postgresql multi-master 系列 Rubyrep 之二 測試1

192.168.56.111  n1
192.168.56.112  n2

n1、n2 節點都已經安裝了 rubyrep 。
Rubyrep 要求每個表都要有主鍵(primary key)。

版本

# cat /etc/centos-release
CentOS Linux release 7.4.1708 (Core) 
# 
# 
# yum list installed |grep -i postgresql
postgresql11.x86_64                11.8-1PGDG.rhel7                    @pgdg11  
postgresql11-contrib.x86_64        11.8-1PGDG.rhel7                    @pgdg11  
postgresql11-debuginfo.x86_64      11.5-1PGDG.rhel7                    @pgdg11  
postgresql11-devel.x86_64          11.8-1PGDG.rhel7                    @pgdg11  
postgresql11-docs.x86_64           11.8-1PGDG.rhel7                    @pgdg11  
postgresql11-libs.x86_64           11.8-1PGDG.rhel7                    @pgdg11  
postgresql11-llvmjit.x86_64        11.8-1PGDG.rhel7                    @pgdg11  
postgresql11-odbc.x86_64           12.01.0000-1PGDG.rhel7              @pgdg11  
postgresql11-plperl.x86_64         11.8-1PGDG.rhel7                    @pgdg11  
postgresql11-plpython.x86_64       11.8-1PGDG.rhel7                    @pgdg11  
postgresql11-pltcl.x86_64          11.8-1PGDG.rhel7                    @pgdg11  
postgresql11-server.x86_64         11.8-1PGDG.rhel7                    @pgdg11  
postgresql11-tcl.x86_64            2.4.0-2.rhel7.1                     @pgdg11  
postgresql11-test.x86_64           11.8-1PGDG.rhel7                    @pgdg11

# su - postgres
Last login: Wed Jan 15 18:34:12 CST 2020 on pts/0
$
$
$ psql -c "select version();"
                                                 version                                                 
---------------------------------------------------------------------------------------------------------
 PostgreSQL 11.8 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-39), 64-bit
(1 row)

n1 節點操作

# su - postgres
$ psql -U yewu yewudb

yewudb=> create table tmp_t0 (
 c0 int8 primary key,
 c1 varchar(100)
);

# su - postgres
$ which rubyrep 
/usr/local/rvm/gems/ruby-2.4.9/bin/rubyrep

$ rubyrep --help
Usage: /usr/local/rvm/gems/ruby-2.4.9/bin/rubyrep [general options] command [parameters, ...]

Asynchronous master-master replication of relational databases.

Available options:
        --verbose                    Show errors with full stack trace
    -v, --version                    Show version information.
        --help                       Show this message

Available commands:
  generate        Generates a configuration file template
  help            Shows detailed help for the specified command
  proxy           Proxies connections from rubyrep commands to the database
  replicate       Starts a replication process
  scan            Scans for differing records between databases
  sync            Syncs records between databases
  uninstall       Removes all rubyrep tables, triggers, etc. from "left" and "right" database

$ rubyrep generate myrubyrep.conf

$ vi myrubyrep.conf

RR::Initializer::run do |config|
  config.left = {
    :adapter  => 'postgresql',
    :database => 'yewudb',
    :username => 'yewu',
    :password => 'yewuyewu',
    :host     => '192.168.56.111'
  }

  config.right = {
    :adapter  => 'postgresql',
    :database => 'yewudb',
    :username => 'yewu',
    :password => 'yewuyewu',
    :host     => '192.168.56.112'
  }

  config.include_tables 'tmp_t0'
  # config.include_tables /^e/ # regexp matching all tables starting with e
  # config.include_tables /./ # regexp matching all tables in the database
end

n2 節點操作

# su - postgres
$ psql -U yewu yewudb

yewudb=> create table tmp_t0 (
 c0 int8 primary key,
 c1 varchar(100)
);

$ rubyrep generate myrubyrep.conf

$ vi myrubyrep.conf

RR::Initializer::run do |config|
  config.left = {
    :adapter  => 'postgresql',
    :database => 'yewudb',
    :username => 'yewu',
    :password => 'yewuyewu',
    :host     => '192.168.56.111'
  }

  config.right = {
    :adapter  => 'postgresql',
    :database => 'yewudb',
    :username => 'yewu',
    :password => 'yewuyewu',
    :host     => '192.168.56.112'
  }

  config.include_tables 'tmp_t0'
  # config.include_tables /^e/ # regexp matching all tables starting with e
  # config.include_tables /./ # regexp matching all tables in the database
end

rubyrep scan

$ rubyrep scan -c myrubyrep.conf

Exception caught: Specified 'postgresql' for database adapter, but the gem is not loaded. Add `gem 'pg'` to your Gemfile (and ensure its version is at the minimum required by ActiveRecord).

這個是 gem install pg 的版本過高，需要卸載掉，再安裝指定的版本

# gem list pg

*** LOCAL GEMS ***

pg (1.2.3)

# gem uninstall pg

# gem install pg -v 0.20.0 -- --with-pg-config=/usr/pgsql-11/bin/pg_config

再執行 scan，就ok

$ rubyrep scan -c myrubyrep.conf
                              tmp_t0 100% .........................   0
							  

rubyrep sync

$ rubyrep sync -c myrubyrep.conf
                              tmp_t0 100% .....................
							  

n1 節點插入數據

yewudb=> insert into tmp_t0 select id,md5(id::varchar) from generate_series(1,1000) as id;

n2 節點查詢數據

yewudb=> select count(1) from tmp_t0;
 count 
-------
     0
(1 row)

怎麼看上去有點土，難道要定時執行 rubyrep sync 命令？

感覺離 multi-master 的目標甚遠。

$ rubyrep sync -c myrubyrep.conf
                              tmp_t0 100% ......................... 1000
							  

參考:
https://wiki.postgresql.org/wiki/Rubyrep

http://www.rubyrep.org/
https://github.com/rubyrep/rubyrep

http://www.rubyrep.org/scanning.html
http://ar.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/PostgreSQLAdapter.html

https://rubygems.org/gems/pg/
https://rubygems.org/gems/pg/versions

http://www.rubyrep.org/sync_command.html
http://www.rubyrep.org/configuration.html