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本篇内容主要讲解“PostgreSQL 12 在日志记录上的改进是什么”，感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷，实用性强。下面就让丸趣 TV 小编来带大家学习“PostgreSQL 12 在日志记录上的改进是什么”吧!
对于每一个客户端连接，PG 都会请求 Postmaster，然后 fork 一个后台进程来处理请求，Postmaster 期望每一个客户端请求发送 startup message 给 PG Server，startup packet 中的信息用于配置 fork 的后台进程。对于 端口扫描、HA 解决方案中的心跳检测等等都会发请求给 PG Server port，PG 会启动进程来处理这些连接，但安全检测、HA 脚本等不同于常规的客户端，对于这些请求，PG 会产生一条日志条目，因此会造成日志文件的膨胀而导致不必要的 IO 开销。
PG 11
使用工具 nc 来访问数据库端口，日志中会产生无用的日志条目。
[xdb@localhost ~]$ psql -c select version();
Timing is on.
Expanded display is used automatically.
version
---------------------------------------------------------------------------------------------------------
PostgreSQL 11.2 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-16), 64-bit
(1 row)
Time: 56.253 ms
[xdb@localhost ~]$
[xdb@localhost ~]$ for i in {1..100}; do nc -zv localhost 5110 ; done
Ncat: 0 bytes sent, 0 bytes received in 0.01 seconds.
Ncat: Version 7.50 ( https://nmap.org/ncat )
Ncat: Connected to ::1:5110.
Ncat: 0 bytes sent, 0 bytes received in 0.01 seconds.
Ncat: Version 7.50 ( https://nmap.org/ncat )
Ncat: Connected to ::1:5110.
Ncat: 0 bytes sent, 0 bytes received in 0.01 seconds.
Ncat: Version 7.50 ( https://nmap.org/ncat )
Ncat: Connected to ::1:5110.
Ncat: 0 bytes sent, 0 bytes received in 0.01 seconds.
Ncat: Version 7.50 ( https://nmap.org/ncat )
Ncat: Connected to ::1:5110.
Ncat: 0 bytes sent, 0 bytes received in 0.01 seconds.
...数据库日志输出
2019-12-09 14:35:55.468 CST,,,16065, ::1:57554 ,5dedeb4b.3ec1,1, ,2019-12-09 14:35:55 CST,,0,LOG,08P01, incomplete startup packet ,,,,,,,,,
2019-12-09 14:35:55.479 CST,,,16067, ::1:57556 ,5dedeb4b.3ec3,1, ,2019-12-09 14:35:55 CST,,0,LOG,08P01, incomplete startup packet ,,,,,,,,,
2019-12-09 14:35:55.490 CST,,,16069, ::1:57558 ,5dedeb4b.3ec5,1, ,2019-12-09 14:35:55 CST,,0,LOG,08P01, incomplete startup packet ,,,,,,,,,
2019-12-09 14:35:55.503 CST,,,16071, ::1:57560 ,5dedeb4b.3ec7,1, ,2019-12-09 14:35:55 CST,,0,LOG,08P01, incomplete startup packet ,,,,,,,,,
2019-12-09 14:35:55.513 CST,,,16073, ::1:57562 ,5dedeb4b.3ec9,1, ,2019-12-09 14:35:55 CST,,0,LOG,08P01, incomplete startup packet ,,,,,,,,,
...这些日志其实是无用的日志信息，可以不作记录。
PG 12
[xdb@localhost ~]$ psql -h localhost -p 5120 -U pg12 -c select version();
Timing is on.
Expanded display is used automatically.
version
---------------------------------------------------------------------------------------------------------
PostgreSQL 12.1 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-16), 64-bit
(1 row)
Time: 60.207 ms
[xdb@localhost ~]$
[xdb@localhost ~]$ for i in {1..100}; do nc -zv localhost 5120 ; done
Ncat: 0 bytes sent, 0 bytes received in 0.01 seconds.
Ncat: Version 7.50 ( https://nmap.org/ncat )
Ncat: Connected to ::1:5120.
Ncat: 0 bytes sent, 0 bytes received in 0.01 seconds.
Ncat: Version 7.50 ( https://nmap.org/ncat )
Ncat: Connected to ::1:5120.
Ncat: 0 bytes sent, 0 bytes received in 0.01 seconds.
Ncat: Version 7.50 ( https://nmap.org/ncat )
Ncat: Connected to ::1:5120.
Ncat: 0 bytes sent, 0 bytes received in 0.01 seconds.
Ncat: Version 7.50 ( https://nmap.org/ncat )
Ncat: Connected to ::1:5120.
Ncat: 0 bytes sent, 0 bytes received in 0.01 seconds.
Ncat: Version 7.50 ( https://nmap.org/ncat )
Ncat: Connected to ::1:5120.
Ncat: 0 bytes sent, 0 bytes received in 0.01 seconds.
[xdb@localhost ~]$
...数据库日志信息，相对于 PG 11，没有出现无用的日志信息
[pg12@localhost ~]$ tail -f $PGDATA/pg_log/postgresql-2019-12-09.log
2019-12-09 14:18:59.317 CST [1813] LOG: ending log output to stderr
2019-12-09 14:18:59.317 CST [1813] HINT: Future log output will go to log destination csvlog .到此，相信大家对“PostgreSQL 12 在日志记录上的改进是什么”有了更深的了解，不妨来实际操作一番吧！这里是丸趣 TV 网站，更多相关内容可以进入相关频道进行查询，关注我们，继续学习！
正文完
发表至： 数据库
2023-07-26
