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Re: SQL*Net more data from client description

From: Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk>
Date: Sat, 27 Jan 2007 15:02:53 -0000
Message-ID: <7P-dnZ1rj-vL9CbYnZ2dnUVZ8tqqnZ2d@bt.com>

Steve,

Coming in late, here, but the doc does seem to have a 'cut and paste' bug.

More data from client isn't about MTU (which is the transport unit of the network) but about the Oracle's SDU (session data unit).

Oracle chats in sizes of the SDU (ca. 2000 bytes I think), and waits for acknowledgement from the far end. The network may chat in smaller units, breaking the Oracle message into a couple of chunks (typical MTU is about 1470 bytes) - but the network does not wait for acknowledgement between the two packets.

"More data" means that there is more data to send than the SDU can hold. An insert of a varchar2(4000) could be sufficient for this to appear.

You can increase the SDU size by fiddling in the listener.ora, tnsnames.ora and sqlnet.ora - the specific details of method varies with version. In the latest version, the easiest option is to put

    default_sdu_size = NNNNN
in the sqlnet.ora.

In the tnsnames.ora you can put
(description =

    (sdu=NNNNN)
    ...
)

I can't remember off-hand where it goes in the listener entries - but I think it wasn't an exact match for the tnsnames entry.

-- 
Regards

Jonathan Lewis
http://jonathanlewis.wordpress.com

Author: Cost Based Oracle: Fundamentals
http://www.jlcomp.demon.co.uk/cbo_book/ind_book.html

The Co-operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html


"Steve Howard" <stevedhoward_at_gmail.com> wrote in message 
news:1169831405.172911.68970_at_a75g2000cwd.googlegroups.com...

> Does the description in the standard docs make any sense to anyone
> besides me?
>
Received on Sat Jan 27 2007 - 09:02:53 CST

Original text of this message

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