RE: datafiles space allocation algorithm
- From: "Christian Antognini" <Christian.Antognini@xxxxxxxxxxxx>
- To: "Kurt Van Meerbeeck" <kurtvm@xxxxxxxxxx>
- Date: Fri, 6 Oct 2006 13:41:49 +0200
Kurt
> This might be true on dictionary managed tablespaces and LMT Uniform
> size, but not so for LMT Autoallocate :
With autoallocate it seams that the size is used instead of the number
of extents...
In the following example one MB for each datafile:
SQL> create tablespace t
2 datafile '/tmp/t1.dbf' size 10m,
3 '/tmp/t2.dbf' size 10m,
4 '/tmp/t3.dbf' size 10m,
5 '/tmp/t4.dbf' size 10m
6 extent management local autoallocate;
SQL> create table t (n number)
2 tablespace t;
SQL> begin
2 for i in 1..30 loop
3 execute immediate 'alter table t allocate extent';
4 end loop;
5 end;
6 /
SQL> select file_id, extent_id, bytes
2 from dba_extents
3 where owner = user and segment_name = 'T
4 order by extent_id;
FILE_ID EXTENT_ID BYTES
---------- ---------- ----------
6 0 65536
6 1 65536
6 2 65536
6 3 65536
6 4 65536
6 5 65536
6 6 65536
6 7 65536
6 8 65536
6 9 65536
6 10 65536
6 11 65536
6 12 65536
6 13 65536
6 14 65536
6 15 65536
7 16 1048576
8 17 1048576
5 18 1048576
6 19 1048576
7 20 1048576
8 21 1048576
5 22 1048576
6 23 1048576
7 24 1048576
8 25 1048576
5 26 1048576
6 27 1048576
7 28 1048576
8 29 1048576
5 30 1048576
SQL> select 65536*16 from dual
65536*16
----------
1048576
Cheers,
Chris
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