Re: DBA_HIST_SQLSTAT
- From: Saibabu Devabhaktuni <saibabu_d@xxxxxxxxx>
- To: free <oracle-l@xxxxxxxxxxxxx>
- Date: Sun, 25 Nov 2012 16:43:35 -0800 (PST)
Back to the original question regarding delta and total columns in
dba_hist_sqlstat.
Unlike in statspack, awr is integrated into database kernel (i.e. it uses x$
tables for snapshot gathering and has it's own x$ tables).
Statspack report sql summary in stats$sql_summary table, it simply sum the
executions by hash_value and hence it includes executions across all the child
cursors.
Awr report delta values for any sql_id by snap_id, instance_id and
plan_hash_value. If multiple child cursors exist with the same execution plan,
then awr only report the stats for the most recent child cursor.
In awr, same sql_id can appear multiple times in the same snap_id if the sql is
executed on more than one node in RAC or if the sql has multiple child cursors
with different execution plan.
Awr report executions_total values since the last time sql is loaded into
library cache and the last time it has been invalidated.
Thanks,
Sai
http://sai-oracle.blogspot.com
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