数据库服务是否运行及运行状态的检查方法

Posted 2021-08-15 瀚高PG实验室

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本文主要介绍检查数据库单机, 流复制, repmgr集群服务是否运行及检查运行状态的方法。

注意事项：

该文档涉及到recovery.conf或done文件只是针对安全版V4.3.X或企业版V5版本，之后的安全版V4.5.X或企业版V6版本不再有recovery.conf或done文件

详细信息
一、单机版数据库的运行状态查看
1、通过数据库自带的操作系统命令 pg_ctl 查看数据库运行状态

数据库正常运行显示如下:

[highgo@localhost ~]$ pg_ctl status

pg_ctl: server is running (PID: 7482)

/opt/HighGoDB-5.6.4/bin/postgres “-D” “/opt/HighGoDB-5.6.4/data”

数据库关闭状态显示如下:

[highgo@localhost ~]$ pg_ctl status

pg_ctl: no server running

2、通过数据库自带的操作系统命令 pg_controldata 查看数据库运行状态

数据库正常运行显示如下:

[highgo@localhost ~]$ pg_controldata

…

Database cluster state: in production

…

数据库关闭状态显示如下:

[highgo@localhost ~]$ pg_controldata

…

Database cluster state: shut down

…

3、通过后台进程看数据库运行状态

正常运行的数据库会存在如下进程

[highgo@localhost ~]$ ps -ef | grep -v grep | grep postgres

highgo 8002 1 0 10:41 pts/0 00:00:00 /opt/HighGoDB-5.6.4/bin/postgres

highgo 8007 8002 0 10:41 ? 00:00:00 postgres: logger process

highgo 8009 8002 0 10:41 ? 00:00:00 postgres: checkpointer process

highgo 8010 8002 0 10:41 ? 00:00:00 postgres: writer process

highgo 8011 8002 0 10:41 ? 00:00:00 postgres: wal writer process

highgo 8012 8002 0 10:41 ? 00:00:00 postgres: autovacuum launcher process

highgo 8013 8002 0 10:41 ? 00:00:00 postgres: archiver process

highgo 8014 8002 0 10:41 ? 00:00:00 postgres: stats collector process

highgo 8015 8002 0 10:41 ? 00:00:00 postgres: bgworker: pg_wait_sampling collector

highgo 8017 8002 0 10:41 ? 00:00:00 postgres: bgworker: performance diagnosis collector

highgo 8018 8002 0 10:41 ? 00:00:00 postgres: bgworker: hg_job_scheduler

highgo 8019 8002 0 10:41 ? 00:00:00 postgres: bgworker: logical replication launcher

ps：(1)显示内容第一列代表数据库在哪个用户底下运行，上方显示数据库运行在highgo用户底下。

(2)显示内容第一行代表数据库运行的主进程。

4、通过文件系统查看数据库是否处于运行状态

数据库处于运行状态时会存在下列文件:

[highgo@localhost data]$ ls -lrth | grep postmaster.pid

-rw------- 1 highgo highgo 82 Jul 23 10:41 postmaster.pid

数据库处于关闭状态时:

[highgo@localhost data]$ ls -lrth | grep postmaster

ps: (1)运行上方命令需要进到数据库data目录，命令：cd $PGDATA

(2)但是如果数据库由于异常宕机，可能会存在残留进程，所以不能仅凭这一条来判定数据库处于正常运行状态

(3)如果查看数据库处于运行状态，但是连接不到数据库，查看进程存在很少，有可能是数据库异常宕机，此时需要删除掉数据目录中的 postmaster.pid 文件并重启数据库

二、主备流复制数据库运行状态的查询
1、通过数据库自带的操作系统命令 pg_ctl 查看数据库运行状态

数据库正常运行显示如下:

[highgo@localhost ~]$ pg_ctl status

pg_ctl: server is running (PID: 7465)

/opt/HighGoDB-5.6.4/bin/postgres “-D” “/opt/HighGoDB-5.6.4/data”

数据库关闭状态显示如下:

[highgo@localhost ~]$ pg_ctl status

pg_ctl: no server running

2、通过数据库自带的操作系统命令 pg_controldata 查看数据库运行状态

流复制主库正常运行时:

[highgo@node1 ~]$ pg_controldata

pg_control version number: 1002

Catalog version number: 201707211

Database system identifier: 6837288046332662480

Database cluster state: in production

…

流复制主库处于关闭状态时:

[highgo@node1 ~]$ pg_controldata

pg_control version number: 1002

Catalog version number: 201707211

Database system identifier: 6837288046332662480

Database cluster state: shut down

…

流复制备库正常运行时:

[highgo@node2 ~]$ pg_controldata

pg_control version number: 1002

Catalog version number: 201707211

Database system identifier: 6837288046332662480

Database cluster state: in archive recovery

…

流复制备库处于关闭状态时:

[highgo@node2 ~]$ pg_controldata

pg_control version number: 1002

Catalog version number: 201707211

Database system identifier: 6837288046332662480

Database cluster state: shut down in recovery

…

3、通过后台进程看数据库运行状态

流复制主库正常运行时:

[highgo@node1 ~]$ ps -ef | grep postgres

highgo 8038 1 0 11:07 pts/0 00:00:00 /opt/HighGoDB-5.6.4/bin/postgres

highgo 8043 8038 0 11:07 ? 00:00:00 postgres: logger process

highgo 8045 8038 0 11:07 ? 00:00:00 postgres: checkpointer process

highgo 8046 8038 0 11:07 ? 00:00:00 postgres: writer process

highgo 8047 8038 0 11:07 ? 00:00:00 postgres: wal writer process

highgo 8048 8038 0 11:07 ? 00:00:00 postgres: autovacuum launcher process

highgo 8049 8038 0 11:07 ? 00:00:00 postgres: archiver process

highgo 8050 8038 0 11:07 ? 00:00:00 postgres: stats collector process

highgo 8051 8038 0 11:07 ? 00:00:00 postgres: bgworker: pg_wait_sampling collector

highgo 8053 8038 0 11:07 ? 00:00:00 postgres: bgworker: performance diagnosis collector

highgo 8054 8038 0 11:07 ? 00:00:00 postgres: bgworker: logical replication launcher

highgo 8055 8038 0 11:07 ? 00:00:00 postgres: wal sender process hgreplica 192.168.179.161(35068) streaming 0/4A000098

流复制备库正常运行时:

[highgo@node2 ~]$ ps -ef | grep postgres

highgo 8004 1 1 11:07 pts/0 00:00:00 /opt/HighGoDB-5.6.4/bin/postgres

highgo 8009 8004 0 11:07 ? 00:00:00 postgres: logger process

highgo 8010 8004 0 11:07 ? 00:00:00 postgres: startup process recovering 00000001000000000000004A

highgo 8011 8004 0 11:07 ? 00:00:00 postgres: checkpointer process

highgo 8012 8004 0 11:07 ? 00:00:00 postgres: writer process

highgo 8013 8004 0 11:07 ? 00:00:00 postgres: stats collector process

highgo 8014 8004 0 11:07 ? 00:00:00 postgres: bgworker: pg_wait_sampling collector

highgo 8015 8004 1 11:07 ? 00:00:00 postgres: wal receiver process streaming 0/4A000098

从上述加粗的内容可以看到，主备库的 wal 进程是有区别的，流复制中主库会向备库发送 wal 日志，所以主库存在 wal sender 进程，备库则会有 wal receiver 进程

ps:

（1）也可以直接进行 wal 进程的查看来进行主备库的区分

流复制主库显示如下:

[highgo@node1 ~]$ ps -ef | grep wal

highgo 8047 8038 0 11:07 ? 00:00:00 postgres: wal writer process

highgo 8055 8038 0 11:07 ? 00:00:00 postgres: wal sender process hgreplica 192.168.179.161(35068) streaming 0/4A00C5B8

流复制备库显示如下:

[highgo@node2 ~]$ ps -ef | grep wal

highgo 8015 8004 0 11:07 ? 00:00:00 postgres: wal receiver process streaming 0/4A00C5B8

（2）另外，如果存在级联备库（向流复制备库请求 wal ），则流复制备库上也会存在 wal sender 进程

4、通过文件系统查看数据库的运行状态

（1）数据库是否处于运行状态:

数据库处于运行状态时会存在下列文件:

[highgo@localhost data]$ ls -lrth | grep postmaster.pid

-rw------- 1 highgo highgo 82 Jul 23 10:41 postmaster.pid

数据库处于关闭状态时:

[highgo@localhost data]$ ls -lrth | grep postmaster

（2）主备库的差别

备库存在 recovery.conf 文件

[highgo@node2 data]$ ls -lrth | grep recovery

-rw-rw-r-- 1 highgo highgo 375 Jun 17 10:12 recovery.conf

如果主备流复制已经做过至少一次主备切换，主库上会存在 recovery.done 文件

[highgo@node2 data]$ ls -lrth | grep recovery

-rw-rw-r-- 1 highgo highgo 375 Jun 15 10:12 recovery.done

三、repmgr 数据库集群运行状态的查询
1、通过数据库自带的操作系统命令 pg_ctl 查看数据库运行状态

数据库正常运行显示如下:

[highgo@node1 ~]$ pg_ctl status

pg_ctl: server is running (PID: 11727)

/opt/HighGo5.6.5-cluster/bin/postgres “-D” “/opt/HighGo5.6.5-cluster/data”

数据库关闭状态显示如下:

[highgo@localhost ~]$ pg_ctl status

pg_ctl: no server running

2、通过数据库自带的操作系统命令 pg_controldata 查看数据库运行状态

集群主库正常运行状态

[highgo@node2 ~]$ pg_controldata

pg_control version number: 1002

Catalog version number: 201707211

Database system identifier: 6836156492751540059

Database cluster state: in production

…

集群备库正常运行状态

[highgo@node1 ~]$ pg_controldata

pg_control version number: 1002

Catalog version number: 201707211

Database system identifier: 6836156492751540059

Database cluster state: in archive recovery

…

集群主库处于关闭状态时:

[highgo@node2 ~]$ pg_controldata

pg_control version number: 1002

Catalog version number: 201707211

Database system identifier: 6836156492751540059

Database cluster state: shut down

…

集群备库处于关闭状态时:

[highgo@node2 ~]$ pg_controldata

pg_control version number: 1002

Catalog version number: 201707211

Database system identifier: 6836156492751540059

Database cluster state: shut down in recovery

3、通过后台进程看数据库运行状态

集群主库正常运行时:

[highgo@node2 ~]$ ps -ef | grep postgres

highgo 19930 1 0 14:21 pts/1 00:00:00 /opt/HighGo5.6.5-cluster/bin/postgres

highgo 19934 19930 0 14:21 ? 00:00:00 postgres: logger process

highgo 19936 19930 0 14:21 ? 00:00:00 postgres: checkpointer process

highgo 19937 19930 0 14:21 ? 00:00:00 postgres: writer process

highgo 19938 19930 0 14:21 ? 00:00:00 postgres: wal writer process

highgo 19939 19930 0 14:21 ? 00:00:00 postgres: autovacuum launcher process

highgo 19940 19930 0 14:21 ? 00:00:00 postgres: archiver process

highgo 19941 19930 0 14:21 ? 00:00:00 postgres: stats collector process

highgo 19942 19930 0 14:21 ? 00:00:00 postgres: bgworker: pg_wait_sampling collector

highgo 19944 19930 0 14:21 ? 00:00:00 postgres: bgworker: performance diagnosis collector

highgo 19945 19930 0 14:21 ? 00:00:00 postgres: bgworker: logical replication launcher

highgo 19946 19930 0 14:21 ? 00:00:00 postgres: wal sender process highgo 192.168.179.153(63390) streaming 0/27023650

集群备库正常运行时:

[highgo@node1 ~]$ ps -ef | grep postgres

highgo 13966 1 0 14:20 pts/1 00:00:00 /opt/HighGo5.6.5-cluster/bin/postgres

highgo 13970 13966 0 14:20 ? 00:00:00 postgres: logger process

highgo 13971 13966 0 14:20 ? 00:00:00 postgres: startup process recovering 000000060000000000000027

highgo 13972 13966 0 14:20 ? 00:00:00 postgres: checkpointer process

highgo 13973 13966 0 14:20 ? 00:00:00 postgres: writer process

highgo 13974 13966 0 14:20 ? 00:00:00 postgres: stats collector process

highgo 13975 13966 0 14:20 ? 00:00:00 postgres: bgworker: pg_wait_sampling collector

highgo 13981 13966 0 14:21 ? 00:00:00 postgres: wal receiver process streaming 0/27023650

ps: 也可以使用流复制中所描述的另一个命令（ps -ef | grep wal）来看 wal 进程

4、通过文件系统查看数据库的运行状态

（1）数据库是否处于以运行状态:

数据库处于运行状态时会存在下列文件:

[highgo@localhost data]$ ls -lrth | grep postmaster.pid

-rw------- 1 highgo highgo 82 Jul 23 10:41 postmaster.pid

数据库处于关闭状态时:

[highgo@localhost data]$ ls -lrth | grep postmaster

（2）主库备库的判断

没有做过主备切换时，备库中只有一个 recovery.conf 文件

做过主备切换后，主备库都会有 recovery.conf 和 recovery.done 两个文件

[highgo@node1 data]$ ls -lrth | grep recovery

-rw------- 1 highgo highgo 229 Jul 23 09:10 recovery.done

-rw------- 1 highgo highgo 229 Jul 23 09:12 recovery.conf

主库中 recovery.conf 时间早于 recovery.done; 备库中 recovery.done 早于 recovery.conf

可以通过查看数据库集群状态的命令；如果主备库显示一致且如下所示，说明集群状态正常

在 status 一栏中出现 * 表示正常状态，如果出现了其他的符号（比如 ！，？），表明集群状态出现了问题

[highgo@node2 ~]$ repmgr cluster show

ID | Name | Role | Status | Upstream | Location | Priority | Replication lag | Last replayed LSN

----±----------------±--------±----------±----------------±---------±---------±----------------±------------------

1 | 192.168.179.153 | standby | running | 192.168.179.154 | default | 100 | 0 bytes | 0/2703D720

2 | 192.168.179.154 | primary | * running | | default | 100 | n/a | none

如果两个数据库中都出现了 recovery.conf 时间早于 recovery.done 的情况，数据库集群出错出现了双主

出现双主的例子（status 中出现了 ！，表明集群状态不正确）

[highgo@node2 ~]$ repmgr cluster show

ID | Name | Role | Status | Upstream | Location | Priority | Replication lag | Last replayed LSN

----±----------------±--------±---------------------±----------------±---------±---------±----------------±------------------

1 | 192.168.179.153 | standby | ! running as primary | 192.168.179.154 | default | 100 | 624 MB | 0/2703D720

2 | 192.168.179.154 | primary | * running | | default | 100 | n/a | none

WARNING: following issues were detected

• node “192.168.179.153” (ID: 1) is registered as standby but running as primary

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