Re: long to clob conversion redo size and new table size
From: Grzegorz <grzegorzof_at_interia.pl>
Date: Mon, 27 Jul 2009 21:16:12 +0200
Message-ID: <h4kudv$r3p$1_at_news.task.gda.pl>
Mark D Powell pisze:
>> id number primary key,
>> some_data long
>>
>> currently 70 mln rows.
>> When I'm doing to_lob conversion via:
>>
>> insert /*+ APPEND NOLOGGING */ into t2 select id, to_lob(some_data)
>> some_data from t1 where id between 1 and 2222222;
>>
>> table t2 clob is defined as 8kb chunk in MSSM tablespace (uniform size 1M)
>>
>> a 63MB redolog is switched every 18 seconds.
>> My question is what is in redo ?
>> The only think which comes to my mind is lob index maintenance but
>> is that true ? Database is 9.2.0.8 and NOARCHOVELPG mode.
>> Second question :
>> How to minimize ne wtable (t2) size (table is insert/select only).
>>
>> Regards.
>> Grzegorz
Date: Mon, 27 Jul 2009 21:16:12 +0200
Message-ID: <h4kudv$r3p$1_at_news.task.gda.pl>
Mark D Powell pisze:
> 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.
Even with NOLOGGING hint ?
How to minimize redo size in that case ?
Regards.
Grzegorz
Received on Mon Jul 27 2009 - 14:16:12 CDT