Simple script to run a trend through the AWR repository for system stats for the current database and schema:
rem rem Script: trend_awr_stat.sql rem Author: Jonathan Lewis rem Dated: Sep 2006 rem Purpose: rem rem Last tested rem 10.2.0.3 rem Not Tested rem 184.108.40.206 rem 220.127.116.11 rem Not relevant rem 18.104.22.168 rem 22.214.171.124 rem rem Warning: rem Requires licence for Diagnostic Pack rem rem Notes: rem Trend through AWR system stats rem Accesses data for current instance and DBID rem rem Hard coded to go 30 days back in history rem rem Reports a timestamp at the start of an interval rem with the activity that happened in that interval rem rem Ignores database restarts rem rem Generally okay to pick up the next snap_id because of rem the way that the AWR code generates snapshot ids rem (Not true for statspack unless you set the sequence rem to nocache). rem rem Change the following define to pick a different statistic rem define m_stat_name = 'SQL*Net message to/from client' define m_stat_name = 'CPU used by this session' set timing off set linesize 180 set pagesize 60 set trimspool on column instance_number new_value m_instance noprint column dbid new_value m_dbid noprint select ins.instance_number, db.dbid from v$instance ins, v$database db ; column value format 999,999,999,999 column curr_value format 999,999,999,999 column prev_value format 999,999,999,999 spool trend_awr_stat with base_line as ( select /*+ materialize */ snp.snap_id, to_char(snp.end_interval_time,'Mon-dd hh24:mi:ss') end_time, sst.value from dba_hist_snapshot snp, dba_hist_sysstat sst where snp.dbid = &m_dbid and snp.instance_number = &m_instance and end_interval_time between sysdate - 30 and sysdate /* */ and sst.dbid = snp.dbid and sst.instance_number = snp.instance_number and sst.snap_id = snp.snap_id and sst.stat_name = '&m_stat_name' /* */ ) select b1.end_time start_of_delta, b1.value prev_value, b2.value curr_value, b2.value - b1.value value from base_line b1, base_line b2 where b2.snap_id = b1.snap_id + 1 order by b1.snap_id ; spool off
Update Feb 2010: Remember my warnings about testing any SQL you get from the Internet. This type of code has behaved reasonably well on all the sites I’ve visited to date – except for a site I was at very recently that had set their AWR retention time to 18 months … the performance was dire (as was the resource utilisation).
Workaround: in the subquery, change the simple /*+ materialize */ hint to: /*+ materialize leading(snp sst) no_merge(snp) push_pred(sst) */.
Ideally, of course, I’d write something that accessed the wrh$ table directly (in fact, I probably have done so a few times already, and one day ).