对表进行delete&shrink&move无法提高rman的备份效率
结论：
首先rman备份时会备份被使用过的块。对表进行delete&shrink&move是无法提高rman的备份效率，resize可以。
delete、shrink、move不会改变备份集合大小。
首先rman备份时会备份被使用过的块。对表进行delete&shrink&move是无法提高rman的备份效率，resize可以。
delete、shrink、move不会改变备份集合大小。
下面将通过对比这个操作与初始表的备份集大小、花费时间来说明这个结论。
DB 10gR201 /OS redhat
1、创建一个1g的tbs,插入一个1g的表t create tablespace tbs datafile '/u01/oradata/sales/tbs01' size 1024m; create table t1 pctfree 99 pctused 0 tablespace tbs as select * from dba_objects where 1=0; insert into t1 select * from dba_objects; insert into t1 select * from dba_objects; commit; 2、对表进行delete、shrink、move、resize等操作后用rman进行备份，记录备份时间以及备份集大小 SQL> col segment_name for a30 SQL> select segment_name,sum(blocks)*8/1024 from dba_extents 2 where tablespace_name = 'TBS' group by segment_name; SEGMENT_NAME SUM(BLOCKS)*8/1024 ------------------------------ ------------------ T1 792 SQL> select tablespace_name,sum(blocks)*8/1024 from dba_data_files 2 where tablespace_name = 'TBS' group by tablespace_name; TABLESPACE_NAME SUM(BLOCKS)*8/1024 ------------------------------------------------------------ ------------------ TBS 1024 SQL> select tablespace_name,sum(blocks)*8/1024 from dba_free_space 2 where tablespace_name = 'TBS' group by tablespace_name; TABLESPACE_NAME SUM(BLOCKS)*8/1024 ------------------------------------------------------------ ------------------ TBS 231.9375 SQL> RMAN> backup tablespace tbs format='/tmp/tbs%U.bak'; Starting backup at 13-MAR-14 using target database control file instead of recovery catalog allocated channel: ORA_DISK_1 channel ORA_DISK_1: sid=213 devtype=DISK channel ORA_DISK_1: starting full datafile backupset channel ORA_DISK_1: specifying datafile(s) in backupset input datafile fno=00006 name=/u01/oradata/sales/tbs01 channel ORA_DISK_1: starting piece 1 at 13-MAR-14 channel ORA_DISK_1: finished piece 1 at 13-MAR-14 piece handle=/tmp/tbs09p33hi1_1_1.bak tag=TAG20140313T190016 comment=NONE channel ORA_DISK_1: backup set complete, elapsed time: 00:01:35 Finished backup at 13-MAR-14 RMAN> -rw-r----- 1 oracle oinstall 830570496 Mar 13 19:01 tbs09p33hi1_1_1.bak 2.2 delete mod(rownum,2)=0 SQL> col segment_name for a30 SQL> select segment_name,sum(blocks)*8/1024 from dba_extents 2 where tablespace_name = 'TBS' group by segment_name; SEGMENT_NAME SUM(BLOCKS)*8/1024 ------------------------------ ------------------ T1 792 SQL> select tablespace_name,sum(blocks)*8/1024 from dba_data_files 2 where tablespace_name = 'TBS' group by tablespace_name; TABLESPACE_NAME SUM(BLOCKS)*8/1024 ------------------------------------------------------------ ------------------ TBS 1024 SQL> select tablespace_name,sum(blocks)*8/1024 from dba_free_space 2 where tablespace_name = 'TBS' group by tablespace_name; TABLESPACE_NAME SUM(BLOCKS)*8/1024 ------------------------------------------------------------ ------------------ TBS 231.9375 SQL> RMAN> backup tablespace tbs format='/tmp/tbs%U.bak'; Starting backup at 13-MAR-14 using channel ORA_DISK_1 channel ORA_DISK_1: starting full datafile backupset channel ORA_DISK_1: specifying datafile(s) in backupset input datafile fno=00006 name=/u01/oradata/sales/tbs01 channel ORA_DISK_1: starting piece 1 at 13-MAR-14 channel ORA_DISK_1: finished piece 1 at 13-MAR-14 piece handle=/tmp/tbs0ap33ia8_1_1.bak tag=TAG20140313T191312 comment=NONE channel ORA_DISK_1: backup set complete, elapsed time: 00:01:37 Finished backup at 13-MAR-14 RMAN> [oracle@laf ~]$ ls -l /tmp/tbs* -rw-r----- 1 oracle oinstall 830570496 Mar 13 19:01 /tmp/tbs09p33hi1_1_1.bak -rw-r----- 1 oracle oinstall 830570496 Mar 13 19:14 /tmp/tbs0ap33ia8_1_1.bak [oracle@laf ~]$ 2.3 shrink SQL> alter table t1 shrink space; Table altered. SQL> col segment_name for a30 SQL> select segment_name,sum(blocks)*8/1024 from dba_extents 2 where tablespace_name = 'TBS' group by segment_name; SEGMENT_NAME SUM(BLOCKS)*8/1024 ------------------------------ ------------------ T1 .0625 SQL> select tablespace_name,sum(blocks)*8/1024 from dba_data_files 2 where tablespace_name = 'TBS' group by tablespace_name; TABLESPACE_NAME SUM(BLOCKS)*8/1024 ------------------------------------------------------------ ------------------ TBS 1024 SQL> select tablespace_name,sum(blocks)*8/1024 from dba_free_space 2 where tablespace_name = 'TBS' group by tablespace_name; TABLESPACE_NAME SUM(BLOCKS)*8/1024 ------------------------------------------------------------ ------------------ TBS 1023.875 SQL> RMAN> backup tablespace tbs format='/tmp/tbs%U.bak'; Starting backup at 13-MAR-14 using channel ORA_DISK_1 channel ORA_DISK_1: starting full datafile backupset channel ORA_DISK_1: specifying datafile(s) in backupset input datafile fno=00006 name=/u01/oradata/sales/tbs01 channel ORA_DISK_1: starting piece 1 at 13-MAR-14 channel ORA_DISK_1: finished piece 1 at 13-MAR-14 piece handle=/tmp/tbs0bp33j66_1_1.bak tag=TAG20140313T192806 comment=NONE channel ORA_DISK_1: backup set complete, elapsed time: 00:01:37 Finished backup at 13-MAR-14 RMAN> -rw-r----- 1 oracle oinstall 830570496 Mar 13 19:01 /tmp/tbs09p33hi1_1_1.bak -rw-r----- 1 oracle oinstall 830570496 Mar 13 19:14 /tmp/tbs0ap33ia8_1_1.bak -rw-r----- 1 oracle oinstall 830570496 Mar 13 19:29 /tmp/tbs0bp33j66_1_1.bak 2.4 move SQL> SQL> alter table t1 move; Table altered. SQL> col segment_name for a30 SQL> select segment_name,sum(blocks)*8/1024 from dba_extents 2 where tablespace_name = 'TBS' group by segment_name; SEGMENT_NAME SUM(BLOCKS)*8/1024 ------------------------------ ------------------ T1 .0625 SQL> select tablespace_name,sum(blocks)*8/1024 from dba_data_files 2 where tablespace_name = 'TBS' group by tablespace_name; TABLESPACE_NAME SUM(BLOCKS)*8/1024 ------------------------------------------------------------ ------------------ TBS 1024 SQL> select tablespace_name,sum(blocks)*8/1024 from dba_free_space 2 where tablespace_name = 'TBS' group by tablespace_name; TABLESPACE_NAME SUM(BLOCKS)*8/1024 ------------------------------------------------------------ ------------------ TBS 1023.875 SQL> RMAN> backup tablespace tbs format='/tmp/tbs%U.bak'; Starting backup at 13-MAR-14 using channel ORA_DISK_1 channel ORA_DISK_1: starting full datafile backupset channel ORA_DISK_1: specifying datafile(s) in backupset input datafile fno=00006 name=/u01/oradata/sales/tbs01 channel ORA_DISK_1: starting piece 1 at 13-MAR-14 channel ORA_DISK_1: finished piece 1 at 13-MAR-14 piece handle=/tmp/tbs0cp33jc1_1_1.bak tag=TAG20140313T193113 comment=NONE channel ORA_DISK_1: backup set complete, elapsed time: 00:01:36 Finished backup at 13-MAR-14 RMAN> -rw-r----- 1 oracle oinstall 830570496 Mar 13 19:01 /tmp/tbs09p33hi1_1_1.bak -rw-r----- 1 oracle oinstall 830570496 Mar 13 19:14 /tmp/tbs0ap33ia8_1_1.bak -rw-r----- 1 oracle oinstall 830570496 Mar 13 19:29 /tmp/tbs0bp33j66_1_1.bak -rw-r----- 1 oracle oinstall 830570496 Mar 13 19:32 /tmp/tbs0cp33jc1_1_1.bak [oracle@laf ~]$ 4、resize SQL> alter tablespace tbs resize 1m; alter tablespace tbs resize 1m * ERROR at line 1: ORA-32773: operation not supported for smallfile tablespace TBS SQL> alter database datafile 6 resize 1m; Database altered. SQL> SQL> SQL> col segment_name for a30 SQL> select segment_name,sum(blocks)*8/1024 from dba_extents 2 where tablespace_name = 'TBS' group by segment_name; SEGMENT_NAME SUM(BLOCKS)*8/1024 ------------------------------ ------------------ T1 .0625 SQL> col segment_name for a30 SQL> select segment_name,sum(blocks)*8/1024 from dba_extents 2 where tablespace_name = 'TBS' group by segment_name; SEGMENT_NAME SUM(BLOCKS)*8/1024 ------------------------------ ------------------ T1 .0625 SQL> select tablespace_name,sum(blocks)*8/1024 from dba_free_space 2 where tablespace_name = 'TBS' group by tablespace_name; TABLESPACE_NAME SUM(BLOCKS)*8/1024 ------------------------------------------------------------ ------------------ TBS .875 SQL> RMAN> backup tablespace tbs format='/tmp/tbs%U.bak'; Starting backup at 13-MAR-14 using channel ORA_DISK_1 channel ORA_DISK_1: starting full datafile backupset channel ORA_DISK_1: specifying datafile(s) in backupset input datafile fno=00006 name=/u01/oradata/sales/tbs01 channel ORA_DISK_1: starting piece 1 at 13-MAR-14 channel ORA_DISK_1: finished piece 1 at 13-MAR-14 piece handle=/tmp/tbs0dp33jns_1_1.bak tag=TAG20140313T193732 comment=NONE channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01 Finished backup at 13-MAR-14 RMAN> RMAN> exit Recovery Manager complete. [oracle@laf ~]$ ls -l /tmp/tbs* -rw-r----- 1 oracle oinstall 830570496 Mar 13 19:01 /tmp/tbs09p33hi1_1_1.bak -rw-r----- 1 oracle oinstall 830570496 Mar 13 19:14 /tmp/tbs0ap33ia8_1_1.bak -rw-r----- 1 oracle oinstall 830570496 Mar 13 19:29 /tmp/tbs0bp33j66_1_1.bak -rw-r----- 1 oracle oinstall 830570496 Mar 13 19:32 /tmp/tbs0cp33jc1_1_1.bak -rw-r----- 1 oracle oinstall 1081344 Mar 13 19:37 /tmp/tbs0dp33jns_1_1.bak [oracle@laf ~]$