Re: Less bytes when transferring table

From: Jared Still <jkstill_at_gmail.com>
Date: Thu, 2 Apr 2009 13:54:58 -0700
Message-ID: <bf46380904021354w506e6cb5rc07c215e3083df84_at_mail.gmail.com>

 On Thu, Apr 2, 2009 at 1:24 PM, Tanel Poder <tanel_at_poderc.com> wrote:

> Yep, Oracle Net does simple compression - when there are lots of rows with
> same consecutive column values sent over sqlnet then Oracle can send the
> column only once plus a count. Anjo Kolk wrote about it in his old blog but
> I couldn't find his article anymore.
>
> Check the simple example (look into difference in bytes sent via SQL*Net
> even though the result data is the same):
>
> SQL> select owner from dba_source order by dbms_random.random;
>
> 299151 rows selected.
> ...

In addition to being a very neat trick, this lends some insight into to how data might be moved more quickly over a slow or overloaded network.

Say you have a few tables to to move across a dblink.

Jared Still
Certifiable Oracle DBA and Part Time Perl Evangelist

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Received on Thu Apr 02 2009 - 15:54:58 CDT