openGauss/MogDB 学习笔记之 -- PITR恢复

openGauss/MogDB 学习笔记之 -- PITR 恢复

概念描述

背景信息

当数据库崩溃或希望回退到数据库之前的某一状态时，MogDB 的即时恢复功能（Point-In-Time Recovery，简称 PITR）可以支持恢复到备份归档数据之后的任意时间点。

说明

PITR 仅支持恢复到物理备份数据之后的某一时间点。 仅主节点可以进行 PITR 恢复，备机需要进行全量 build 达成与主机数据同步。

前提条件

基于经过物理备份的全量数据文件。 基于已归档的 WAL 日志文件。

PITR 恢复流程

将物理备份的文件替换目标数据库目录。 删除数据库目录下 pg_xlog/中的所有文件。 将归档的 WAL 日志文件复制到 pg_xlog 文件中（此步骤可以省略，通过配置 recovery.conf 恢复命令文件中的 restore_command 项替代）。 在数据库目录下创建恢复命令文件 recovery.conf，指定数据库恢复的程度。 启动数据库。 连接数据库，查看是否恢复到希望预期的状态。 若已经恢复到预期状态，通过 pg_xlog_replay_resume()指令使主节点对外提供服务。

恢复目标设置(四选一)

recovery_target_name = ‘restore_point_1’ ## 还原到一个使用 pg_create_restore_point()创建的还原点 recovery_target_time = ‘2020-01-01 12:00:00’ ## 还原到一个指定时间戳 recovery_target_xid = ‘3000’ ## 还原到一个事务 ID recovery_target_lsn = ‘0/0FFFFFF’ ## 还原到日志的指定 LSN 点 recovery_target_inclusive = true ## 声明是否在指定恢复目标之后停止(true) 或 之前停止(false),不支持 recovery_target_name 配置#注意：如果不配置任何恢复目标 或 配置目标不存在，则默认恢复到最新的 WAL 日志点。

测试验证

1、环境准备(gs_baasebackup 备份)

[omm@db1 db1]$ gs_basebackup -U em_ljc -W -h ... -p 26000 -D /home/omm/gs_pitr

Password:

INFO: The starting position of the xlog copy of the full build is: 4/EA000028. The slot minimum LSN is: 0/0.

[2022-10-29 14:18:24]:begin build tablespace list

[2022-10-29 14:18:24]:finish build tablespace list

[2022-10-29 14:18:24]:begin get xlog by xlogstream

[2022-10-29 14:18:24]: check identify system success

[2022-10-29 14:18:24]: send START_REPLICATION 4/EA000000 success

[2022-10-29 14:18:24]: keepalive message is received

[2022-10-29 14:18:24]: keepalive message is received

[2022-10-29 14:18:27]: keepalive message is received

[2022-10-29 14:18:30]: keepalive message is received

[2022-10-29 14:18:30]: keepalive message is received

[2022-10-29 14:18:33]: keepalive message is received

[2022-10-29 14:18:36]: keepalive message is received

[2022-10-29 14:18:36]: keepalive message is received

[2022-10-29 14:18:39]: keepalive message is received

[2022-10-29 14:18:42]: keepalive message is received

[2022-10-29 14:18:42]: keepalive message is received

[2022-10-29 14:18:45]: keepalive message is received

[2022-10-29 14:18:47]: keepalive message is received

[2022-10-29 14:18:50]: keepalive message is received

[2022-10-29 14:18:53]: keepalive message is received

[2022-10-29 14:18:56]: keepalive message is received

[2022-10-29 14:18:59]: keepalive message is received

[2022-10-29 14:18:59]: keepalive message is received

[2022-10-29 14:19:02]: keepalive message is received

[2022-10-29 14:19:05]: keepalive message is received

[2022-10-29 14:19:05]: keepalive message is received

[2022-10-29 14:19:08]: keepalive message is received

[2022-10-29 14:19:11]: keepalive message is received

[2022-10-29 14:19:11]: keepalive message is received

[2022-10-29 14:19:14]: keepalive message is received

[2022-10-29 14:19:17]: keepalive message is received

[2022-10-29 14:19:17]: keepalive message is received

[2022-10-29 14:19:20]: keepalive message is received

[2022-10-29 14:19:23]: keepalive message is received

[2022-10-29 14:19:23]: keepalive message is received

[2022-10-29 14:19:29]:gs_basebackup: base backup successfully

[omm@db1 db1]$

2、创建测试数据（还原点 recovery_target_name ）

miao=> create table t1 (id int,tm timestamp,LSN varchar(20));

insert into t1 values(1,now(),'Started');

select * from t1;

select * from pg_switch_xlog();

CREATE TABLE

miao=> insert into t1 values(1,now(),'Started');

INSERT 0 1

miao=> select * from t1;

id | tm | lsn

----+----------------------------+---------

1 | 2022-10-29 14:22:52.273009 | Started

(1 row)

miao=> select * from pg_switch_xlog();

pg_switch_xlog

4/EC0029F8

(1 row)

miao=>

-- 创建一个还原点 restore_point_1

miao=> select pg_create_restore_point('restore_point_1');

pg_create_restore_point

4/ED00EF40

(1 row)

3、第 2 次插入数据（时间 recovery_target_time ）

miao=> insert into t1 values(2,now(),'First Insert');

INSERT 0 1

miao=> select * from t1;

id | tm | lsn

----+----------------------------+--------------

1 | 2022-10-29 14:22:52.273009 | Started

2 | 2022-10-29 14:26:10.55628 | First Insert

(2 rows)

miao=> select pg_switch_xlog();

select now();

pg_switch_xlog

4/ED017848

(1 row)

miao=> select now();

now

2022-10-29 14:26:10.754567+08

(1 row)

4、第 3 次插入数据（LSN recovery_target_lsn ）

miao=> insert into t1 values(3,now(),'Second Insert');

INSERT 0 1

miao=> select * from t1;

id | tm | lsn

----+----------------------------+---------------

1 | 2022-10-29 14:22:52.273009 | Started

2 | 2022-10-29 14:26:10.55628 | First Insert

3 | 2022-10-29 14:31:13.220708 | Second Insert

(3 rows)

miao=> select pg_switch_xlog();

select * from pg_current_xlog_location();

pg_switch_xlog

4/EE0230C0

(1 row)

miao=>

miao=> select * from pg_current_xlog_location();

pg_current_xlog_location

4/EF000148

(1 row)

5、模拟故障删除目录

[omm@db1 gs_pitr]$ cp /archivelog/* /home/omm/gs_pitr/archivelog/

[omm@db1 gs_pitr]$ gs_om -t stop

Stopping cluster.

Successfully stopped cluster.

End stop cluster.

[omm@db1 gs_pitr]$ rm -fr /mogdb/data/db1/

6、第一阶段恢复（按照还原点进行恢复）

[omm@db1 data]$ mkdir /mogdb/data/db1/

[omm@db1 db1]$ cp -fr /home/omm/gs_pitr/* /mogdb/data/db1/

[omm@db1 db1]$ vi recovery.conf

restore_command = 'cp /mogdb/data/db1/archivelog/%f %p'

recovery_target_name = 'restore_point_1' ## 恢复到指定的还原点restore_point_1,此时后面2条数据

recovery_target_inclusive = true

[omm@db1 db1]$ gs_om -t start

Starting cluster.

[SUCCESS] db1

2022-10-29 15:22:47.061 635cd4c6.1 [unknown] 140295007823424 [unknown] 0 dn_6001 01000 0 [BACKEND] WARNING: could not create any HA TCP/IP sockets

2022-10-29 15:22:47.064 635cd4c6.1 [unknown] 140295007823424 [unknown] 0 dn_6001 01000 0 [BACKEND] WARNING: Failed to initialize the memory protect for g_instance.attr.attr_storage.cstore_buffers (1024 Mbytes) or shared memory (1967 Mbytes) is larger.

Successfully started.

[omm@db1 db1]$ gsql -d miao -p 26000 -U dbmt -r

Password for user dbmt:

gsql ((MogDB 2.1.1 build b5f25b20) compiled at 2022-03-21 14:42:30 commit 0 last mr )

Non-SSL connection (SSL connection is recommended when requiring high-security)

Type "help" for help.

miao=> \d

List of relations

Schema | Name | Type | Owner | Storage

--------+--------------------------------+-------+-------+------------------------------------------------------

dbmt | b1921101_bak | table | dbmt | {orientation=row,compression=no,storage_type=ustore}

dbmt | cc_chx | table | dbmt | {orientation=row,compression=no,storage_type=ustore}

dbmt | cd_material | table | dbmt | {orientation=row,compression=no,storage_type=ustore}

dbmt | customer_me_degree_wbinfo | table | dbmt | {orientation=row,compression=no,storage_type=ustore}

dbmt | customer_me_degree_wbinfo_test | table | dbmt | {orientation=row,compression=no,storage_type=ustore}

dbmt | erp_i_contract_class | table | dbmt | {orientation=row,compression=no,storage_type=ustore}

dbmt | scm_warning_reauidt_detail | table | dbmt | {orientation=row,compression=no,storage_type=ustore}

dbmt | sm_filemanagerconfig | table | dbmt | {orientation=row,compression=no,storage_type=ustore}

dbmt | t_o | table | dbmt | {orientation=row,compression=no,storage_type=ustore}

dbmt | t_o_t | table | dbmt | {orientation=row,compression=no,storage_type=ustore}

dbmt | t_p_t | table | dbmt | {orientation=row,compression=no,storage_type=USTORE}

dbmt | temp1 | table | dbmt | {orientation=row,compression=no,storage_type=ustore}

dbmt | tiji_update | table | dbmt | {orientation=row,compression=no,storage_type=ustore}

dbmt | tmp_mis_code_zq | table | dbmt | {orientation=row,compression=no,storage_type=ustore}

dbmt | tmp_mul_stock_detail_20200614 | table | dbmt | {orientation=row,compression=no,storage_type=ustore}

dbmt | tmp_output_bill_20190821 | table | dbmt | {orientation=row,compression=no,storage_type=ustore}

dbmt | tmp_project_party | table | dbmt | {orientation=row,compression=no,storage_type=ustore}

dbmt | tmp_unit_vol | table | dbmt | {orientation=row,compression=no,storage_type=ustore}

dbmt | tmp_user_rep | table | dbmt | {orientation=row,compression=no,storage_type=ustore}

dbmt | ur_s_role | table | dbmt | {orientation=row,compression=no,storage_type=ustore}

dbmt | w_work_cooperate_gjback0721 | table | dbmt | {orientation=row,compression=no,storage_type=ustore}

dbmt | yang_tempate3 | table | dbmt | {orientation=row,compression=no,storage_type=ustore}

public | t1 | table | omm | {orientation=row,compression=no,storage_type=USTORE}

(105 rows)

miao=> select * from t1;

id | tm | lsn

----+----------------------------+---------

1 | 2022-10-29 14:22:52.273009 | Started

(1 row)

miao=>

7、 第二阶段恢复(按照时间进行还原)

[omm@db1 db1]$ vi recovery.conf

restore_command = 'cp /mogdb/data/db1/archivelog/%f %p'

recovery_target_time = '2022-10-29 14:26:44'

recovery_target_inclusive = true

~

"recovery.conf" [New] 3L, 137C written

[omm@db1 db1]$ gs_om -t start

Starting cluster.

[SUCCESS] db1

2022-10-29 15:22:47.061 635cd4c6.1 [unknown] 140295007823424 [unknown] 0 dn_6001 01000 0 [BACKEND] WARNING: could not create any HA TCP/IP sockets

2022-10-29 15:22:47.064 635cd4c6.1 [unknown] 140295007823424 [unknown] 0 dn_6001 01000 0 [BACKEND] WARNING: Failed to initialize the memory protect for g_instance.attr.attr_storage.cstore_buffers (1024 Mbytes) or shared memory (1967 Mbytes) is larger.

Successfully started.

[omm@db1 db1]$ gsql -d miao -U dbmt -p 26999 -r

failed to connect /opt/mogdb/tools/omm_mppdb:26999.

[omm@db1 db1]$ gsql -d miao -U dbmt -p 26000 -r

Password for user dbmt:

gsql ((MogDB 2.1.1 build b5f25b20) compiled at 2022-03-21 14:42:30 commit 0 last mr )

Non-SSL connection (SSL connection is recommended when requiring high-security)

Type "help" for help.

miao=> select * from t1;

id | tm | lsn

----+----------------------------+--------------

1 | 2022-10-29 14:22:52.273009 | Started

2 | 2022-10-29 14:26:10.55628 | First Insert

(2 rows)

8、 第三阶段恢复(按照 lsn 进行恢复)

restore_command = 'cp /mogdb/data/db1/archivelog/%f %p'

recovery_target_lsn = '4/EE0230C0'

recovery_target_inclusive = true

[omm@db1 archivelog]$ gs_om -t stop

Stopping cluster.

[omm@db1 db1]$ gs_om -t start

Starting cluster.

[SUCCESS] db1

2022-10-29 16:08:54.842 635cdf96.1 [unknown] 140627704972864 [unknown] 0 dn_6001 01000 0 [BACKEND] WARNING: could not create any HA TCP/IP sockets

2022-10-29 16:08:54.887 635cdf96.1 [unknown] 140627704972864 [unknown] 0 dn_6001 01000 0 [BACKEND] WARNING: Failed to initialize the memory protect for g_instance.attr.attr_storage.cstore_buffers (1024 Mbytes) or shared memory (1967 Mbytes) is larger.

Successfully started.

[omm@db1 db1]$ gsql -d miao -U dbmt -p 26000

Password for user dbmt:

gsql ((MogDB 2.1.1 build b5f25b20) compiled at 2022-03-21 14:42:30 commit 0 last mr )

Non-SSL connection (SSL connection is recommended when requiring high-security)

Type "help" for help.

miao=> select 8 from t1;

?column?

    8
    8
    8

(3 rows)

miao=> select * from t1;

id | tm | lsn

----+----------------------------+---------------

1 | 2022-10-29 14:22:52.273009 | Started

2 | 2022-10-29 14:26:10.55628 | First Insert

3 | 2022-10-29 14:31:13.220708 | Second Insert

(3 rows)

miao=>

9、 手动结束 PITR 状态

miao=> select pg_is_in_recovery();

pg_is_in_recovery

t

(1 row)

miao=> select pg_xlog_replay_resume();

pg_xlog_replay_resume

(1 row)

[omm@db1 db1]$ gsql -d miao -U dbmt -p 26000 -r

Password for user dbmt:

gsql ((MogDB 2.1.1 build b5f25b20) compiled at 2022-03-21 14:42:30 commit 0 last mr )

Non-SSL connection (SSL connection is recommended when requiring high-security)

Type "help" for help.

miao=> select pg_is_in_recovery();

pg_is_in_recovery

f

(1 row)

miao=>