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用第三方语言编写PostgreSQL存储函数

来源:网络 作者:佚名 点击: 时间:2018-03-14 17:46
[摘要] 在PostgreSQL里,所有的存储函数需求都可以用PLPGSQL来实现。同时也支持用第三方语言来编写,这个就得看自己哪个方面熟练了。
在PostgreSQL里,所有的存储函数需求都可以用PLPGSQL来实现。同时也支持用第三方语言来编写,这个就得看自己哪个方面熟练了。
比如,简单的插入表的存储函数:
CREATE OR REPLACE FUNCTION ytt.insert_plpgsql(f_num integer)
 RETURNS void
 LANGUAGE plpgsql
AS $ytt$
declare i int := 0;
              v_rank int := 0;
	      v_log_time timestamp;
begin
while i < f_num 
loop
    v_rank = ceil(random()*100);
    v_log_time = now() - '1 day'::interval*ceil(random()*50);
    insert into t1 (rank,log_time) values (v_rank,v_log_time);
    i = i + 1;
end loop;
end;
$ytt$;
现在来插入100W条记录,花费时间大概为27秒。
t_girl=# select insert_plpgsql(1000000); insert_plpgsql ---------------- (1 row) Time: 27286.668 ms
t_girl=# \dx plpythonu List of installed extensions Name | Version | Schema | Description -----------+---------+------------+------------------------------------------ plpythonu | 1.0 | pg_catalog | PL/PythonU untrusted procedural language (1 row)
CREATE OR REPLACE FUNCTION ytt.insert_py(f_num integer)
 RETURNS void
 LANGUAGE plpythonu
AS $ytt$
import datetime
import random
i = 0
while i < f_num:
    v_rank = random.randrange(0,100)
    v_log_time = datetime.datetime.now() - datetime.timedelta(days=random.randrange(0,50))
    query0 = "insert into ytt.t1 (rank,log_time) values (" + str(v_rank) + ",'" + str(v_log_time)+ "')"
    plpy.execute(query0)
    i += 1
$ytt$;t_girl=# select insert_py(1000000); insert_py ----------- (1 row) Time: 86061.558 ms
CREATE OR REPLACE FUNCTION ytt.insert_multi_py(f_num integer, f_values integer) RETURNS text LANGUAGE plpythonu AS $ytt$ import datetime import random i = 0 j = 0 query0 = "insert into ytt.t1(rank,log_time) values " data0 = '' if (f_num/f_values)*f_values < f_num: return 'Parameters should be times relation.(f_num:1000,f_values:10)' else: while i < int(f_num/f_values): j = 0 while j < f_values: v_rank = random.randrange(0,100) v_log_time = datetime.datetime.now() - datetime.timedelta(days=random.randrange(0,50)) data0 = data0 + ",(" + str(v_rank) + ",'" + str(v_log_time)+ "')" j += 1 result0 = query0 + data0[1:len(data0)] plpy.execute(result0) data0 = '' i += 1 return 'Inserting ' + str(f_num) + ' rows' $ytt$;
t_girl=# select insert_multi_py(1000000,20);
    insert_multi_py     
------------------------
 Inserting 1000000 rows
(1 row)


Time: 27587.715 ms
t_girl=# 
------分隔线----------------------------