Re: Too many db calls

From: Connor McDonald <hamcdc_at_yahoo.co.uk>
Date: Sat, 16 Nov 2002 10:13:59 -0800
Message-ID: <F001.005050E2.20021116101359@fatcity.com>

On index-obsessed apps, you'll often see massive amount of LIO to a target of a nested loop. ie, scan mega table and then index probe the inner table for every row of the mega table...

Generally you'll see smoke coming out of the index root/branch blocks on the target table :-)

hth
connor

• Greg Moore <sqlgreg_at_pacbell.net> wrote: > A while back someone mentioned that the two main
  > causes of slow SQL are
  > excesive LIO's and excesscive database calls, which
  > show up as excessive CPU
  > use and excessive network traffic, respectively.
  >
  > Regarding the database calls, is there a "classic"
  > reason for this problem?
  >
  > My best guess is it's caused by an SQL statement in
  > a PL/SQL loop, which
  > could be rewritten as a single SQL statement. But
  > is this the single,
  > commonly seen cause for this problem, or are there
  > other common ways this
  > inefficiency is introduced?
  >
  > Thanks in advance for help in understanding this.
  >
  > --
  > Please see the official ORACLE-L FAQ:
  > http://www.orafaq.com
  > --
  > Author: Greg Moore
  > INET: sqlgreg_at_pacbell.net
  >
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Received on Sat Nov 16 2002 - 12:13:59 CST