| How does Oracle allocate a new extent ? [message #175869] |
Mon, 05 June 2006 15:35  |
agostino_neto
Messages: 180
Registered: July 2005
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Senior Member |
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Hi all,
I have noticed that when a new datafile is added to the database. Extents are not always created from the top to the bottom of the file.
When querying dba_extents, dba_data_files and dba_objects, I can see that sometimes newer extents begins at a smaller block than the previous one. How does Oracle allocate a new extent and for what reason ?
Thanks.
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| Re: How does Oracle allocate a new extent ? [message #175905 is a reply to message #175869] |
Tue, 06 June 2006 00:29  |
shahnazurs
Messages: 240
Registered: June 2005
Location: India
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Senior Member |
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Hi,
you said you created one datafile i.e. you created logical structure called tablespace!
different types of extent management present in oracle 9i, one is dictionary management & other one is local...
could you please let me know which version of oracle you are interested?
Thanks,
Shahnaz
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| Re: How does Oracle allocate a new extent ? [message #176061 is a reply to message #175869] |
Tue, 06 June 2006 13:15 |
smartin
Messages: 1803
Registered: March 2005
Location: Jacksonville, Florida
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Senior Member |
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It is a "not documented", internal, proprietary, "subject to change" algorithm based on version and on oracles whim. You control which objects are assigned to which tablespaces, and oracle divides data from a single tablespace throughout the datafiles in that tablespace however oracle sees fit.
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