Re: long to clob conversion redo size and new table size

From: Mark D Powell <Mark.Powell_at_eds.com>
Date: Mon, 27 Jul 2009 12:07:36 -0700 (PDT)
Message-ID: <196e56aa-9136-4d9c-b571-5697960955c9_at_12g2000pri.googlegroups.com>



On Jul 27, 12:19 pm, Grzegorz <grzegor..._at_interia.pl> wrote:
> Hi,
>         I've got 300GB table t1 with 2 columns:
>
> id number primary key,
> some_data long
>
> currently 70 mln rows.
> When I'm doing to_lob conversion via:
>
> insert /*+ APPEND NOLOGGING */ into t2 select id, to_lob(some_data)
> some_data from t1 where id between 1 and 2222222;
>
> table t2 clob is defined as 8kb chunk in MSSM tablespace (uniform size 1M)
>
> a 63MB redolog is switched every 18 seconds.
> My question is what is in redo ?
> The only think which comes to my mind is lob index maintenance but
> is that true ? Database is 9.2.0.8 and NOARCHOVELPG mode.
> Second question :
> How to minimize ne wtable (t2) size (table is insert/select only).
>
> Regards.
> Grzegorz

LOB data is forward recoverable just like any other data. The LOB inserts are being logged.

HTH -- Mark D Powell -- Received on Mon Jul 27 2009 - 14:07:36 CDT

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