Postgresql - 恢复数据库到指定时间 Point-in-Time Recovery (PITR)
在有些时候需要用备份数据恢复到任意的时间点，该如何操作。
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CentOS 7 + pg 10.4
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1. 初始化数据库参数
# 创建archive目录，并授权到postgres用户
mkdir /data/archive/
chown -R postgres:postgres /data/archive/
# 修改数据库配置文件
vim /usr/local/pgsql/data/postgresql.conf
archive_mode = onarchive_timeout = 300 # 单位是秒，此处以5分钟为限强制归档，仅作测试archive_command = 'cp -i %p /data/archive/%f' # 会将pg_wal中的日志cp过去。wal_level = archive
# 初始化数据
# 创建表所用序列
create sequence seq_test01_id;
# 创建表
create table test01(
id int not null default nextval('seq_test01_id'::regclass) primary key,
col1 varchar(128),
ctime time);
2. 做基础备份
# 开启热备
psql -U postgres -d postgres -c "select pg_start_backup('label');"
# 备份data目录
cd /usr/local/pgsql/data
tar -cvf /data/backup/data.tar *
# 关闭热备
psql -U postgres -d mytest -c "select pg_stop_backup();"
# 切日志
psql -U postgres -d mytest -c "select pg_switch_wal();"
3.
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# 为表插入数据
create or replace function insert_test01() returns void
AS $$
begin
for i in 1..10 loop
PERFORM pg_sleep(2);
insert into test01(col1,ctime) values('aaa', now());
end loop;
end;
$$ LANGUAGE plpgsql;
select insert_test01();
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# 为表插入数据
insert into test01(col1,ctime) values('aaa', now());
select pg_sleep(2);
insert into test01(col1,ctime) values('aaa', now());
select pg_sleep(2);
insert into test01(col1,ctime) values('aaa', now());
select pg_sleep(2);
insert into test01(col1,ctime) values('aaa', now());
select pg_sleep(2);
insert into test01(col1,ctime) values('aaa', now());
select pg_sleep(2);
insert into test01(col1,ctime) values('aaa', now());
select pg_sleep(2);
insert into test01(col1,ctime) values('aaa', now());
select pg_sleep(2);
insert into test01(col1,ctime) values('aaa', now());
mytest=# select * from test01 ;
id | col1 | ctime
----+------+-----------------
1 | aaa | 05:52:03.675805
2 | aaa | 05:52:05.687527
3 | aaa | 05:52:07.695315
4 | aaa | 05:52:09.702641
5 | aaa | 05:52:11.711283
6 | aaa | 05:52:13.718943
7 | aaa | 05:52:15.726526
8 | aaa | 05:52:19.710031
(8 rows)
# 损坏数据
select now();
2018-06-19 06:03:29.391014-04
delete from test01 ;
4. 恢复
# 停服务
service postgresql stop
# 把之前的备份文件恢复到data目录
cd /usr/local/pgsql/data
rm -rf *
tar xvf data.tar
# 配置xlog文件
rm -rf pg_xlog
mkdir -p pg_xlog/archive_status
chown -R postgres:postgres pg_xlog
# 修改recovery.conf配置，恢复数据库到指定时间点
vim recovery.conf
restore_command = 'cp /data/archive/%f "%p"' # archive 目录
archive_cleanup_command='pg_archivecleanup /data/archive %r'
recovery_target_time='2018-06-19 06:03:05'
# 启动数据库服务
service postgresql start
5. 查看恢复数据
psql -U mytest -d mytest
mytest=# select * from test01 ;
id | col1 | ctime
----+------+-----------------
1 | aaa | 06:02:53.992508
2 | aaa | 06:02:56.111994
3 | aaa | 06:02:58.11978
4 | aaa | 06:03:00.127555
5 | aaa | 06:03:02.134798
6 | aaa | 06:03:04.142521