Re: Amount of space used by a segment changes when datafile size changed in ASSM tablespace
- From: Peter Hitchman <pjhoraclel@xxxxxxxxx>
- To: oracle-l <oracle-l@xxxxxxxxxxxxx>
- Date: Mon, 22 Apr 2013 14:04:22 +0100
Having done some more tests. When the allocated space for the tablespace
represents amounts to some fraction of an extent, the reported used space
for the tablespace changes by minus (1-the fractional part of an extent).
e.g. With a 4MB extent size and 948MB allocated (237 extents) with 756MB
used, changing the allocated space to 949MB (237.25 extents),
the reported used space changes to (756-(
(1-0.25)*4)=(756-(0.75*4))=(756-3)=753MB.
Pete
On 10 April 2013 16:45, Peter Hitchman <pjhoraclel@xxxxxxxxx> wrote:
> Hi
> I seem to be getting this behaviour because some the sizes I specified
> were not a multiple of the extent size.
>
> Regards
> Pete
>
>
> On 8 April 2013 16:52, Hemant K Chitale <hemantkchitale@xxxxxxxxx> wrote:
>
>> Looks like an OEM bug. Oracle doesn't change the size of a pre-existing
>> extent.
>>
>> Sent from my android phone.
>> On Apr 8, 2013 11:32 PM, "Peter Hitchman" <pjhoraclel@xxxxxxxxx> wrote:
>>
>>> Oracle Enterprise Edition 11.1.0.7.5
>>> Linux 64 bit RHL 4.5
>>>
>>> I have a question about space allocation in ASSM tablespaces.
>>>
>>> I am using a 8KB block size and 8MB extents.
>>>
>>> I started off with a single extent segment reported as using 9MB
>>> according
>>> to OEM, I checked dba_data_files and dba_free_space_coalesced and the sum
>>> of bytes used minus the total free bytes used agreed this figure.
>>>
>>> When I increased the file size from 33MB to 40MB, the amount of space
>>> used
>>> is reported as 16MB.
>>> When I shrink the file to 33MB, the amount of space used goes back down
>>> to
>>> 9MB.
>>> When I shrink the file to 32MB the amount of space used goes up to 16MB.
>>>
>>> I feel I should understand this, but it is escaping me.
>>>
>>> Regards
>>>
>>> Pete
>>>
>>>
>>> --
>>> //www.freelists.org/webpage/oracle-l
>>>
>>>
>>>
>
>
> --
> Regards
>
> Pete
>
--
Regards
Pete
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