2026-03-12 21:01:38

tiddlywiki/Pending stats - scratchpad - 01.txt

@@ -0,0 +1,68 @@
+Optimizer Statistics Gathering – pending and history
+https://www.dbi-services.com/blog/optimizer-statistics-gathering-pending-and-history/
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+create user XIZOR identified by secret;
+grant connect, resource to XIZOR;
+grant unlimited tablespace to XIZOR;
+grant select any dictionary to XIZOR;
+
+connect XIZOR/secret
+
+create table DEMO as select rownum n from dual;
+
+col analyzed for a30
+col published_prefs for a30
+
+select num_rows,cast(last_analyzed as timestamp) analyzed,dbms_stats.get_prefs('PUBLISH',owner,table_name) published_prefs from dba_tab_statistics where owner='XIZOR' and table_name in ('DEMO');
+
+
+insert into DEMO select rownum n from xmltable('1 to 41');
+
+
+set pages 999 lines 200
+
+select /*+ gather_plan_statistics */ count(*) from DEMO;
+
+select * from table(dbms_xplan.display_cursor(format=>'basic +rows +rowstats last'));
+
+exec dbms_stats.set_table_prefs('XIZOR','DEMO','PUBLISH','FALSE');
+
+
+exec dbms_stats.gather_table_stats('XIZOR','DEMO');
+
+
+select num_rows,cast(last_analyzed as timestamp) analyzed,dbms_stats.get_prefs('PUBLISH',owner,table_name) published_prefs from dba_tab_pending_stats where owner='XIZOR' and table_name in ('DEMO');
+
+exec dbms_stats.delete_pending_stats('XIZOR','DEMO');
+
+exec dbms_stats.publish_pending_stats('XIZOR','DEMO',no_invalidate=>false);
+
+exec dbms_stats.set_table_prefs('XIZOR','DEMO','PUBLISH','TRUE');
+
+exec dbms_stats.restore_table_stats('XIZOR','DEMO',sysdate-1,no_invalidate=>false);
+
+
+
+select report from table(dbms_stats.diff_table_stats_in_history('XIZOR','DEMO',sysdate-1,sysdate,0));
+
+select 
+	end_time,end_time-start_time,operation,target,
+	regexp_replace(regexp_replace(notes,'" val="','=>'),'(||)',' '),
+	status 
+from 
+	DBA_OPTSTAT_OPERATIONS where regexp_like(target,'"?'||'XIZOR'||'"?."?'||'DEMO'||'"?') order by end_time desc fetch first 10 rows only
+/
+
+
+select table_name,stats_update_time from dba_tab_stats_history where owner='XIZOR' and table_name='DEMO';
+
+set long 2000000
+set pagesize 1000
+
+select * from table(dbms_stats.diff_table_stats_in_history(
+                    ownname => 'XIZOR',
+                    tabname => 'DEMO',
+                    time1 => systimestamp-1,
+                    time2 => systimestamp,
+                    pctthreshold => 0));