Re: Re: Used size of a datafile.
- From: "biti_rainy" <biti_rainy@xxxxxxxxx>
- To: "jhn.aida@xxxxxx" <jhn.aida@xxxxxx>, "jkstill@xxxxxxxxx" <jkstill@xxxxxxxxx>
- Date: Sun, 9 Jan 2005 21:21:24 +0800
hi,Jesper Haure Norrevang OS file is one oracle blocks bigger than oracle files . 2k/4k/8k/16k blocks LMT datafile has 8 oracle blocks oracle file header and bitmap . there is difference for dba_extents and (dba_data_files - dba_free_space) and please notice the left space with a datafile that less than min extent. anyway,i think all that is not important. Best regards msn: biti_rainy@xxxxxxxxxxx a dba from alibaba(china) ---- from the mail----- >Thanks Jared, > >I think you have a good point here. >I don't like when ad hoc SQL made by >the DBA shows up as the most resource >consuming statements in the database. >I admit that my statement do not perform >well. > >It reminds me, that the sum of bytes >in DBA_FREE_SPACE and DBA_EXTENTS for >a tablespace do not match the actual >size of the datafiles. The difference is: >- 1 block file header, >- 1 block HEADER of bitmap used with locally > managed tablespaces (LMT). >- 6 blocks (may be more?) of LMT-bitmaps. > >The difference can be seen in >DBA_DATA_FILES as the difference between >USER_BYTES and BYTES. > >Regards >Jesper Haure Norrevang > > >----- Original Message ----- >From: Jared Still <jkstill@xxxxxxxxx> >Date: Saturday, January 8, 2005 8:09 pm >Subject: Re: Used size of a datafile. > >> You may consider using DBA_FREE_SPACE rather than DBA_EXTENTS. >> >> If there are a lot of objects in your database, it may be >> (possibly much) less >> expensive to query DBA_FREE_SPACE. >> >> On Sat, 08 Jan 2005 11:15:32 +0100, Jesper Haure Norrevang >> <jhn.aida@xxxxxx> wrote: >> > Vinod, >> > >> > select >> > f.tablespace_name, >> > f.file_name, >> > sum(e.bytes) / 1024 / 1024 MB >> > from dba_extents e, dba_data_files f >> > where e.file_id = f.file_id >> > group by f.tablespace_name, f.file_name >> > order by f.tablespace_name, f.file_name; >> > >> >> >> -- >> Jared Still >> Certifiable Oracle DBA and Part Time Perl Evangelist >> -- >> http://www.freelists.org/webpage/oracle-l >> > >-- >http://www.freelists.org/webpage/oracle-l > -- http://www.freelists.org/webpage/oracle-l
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