undo过大的常见处理方式

Posted 2020-09-21

一、普通情况下的操作：
undo表空间处理方式一般采用如下：
1、创建新的undo表空间
create undo tablespace undotbs3 datafile‘+ORA_DATA_02‘ size 30G;
alter tablespace undotbs3 add datafile‘+ORA_DATA_02‘ size 30G;-------可以添加数据文件来增大表空间，也可以通过resize扩大数据文件来扩大表空间
2、切换undo表空间
ALTER SYSTEM SET UNDO_TABLESPACE=UNDOTBS3 scope=both;
3、删除旧的undo表空间------操作到这一步其实就可以了，但是为了保证表空间还是原来的名字，就需要再来一遍创建、切换、删除旧的undo表空间
drop tablespace UNDOTBS1 including contents and datafiles;
4、创建undo表空间
5、切换undo表空间
6、删掉旧的undo表空间

针对ASM管理的rac，不同节点使用不同undo表空间的，需要在每个节点进行修改（一般rac不会所有节点共用一个undo表空间）

二、特殊情况之一
这两天处理项目undo表空间问题时，在删除旧的undo表空间时报错（ORA-30013）
SQL> drop tablespace UNDOTBS1 including contents and datafiles;
drop tablespace UNDOTBS1 including contents and datafiles
*
ERROR at line 1:
ORA-30013: 还原表空间 ‘UNDOTBS1‘ 当前正在使用中


以上情况的处理方式

1、这时候就需要查询回滚段情况了：
select segment_name,owner,tablespace_name,status from dba_rollback_segs  where tablespace_name=‘UNDOTBS4‘ and status = ‘ONLINE‘;
----查看回滚段中的事物sid，serial#
select SID, MACHINE,PADDR,SADDR,substr(username,1,10) username,serial#,segment_name from v$transaction,dba_rollback_segs,v$session where saddr=ses_addr and xidusn=segment_id;
----oracle级别杀掉会话
alter system kill session ‘SID,SERIAL#‘;


2、终极绝招(绝对不是重启试试)：
如果还杀不掉的话，就需要先杀掉操作系统级别的进程，再在oracle级别杀掉会话。
-----------------------如下查看更加详细的事物进程号（oracle级别、系统级别）----------------------
set line 200
set pagesize 999
col Sid for 99999
col MACHINE for a15
col ThreadID for 99999
col segment_name for a30
col tablespace_name for a10
col db_username for a10
col OSUser for a10
col program for a40
select s.Sid AS "Sid",
s.Serial#  "Serial#",
p.spid "ThreadID",
s.MACHINE,
seg.segment_name,
seg.tablespace_name,
seg.status,
substr(s.username,1,10) db_username,
s.OSUser "OSUser",
s.Program AS "Program"
from v$transaction,dba_rollback_segs seg,v$session s,v$process p
where saddr=ses_addr and xidusn=segment_id and p.addr=s.paddr(+);

三、赠送两个我认为写的比较好的常用的查询表空间的语句

-----查看数据库各个表空间的使用情况---------------------------------
SET linesize 200
col tablespace_name format a15
SELECT a.tablespace_name,
       round(((a.bytes - b.bytes) * 100) / a.maxbytes,
             2) "% USED",
       round(((a.maxbytes - a.bytes + b.bytes) * 100) / a.maxbytes,
             2) "% FREE",
       round(a.maxbytes / 1024 / 1024 / 1024,
             2) "TOTAL(G)",
       round((a.bytes - b.bytes) / 1024 / 1024 / 1024,
             2) "USED(G)",
       round((a.maxbytes - a.bytes + b.bytes) / 1024 / 1024 / 1024,
             2) "FREE(G)",
       round(a.maxbytes / 1024 / 1024,
             2) "TOTAL(M)",
       round((a.bytes - b.bytes) / 1024 / 1024,
             2) "USED(M)",
       round((a.maxbytes - a.bytes + b.bytes) / 1024 / 1024,
             2) "FREE(M)"
  FROM (SELECT ddf.tablespace_name,
               SUM(decode(ddf.autoextensible,
                          ‘NO‘,
                          ddf.bytes,
                          (sqrt((ddf.bytes + ddf.maxbytes) *
                                (ddf.bytes + ddf.maxbytes)) +
                          sqrt((ddf.bytes - ddf.maxbytes) *
                                (ddf.bytes - ddf.maxbytes))) / 2)) maxbytes,
               SUM(ddf.bytes) bytes
          FROM dba_data_files ddf
         GROUP BY ddf.tablespace_name) a,
       (SELECT dfs.tablespace_name,
               SUM(dfs.bytes) bytes
          FROM dba_free_space dfs
         GROUP BY dfs.tablespace_name) b
 WHERE a.tablespace_name = b.tablespace_name(+)
 ORDER BY round(((a.bytes - b.bytes) * 100) / a.maxbytes,
                2) DESC;

-----查看数据库各个表空间的使用情况---------------------------------

SELECT D.TABLESPACE_NAME,
       SPACE || ‘M‘ "SUM_SPACE(M)",
       BLOCKS "SUM_BLOCKS",
       SPACE - NVL (FREE_SPACE, 0) || ‘M‘ "USED_SPACE(M)",
       ROUND ( (1 - NVL (FREE_SPACE, 0) / SPACE) * 100, 2) || ‘%‘
          "USED_RATE(%)",
       FREE_SPACE || ‘M‘ "FREE_SPACE(M)"
  FROM (  SELECT TABLESPACE_NAME,
                 ROUND (SUM (BYTES) / (1024 * 1024), 2) SPACE,
                 SUM (BLOCKS) BLOCKS
            FROM DBA_DATA_FILES
        GROUP BY TABLESPACE_NAME) D,
       (  SELECT TABLESPACE_NAME,
                 ROUND (SUM (BYTES) / (1024 * 1024), 2) FREE_SPACE
            FROM DBA_FREE_SPACE
        GROUP BY TABLESPACE_NAME) F
 WHERE D.TABLESPACE_NAME = F.TABLESPACE_NAME(+)
UNION ALL                                                          
SELECT D.TABLESPACE_NAME,
       SPACE || ‘M‘ "SUM_SPACE(M)",
       BLOCKS SUM_BLOCKS,
       USED_SPACE || ‘M‘ "USED_SPACE(M)",
       ROUND (NVL (USED_SPACE, 0) / SPACE * 100, 2) || ‘%‘ "USED_RATE(%)",
       NVL (FREE_SPACE, 0) || ‘M‘ "FREE_SPACE(M)"
  FROM (  SELECT TABLESPACE_NAME,
                 ROUND (SUM (BYTES) / (1024 * 1024), 2) SPACE,
                 SUM (BLOCKS) BLOCKS
            FROM DBA_TEMP_FILES
        GROUP BY TABLESPACE_NAME) D,
       (  SELECT TABLESPACE_NAME,
                 ROUND (SUM (BYTES_USED) / (1024 * 1024), 2) USED_SPACE,
                 ROUND (SUM (BYTES_FREE) / (1024 * 1024), 2) FREE_SPACE
            FROM V$TEMP_SPACE_HEADER
        GROUP BY TABLESPACE_NAME) F
 WHERE D.TABLESPACE_NAME = F.TABLESPACE_NAME(+)
ORDER BY 1;