Simple remote function call
節點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
修改數據庫節點pg_hba.conf:
修改兩個數據節點的pg_hba.conf，保證代理節點可以訪問。
# TYPE DATABASE USER ADDRESS METHOD
host all all 192.168.7.177/32 trust
在SQL/MED方法在pl/proxy節點進行集群配置：
proxy=# create schema plproxy; --下面的函數都是創建在plproxy這個schema下面
CREATE SCHEMA
proxy=# create user bill superuser;
CREATE ROLE
--創建一個使用plproxy FDW的服務器
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
--創建用戶映射
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測試
在兩個數據節點創建測試表：
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數據水平拆分測試
在每個數據節點創建insert函數接口
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節點一樣
2、在PL/Proxy數據庫創建同名的insert函數接口
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數據庫創建讀的函數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節點插入數據進行測試
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、在節點數據庫查看數據分布情況
pl_db1=# select * from users;
userid | name
--------+-------
1001 | Sven
1003 | Steve
1004 | bill
(3 rows)
我們在proxy節點查詢下：
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)
因為創建insert_user函數時使用的是ROW ON ANY，表示隨機再一臺機器上進行執行，因此實現了數據在不同節點的隨機分布，接下來改成ROW ON ALL，實驗在不同節點進行數據的復制。
run on , 是數字常量, 范圍是0 到 nodes-1; 例如有4個節點 run on 0; (run on 4則報錯).
run on ANY,
run on function(…), 這里用到的函數返回結果必須是int2, int4 或 int8.
run on ALL, 這種的plproxy函數必須是returns setof…, 實體函數沒有setof的要求.
3、2數據復制測試
選擇users表作為實驗對象；我們先清理表users數據;在數據節點創建truncatet函數接口
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數據庫創建同名的truncate函數接口
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
–檢查發現數據已經清理掉了
proxy=# SELECT TRUNC_USER();
trunc_user
------------
1
1
(2 rows)
3、在PL/Proxy數據庫創建函數接口 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、插入幾條數據
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、查看每個節點數據情況
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)
兩個數據節點的數據一樣，實現了數據的復制。
以上為個人經驗，希望能給大家一個參考，也希望大家多多支持腳本之家。如有錯誤或未考慮完全的地方，望不吝賜教。
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