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TABLESPACE EXTENT [message #547934]

Mon, 19 March 2012 02:10

sathish16787
Messages: 56
Registered: September 2011
Location: mumbai

Member

1.2 million chained rows, 1.7 million blocks, etc. Initial extent for this table is 64k and next 1 mb. I would try to calculate this out better for efficiency and performance. This will not be efficient as it stands.So kindly help me to calculate the size.

Regards,
SathishKumar.K

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Re: TABLESPACE EXTENT [message #547936 is a reply to message #547934]

Mon, 19 March 2012 02:31

msol25
Messages: 396
Registered: June 2011

Senior Member

Hi Satish,

Please execute query:


  select sum(bytes)/1048576 "Size in Mb"
  from   user_segments
  where  segment_name = 'TABLE_NAME';

Thanks

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Re: TABLESPACE EXTENT [message #547937 is a reply to message #547936]

Mon, 19 March 2012 02:40

sathish16787
Messages: 56
Registered: September 2011
Location: mumbai

Member

Hi,

It has 10 Million records and it will grow atleast around 800K records per month.

Regards,
Sathish

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Re: TABLESPACE EXTENT [message #547939 is a reply to message #547934]

Mon, 19 March 2012 02:46

Michel Cadot
Messages: 68772
Registered: March 2007
Location: Saint-Maur, France, https...

Senior Member
Account Moderator

Quote:

1.2 million chained rows

Are these really chained rows or are they also migrated rows?

Quote:

I would try to calculate this out better for efficiency and performance.

Do not calculate anything and use autoallocate (system managed) LMT (Locally Managed Tablespace).

Regards
Michel

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Re: TABLESPACE EXTENT [message #547966 is a reply to message #547939]

Mon, 19 March 2012 05:24

sathish16787
Messages: 56
Registered: September 2011
Location: mumbai

Member

Hi ,

It is migrated rows.

Regards,
Sathish

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Re: TABLESPACE EXTENT [message #547974 is a reply to message #547966]

Mon, 19 March 2012 06:06

Michel Cadot
Messages: 68772
Registered: March 2007
Location: Saint-Maur, France, https...

Senior Member
Account Moderator

So first fix your application so that Oracle does not have to migrate so much rows.

Regards
Michel

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Re: TABLESPACE EXTENT [message #547977 is a reply to message #547966]

Mon, 19 March 2012 06:36

John Watson
Messages: 8991
Registered: January 2010
Location: Global Village

Senior Member

As you have over 10% migrated rows, you may want to increase the PCTFREE for the table.

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Re: TABLESPACE EXTENT [message #548076 is a reply to message #547977]

Tue, 20 March 2012 04:25

sathish16787
Messages: 56
Registered: September 2011
Location: mumbai

Member

Hi,

How to increase PCTFREE from 10 to 15 in oracle 11g R2?

Regards,
Sathish

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Re: TABLESPACE EXTENT [message #548078 is a reply to message #548076]

Tue, 20 March 2012 04:34

Michel Cadot
Messages: 68772
Registered: March 2007
Location: Saint-Maur, France, https...

Senior Member
Account Moderator

Did you try ALTER TABLE?

Regards
Michel

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Re: TABLESPACE EXTENT [message #548086 is a reply to message #548076]

Tue, 20 March 2012 05:10

John Watson
Messages: 8991
Registered: January 2010
Location: Global Village

Senior Member

Are you certain of the algorithm you used to calculate that 15% is correct? You need to investigate the ratio between the size of row at insertion, and the size following updates.

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Re: TABLESPACE EXTENT [message #548089 is a reply to message #548078]

Tue, 20 March 2012 05:29

sathish16787
Messages: 56
Registered: September 2011
Location: mumbai

Member

Hi,

But it wont affect current block.so is there any other way to do this .

Regards,
Sathish

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Re: TABLESPACE EXTENT [message #548092 is a reply to message #548089]

Tue, 20 March 2012 05:37

John Watson
Messages: 8991
Registered: January 2010
Location: Global Village

Senior Member

Open the Administrator's Guide, go to the index, and look for "migrated rows".

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Re: TABLESPACE EXTENT [message #548230 is a reply to message #548078]

Tue, 20 March 2012 23:22

sathish16787
Messages: 56
Registered: September 2011
Location: mumbai

Member

Hi,

Could you please help me .how to find max row length for a table.

Regards
Sathish

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Re: TABLESPACE EXTENT [message #548236 is a reply to message #548230]

Wed, 21 March 2012 00:22

Michel Cadot
Messages: 68772
Registered: March 2007
Location: Saint-Maur, France, https...

Senior Member
Account Moderator

What do you call "row length"?

Regards
Michel

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