PostgreSQL database backup master node down the test data recovery

Data master node goes down, the standby database data recovery

background

In the node out of service, and then continue to write data to the main library, then put away the host is down, start from the library, copy the log during an incremental wal down to the main library from the archive catalog, execute recovery script, it will put additional incremental data down to the host database.

• surroundings

server	Character
10.10.56.16	master
10.10.56.18	slave

- 16 master's configuration pg_hba,conffile

host    all             all             10.10.56.0/0            md5
host    replication     all             10.10.56.0/0            trust
"pg_hba.conf" 96L, 4652C                                                  

• 16 master's configuration postgresql.conf

listen_addresses = '*'
max_connections = 1000 
wal_level = logical 
archive_mode = on  
archive_command = '/bin/true' 
log_destination = 'csvlog'
logging_collector = on 
log_filename = 'postgresql-%Y-%m-%d.log' 
log_rotation_size = 20MB 
log_statement = 'mod'
log_replication_commands = on
deadlock_timeout = 100ms 

• Configuration 18 slave, initialize the database from the master pg_basebackup

 /opt/pgsql-10/bin/pg_basebackup -h 10.10.56.16 -U repl -W -Fp -Pv -Xs -R -D /pgdata/10/poc/data/

• 18 configuration recovery.conf, restore data from the archive directory

#standby_mode = 'on'
#primary_conninfo = 'user=repl password=123456 host=10.10.56.16 port=5432 sslmode=disable sslcompression=1 target_session_attrs=any'
restore_command = 'cp /pgdata/10/archive/%f %p'

Above to achieve the main stream from the asynchronous replication

Started 16 inquiries, the main library for the f

pocdb=# select pg_is_in_recovery();
 pg_is_in_recovery
-------------------
 f
(1 row)

Time: 0.786 ms
pocdb=#

• Create a user repl in 16, create a table, slightly

• When the main reservoir 16 is normally, p is the data table

pocdb=# select max(id) from p;
   max
---------
 3774121
(1 row)

• Data from the database table 18 p

pocdb=# select max(id) from p;
   max
---------
 3774121
(1 row)

• Main library down the front (16)

pocdb=# select max(id) from p;
   max
---------
 4005263
(1 row)

Primary library (16) back down, after recovery from the library, data has been added:

postgres@clw-db3:/pgdata/10/poc/data> /opt/pgsql-10/bin/psql pocdb
psql (10.3)
Type "help" for help.

pocdb=# select max(id) from p;
   max
---------
 4005263
(1 row)