Re: TX locks
- From: "Jonathan Lewis" <jonathan@xxxxxxxxxxxxxxxxxx>
- To: <oracle-l@xxxxxxxxxxxxx>
- Date: Fri, 28 May 2004 07:34:52 +0100
You're thinking of the 'unindexed foreign key'
anomaly. You can get TX/4 locks even when
there is a foreign key index.
session 1: insert new child for parent X
session 2: delete parent X
Session 2 waits for session 1 to commit.
Regards
Jonathan Lewis
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----- Original Message -----
From: "Bobak, Mark" <Mark.Bobak@xxxxxxxxxxxxxxx>
To: <oracle-l@xxxxxxxxxxxxx>
Sent: Thursday, May 27, 2004 11:01 PM
Subject: RE: TX locks
Jonathan,
Wouldn't PK/FK activity result in TM waits, rather than TX waits?
-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx on behalf of Jonathan Lewis
Sent: Thu 5/27/2004 3:50 PM
To: oracle-l@xxxxxxxxxxxxx
Cc:
Subject: Re: TX locks
Other common causes of TX/4 waits on a TX/6
Bitmap indexes on OLTP tables - with updates to
the bitmapped column, or inserts/delete of rows.
Updates colliding on rows in IOTs.
Several variations of pk/fk activity split across
two sessions.
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