 WRI$_OPTSTAT_HISTHEAD_HISTORY TABLE
Show how big the indexes are ready for a rebuild after stats have been purged
col Mb form 9,999,999
col SEGMENT_NAME form a40
col SEGMENT_TYPE form a6
set lines 120
select sum(bytes/1024/1024) Mb, segment_name,segment_type from dba_segments
where tablespace_name = 'SYSAUX'
and segment_name like '%OPT%'
and segment_type='INDEX'
group by segment_name,segment_type order by 1 asc
/
MB SEGMENT_NAME SEGMEN
---------- ---------------------------------------- ------
0 WRH$_OPTIMIZER_ENV_PK INDEX
0 I_WRI$_OPTSTAT_OPR_STIME INDEX
0 I_WRI$_OPTSTAT_AUX_ST INDEX
88 I_WRI$_OPTSTAT_TAB_ST INDEX
105 I_WRI$_OPTSTAT_IND_ST INDEX
105 I_WRI$_OPTSTAT_H_ST INDEX
195 I_WRI$_OPTSTAT_TAB_OBJ#_ST INDEX
213 I_WRI$_OPTSTAT_H_OBJ#_ICOL#_ST INDEX
214 I_WRI$_OPTSTAT_IND_OBJ#_ST INDEX
2,055 I_WRI$_OPTSTAT_HH_ST INDEX
3,883 I_WRI$_OPTSTAT_HH_OBJ_ICOL_ST INDEX
Note that you cannot enable row movement and shrink the tables as the indexes are function based
alter table WRI$_OPTSTAT_IND_HISTORY enable row movement;
alter table WRI$_OPTSTAT_IND_HISTORY shrink space;
*
ERROR at line 1:
ORA-10631: SHRINK clause should not be specified for this object
select 'alter table '||segment_name||' move tablespace SYSAUX;' from dba_segments where tablespace_name = 'SYSAUX'
and segment_name like '%OPT%' and segment_type='TABLE'
Run the rebuild table commands – note that this does cause any gather_stats jobs to fail
alter table WRI$_OPTSTAT_TAB_HISTORY move tablespace sysaux;
alter table WRI$_OPTSTAT_IND_HISTORY move tablespace sysaux;
alter table WRI$_OPTSTAT_HISTHEAD_HISTORY move tablespace sysaux;
alter table WRI$_OPTSTAT_HISTGRM_HISTORY move tablespace sysaux;
alter table WRI$_OPTSTAT_AUX_HISTORY move tablespace sysaux;
alter table WRI$_OPTSTAT_OPR move tablespace sysaux;
alter table WRH$_OPTIMIZER_ENV move tablespace sysaux;
Script to generate rebuild statements
select 'alter index '||segment_name||' rebuild online parallel (degree 14);' from dba_segments where tablespace_name = 'SYSAUX'
and segment_name like '%OPT%' and segment_type='INDEX'
Once completed it is best to check that the indexes (indices) are usable
select di.index_name,di.index_type,di.status from dba_indexes di , dba_tables dt
where di.tablespace_name = 'SYSAUX'
and dt.table_name = di.table_name
and di.table_name like '%OPT%'
order by 1 asc
/
SQL>
INDEX_NAME INDEX_TYPE STATUS
------------------------------ --------------------------- --------
I_WRI$_OPTSTAT_AUX_ST FUNCTION-BASED NORMAL VALID
I_WRI$_OPTSTAT_HH_OBJ_ICOL_ST FUNCTION-BASED NORMAL VALID
I_WRI$_OPTSTAT_HH_ST FUNCTION-BASED NORMAL VALID
I_WRI$_OPTSTAT_H_OBJ#_ICOL#_ST FUNCTION-BASED NORMAL VALID
I_WRI$_OPTSTAT_H_ST FUNCTION-BASED NORMAL VALID
I_WRI$_OPTSTAT_IND_OBJ#_ST FUNCTION-BASED NORMAL VALID
I_WRI$_OPTSTAT_IND_ST FUNCTION-BASED NORMAL VALID
I_WRI$_OPTSTAT_OPR_STIME FUNCTION-BASED NORMAL VALID
I_WRI$_OPTSTAT_TAB_OBJ#_ST FUNCTION-BASED NORMAL VALID
I_WRI$_OPTSTAT_TAB_ST FUNCTION-BASED NORMAL VALID
WRH$_OPTIMIZER_ENV_PK NORMAL VALID
Finally lets see what space has been saved with a retention date of 1 day and a gather schema stats for the SYSASDM schema
exec dbms_stats.alter_stats_history_retention(1);
select dbms_stats.get_stats_history_retention from dual;
MB SEGMENT_NAME SEGMEN
---------- ---------------------------------------- ------
0 WRI$_OPTSTAT_OPR TABLE
0 WRI$_OPTSTAT_AUX_HISTORY TABLE
3 WRI$_OPTSTAT_TAB_HISTORY TABLE
4 WRI$_OPTSTAT_IND_HISTORY TABLE
8 WRI$_OPTSTAT_HISTGRM_HISTORY TABLE
104 WRI$_OPTSTAT_HISTHEAD_HISTORY TABLE
MB SEGMENT_NAME SEGMEN
---------- ---------------------------------------- ------
0 WRH$_OPTIMIZER_ENV_PK INDEX
0 I_WRI$_OPTSTAT_OPR_STIME INDEX
0 I_WRI$_OPTSTAT_AUX_ST INDEX
2 I_WRI$_OPTSTAT_IND_ST INDEX
2 I_WRI$_OPTSTAT_TAB_ST INDEX
3 I_WRI$_OPTSTAT_TAB_OBJ#_ST INDEX
4 I_WRI$_OPTSTAT_IND_OBJ#_ST INDEX
5 I_WRI$_OPTSTAT_H_ST INDEX
9 I_WRI$_OPTSTAT_H_OBJ#_ICOL#_ST INDEX
41 I_WRI$_OPTSTAT_HH_ST INDEX
96 I_WRI$_OPTSTAT_HH_OBJ_ICOL_ST INDEX
Ref
====
For more information : FAQ: Automatic Statistics Collection ( Doc ID 1233203.1 )
Suggestions if Your SYSAUX Tablespace Grows Rapidly or Too Large (Doc ID 1292724.1)
https://jhdba.wordpress.com/tag/dbms_stats-purge_stats/
