| segment size [message #397292] |
Thu, 09 April 2009 23:22  |
sundarfaq
Messages: 235
Registered: October 2007
Location: Chennai
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Senior Member |
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Hi all,
I have inserted 2 lacks records into bank_transaction table. After that, I have checked size of the bank transaction table it shows 312.34MB. I have verified from below query.
SELECT SUM (BYTES) / 1024 / 1204
FROM user_segments
WHERE segment_name = 'BANK_TRANSACTION';
After, I have deleted one lacks records into this table. I have checked size of this segments it shows 312.34MB. I have exported this table using exp utility. The size of the dump size only 122MB. I have imported this dump file into other database. After I have checked the size of the table is 312MB. Actually the size of the segment should be 122 mb + datafiles header size and other allocated size 50MB. Totally, it must be 170mb. But It shows 312MB. I don't know why it varies?
Why size of the segments is high compare than dump file size?
Thanks,
Michael
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| Re: segment size [message #397296 is a reply to message #397292] |
Thu, 09 April 2009 23:29  |
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Michel Cadot
Messages: 68718
Registered: March 2007
Location: Saint-Maur, France, https...
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Senior Member
Account Moderator |
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It depends on tablespace parameters, segment parameters, data.
If you have 2500 bytes of data in each row and 4K block then you lose 1500 bytes for each row.
Regards
Michel
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