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Total estimation using BLOCKS method - datapump [message #581365] Fri, 05 April 2013 01:33 Go to next message
ishika_20
Messages: 334
Registered: December 2006
Location: delhi
Senior Member
Dear All,

I have analyzed that, datapump estimation is 9.902GB. When i check size of .dmp file, it's shows 1.44Gb.

Export: Release 11.2.0.1.0 - Production on Fri Apr 5 02:00:05 2013

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Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
Starting "SYSTEM"."SYS_EXPORT_FULL_01":  system/******** dumpfile=expdp_LVGITRN_30_24_050413.dmp directory=DP_DIR logfile=expdp_LVGITRN_30_24_050413.log full=y exclude=statistics 
Estimate in progress using BLOCKS method...
Processing object type DATABASE_EXPORT/SCHEMA/TABLE/TABLE_DATA
Total estimation using BLOCKS method: [bold]9.902 GB [/bold]



Please let me know why it is happening? What's the reason behind it? Why Datapump estimate so much than actual size?

Eager to know the concept behind it.

Regards,
Ishika
Re: Total estimation using BLOCKS method - datapump [message #581366 is a reply to message #581365] Fri, 05 April 2013 01:45 Go to previous messageGo to next message
Michel Cadot
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I don't understand what is the question.
DataPump estimate this size based on the size of the objects.
So what? An estimation can be wrong.

Regards
Michel

[Updated on: Fri, 05 April 2013 01:46]

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Re: Total estimation using BLOCKS method - datapump [message #581372 is a reply to message #581366] Fri, 05 April 2013 02:15 Go to previous messageGo to next message
ishika_20
Messages: 334
Registered: December 2006
Location: delhi
Senior Member
Dear Michel,

I just want to know, how it's estimate the size of the objects?

If possible, provide me some link.

Thanks,
Ishika
Re: Total estimation using BLOCKS method - datapump [message #581375 is a reply to message #581372] Fri, 05 April 2013 02:20 Go to previous messageGo to next message
Michel Cadot
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From the number of blocks.

Regards
Michel
Re: Total estimation using BLOCKS method - datapump [message #581376 is a reply to message #581372] Fri, 05 April 2013 02:22 Go to previous messageGo to next message
Michel Cadot
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Quote:
If possible, provide me some link.


It took me 10 seconds to find it in the documentation, so I think you should also find it in minutes.

Regards
Michel
Re: Total estimation using BLOCKS method - datapump [message #581383 is a reply to message #581376] Fri, 05 April 2013 02:58 Go to previous messageGo to next message
ishika_20
Messages: 334
Registered: December 2006
Location: delhi
Senior Member
Dear Michel,

Even i saw this in site.

BLOCKS  The estimate is calculated by multiplying the number of database blocks used by the source objects, times the appropriate block sizes.


But my confusion is-
I have not used compression parameter in expdp, then why there is so much differences between estimation and actual one? If, it is internal calculation by oracle and difficult to know about the calculation then my question is wrong.


Regards,
Ishika
Re: Total estimation using BLOCKS method - datapump [message #581400 is a reply to message #581383] Fri, 05 April 2013 07:44 Go to previous messageGo to next message
Michel Cadot
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Because blocks are not full of data.

Regards
Michel
Re: Total estimation using BLOCKS method - datapump [message #581402 is a reply to message #581400] Fri, 05 April 2013 07:49 Go to previous messageGo to next message
Michel Cadot
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If you want a more precise estimation use STATISTICS estimation, assuming your statistics are up to date.

Regards
Michel
Re: Total estimation using BLOCKS method - datapump [message #581404 is a reply to message #581402] Fri, 05 April 2013 08:29 Go to previous message
ishika_20
Messages: 334
Registered: December 2006
Location: delhi
Senior Member
Dear Michel,

My backup-schedule runs after the stat job completed. But you are right "Blocks are not full of data". This is the reason, why block estimation shows more sizes.

Thank you for your answer Michel.

Regards,
Ishika
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