Posts Tagged AWR
A handy little script that I have used in the Oracle Database 11g Performance Tuning course this week. It queries the AWR Snapshots for SQL statements and sorts them by elapsed time:
SQL> col parsed format a6 col sql_text format a40 set lines 200 set pages 300 select sql_text, parsing_schema_name as parsed, elapsed_time_delta/1000/1000 as elapsed_sec, stat.snap_id, to_char(snap.end_interval_time,'dd.mm hh24:mi:ss') as snaptime, txt.sql_id from dba_hist_sqlstat stat, dba_hist_sqltext txt, dba_hist_snapshot snap where stat.sql_id=txt.sql_id and stat.snap_id=snap.snap_id and snap.begin_interval_time>=sysdate-1 and lower(sql_text) like '%&t%' and parsing_schema_name not in ('SYS','SYSMAN','MDSYS','WKSYS') order by elapsed_time_delta asc;
sysdate-1 returns SQL up to yesterday and can be modified to retrieve SQL as long as there are AWR snapshots of course. &t is a substring of the SQL, we may be interested in. With the sql_id, we can also retrieve the execution plan from the snapshots:
SQL> select plan_table_output from table (dbms_xplan.display_awr('&sqlid'));
The amount of SQL that gets collected into a snapshot can be modified with
SQL> begin dbms_workload_repository.modify_snapshot_settings ( topnsql=>'MAXIMUM'); end; /
MAXIMUM (uppercase!) takes all SQL from the Library Cache into the snapshot – alternative, we can specify a number of Top SQL to collect. The example is from an 11g Database, but it should work the same with 10g already.