| tablespace locally managed [message #19662] |
Wed, 03 April 2002 02:20  |
hanu
Messages: 21
Registered: March 2002
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Junior Member |
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How to say the tablespace is locally managed?
What is the purpose of that type of tablespace?
What is the difference between locally managed tablespace and dictionary managed tablespace?
Thanks in advance.
Hanu
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| Re: tablespace locally managed [message #19664 is a reply to message #19662] |
Wed, 03 April 2002 03:13  |
Mike
Messages: 417
Registered: September 1998
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Senior Member |
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Hi,
The difference between locally managed tablespace and dictionary managed tablespace is, as far as I know, the way Oracle manages the free space in the tablespaces and related data files.
A locally managed tablespace maintains a bitmap in each datafile to keep track of the free or used status of blocks in that datafile.
For a tablespace that uses the data dictionary to manage its extents, Oracle updates the appropriate tables in the data dictionay whenever an extent is allocated or freed for reuse.
The advantage of localy managed tablespaces is:
- It Avoids recursive space management operations, which can occur in dictionary-managed tablespaces.
- Local management of extents automatically tracks adjacent free space, eliminating the need to coalesce free extents.
It is recommanded to use localy manged tablespaces. To see how an existing tablespace is managed have a look at the view DBA_TABLESPACES.
Hope that helps
Mike
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