域名預(yù)訂/競價，好“米”不錯過

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，表示隨機再一臺機器上進行執(zhí)行，因此實現(xiàn)了數(shù)據(jù)在不同節(jié)點的隨機分布，接下來改成ROW ON ALL，實驗在不同節(jié)點進行數(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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