UNDO表空间

oracle226

---

---

UNDO表空间

查看PPT

SQL > showparameter undo ; NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ undo_management string AUTO --自动管理 undo_retention integer 900 --inactive的undo块数据保持时间，设置为最长的select时间 undo_tablespace string UNDOTBS1 --默认的undo表空间 SQL > selectdt.tablespace_name ,dt.block_size ,dt.contents ,dt.retention fromdba_tablespaces dt wheredt.contents = 'UNDO' ; TABLESPACE_NAME BLOCK_SIZE CONTENTS RETENTION ------------------------------ ---------- --------- -----------查询表空间 UNDOTBS1 8192 UNDO GUARANTEE --下面是查询某个表空间对应的数据文件 SQL > selectddf.file_name ,ddf.tablespace_name ,ddf.blocks ,ddf.online_status fromdba_data_files ddf whereddf.tablespace_name = 'UNDOTBS1' ; FILE_NAME TABLESPACE_NAME BLOCKS ONLINE_STATUS -------------------------------------------------------------------------------- ------------------------------ ---------- ------------- /u01 /app /oracle /oradata /jiagulun /undotbs01.dbf UNDOTBS1 78720 ONLINE SQL > SQL > create undo tablespaceundotbs2 datafile '/u01/app/oracle/oradata/jiagulun/undotbs02.dbf' size 10m 2 autoextend on ; --创建undo表空间 Tablespacecreated SQL > selectddf.file_name ,ddf.tablespace_name ,ddf.blocks ,ddf.online_status fromdba_data_files ddf whereddf.tablespace_name = 'UNDOTBS2' ; FILE_NAME TABLESPACE_NAME BLOCKS ONLINE_STATUS -------------------------------------------------------------------------------- ------------------------------ ---------- ------------- /u01 /app /oracle /oradata /jiagulun /undotbs02.dbf UNDOTBS2 1280 ONLINE SQL > alter tablespaceundotbs2 add datafile '/u01/app/oracle/oradata/jiagulun/undotbs03.dbf' size 10m autoextend on ; Tablespacealtered --为某个undo表空间添加数据文件 SQL > selectdt.tablespace_name ,dt.block_size ,dt.contents ,dt.retention fromdba_tablespaces dt wheredt.contents = 'UNDO' ; TABLESPACE_NAME BLOCK_SIZE CONTENTS RETENTION ------------------------------ ---------- --------- ----------- UNDOTBS1 8192 UNDO GUARANTEE UNDOTBS2 8192 UNDO NOGUARANTEE SQL > SQL > alter systemundo_tablespace = 'UNDOTBS2' ; alter systemundo_tablespace = 'UNDOTBS2' ORA - 02065 :非法的 ALTER SYSTEM选项 SQL > alter system SETundo_tablespace = 'UNDOTBS2' ; Systemaltered --修改系统使用的表空间 SQL > showparameter undo_tablespace ; NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ undo_tablespace string UNDOTBS2 SQL > selectdt.tablespace_name ,dt.block_size ,dt.contents ,dt.retention fromdba_tablespaces dt wheredt.contents = 'UNDO' ; TABLESPACE_NAME BLOCK_SIZE CONTENTS RETENTION ------------------------------ ---------- --------- ----------- UNDOTBS1 8192 UNDO GUARANTEE UNDOTBS2 8192 UNDO NOGUARANTEE SQL > alter tablespaceundotbs1 retention guarantee ; ; Tablespacealtered SQL > SQL > selectdt.tablespace_name ,dt.block_size ,dt.contents ,dt.retention fromdba_tablespaces dt wheredt.contents = 'UNDO' ; TABLESPACE_NAME BLOCK_SIZE CONTENTS RETENTION ------------------------------ ---------- --------- ----------- UNDOTBS1 8192 UNDO GUARANTEE UNDOTBS2 8192 UNDO NOGUARANTEE SQL > alter tablespaceundotbs2 retention guarantee ; Tablespacealtered SQL > selectdt.tablespace_name ,dt.block_size ,dt.contents ,dt.retention fromdba_tablespaces dt wheredt.contents = 'UNDO' ; TABLESPACE_NAME BLOCK_SIZE CONTENTS RETENTION ------------------------------ ---------- --------- ----------- UNDOTBS1 8192 UNDO GUARANTEE UNDOTBS2 8192 UNDO GUARANTEE SQL > SQL > alter tablespaceundotbs2 retention noguarantee ; Tablespacealtered SQL > selectdt.tablespace_name ,dt.block_size ,dt.contents ,dt.retention fromdba_tablespaces dt wheredt.contents = 'UNDO' ; TABLESPACE_NAME BLOCK_SIZE CONTENTS RETENTION ------------------------------ ---------- --------- ----------- UNDOTBS1 8192 UNDO GUARANTEE UNDOTBS2 8192 UNDO NOGUARANTEE SQL > selectto_char (us.BEGIN_TIME , 'yyyy-mm-dd :hh24:mi:ss' ), to_char (us.END_TIME , 'yyyy-mm-dd hh24:mi:ss' ), us.UNDOBLKS ,us.TXNCOUNT fromv$undostat us ; --查询undo状态信息：undoblks表示在这段时间内使用块大小 --txncount：表示这段时间的事务多少 TO_CHAR (US.BEGIN_TIME , 'YYYY-MM TO_CHAR(US.END_TIME,'YYYY -MM -D UNDOBLKS TXNCOUNT ------------------------------ ------------------------------ ---------- ---------- TO_CHAR (US.BEGIN_TIME , 'YYYY-MM TO_CHAR(US.END_TIME,'YYYY -MM -D UNDOBLKS TXNCOUNT ------------------------------ ------------------------------ ---------- ---------- 2015 - 01 - 20 : 16 : 49 : 54 2015 - 01 - 20 16 : 59 : 54 308 185 2015 - 01 - 20 : 16 : 39 : 54 2015 - 01 - 20 16 : 49 : 54 193 139 2015 - 01 - 20 : 16 : 29 : 54 2015 - 01 - 20 16 : 39 : 54 201 120 2015 - 01 - 20 : 16 : 19 : 54 2015 - 01 - 20 16 : 29 : 54 279 614 2015 - 01 - 20 : 16 : 09 : 54 2015 - 01 - 20 16 : 19 : 54 246 179 25 rowsselected SQL >