第二届openGauss每日一练活动开始了，前几天没跟上，周末时间来补上，开始深入学习openGauss，要坚持学习哦！

一、学习目标

学习从操作系统层面和使用openGauss工具查看数据库的状态、版本和数据文件目录。

1. 从操作系统层面查看数据库进程和线程,判断数据库是否启动。
2. 使用gs_ctl工具查看数据库状态,判断数据库是否启动。
3. 使用gs_ctl 查看数据文件的目录。
4. 从环境变量查看数据文件的目录。
5. 在gsql中查看数据文件目录、数据库版本

二、课程学习

gs_ctl是openGauss提供的数据库服务控制工具，可以用来启停数据库服务和查询数据库状态。主要供openGauss管理模块调用。

gs_ctl工具由操作系统用户omm执行。可以执行：
启动、停止、重启openGauss节点。

三、课程作业

1. 操作系统层面查看数据库进程和线程。如果数据库启动，则有相应的进程和线程。

查看实例中的进程
ps -ef|grep gauss
查看实例中的线程
ps -Tp 1

实训环境示例：

root@modb:~# su - omm
omm@modb:~$ ps -ef|grep gauss
omm          1     0  0 18:40 ?        00:00:05 gaussdb
omm        521   517  0 19:03 pts/0    00:00:00 grep gauss
omm@modb:~$ ps -Tp 1PID  SPID TTY          TIME CMD1     1 ?        00:00:00 gaussdb1   293 ?        00:00:00 jemalloc_bg_thd1   299 ?        00:00:00 gaussdb1   300 ?        00:00:00 syslogger1   301 ?        00:00:00 jemalloc_bg_thd1   302 ?        00:00:00 alarm1   303 ?        00:00:00 reaper1   304 ?        00:00:00 jemalloc_bg_thd1   305 ?        00:00:00 jemalloc_bg_thd1   349 ?        00:00:00 checkpointer1   350 ?        00:00:00 Spbgwriter1   351 ?        00:00:00 pagewriter1   352 ?        00:00:00 pagewriter1   353 ?        00:00:00 pagewriter1   354 ?        00:00:00 pagewriter1   355 ?        00:00:00 pagewriter1   356 ?        00:00:00 WALwriter1   357 ?        00:00:00 WALwriteraux1   358 ?        00:00:00 AVClauncher1   359 ?        00:00:00 Jobscheduler1   360 ?        00:00:00 asyncundolaunch1   361 ?        00:00:00 globalstats1   362 ?        00:00:00 applylauncher1   363 ?        00:00:00 statscollector1   365 ?        00:00:02 ashworker1   366 ?        00:00:00 TrackStmtWorker1   367 ?        00:00:00 auditor1   364 ?        00:00:00 percentworker1   368 ?        00:00:00 2pccleaner1   369 ?        00:00:00 faultmonitor1   370 ?        00:00:00 WLMworker1   371 ?        00:00:00 WLMmonitor1   373 ?        00:00:00 undorecycler1   372 ?        00:00:00 WLMarbiter
omm@modb:~$ 

2. 使用gs_ctl工具查看数据库状态，如果数据库启动，显示gs_ctl: server is running (PID: 1)

gs_ctl status

omm@modb:~$ gs_ctl status
[2022-11-27 19:06:28.525][536][][gs_ctl]: gs_ctl status,datadir is /var/lib/opengauss/data 
gs_ctl: server is running (PID: 1)
/usr/local/opengauss/bin/gaussdb
omm@modb:~$ 

3. 使用gs_ctl 查看数据文件的目录

gs_ctl notify

omm@modb:~$ gs_ctl notify
[2022-11-27 19:07:31.613][544][][gs_ctl]: gs_ctl notify ,datadir is /var/lib/opengauss/data 
[2022-11-27 19:07:31.614][544][][gs_ctl]: the parameter of notify must be specified
omm@modb:~$ 

4. 查看omm用户的环境变量:

cat ~/.bashrc

omm@modb:~$ cat ~/.bashrc
# ~/.bashrc: executed by bash(1) for non-login shells.
# see /usr/share/doc/bash/examples/startup-files (in the package bash-doc)
# for examples# If not running interactively, don't do anything
case $- in*i*) ;;*) return;;
esac# don't put duplicate lines or lines starting with space in the history.
# See bash(1) for more options
HISTCONTROL=ignoreboth# append to the history file, don't overwrite it
shopt -s histappend# for setting history length see HISTSIZE and HISTFILESIZE in bash(1)
HISTSIZE=1000
HISTFILESIZE=2000# check the window size after each command and, if necessary,
# update the values of LINES and COLUMNS.
shopt -s checkwinsize# If set, the pattern "**" used in a pathname expansion context will
# match all files and zero or more directories and subdirectories.
#shopt -s globstar# make less more friendly for non-text input files, see lesspipe(1)
#[ -x /usr/bin/lesspipe ] && eval "$(SHELL=/bin/sh lesspipe)"# set variable identifying the chroot you work in (used in the prompt below)
if [ -z "${debian_chroot:-}" ] && [ -r /etc/debian_chroot ]; thendebian_chroot=$(cat /etc/debian_chroot)
fi# set a fancy prompt (non-color, unless we know we "want" color)
case "$TERM" inxterm-color|*-256color) color_prompt=yes;;
esac# uncomment for a colored prompt, if the terminal has the capability; turned
# off by default to not distract the user: the focus in a terminal window
# should be on the output of commands, not on the prompt
#force_color_prompt=yesif [ -n "$force_color_prompt" ]; thenif [ -x /usr/bin/tput ] && tput setaf 1 >&/dev/null; then# We have color support; assume it's compliant wit#alias egrep='egrep --color=auto'
fi# colored GCC warnings and errors
#export GCC_COLORS='error=01;31:warning=01;35:note=01;36:caret=01;32:locus=01:quote=01'# some more ls aliases
#alias ll='ls -l'
#alias la='ls -A'
#alias l='ls -CF'# Alias definitions.
# You may want to put all your additions into a separate file like
# ~/.bash_aliases, instead of adding them here directly.
# See /usr/share/doc/bash-doc/examples in the bash-doc package.if [ -f ~/.bash_aliases ]; then. ~/.bash_aliases
fi. /etc/bash_completionfi
fi
export GAUSSHOME=/usr/local/opengauss
export PATH=$GAUSSHOME/bin:$PATH 
export LD_LIBRARY_PATH=$GAUSSHOME/lib:$LD_LIBRARY_PATH
export PGDATA=/var/lib/opengauss/data
h Ecma-48# (ISO/IEC-6429). (Lack of such support is extremely rare, and such# a case would tend to support setf rather than setaf.)color_prompt=yeselsecolor_prompt=fi
fiif [ "$color_prompt" = yes ]; thenPS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
elsePS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '
fi
unset color_prompt force_color_prompt# If this is an xterm set the title to user@host:dir
case "$TERM" in
xterm*|rxvt*)PS1="\[\e]0;${debian_chroot:+($debian_chroot)}\u@\h: \w\a\]$PS1";;
*);;
esac# enable color support of ls and also add handy aliases
if [ -x /usr/bin/dircolors ]; thentest -r ~/.dircolors && eval "$(dircolors -b ~/.dircolors)" || eval "$(dircolors -b)"alias ls='ls --color=auto'#alias dir='dir --color=auto'#alias vdir='vdir --color=auto'#alias grep='grep --color=auto'#alias fgrep='fgrep --color=auto'# enable programmable completion features (you don't need to enable
# this, if it's already enabled in /etc/bash.bashrc and /etc/profile
# sources /etc/bash.bashrc).
if ! shopt -oq posix; thenif [ -f /usr/share/bash-completion/bash_completion ]; then. /usr/share/bash-completion/bash_completionelif [ -f /etc/bash_completion ]; then
omm@modb:~$ 

5. 从环境变量查看数据文件的目录

grep -i PGDATA ~/.bashrc

omm@modb:~$ grep -i PGDATA ~/.bashrc
export PGDATA=/var/lib/opengauss/data

6. 在gsql中查看数据文件的目录、数据库版本

su - omm
gsql -r
show data_directory ;
select version();

root@modb:~# su - omm
omm@modb:~$ gsql -r
gsql ((openGauss 3.0.0 build 02c14696) compiled at 2022-04-01 18:12:00 commit 0 last mr  )
Non-SSL connection (SSL connection is recommended when requiring high-security)
Type "help" for help.omm=# show data_directory;data_directory      
-------------------------/var/lib/opengauss/data
(1 row)omm=# select version();
-----------------------------------------------------------------------------------------------
--------------------------------------------------------(openGauss 3.0.0 build 02c14696) compiled at 2022-04-01 18:12:00 commit 0 last mr   on aarch64
-unknown-linux-gnu, compiled by g++ (GCC) 7.3.0, 64-bit
(1 row)version                omm=#