Re: DWH varchar2(4000)

From: Ricard Martinez <ricard.martinez_at_gmail.com>
Date: Mon, 22 Dec 2014 17:03:40 +0000
Message-ID: <CAFGV9uk7hudaLygf8mG_gkwexEokG0O_NXoMw8_pMUzJreBT5g_at_mail.gmail.com>

Thanks for that Martin.
Pretty interesting and disturbing at the same time.

Regards

On Mon, Dec 22, 2014 at 4:44 PM, Martin Preiss <mtnpreiss_at_gmx.de> wrote:

> Ricard,
>
> another point that could result in difficulties has been mention by
> Nicolay Savvinov recently: rows with a potential row length (i.e. the
> addition of data type sizes of the different columns) that is bigger than
> the block size result in a row-by-row processing and supress bulk
> operations: http://savvinov.com/2014/12/15/4k-bug-is-not-a-bug/.
>
> Regards
>
> Martin Preiss
>
> Am 22.12.2014 16:01, schrieb Ricard Martinez:
>
> Hi list,
>
> We have a DWH database on 11.2.0.4.
> The developers/data modelers are creating all the tables with
> varchar2(4000) as standard by default. They don't care if they just insert
> 10 bytes, 200 or nothing.
> When asked about why this standard is in place, the answer is just: "Just
> in case we need it".
>
> For my point of view this is not a good practice, as can cause memory
> waste on client applications, as well as data garbage or errors like ORA-01450:
> maximum key length (3218) exceeded.
>
> But as i'm not a DWH expert, maybe im missing information that proves
> that this is really a good practice, and not just a laziness way of
> working.
>
> I will be glad to know your opinion, or point me to any doc/test that
> proves me wrong, in order to learn about this.
>
> Thanks
>
>
>

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Received on Mon Dec 22 2014 - 18:03:40 CET