摘要：但如果涉及到跨大版本升級比如升級到，這種直接替換軟件就不行了，因為跨版本的內部存儲形式發生了變化官方對于升級提供了種方法，這里遷移我使用了來進行處理細節可以參考官方文檔。

最近使用 postgresql 命令行比較多，就找了個類似 mycli 工具，pgcli，這個是針對 postgresql 的，興沖沖的安裝了

brew install pgcli

沒想到這貨自動幫我升級了 postgresql，我原來使用的是 9.5.7, 自動幫我升級到了 9.6.3

查看升級日志 pg_upgrade_server.log

pg_ctl: another server might be running; trying to start server anyway
waiting for server to start....FATAL:  database files are incompatible with server
DETAIL:  The data directory was initialized by PostgreSQL version 9.5, which is not compatible with this version 9.6.3.
 stopped waiting
pg_ctl: could not start server
Examine the log output.

這是需要遷移數據的節奏啊，遷移之前需要的明白點什么

postgresql 中的升級，如果針對小版本的升級，比如 9.6.1 升級到 9.6.3(當前的最新版本)，只需要用 9.6.3 版本的軟件替換 9.6.1 版本的軟件即可，不需要做額外的操作，因為整個大版本是相互兼容的，內部存儲形式也是兼容的。但如果涉及到跨大版本升級比如 9.5.7 升級到 9.6.3，這種直接替換軟件就不行了，因為跨版本的內部存儲形式發生了變化

官方對于升級提供了 3 種方法，這里遷移我使用了 pg_upgrade 來進行處理, 細節可以參考官方文檔。

再進行下一步之前，把 postgresql 服務關掉，執行如下命令

brew services stop postgresql

mv /usr/local/var/postgresql /usr/local/var/postgresql.old

initdb /usr/local/var/postgres -E utf8 --locale=zh_CN.UTF-8

運行結果

The files belonging to this database system will be owned by user "allen".
This user must also own the server process.

The database cluster will be initialized with locale "zh_CN.UTF-8".
initdb: could not find suitable text search configuration for locale "zh_CN.UTF-8"
The default text search configuration will be set to "simple".

Data page checksums are disabled.

creating directory /usr/local/var/postgres ... ok
creating subdirectories ... ok
selecting default max_connections ... 100
selecting default shared_buffers ... 128MB
selecting dynamic shared memory implementation ... posix
creating configuration files ... ok
running bootstrap script ... ok
performing post-bootstrap initialization ... ok
syncing data to disk ... ok

WARNING: enabling "trust" authentication for local connections
You can change this by editing pg_hba.conf or using the option -A, or
--auth-local and --auth-host, the next time you run initdb.

Success. You can now start the database server using:

    pg_ctl -D /usr/local/var/postgres -l logfile start

pg_upgrade 語法簡單如下：

pg_upgrade -b 舊版本的bin目錄 -B 新版本的bin目錄 -d 舊版本的數據目錄 -D 新版本的數據目錄 [其他選項...]

然后運行遷移命令

pg_upgrade -b /usr/local/Cellar/postgresql@9.5/9.5.7/bin -B /usr/local/bin  -d /usr/local/var/postgres.old -D /usr/local/var/postgres  

運行結果

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
Creating dump of global objects                             ok
Creating dump of database schemas
                                                            ok
Checking for presence of required libraries                 ok
Checking database user is the install user                  ok
Checking for prepared transactions                          ok

If pg_upgrade fails after this point, you must re-initdb the
new cluster before continuing.

Performing Upgrade
------------------
Analyzing all rows in the new cluster                       ok
Freezing all rows on the new cluster                        ok
Deleting files from new pg_clog                             ok
Copying old pg_clog to new server                           ok
Setting next transaction ID and epoch for new cluster       ok
Deleting files from new pg_multixact/offsets                ok
Copying old pg_multixact/offsets to new server              ok
Deleting files from new pg_multixact/members                ok
Copying old pg_multixact/members to new server              ok
Setting next multixact ID and offset for new cluster        ok
Resetting WAL archives                                      ok
Setting frozenxid and minmxid counters in new cluster       ok
Restoring global objects in the new cluster                 ok
Restoring database schemas in the new cluster
                                                            ok
Copying user relation files
                                                            ok
Setting next OID for new cluster                            ok
Sync data directory to disk                                 ok
Creating script to analyze new cluster                      ok
Creating script to delete old cluster                       ok

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

最后提示生成兩個腳本，一個是 analyze_new_cluster.sh，需要在新版本中執行，用來收集統計信息，另一個是 delete_old_cluster.sh，用來刪除舊版本集群數據，當然為了安全起見可以等系統運行幾天沒問題再來刪除。

運行下 analyze_new_cluster.sh 腳本

./analyze_new_cluster.sh

運行結果如下：

This script will generate minimal optimizer statistics rapidly
so your system is usable, and then gather statistics twice more
with increasing accuracy.  When it is done, your system will
have the default level of optimizer statistics.

If you have used ALTER TABLE to modify the statistics target for
any tables, you might want to remove them and restore them after
running this script because they will delay fast statistics generation.

If you would like default statistics as quickly as possible, cancel
this script and run:
    "/usr/local/bin/vacuumdb" --all --analyze-only

vacuumdb: processing database "activity_tool": Generating minimal optimizer statistics (1 target)
vacuumdb: processing database "allen": Generating minimal optimizer statistics (1 target)
vacuumdb: processing database "cw": Generating minimal optimizer statistics (1 target)
vacuumdb: processing database "djexample": Generating minimal optimizer statistics (1 target)
vacuumdb: processing database "finance": Generating minimal optimizer statistics (1 target)
vacuumdb: processing database "iop": Generating minimal optimizer statistics (1 target)
vacuumdb: processing database "learn": Generating minimal optimizer statistics (1 target)
vacuumdb: processing database "postgres": Generating minimal optimizer statistics (1 target)
vacuumdb: processing database "servicemall": Generating minimal optimizer statistics (1 target)
vacuumdb: processing database "store": Generating minimal optimizer statistics (1 target)
vacuumdb: processing database "template1": Generating minimal optimizer statistics (1 target)
vacuumdb: processing database "test_store": Generating minimal optimizer statistics (1 target)
vacuumdb: processing database "uio": Generating minimal optimizer statistics (1 target)
vacuumdb: processing database "vbdev": Generating minimal optimizer statistics (1 target)
vacuumdb: processing database "vbdevelop": Generating minimal optimizer statistics (1 target)
vacuumdb: processing database "xiuzan": Generating minimal optimizer statistics (1 target)
vacuumdb: processing database "xzdevelop": Generating minimal optimizer statistics (1 target)
vacuumdb: processing database "activity_tool": Generating medium optimizer statistics (10 targets)
vacuumdb: processing database "allen": Generating medium optimizer statistics (10 targets)
vacuumdb: processing database "cw": Generating medium optimizer statistics (10 targets)
vacuumdb: processing database "djexample": Generating medium optimizer statistics (10 targets)
vacuumdb: processing database "finance": Generating medium optimizer statistics (10 targets)
vacuumdb: processing database "iop": Generating medium optimizer statistics (10 targets)
vacuumdb: processing database "learn": Generating medium optimizer statistics (10 targets)
vacuumdb: processing database "postgres": Generating medium optimizer statistics (10 targets)
vacuumdb: processing database "servicemall": Generating medium optimizer statistics (10 targets)
vacuumdb: processing database "store": Generating medium optimizer statistics (10 targets)
vacuumdb: processing database "template1": Generating medium optimizer statistics (10 targets)
vacuumdb: processing database "test_store": Generating medium optimizer statistics (10 targets)
vacuumdb: processing database "uio": Generating medium optimizer statistics (10 targets)
vacuumdb: processing database "vbdev": Generating medium optimizer statistics (10 targets)
vacuumdb: processing database "vbdevelop": Generating medium optimizer statistics (10 targets)
vacuumdb: processing database "xiuzan": Generating medium optimizer statistics (10 targets)
vacuumdb: processing database "xzdevelop": Generating medium optimizer statistics (10 targets)
vacuumdb: processing database "activity_tool": Generating default (full) optimizer statistics
vacuumdb: processing database "allen": Generating default (full) optimizer statistics
vacuumdb: processing database "cw": Generating default (full) optimizer statistics
vacuumdb: processing database "djexample": Generating default (full) optimizer statistics
vacuumdb: processing database "finance": Generating default (full) optimizer statistics
vacuumdb: processing database "iop": Generating default (full) optimizer statistics
vacuumdb: processing database "learn": Generating default (full) optimizer statistics
vacuumdb: processing database "postgres": Generating default (full) optimizer statistics
vacuumdb: processing database "servicemall": Generating default (full) optimizer statistics
vacuumdb: processing database "store": Generating default (full) optimizer statistics
vacuumdb: processing database "template1": Generating default (full) optimizer statistics
vacuumdb: processing database "test_store": Generating default (full) optimizer statistics
vacuumdb: processing database "uio": Generating default (full) optimizer statistics
vacuumdb: processing database "vbdev": Generating default (full) optimizer statistics
vacuumdb: processing database "vbdevelop": Generating default (full) optimizer statistics
vacuumdb: processing database "xiuzan": Generating default (full) optimizer statistics
vacuumdb: processing database "xzdevelop": Generating default (full) optimizer statistics

Done

brew services start postgresql

查看下服務狀態

brew services list

運行結果

Name           Status  User  Plist
postgresql     started allen /Users/allen/Library/LaunchAgents/homebrew.mxcl.postgresql.plist

接著就可以愉快的使用 pgcli 了。

參考借鑒文章和文檔

https://www.postgresql.org/do...

https://stackoverflow.com/que...

http://www.cnblogs.com/space-...

http://www.cnblogs.com/shineq...

http://www.linuxidc.com/Linux...