Oracle数据库备份还原详解

理论准备

oracle 数据库提供expdp和impdp命令用于备份和恢复数据库。

具体可查阅oracle官方文档 https://docs.oracle.com/en/database/oracle/oracle-database/12.2/sutil/database-utilities.pdf

备份和还原主要有

full_mode:整个数据库进行备份还原。

schema mode：默认导出模式，schema 模式。

table mode：表模式。

tablespace mode：表空间模式。

实践

验证1：备份某一时刻数据库数据，通过恢复语句能够恢复到备份时刻的数据。

切换用户后登录

[root@linuxtestb538 ~]# su oracle
bash-4.2$ sqlplus / as sysdba

sql*plus: release 19.0.0.0.0 - production on tue nov 23 14:40:45 2021
version 19.3.0.0.0

copyright (c) 1982, 2019, oracle.  all rights reserved.


connected to:
oracle database 19c enterprise edition release 19.0.0.0.0 - production
version 19.3.0.0.0

sql> 

连接到对应用户下

sql> conn test/test@mypdb
connected.

创建了test_tab表

create table test_tab(
id number(9) not null,
title varchar2(20)
);

插入一条数据

insert into test_tab values(1,'hello world');

导出数据文件(推出数据库连接)

expdp test/test@mypdb schemas=test dumpfile=test20211119_all.dmp logfile=20211119_all.dmp directory=data_pump_dir 

插入一条数据

insert into test_tab values(2,'hello test');

目前数据库中存在两条数据,而数据导出的时候只有一条hello world的数据。

sql> select * from test_tab;

        id title
---------- --------------------
         1 hello world
         2 hello test

现在我们通过impdp命令恢复数据库数据

bash-4.2$ impdp test/test@mypdb schemas=test directory=data_pump_dir dumpfile=test20211119_all.dmp logfile=20211119_recov.dmp;

import: release 19.0.0.0.0 - production on tue nov 23 14:52:21 2021
version 19.3.0.0.0

copyright (c) 1982, 2019, oracle and/or its affiliates.  all rights reserved.

connected to: oracle database 19c enterprise edition release 19.0.0.0.0 - production
master table "test"."sys_import_schema_01" successfully loaded/unloaded
starting "test"."sys_import_schema_01":  test/********@mypdb schemas=test directory=data_pump_dir dumpfile=test20211119_all.dmp logfile=20211119_recov.dmp 
processing object type schema_export/user
ora-31684: object type user:"test" already exists

processing object type schema_export/system_grant
processing object type schema_export/role_grant
processing object type schema_export/default_role
processing object type schema_export/pre_schema/procact_schema
processing object type schema_export/table/table
ora-39151: table "test"."test_tab" exists. all dependent metadata and data will be skipped due to table_exists_action of skip

processing object type schema_export/table/table_data
processing object type schema_export/table/statistics/table_statistics
processing object type schema_export/statistics/marker
job "test"."sys_import_schema_01" completed with 2 error(s) at tue nov 23 14:52:37 2021 elapsed 0 00:00:14

从输入信息中看到test_tab表已经存在所以相关的备份数据跳过不处理，但我们的本意需要让备份数据去覆盖现有数据不管现在表 是否已经存在。那我们需要增加 table_exists_action=replace的参数

impdp test/test@mypdb schemas=test table_exists_action=replace directory=data_pump_dir dumpfile=test20211119_all.dmp logfile=20211119_recov.dmp;

import: release 19.0.0.0.0 - production on tue nov 23 14:55:57 2021
version 19.3.0.0.0

copyright (c) 1982, 2019, oracle and/or its affiliates.  all rights reserved.

connected to: oracle database 19c enterprise edition release 19.0.0.0.0 - production
master table "test"."sys_import_schema_01" successfully loaded/unloaded
starting "test"."sys_import_schema_01":  test/********@mypdb schemas=test table_exists_action=replace directory=data_pump_dir dumpfile=test20211119_all.dmp logfile=20211119_recov.dmp 
processing object type schema_export/user
ora-31684: object type user:"test" already exists

processing object type schema_export/system_grant
processing object type schema_export/role_grant
processing object type schema_export/default_role
processing object type schema_export/pre_schema/procact_schema
processing object type schema_export/table/table
processing object type schema_export/table/table_data
. . imported "test"."test_tab"                           5.539 kb       1 rows
processing object type schema_export/table/statistics/table_statistics
processing object type schema_export/statistics/marker
job "test"."sys_import_schema_01" completed with 1 error(s) at tue nov 23 14:56:25 2021 elapsed 0 00:00:27

连接到数据库后,查询test_tab表，发现数据已经恢复到只有一条hello world的时候，验证通过。

sql> select * from test_tab;

        id title
---------- --------------------
         1 hello world

验证2：备份数据的时候不想备份所有表，要根据条件过滤掉某些表进行备份，恢复的时候只恢复备份出来的表数据。

我们再创建一张his开头的表

create table his_test_tab(
id number(9) not null,
title varchar2(20)
);

插入数据

insert into his_test_tab values(1,'hello world');

导出数据

bash-4.2$ expdp test/test@mypdb schemas=test dumpfile=test20211123-1_all.dmp logfile=20211123-1_all.dmp directory=data_pump_dir exclude=table:\"like \'his%\'\";

export: release 19.0.0.0.0 - production on tue nov 23 15:16:39 2021
version 19.3.0.0.0

copyright (c) 1982, 2019, oracle and/or its affiliates.  all rights reserved.

connected to: oracle database 19c enterprise edition release 19.0.0.0.0 - production
starting "test"."sys_export_schema_01":  test/********@mypdb schemas=test dumpfile=test20211123-1_all.dmp logfile=20211123-1_all.dmp directory=data_pump_dir exclude=table:"like 'his%'" 
processing object type schema_export/table/table_data
processing object type schema_export/table/index/statistics/index_statistics
processing object type schema_export/table/statistics/table_statistics
processing object type schema_export/statistics/marker
processing object type schema_export/user
processing object type schema_export/system_grant
processing object type schema_export/role_grant
processing object type schema_export/default_role
processing object type schema_export/pre_schema/procact_schema
processing object type schema_export/table/table
processing object type schema_export/table/comment
processing object type schema_export/table/index/index
. . exported "test"."test_tab"                           5.539 kb       1 rows
master table "test"."sys_export_schema_01" successfully loaded/unloaded
******************************************************************************
dump file set for test.sys_export_schema_01 is:
  /opt/oracle/admin/orclcdb/dpdump/d0f96921d5e99512e0534390140a837f/test20211123-1_all.dmp
job "test"."sys_export_schema_01" successfully completed at tue nov 23 15:17:39 2021 elapsed 0 00:01:00

在test_tab和his_test_tab 表中新增数据

sql> insert into test_tab values(2,'hello test');

1 row created.

sql> insert into his_tab values(2,'hello test');
insert into his_tab values(2,'hello test')
            *
error at line 1:
ora-00942: table or view does not exist


sql> select * from test_tab;

        id title
---------- --------------------
         1 hello world
         2 hello test

sql> select * from his_test_tab;

        id title
---------- --------------------
         1 hello world
         2 hello test

插入数据后test_tab和his_test_tab表中

还原数据

bash-4.2$ impdp test/test@mypdb schemas=test table_exists_action=replace directory=data_pump_dir dumpfile=test20211123-1_all.dmp logfile=20211123_recov.dmp;

import: release 19.0.0.0.0 - production on tue nov 23 15:24:37 2021
version 19.3.0.0.0

copyright (c) 1982, 2019, oracle and/or its affiliates.  all rights reserved.

connected to: oracle database 19c enterprise edition release 19.0.0.0.0 - production
master table "test"."sys_import_schema_01" successfully loaded/unloaded
starting "test"."sys_import_schema_01":  test/********@mypdb schemas=test table_exists_action=replace directory=data_pump_dir dumpfile=test20211123-1_all.dmp logfile=20211123_recov.dmp 
processing object type schema_export/user
ora-31684: object type user:"test" already exists

processing object type schema_export/system_grant
processing object type schema_export/role_grant
processing object type schema_export/default_role
processing object type schema_export/pre_schema/procact_schema
processing object type schema_export/table/table
processing object type schema_export/table/table_data
. . imported "test"."test_tab"                           5.539 kb       1 rows
processing object type schema_export/table/statistics/table_statistics
processing object type schema_export/statistics/marker
job "test"."sys_import_schema_01" completed with 1 error(s) at tue nov 23 15:24:47 2021 elapsed 0 00:00:09

确认结果

sql> select * from his_test_tab;

        id title
---------- --------------------
         1 hello world
         2 hello test

sql> select * from test_tab;

        id title
---------- --------------------
         1 hello world

结果符合预期test_tab数据被还原，his_test_tab数据没有被还原。通过备份日志也可以看到我们只备份了test_tab表中的数据。

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