cache buffer chaining
- From: "Leonard, George" <GLeonard@xxxxxxxxxxxxx>
- To: <oracle-l@xxxxxxxxxxxxx>
- Date: Thu, 17 Feb 2005 11:30:19 +0200
Hi all
I have a query that is currently doing a huge amount of table scans
(know the resolution to this) and is also causing a lot of cache buffer
chaining (Top wait event, 20 min in a 29 min window, multi CPU machine).
The query in question is of one table and 2 views. The view themselves
are selects from views.
All the tables that makes up the data is very small records and there is
no chaining for the relevant tables.
There are about 6 tables involved, one table being 15Mb and the other a
couple of 8K blocks (max 1000 rows).
Wondering what be causing the chaining.
Only idea I have is that the views that are building the records ends up
being longer than 8K, but can not imagine this considering how narrow
each of the tables actually are.
The only table that could be causing this is the 15Mb main table (it has
2 columns of varchar2(4000) but these columns are all but empty except
for a couple of records where the column (varchar2(4000)) currently
contains a ip address.
Ideas.
George
________________________________________________
George Leonard
Oracle Database Administrator
New Dawn Technologies @ Wesbank
E-mail:gleonard@xxxxxxxxxxxxx
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