#多实例的停止数据服务（升级前需要停止数据库服务）
Darren2:postgres:/usr/local/pgsql:>/usr/local/pgsql/pgsql9.5.9/bin/pg_ctl stop -m fast -D /usr/local/pgsql/pgsql9.5.9/data
Darren2:postgres:/usr/local/pgsql:>/usr/local/pgsql/pgsql9.6.5/bin/pg_ctl stop -m fast -D /usr/local/pgsql/pgsql9.6.5/data
pg_upgrade参数解析
-b, --old-bindir=BINDIR old cluster executable directory
-B, --new-bindir=BINDIR new cluster executable directory
-d, --old-datadir=DATADIR old cluster data directory
-D, --new-datadir=DATADIR new cluster data directory
-p, --old-port=PORT old cluster port number (default 50432)
-P, --new-port=PORT new cluster port number (default 50432)
-c, --check check clusters only, don't change any data
-j, --jobs number of simultaneous processes or threads to use
-k, --link link instead of copying files to new cluster
-r, --retain retain SQL and log files after success
-U, --username=NAME cluster superuser (default "postgres")
-v, --verbose enable verbose internal logging
pg_upgrade有两种升级方式，一个是缺省的通过拷贝数据文件到新的data目录下，一个是创建硬链接。拷贝的方式升级较慢，但是原库还可用；硬链接的方式升级较快，但是原库不可用。
使用9.6.5的pg_upgrade检测兼容性
Darren2:postgres:/usr/local/pgsql:>/usr/local/pgsql/pgsql9.6.5/bin/pg_upgrade -b /usr/local/pgsql/pgsql9.5.9/bin -B /usr/local/pgsql/pgsql9.6.5/bin -d /usr/local/pgsql/pgsql9.5.9/data -D /usr/local/pgsql/pgsql9.6.5/data -p 5432 -P 5431 -U postgres -j 8 -k -c
Performing Consistency Checks
-----------------------------
Checking cluster versions ok
Checking database user is the install user ok
Checking database connection settings ok
Checking for prepared transactions ok
Checking for reg* system OID user data types ok
Checking for contrib/isn with bigint-passing mismatch ok
Checking for roles starting with 'pg_' ok
Checking for presence of required libraries ok
Checking database user is the install user ok
Checking for prepared transactions ok
正式升级
Darren2:postgres:/usr/local/pgsql:>/usr/local/pgsql/pgsql9.6.5/bin/pg_upgrade -b /usr/local/pgsql/pgsql9.5.9/bin -B /usr/local/pgsql/pgsql9.6.5/bin -d /usr/local/pgsql/pgsql9.5.9/data -D /usr/local/pgsql/pgsql9.6.5/data -p 5432 -P 5431 -U postgres -j 8 -k -r -v
......
Upgrade Complete
----------------
Optimizer statistics are not transferred by pg_upgrade so,
once you start the new server, consider running:
./analyze_new_cluster.sh
Running this script will delete the old cluster's data files:
./delete_old_cluster.sh
#生成2个脚本, 用于收集统计信息和删除老集群，和一些有关升级过程的日志信息
Darren2:postgres:/usr/local/pgsql:>ls -ltr
-rw-r--r--. 1 postgres dba 2215 Oct 18 01:37 pg_upgrade_dump_globals.sql
-rw-------. 1 postgres dba 2237 Oct 18 01:37 pg_upgrade_dump_13241.custom
-rw-------. 1 postgres dba 2228 Oct 18 01:37 pg_upgrade_dump_1.custom
-rw-------. 1 postgres dba 3733 Oct 18 01:37 pg_upgrade_dump_16386.custom
-rw-------. 1 postgres dba 2422 Oct 18 01:37 pg_upgrade_dump_13241.log
-rw-------. 1 postgres dba 2409 Oct 18 01:37 pg_upgrade_dump_1.log
-rw-------. 1 postgres dba 2686 Oct 18 01:37 pg_upgrade_dump_16386.log
-rw-------. 1 postgres dba 240810 Oct 18 01:37 pg_upgrade_utility.log
-rwx------. 1 postgres dba 112 Oct 18 01:37 delete_old_cluster.sh
-rwx------. 1 postgres dba 809 Oct 18 01:37 analyze_new_cluster.sh
-rw-------. 1 postgres dba 2956 Oct 18 01:37 pg_upgrade_server.log
-rw-------. 1 postgres dba 42227 Oct 18 01:37 pg_upgrade_internal.log
#启动新的数据库集群
Darren2:postgres:/usr/local/pgsql:>/usr/local/pgsql/pgsql9.6.5/bin/pg_ctl start -D /usr/local/pgsql/pgsql9.6.5/data