這篇文章主要介紹了Postgresql分布式插件plproxy的使用詳解，具有很好的參考價值，希望對大家有所幫助。一起跟隨小編過來看看吧。
Simple remote function call
節(jié)點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');
節(jié)點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
節(jié)點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
節(jié)點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;
節(jié)點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
節(jié)點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;
補(bǔ)充：PostgreSQL 水平分庫——plproxy
1、PL/Proxy安裝
1、1 編譯安裝
tar -zxvf plproxy-2.7.tar.gz
cd plproxy-2.7
source /home/postgres/.bashrc
make
make install
1、2 創(chuàng)建pl/proxy擴(kuò)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
修改數(shù)據(jù)庫節(jié)點pg_hba.conf:
修改兩個數(shù)據(jù)節(jié)點的pg_hba.conf，保證代理節(jié)點可以訪問。
# TYPE DATABASE USER ADDRESS METHOD
host all all 192.168.7.177/32 trust
在SQL/MED方法在pl/proxy節(jié)點進(jìn)行集群配置：
# TYPE DATABASE USER ADDRESS METHOD
host all all 192.168.7.177/32 trust
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測試
在兩個數(shù)據(jù)節(jié)點創(chuàng)建測試表：
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數(shù)據(jù)水平拆分測試
在每個數(shù)據(jù)節(jié)點創(chuàng)建insert函數(shù)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節(jié)點一樣
2、在PL/Proxy數(shù)據(jù)庫創(chuàng)建同名的insert函數(shù)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數(shù)據(jù)庫創(chuàng)建讀的函數(shù)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節(jié)點插入數(shù)據(jù)進(jìn)行測試
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、在節(jié)點數(shù)據(jù)庫查看數(shù)據(jù)分布情況
pl_db1=# select * from users;
userid | name
--------+-------
1001 | Sven
1003 | Steve
1004 | bill
(3 rows)
我們在proxy節(jié)點查詢下：
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)
因為創(chuàng)建insert_user函數(shù)時使用的是ROW ON ANY，表示隨機(jī)再一臺機(jī)器上進(jìn)行執(zhí)行，因此實現(xiàn)了數(shù)據(jù)在不同節(jié)點的隨機(jī)分布，接下來改成ROW ON ALL，實驗在不同節(jié)點進(jìn)行數(shù)據(jù)的復(fù)制。
run on , 是數(shù)字常量, 范圍是0 到 nodes-1; 例如有4個節(jié)點 run on 0; (run on 4則報錯).
run on ANY,
run on function(…), 這里用到的函數(shù)返回結(jié)果必須是int2, int4 或 int8.
run on ALL, 這種的plproxy函數(shù)必須是returns setof…, 實體函數(shù)沒有setof的要求.
3、2數(shù)據(jù)復(fù)制測試
選擇users表作為實驗對象；我們先清理表users數(shù)據(jù);在數(shù)據(jù)節(jié)點創(chuàng)建truncatet函數(shù)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數(shù)據(jù)庫創(chuàng)建同名的truncate函數(shù)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
–檢查發(fā)現(xiàn)數(shù)據(jù)已經(jīng)清理掉了
proxy=# SELECT TRUNC_USER();
trunc_user
------------
1
1
(2 rows)
3、在PL/Proxy數(shù)據(jù)庫創(chuàng)建函數(shù)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、插入幾條數(shù)據(jù)
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、查看每個節(jié)點數(shù)據(jù)情況
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)
兩個數(shù)據(jù)節(jié)點的數(shù)據(jù)一樣，實現(xiàn)了數(shù)據(jù)的復(fù)制。
文章來源：腳本之家
來源地址：https://www.jb51.net/article/204402.htm
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