Re: explain plan, can you explain this?

  • From: "John Kanagaraj" <john.kanagaraj@xxxxxxxxx>
  • To: dannorris@xxxxxxxxxxxxx
  • Date: Wed, 9 Jan 2008 20:08:49 -0800

Dan,

> The very interesting part is that in a one-hour statspack, this statement
> generates 30 mil buffer gets, executed 111,388 times (about 273 buffer gets
> per exec). When combined with the facts below, it becomes a puzzler:

This is only slightly related to the issue, but STATSPACK's SQL is a
capture of V$SQL "as-is" when the snapshot took place. SPREPORT does
NOT perform a Diff as it does with other stats (i.e. end_stat -
begin_stat). The 111,388 executions is *cumulative* since that SQL was
last loaded/parsed. This is apparent if you look at the STATSPACK
source at $OH/rdbms/admin/spcpkg.sql.

You should look at Tim G's "sphistory.sql" to determine the periodic
progression of execution and other stats for a given SQL.

-- 
John Kanagaraj <><
DB Soft Inc
http://www.linkedin.com/in/johnkanagaraj
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