为什么PostgreSQL的服务在系统服务和pg_ctl之间是不同的？

Question

普通用户安装了PostgreSQL 10。

启用并启动其服务：

sudo systemctl start postgresql-10
sudo systemctl enable postgresql-10

然后使用postgres用户登录：

sudo su - postgres

将此设置添加到.bash_profile文件中：

export PATH=$PATH:/usr/pgsql-10/bin/

通过PostgreSQL重新启动pg_ctl：

-bash-4.2$ pg_ctl restart

然后退出到普通用户并再次检查postgresql的状态，它失败了。即使用这种方式重新启动也不能成功：

sudo systemctl restart postgresql-10
sudo systemctl stop postgresql-10

它总是failed。

但是如果我使用postgres用户来测试重新启动、停止、启动，它们都可以成功。

这两种方式并不能控制相同的过程？

添加PostgreSQL10服务内容

$ sudo systemctl cat postgresql-10.service

# /usr/lib/systemd/system/postgresql-10.service
# It's not recommended to modify this file in-place, because it will be
# overwritten during package upgrades.  If you want to customize, the
# best way is to create a file "/etc/systemd/system/postgresql-10.service",
# containing
#       .include /usr/lib/systemd/system/postgresql-10.service
#       ...make your changes here...
# For more info about custom unit files, see
# http://fedoraproject.org/wiki/Systemd#How_do_I_customize_a_unit_file.2F_add_a_custom_unit_file.3F

# Note: changing PGDATA will typically require adjusting SELinux
# configuration as well.

# Note: do not use a PGDATA pathname containing spaces, or you will
# break postgresql-setup.
[Unit]
Description=PostgreSQL 10 database server
Documentation=https://www.postgresql.org/docs/10/static/
After=syslog.target
After=network.target

[Service]
Type=notify

User=postgres
Group=postgres

# Note: avoid inserting whitespace in these Environment= lines, or you may
# break postgresql-setup.

# Location of database directory
Environment=PGDATA=/var/lib/pgsql/10/data/

# Where to send early-startup messages from the server (before the logging
# options of postgresql.conf take effect)
# This is normally controlled by the global default set by systemd
# StandardOutput=syslog

# Disable OOM kill on the postmaster
OOMScoreAdjust=-1000
Environment=PG_OOM_ADJUST_FILE=/proc/self/oom_score_adj
Environment=PG_OOM_ADJUST_VALUE=0

ExecStartPre=/usr/pgsql-10/bin/postgresql-10-check-db-dir ${PGDATA}
ExecStart=/usr/pgsql-10/bin/postmaster -D ${PGDATA}
ExecReload=/bin/kill -HUP $MAINPID
KillMode=mixed
KillSignal=SIGINT


# Do not set any timeout value, so that systemd will not kill postmaster
# during crash recovery.
TimeoutSec=0

[Install]
WantedBy=multi-user.target

Answer 1

如果您使用pg_ctl手动启动服务器，systemd就不知道了。

它将很高兴地尝试启动服务器，这将失败(因为服务器已经在运行)，并且它无法停止服务器，因为它不知道它正在运行。

因此，在启动和停止服务时始终使用systemctl。重新加载pg_ctl reload是很好的。