Setting up everything at one time

While developping pgpool-II 3.3, I created a small script to make developer's life a little bit easier. However, the tool might be useful for PostgreSQL/pgpool-II beginners. So I decided to introduce it in my blog.

Disclaimer: the environment created by the tool below should never be used for production.

The script is called "pgpool_setup".  It creates followings by just one command under current directory. The directory must be empty. PostgreSQL and pgpool binaries must be installed and in your command search path beforehand.

• PostgreSQL clusters. You can choose "streaming replication mode" or "native replication mode". The former you already know, I assume. The latter is just a set of identical PostgreSQL clusters except the port numbers are different.
• If you choose streaming replication mode, one primary server and standby servers are ready after the command runs (even with WAL archival is enabled).
• By default those PostgreSQL cluster port number start from 11000 and continues 11001, 11002 and so on.
• The port numbers of pgpool and pcp follow.
• One pgpool server, with failover/online recovery/followmaster command are all set.
• A test database "test" is created.
• pcp commands(which are for pgpool administrator) account and password are ready for you.

By running pgpool_setup, you are ready to start pgpool and PostgreSQL with complete settings (at least for testing pupose) on your computer. I use this tool to create multiple groups  of pgpool+PostgreSQL set on my laptop.

So here's a sample session.

$ pgpool_setup
Satrting set up in streaming replication mode
creating startall and shutdownall
creating failover script
creating database cluster /home/t-ishii/work/git.postgresql.org/tmp2/data0...done.
update postgreql.conf
creating pgpool_remote_start
creating basebackup.sh
creating recovery.conf
creating database cluster /home/t-ishii/work/git.postgresql.org/tmp2/data1...done.
update postgreql.conf
creating pgpool_remote_start
creating basebackup.sh
creating recovery.conf
temporarily start data0 cluster to create extensions
temporarily start pgpool-II to create standby nodes
waiting for failover happens...done.
 node_id | hostname | port  | status | lb_weight |  role   
---------+----------+-------+--------+-----------+---------
 0       | /tmp     | 11000 | 2      | 0.500000  | primary
 1       | /tmp     | 11001 | 3      | 0.500000  | standby
(2 rows)

recovery node 1...done.
creating follow master script
Pager usage is off.
 node_id | hostname | port  | status | lb_weight |  role   
---------+----------+-------+--------+-----------+---------
 0       | /tmp     | 11000 | 2      | 0.500000  | primary
 1       | /tmp     | 11001 | 2      | 0.500000  | standby
(2 rows)

shutdown all

pgpool-II setting for streaming replication mode is done.
To start the whole system, use /home/t-ishii/work/git.postgresql.org/tmp2/startall.
To shutdown the whole system, use /home/t-ishii/work/git.postgresql.org/tmp2/shutdownall.
pcp command user name is "t-ishii", password is "t-ishii".
Each PostgreSQL, pgpool-II and pcp port is as follows:
#1 port is 11000
#2 port is 11001
pgpool port is 11002
pcp port is 11003
The info above is in README.port.
$ ls
README.port  bashrc.ports*  data1/  log/              run/          startall*
archivedir/  data0/         etc/    pgpool_setup.log  shutdownall

# So here you can see PostgreSQL cluster 0 as "data0" and cluster 1 as
# "data1".  You can start everything (pgpool and PostgreSQL) by using
# "startall", which is creaeted by the comand.

$ sh startall
waiting for server to start.... done
server started
waiting for server to start.... done
server started

# Make sure primary and standby are running.  "show pool_nodes" shows
# the info. Port 11002 is the port for pgpool.  As you can see
# primary's port is 11000 and standby's port is 11001.
# Status "2" means up and running.

$ psql -p 11002 -c 'show pool_nodes' test
 node_id | hostname | port  | status | lb_weight |  role   
---------+----------+-------+--------+-----------+---------
 0       | /tmp     | 11000 | 2      | 0.500000  | primary
 1       | /tmp     | 11001 | 2      | 0.500000  | standby
(2 rows)

# Now let's make sure that streaming replication is activated.

$ psql -p 11002 test
Pager usage is off.
psql (9.3beta1)
Type "help" for help.

test=# create table t1(i int);
CREATE TABLE
test=# insert into t1 values(1);
INSERT 0 1
test=# select * from t1;
 i 
---
 1
(1 row)

test=# \q

# Connect to standby.
$ psql -p 11001 test
Pager usage is off.
psql (9.3beta1)
Type "help" for help.

test=# select * from t1;
 i 
---
 1
(1 row)

test=# \q

# Ok, "t1" is propagated.

# Next test failover. So shutdown standby.

$ pg_ctl -D data1 -m f stop
waiting for server to shut down.... done
server stopped
$ psql -p 11002 -c 'show pool_nodes' test
 node_id | hostname | port  | status | lb_weight |  role   
---------+----------+-------+--------+-----------+---------
 0       | /tmp     | 11000 | 2      | 0.500000  | primary
 1       | /tmp     | 11001 | 3      | 0.500000  | standby
(2 rows)

# Note that status "3" means down.

# Let's stary standby and make it online.
$ pg_ctl -D data1 start
server starting
$ pcp_attach_node 1 localhost 11003 t-ishii t-ishii 1
$ psql -p 11002 -c 'show pool_nodes' test
 node_id | hostname | port  | status | lb_weight |  role   
---------+----------+-------+--------+-----------+---------
 0       | /tmp     | 11000 | 2      | 0.500000  | primary
 1       | /tmp     | 11001 | 2      | 0.500000  | standby
(2 rows)

# Next test is promotion. Let's stop primary and see if standby promotes.

$ pg_ctl -D data0 -m f stop
waiting for server to shut down.... done
server stopped

# Wait for while to let our failover script and follow master script do the job.

$ psql -p 11002 -c 'show pool_nodes' test
 node_id | hostname | port  | status | lb_weight |  role   
---------+----------+-------+--------+-----------+---------
 0       | /tmp     | 11000 | 2      | 0.500000  | standby
 1       | /tmp     | 11001 | 2      | 0.500000  | primary
(2 rows)

# Ok, now node 0 is standby, and 1 is primary. 

pgpool_setup is available in Pgpool-II 3.4 or later.