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Postgresql分布式插件plproxy的使用详解_PostgreSQL_

2023-05-27 510人已围观

简介 Postgresql分布式插件plproxy的使用详解_PostgreSQL_

Simple remote function call

节点61/62(datanode)

 CREATE TABLE users (username text, email text); insert into users values ('user0', 'user0@gmail.com'); insert into users values ('user1', 'user1@gmail.com'); insert into users values ('user2', 'user2@gmail.com');

节点60(proxy)

 create or replace extension plproxy; CREATE FUNCTION get_user_email(i_username text) RETURNS SETOF text AS $$ CONNECT 'host=localhost port=9461 dbname=postgres connect_timeout=10'; SELECT email FROM users WHERE username = $1; $$ LANGUAGE plproxy; SELECT * from get_user_email('user0');

Configuring Pl/Proxy clusters with SQL/MED

节点60(proxy)

 CREATE FOREIGN DATA WRAPPER plproxy; CREATE SERVER usercluster FOREIGN DATA WRAPPER plproxy OPTIONS (connection_lifetime '1800', p0 'host=localhost port=9461 dbname=postgres connect_timeout=10', p1 'host=localhost port=9462 dbname=postgres connect_timeout=10' ); CREATE USER MAPPING FOR PUBLIC SERVER usercluster;

Partitioned remote call

节点60(proxy)

 CREATE OR REPLACE FUNCTION insert_user(i_username text, i_emailaddress text) RETURNS integer AS $$ CLUSTER 'usercluster'; RUN ON hashtext(i_username); $$ LANGUAGE plproxy;

节点61/62(datanode)

 CREATE OR REPLACE FUNCTION insert_user(i_username text, i_emailaddress text) RETURNS integer AS $$ INSERT INTO users (username, email) VALUES ($1,$2); SELECT 1; $$ LANGUAGE SQL;

Putting it all together

节点60(proxy)

 SELECT insert_user('Sven','sven@somewhere.com'); SELECT insert_user('Marko', 'marko@somewhere.com'); SELECT insert_user('Steve','steve@somewhere.cm');

plproxy–2.7.0.sql

 -- handler function CREATE FUNCTION plproxy_call_handler () RETURNS language_handler AS 'plproxy' LANGUAGE C; -- validator function CREATE FUNCTION plproxy_validator (oid) RETURNS void AS 'plproxy' LANGUAGE C; -- language CREATE LANGUAGE plproxy HANDLER plproxy_call_handler VALIDATOR plproxy_validator; -- validator function CREATE FUNCTION plproxy_fdw_validator (text[], oid) RETURNS boolean AS 'plproxy' LANGUAGE C; -- foreign data wrapper CREATE FOREIGN DATA WRAPPER plproxy VALIDATOR plproxy_fdw_validator;

补充：PostgreSQL 水平分库——plproxy

1、PL/Proxy安装

1、1 编译安装

 tar -zxvf plproxy-2.7.tar.gz cd plproxy-2.7 source /home/postgres/.bashrc make make install

1、2 创建pl/proxy扩展

 itm_pg@pgs-> psql psql (10.3) Type "help" for help. postgres=# create database proxy; CREATE DATABASE postgres=# \c proxy You are now connected to database "proxy" as user "postgres". proxy=# create extension plproxy; CREATE EXTENSION proxy=# \dx List of installed extensions Name | Version | Schema | Description ---------+---------+------------+----------------------------------------------- ----------- plpgsql | 1.0 | pg_catalog | PL/pgSQL procedural language plproxy | 2.8.0 | public | Database partitioning implemented as procedura l language (2 rows)

2、pl/proxy配置

修改数据库节点pg_hba.conf:

修改两个数据节点的pg_hba.conf，保证代理节点可以访问。

 # TYPE DATABASE USER ADDRESS METHOD host all all 192.168.7.177/32 trust

在SQL/MED方法在pl/proxy节点进行集群配置：

 proxy=# create schema plproxy; --下面的函数都是创建在plproxy这个schema下面 CREATE SCHEMA proxy=# create user bill superuser; CREATE ROLE --创建一个使用plproxy FDW的服务器 proxy=# CREATE SERVER cluster_srv1 FOREIGN DATA WRAPPER plproxy proxy-# OPTIONS ( proxy(# connection_lifetime '1800', proxy(# disable_binary '1', proxy(# p0 'dbname=pl_db0 host=192.168.7.166', proxy(# p1 'dbname=pl_db1 host=192.168.17.190' proxy(# ); CREATE SERVER proxy=# \des List of foreign servers Name | Owner | Foreign-data wrapper --------------+-------+---------------------- cluster_srv1 | bill | plproxy (1 row) proxy=# grant usage on FOREIGN server cluster_srv1 to bill; GRANT --创建用户映射 proxy=# create user mapping for bill server cluster_srv1 options (user 'bill'); CREATE USER MAPPING proxy=# \deu List of user mappings Server | User name --------------+----------- cluster_srv1 | bill (1 row)

配置完成！在"CLUSTER"模式中；才需要上述配置；在"CONNECT"模式中是不需要的。

3、pl/proxy测试

在两个数据节点创建测试表：

 postgres=# create database pl_db1; CREATE DATABASE postgres=# create user bill superuser; CREATE ROLE postgres=# \c pl_db1 bill You are now connected to database "pl_db1" as user "bill". pl_db1=# create table users(userid int, name text); CREATE TABLE

3、1数据水平拆分测试

在每个数据节点创建insert函数接口

 pl_db1=# CREATE OR REPLACE FUNCTION insert_user(i_id int, i_name text) pl_db1-# RETURNS integer AS $$ pl_db1$# INSERT INTO users (userid, name) VALUES ($1,$2); pl_db1$# SELECT 1; pl_db1$# $$ LANGUAGE SQL; CREATE FUNCTION

–pl_db0节点一样

2、在PL/Proxy数据库创建同名的insert函数接口

 proxy=# CREATE OR REPLACE FUNCTION insert_user(i_id int, i_name text) proxy-# RETURNS integer AS $$ proxy$# CLUSTER 'cluster_srv1'; proxy$# RUN ON ANY; proxy$# $$ LANGUAGE plproxy; CREATE FUNCTION

3、在PL/Proxy数据库创建读的函数get_user_name()

 proxy=# CREATE OR REPLACE FUNCTION get_user_name() proxy-# RETURNS TABLE(userid int, name text) AS $$ proxy$# CLUSTER 'cluster_srv1'; proxy$# RUN ON ALL ; proxy$# SELECT userid,name FROM users; proxy$# $$ LANGUAGE plproxy; CREATE FUNCTION

4、在pl/proxy节点插入数据进行测试

 SELECT insert_user(1001, 'Sven'); SELECT insert_user(1002, 'Marko'); SELECT insert_user(1003, 'Steve'); SELECT insert_user(1004, 'bill'); SELECT insert_user(1005, 'rax'); SELECT insert_user(1006, 'ak'); SELECT insert_user(1007, 'jack'); SELECT insert_user(1008, 'molica'); SELECT insert_user(1009, 'pg'); SELECT insert_user(1010, 'oracle');

5、在节点数据库查看数据分布情况

 pl_db1=# select * from users; userid | name --------+------- 1001 | Sven 1003 | Steve 1004 | bill (3 rows)

我们在proxy节点查询下：

 proxy=# SELECT USERID,NAME FROM GET_USER_NAME(); userid | name --------+-------- 1005 | rax 1006 | ak 1008 | molica 1009 | pg 1002 | Marko 1004 | bill 1007 | jack 1010 | oracle 1001 | Sven 1003 | Steve (10 rows)

因为创建insert_user函数时使用的是ROW ON ANY，表示随机再一台机器上进行执行，因此实现了数据在不同节点的随机分布，接下来改成ROW ON ALL，实验在不同节点进行数据的复制。

run on , 是数字常量, 范围是0 到 nodes-1; 例如有4个节点 run on 0; (run on 4则报错).

run on ANY,

run on function(…), 这里用到的函数返回结果必须是int2, int4 或 int8.

run on ALL, 这种的plproxy函数必须是returns setof…, 实体函数没有setof的要求.

3、2数据复制测试

选择users表作为实验对象；我们先清理表users数据;在数据节点创建truncatet函数接口

 pl_db1=# CREATE OR REPLACE FUNCTION trunc_user() pl_db1-# RETURNS integer AS $$ pl_db1$# truncate table users; pl_db1$# SELECT 1; pl_db1$# $$ LANGUAGE SQL; CREATE FUNCTION

2、在PL/Proxy数据库创建同名的truncate函数接口

 proxy=# CREATE OR REPLACE FUNCTION trunc_user() proxy-# RETURNS SETOF integer AS $$ proxy$# CLUSTER 'cluster_srv1'; proxy$# RUN ON ALL; proxy$# $$ LANGUAGE plproxy; CREATE FUNCTION

–检查发现数据已经清理掉了

 proxy=# SELECT TRUNC_USER(); trunc_user ------------ 1 1 (2 rows)

3、在PL/Proxy数据库创建函数接口 insert_user_2

 proxy=# CREATE OR REPLACE FUNCTION insert_user_2(i_id int, i_name text) proxy-# RETURNS SETOF integer AS $$ proxy$# CLUSTER 'cluster_srv1'; proxy$# RUN ON ALL; proxy$# TARGET insert_user; proxy$# $$ LANGUAGE plproxy; CREATE FUNCTION

4、插入几条数据

 proxy=# SELECT insert_user_2(1004, 'bill'); insert_user_2 --------------- 1 1 (2 rows) proxy=# SELECT insert_user_2(1005, 'rax'); insert_user_2 --------------- 1 1 (2 rows) proxy=# SELECT insert_user_2(1006, 'ak'); insert_user_2 --------------- 1 1 (2 rows) proxy=# SELECT insert_user_2(1007, 'jack'); insert_user_2 --------------- 1 1 (2 rows)

5、查看每个节点数据情况

 pl_db1=# select * from users; userid | name --------+------- 1004 | bill 1005 | rax 1006 | ak 1007 | jack (4 rows) pl_db0=# select * from users; userid | name --------+------- 1004 | bill 1005 | rax 1006 | ak 1007 | jack (4 rows)

两个数据节点的数据一样，实现了数据的复制。

以上为个人经验，希望能给大家一个参考，也希望大家多多支持。如有错误或未考虑完全的地方，望不吝赐教。

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