我们知道pg_upgrade和pg_dump/pg_restore可以实现大版本升级数据库，那么小版本如何升级，比如从9.6.3到9.6.5？

原理：用新版本的软件程序启动，指定老的的数据目录

安装pgsql9.6.3

mkdir -p /usr/local/pgsql/pgsql9.6.3/{data,arch}

groupadd dba

useradd -g dba -G root postgres -d /usr/local/pgsql

tar xf postgresql-9.6.3.tar.gz

chmod -R 755 /usr/local/pgsql

chown -R postgres:dba /usr/local/pgsql

chmod -R 700 /usr/local/pgsql/pgsql9.6.3/data/

./configure --prefix=/usr/local/pgsql/pgsql9.6.3/

make world && make install-world

cd /usr/local/pgsql/pgsql9.6.3/bin

./initdb -D /usr/local/pgsql/pgsql9.6.3/data  -U postgres -E UTF8  -W

vim pg_hba.conf

host all all 0.0.0.0/0 md5

vim postgresql.conf

listen_addresses = '*'

wal_level = replica

port = 5432

max_connections = 300

shared_buffers = 128MB

logging_collector = on

log_directory = 'pg_log'

log_filename = 'postgresql-%Y-%m-%d_%H%M%S.log'

archive_mode = on

archive_command = 'test ! -f /usr/local/pgsql/pgsql9.6.5/arch/%f  &&  cp %p /usr/local/pgsql/pgsql9.6.5/arch/%f'

/usr/local/pgsql/pgsql9.6.3/bin/pg_ctl start -D /usr/local/pgsql/pgsql9.6.3/data

#生成测试数据

create database testdb1;

\c testdb1;

create table t1(id int primary key, info text);

insert into t1 select generate_series(1,1000000),'helloWorld';

安装pgsql9.6.5

mkdir -p /usr/local/pgsql/pgsql9.6.5/{data,arch}

groupadd dba

useradd -g dba -G root postgres -d /usr/local/pgsql

tar xf postgresql-9.6.5.tar.gz

chmod -R 755 /usr/local/pgsql

chown -R postgres:dba /usr/local/pgsql

chmod -R 700 /usr/local/pgsql/pgsql9.6.5/data/

./configure --prefix=/usr/local/pgsql/pgsql9.6.5/

make world && make install-world

cd /usr/local/pgsql/pgsql9.6.5/bin

/usr/local/pgsql/pgsql9.6.5/bin/initdb -D /usr/local/pgsql/pgsql9.6.5/data  -U postgres -E UTF8  -W

vim pg_hba.conf

host all all 0.0.0.0/0 md5

vim postgresql.conf

listen_addresses = '*'

wal_level = replica

port = 5431

max_connections = 300

shared_buffers = 128MB

logging_collector = on

log_directory = 'pg_log'

log_filename = 'postgresql-%Y-%m-%d_%H%M%S.log'

archive_mode = on

archive_command = 'test ! -f /usr/local/pgsql/pgsql9.6.5/arch/%f  &&  cp %p /usr/local/pgsql/pgsql9.6.5/arch/%f'

/usr/local/pgsql/pgsql9.6.5/bin/pg_ctl start -D /usr/local/pgsql/pgsql9.6.5/data

/usr/local/pgsql/pgsql9.6.5/bin/pg_ctl stop -m fast -D /usr/local/pgsql/pgsql9.6.5/data

#停止老的数据库9.6.3

/usr/local/pgsql/pgsql9.6.3/bin/pg_ctl stop -m fast -D /usr/local/pgsql/pgsql9.6.3/data

#用9.6.5的软件程序启动，指定9.6.3的数据目录

/usr/local/pgsql/pgsql9.6.5/bin/pg_ctl start -D /usr/local/pgsql/pgsql9.6.3/data

postgres=# select version();

                                                 version                                                 

---------------------------------------------------------------------------------------------------------

PostgreSQL 9.6.5 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-4), 64-bit

testdb1=# select count(*) from t1;

  count  

---------

1000000