Oracle purge 用法介绍

时间：2014-06-05 05:58:46 收藏：0 阅读：281

1、用途：

清除oracle 回收站(recyclebin)中的表和索引并释放与其相关的空间，还可清空回收站，或者清除表空间中记录的已删除的部分表空间。

注意：purge后不能回滚和恢复。

2、语法：

3、示例说明：

1）首先查一下回收站：

SELECT * FROM RECYCLEBIN;

2）创建并删除同一表三次：

--版本1
CREATE TABLE recycle_tmp(version NUMBER(10));
INSERT INTO recycle_tmp VALUES(1);
COMMIT;
DROP TABLE recycle_tmp;
SELECT object_name, original_name, operation, droptime FROM RECYCLEBIN;

回收站有1条记录：

OBJECT_NAME ORIGINAL_NAME OPERATION DROPTIME
------------------------------ -------------------------------- --------- -------------------
BIN$Ncu0aCGFSXGwbg3KwS5nHA==$0 RECYCLE_TMP DROP 2014-05-28:22:00:06

--版本2
CREATE TABLE recycle_tmp(version NUMBER(10));
INSERT INTO recycle_tmp VALUES(2);
COMMIT;
DROP TABLE recycle_tmp;
SELECT object_name, original_name, operation, droptime FROM RECYCLEBIN;

回收站有2条记录：

OBJECT_NAME ORIGINAL_NAME OPERATION DROPTIME
------------------------------ -------------------------------- --------- -------------------
BIN$34btciE8RySPmHqIlCGnVg==$0 RECYCLE_TMP DROP 2014-05-28:22:03:49
BIN$Ncu0aCGFSXGwbg3KwS5nHA==$0 RECYCLE_TMP DROP 2014-05-28:22:00:06

--版本3
CREATE TABLE recycle_tmp(version NUMBER(10));
INSERT INTO recycle_tmp VALUES(3);
COMMIT;
DROP TABLE recycle_tmp;
SELECT object_name, original_name, operation, droptime FROM RECYCLEBIN;

回收站有3条记录：

OBJECT_NAME ORIGINAL_NAME OPERATION DROPTIME
------------------------------ -------------------------------- --------- -------------------
BIN$34btciE8RySPmHqIlCGnVg==$0 RECYCLE_TMP DROP 2014-05-28:22:03:49
BIN$pNtKhKu4TY+qYYIQhTsdgg==$0 RECYCLE_TMP DROP 2014-05-28:22:04:02
BIN$Ncu0aCGFSXGwbg3KwS5nHA==$0 RECYCLE_TMP DROP 2014-05-28:22:00:06

3）清空版本1（默认删除最早版本）

PURGE TABLE recycle_tmp; 
SELECT object_name, original_name, operation, droptime FROM RECYCLEBIN;

OBJECT_NAME ORIGINAL_NAME OPERATION DROPTIME
------------------------------ -------------------------------- --------- -------------------
BIN$34btciE8RySPmHqIlCGnVg==$0 RECYCLE_TMP DROP 2014-05-28:22:03:49
BIN$pNtKhKu4TY+qYYIQhTsdgg==$0 RECYCLE_TMP DROP 2014-05-28:22:04:02

4）清空版本2（根据回收站OBJECT_NAME清除表）

PURGE TABLE  "BIN$34btciE8RySPmHqIlCGnVg==$0";
SELECT object_name, original_name, operation, droptime FROM RECYCLEBIN;

OBJECT_NAME ORIGINAL_NAME OPERATION DROPTIME
------------------------------ -------------------------------- --------- -------------------
BIN$pNtKhKu4TY+qYYIQhTsdgg==$0 RECYCLE_TMP DROP 2014-05-28:22:04:02

5）还原版本3（使用闪回flashback）

--还原版本3
FLASHBACK TABLE recycle_tmp TO BEFORE DROP;
SELECT object_name, original_name, operation, droptime FROM RECYCLEBIN;

未选定行（此时回收站已空）

SELECT * FROM recycle_tmp;

VERSION
--------------------------
3

6）删除版本3，后清空回收站

DROP TABLE recycle_tmp;
PURGE RECYCLEBIN; 
SELECT object_name, original_name, operation, droptime FROM RECYCLEBIN;

回收站已清空。

未选定行（已清空）

-----------------------------

By Dylan.

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