Re: SQL*Net message to client
- From: "Jonathan Lewis" <jonathan@xxxxxxxxxxxxxxxxxx>
- To: "Ray Stell" <stellr@xxxxxxxxxx>
- Date: Wed, 23 Nov 2005 22:53:12 -0000
Some of the information you can infer by looking
at the output of the following query:
select view_definition from v$fixed_view_definition
where view_name = 'GV$SESSION_WAIT'
/
This gives the definition of (g)v$session_wait in
terms of the underlying X$ objects, and shows
you the way in which some of the v$ columns
are derived by decodes from (particularly)
the microsecond wait time.
'Client' in this wait event is simply a session
at the far end of an SQL*Net link - i.e.
incoming database link or normal end-user/batch
connection.
In a normal client/server dialogue, e.g. SQL*Plus
running a simple query and fetching lots of rows
one at a time, you would expect to see this event
coming and going very rapidly (alternating with
SQL*Net message from client).
Regards
Jonathan Lewis
http://www.jlcomp.demon.co.uk/faq/ind_faq.html
The Co-operative Oracle Users' FAQ
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Public Appearances - schedule updated 4th Nov 2005
----- Original Message -----
From: "Ray Stell" <stellr@xxxxxxxxxx>
To: "Jonathan Lewis" <jonathan@xxxxxxxxxxxxxxxxxx>
Cc: "oracle-l" <oracle-l@xxxxxxxxxxxxx>
Sent: Wednesday, November 23, 2005 10:08 PM
Subject: Re: SQL*Net message to client
Let me first give thanks for your help.
If you don't mind teaching me to fish, how could I have ascertained this
explanation on my own?
Little more can be collected on this event. The impatient dba took the
sledge hammer approach to the log switch-hung db.
There were no user sessions listed in v$session. The other wait events
were the log switch and a 220 buffer busy, both waiting for the same
period of time. Oradocs say the 220 is, "during buffer lookup for a
CURRENT copy of a buffer we have found the buffer but someone holds it
in an incompatible mode so we have to wait."
So, I'm curious who this client might have been. There is no knowing
for certain since the evidence has been destroyed. What are the
possible "clients?" Seems like a bug, unless client means something
I don't think it means.
On Wed, Nov 23, 2005 at 07:56:01PM -0000, Jonathan Lewis wrote:
wait_time=-1 means less than 1 hundredth
of a second for 8i, and less than 50 milliseconds
for later versions of 9.
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