pg 模拟主库down机之pg_kaboom

    为了测试pg模拟down机，可使用插件pg_kaboom:GitHub - pgguru/pg_kaboom: Devious SQL-based SQL tools to crash your PostgreSQL server

$ git clone git@github.com:CrunchyData/pg_kaboom.git
$ cd pg_kaboom
$ make PG_CONFIG=path/to/pg_config && make install PG_CONFIG=path/to/pg_config
$ psql -c 'CREATE EXTENSION pg_kaboom' -U pg13 -d postgres

开始模拟：

[pg13@hdp1 ~]$ psql -d postgres
psql (13.3, server 13.2)
Type "help" for help.
 
postgres=# SET pg_kaboom.disclaimer = 'I can afford to lose this data and server';
SET
postgres=# SET pg_kaboom.execute = on;
SET
postgres=# SELECT pg_kaboom('segfault');
ERROR:  for safety, pg_kaboom.disclaimer must be explicitly set to 'I can afford to lose this data and server'
 
#这里需要再次确认
postgres=# SET pg_kaboom.disclaimer = 'I can afford to lose this data and server';
SET
 
postgres=# SELECT pg_kaboom('segfault');
server closed the connection unexpectedly
        This probably means the server terminated abnormally
        before or while processing the request.
The connection to the server was lost. Attempting reset: Failed.
 
#目前已经down机
!?>

 所以我们可以通过这个工具模拟主库down机。来测试主备切换、生成数据库core文件等工作。

除了上述函数pg_kaboom的参数segfault之外，参数还有以下几个：

• break-archive :: install a broken archive_command and force a restart

• fill-log :: allocate all of the space inside the logs directory

• fill-pgdata :: allocate all of the space inside the $PGDATA directory

• fill-pgwal :: allocate all of the space inside the $PGDATA/pg_wal directory

• mem :: allocate some memory

• restart :: do an immediate restart of the server

• rm-pgdata :: do a rm -Rf $PGDATA

• segfault :: cause a segfault in the running backend process

• signal :: send a SIGKILL to the Postmaster process

• xact-wrap :: force the database to run an xact-wraparound vacuum

You can also use the following "special" weapons:

• random :: choose a random weapon

• null :: don't do anything, just go through the normal flow