Partition Change Layout

I have a huge table that is partitioned by month going all the way back to July 2000. As the partitions are backup they are made read only because the data never changes.

I have to add a column to the table. How does this affect the read only tablespaces associated with this table? Do have have to make those partitions read write again and then back them up again??

what backup/restore methodology do you use?

You will not be able to add a column to a table that has readonly tablespaces, as oracle will not be able to go back and add the pointer to that column to the old rows. You'll have to make them r/w, make the change, then r/o and backed up again.

Quote:

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Originally posted by jhmartin
You will not be able to add a column to a table that has readonly tablespaces, as oracle will not be able to go back and add the pointer to that column to the old rows. You'll have to make them r/w, make the change, then r/o and backed up again.

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I'm thinking that was more of a guess than actual fact.

Code:

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system@lx920> create tablespace ro datafile '/u01/app/oracle/product/920/oradata/lx920/ro01.dbf'
  2  size 10m autoextend on next 10m maxsize 2047m
  3  extent management local;

Tablespace created.

Elapsed: 00:00:01.27
system@lx920> create tablespace rw datafile '/u01/app/oracle/product/920/oradata/lx920/rw01.dbf'
  2  size 10m autoextend on next 10m maxsize 2047m
  3  extent management local;

Tablespace created.

Elapsed: 00:00:00.63
system@lx920> create table t (id number(10), name varchar2(20))
  2  partition by range (id)
  3  (partition p1 values less than (10) tablespace ro,
  4  partition p2 values less than (20) tablespace ro,
  5  partition p3 values less than (30) tablespace rw,
  6  partition p4 values less than (maxvalue) tablespace rw);

Table created.

Elapsed: 00:00:00.49
system@lx920> declare
  2    i integer;
  3  begin
  4    for i in 1..50 loop
  5        insert into t values (i, to_char(i));
  6    end loop;
  7  end;
  8  /

PL/SQL procedure successfully completed.

Elapsed: 00:00:00.22
system@lx920> commit;

Commit complete.

Elapsed: 00:00:00.00
system@lx920> alter tablespace ro read only;

Tablespace altered.

Elapsed: 00:00:00.07
system@lx920> delete from t where id = 1;
delete from t where id = 1
            *
ERROR at line 1:
ORA-00372: file 9 cannot be modified at this time
ORA-01110: data file 9: '/u01/app/oracle/product/920/oradata/lx920/ro01.dbf'


Elapsed: 00:00:00.04
system@lx920> alter table t add (the_dt date);

Table altered.

Elapsed: 00:00:00.16

system@lx920> desc t
 Name                          Null?    Type
 ----------------------------- -------- --------------------
 ID                                    NUMBER(10)
 NAME                                  VARCHAR2(20)
 THE_DT                                DATE

system@lx920> update t set the_dt = sysdate;
update t set the_dt = sysdate
      *
ERROR at line 1:
ORA-00372: file 9 cannot be modified at this time
ORA-01110: data file 9:
'/u01/app/oracle/product/920/oradata/lx920/ro01.dbf'


Elapsed: 00:00:00.05
system@lx920> update t set the_dt = sysdate where id > 30;

20 rows updated.

Elapsed: 00:00:00.01
system@lx920> commit;

Commit complete.

Elapsed: 00:00:00.01
system@lx920> alter table t drop partition p1;

Table altered.

Elapsed: 00:00:00.22
system@lx920> l
  1  select segment_name, partition_name, tablespace_name
  2  from dba_segments
  3* where segment_name = 'T'
system@lx920> /

SEGMENT_NAME        PARTITION_NAME                TABLESPACE_NAME
-------------------- ------------------------------ ------------------------------
T                    P2                            RO
T                    P3                            RW
T                    P4                            RW

Elapsed: 00:00:00.05

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