提高Postgresql中的函数性能_Sql_Performance_Postgresql_Function

提高Postgresql中的函数性能

sql performance postgresql function

提高Postgresql中的函数性能,sql,performance,postgresql,function,Sql,Performance,Postgresql,Function,下面的函数是创建一个临时表，然后在其中填充数据该临时表应该在点击网站上的按钮时显示我试图提高性能的步骤： 1.修改了postgresql.conf文件。 2.在临时表中添加了索引 CREATE OR REPLACE FUNCTION lastonemonth() RETURNS void AS $BODY$ DECLARE query1 text; query2 text; var_loop1 RECORD; dealerName text; cur_minus_

下面的函数是创建一个临时表，然后在其中填充数据

该临时表应该在点击网站上的按钮时显示

我试图提高性能的步骤： 1.修改了postgresql.conf文件。 2.在临时表中添加了索引

CREATE OR REPLACE FUNCTION lastonemonth()
  RETURNS void AS
$BODY$
  DECLARE
  query1 text;
  query2 text;
  var_loop1 RECORD;
  dealerName text;
  cur_minus_2_month text; 
  var_sum_of_quantity numeric;
  var_net_value numeric;
  var_average_price_nsr numeric; 
  BEGIN
  EXECUTE 'DROP TABLE IF EXISTS LOM CASCADE';
  EXECUTE 'CREATE TEMP TABLE LOM ( dealer_name text PRIMARY KEY , sum_of_quantity numeric, net_value numeric, average_price_nsr numeric)';
  EXECUTE 'CREATE UNIQUE INDEX dealer_name_idx ON LOM (dealer_name)';

  query1:= 'SELECT DISTINCT dealer FROM customernotorderdb_temp WHERE month IN ( to_char( now() - interval ''2 month'', ''YYYYMM'') , to_char( now() - interval ''3 month'', ''YYYYMM''))EXCEPT SELECT DISTINCT dealer FROM customernotorderdb_temp WHERE month IN ( to_char( now() - interval ''1 month'', ''YYYYMM''), to_char(now(), ''YYYYMM'') )';
  FOR var_loop1 IN EXECUTE (query1)
  LOOP
      dealerName:= var_loop1.dealer;
      INSERT INTO LOM(dealer_name) VALUES(dealerName);
      EXECUTE 'SELECT month FROM customernotorderdb_temp WHERE dealer LIKE ''%'||dealerName||'%'' AND month IN(to_char( now() - interval ''2 month'', ''YYYYMM''))' INTO cur_minus_2_month;

      --RAISE NOTICE 'cur_minus_2_month( % )', cur_minus_2_month;
      IF cur_minus_2_month IS NOT NULL 
      THEN
          EXECUTE 'SELECT SUM(saleqtypermt) FROM customernotorderdb_temp WHERE dealer LIKE ''%'||dealerName||'%'' AND month IN (to_char( now() - interval ''2 month'', ''YYYYMM''),to_char( now() - interval ''3 month'', ''YYYYMM''),to_char( now() - interval ''4 month'', ''YYYYMM''),to_char( now() - interval ''5 month'', ''YYYYMM''),to_char( now() - interval ''6 month'', ''YYYYMM''),to_char( now() - interval ''7 month'', ''YYYYMM''),to_char( now() -interval ''8 month'', ''YYYYMM''),to_char( now() - interval ''9 month'', ''YYYYMM''),to_char( now() - interval ''10 month'', ''YYYYMM''),to_char( now() - interval ''11 month'', ''YYYYMM''),to_char( now() - interval ''12 month'', ''YYYYMM''),to_char( now() - interval ''13 month'', ''YYYYMM''))' INTO var_sum_of_quantity;
          EXECUTE 'SELECT SUM(basic_value-rate_diff) FROM customernotorderdb_temp WHERE dealer LIKE ''%'||dealerName||'%'' AND month IN (to_char( now() - interval ''2 month'', ''YYYYMM''),to_char( now() - interval ''3 month'', ''YYYYMM''),to_char( now() - interval ''4 month'', ''YYYYMM''),to_char( now() - interval ''5 month'', ''YYYYMM''),to_char( now() - interval ''6 month'', ''YYYYMM''),to_char( now() - interval ''7 month'', ''YYYYMM''),to_char( now() -interval ''8 month'', ''YYYYMM''),to_char( now() - interval ''9 month'', ''YYYYMM''),to_char( now() - interval ''10 month'', ''YYYYMM''),to_char( now() - interval ''11 month'', ''YYYYMM''),to_char( now() - interval ''12 month'', ''YYYYMM''),to_char( now() - interval ''13 month'', ''YYYYMM''))' INTO var_net_value;
          EXECUTE 'SELECT SUM(avgpricensr) FROM customernotorderdb_temp WHERE dealer LIKE ''%'||dealerName||'%'' AND month IN (to_char( now() - interval ''2 month'', ''YYYYMM''),to_char( now() - interval ''3 month'', ''YYYYMM''),to_char( now() - interval ''4 month'', ''YYYYMM''),to_char( now() - interval ''5 month'', ''YYYYMM''),to_char( now() - interval ''6 month'', ''YYYYMM''),to_char( now() - interval ''7 month'', ''YYYYMM''),to_char( now() -interval ''8 month'', ''YYYYMM''),to_char( now() - interval ''9 month'', ''YYYYMM''),to_char( now() - interval ''10 month'', ''YYYYMM''),to_char( now() - interval ''11 month'', ''YYYYMM''),to_char( now() - interval ''12 month'', ''YYYYMM''),to_char( now() - interval ''13 month'', ''YYYYMM''))' INTO var_average_price_nsr;
          --RAISE NOTICE 'A [ %   % ]', dealername,var_net_value;
          UPDATE LOM SET sum_of_quantity=var_sum_of_quantity,
                         net_value=var_net_value,
                         average_price_nsr=var_average_price_nsr 
          WHERE dealer_name=var_loop1.dealer;

      ELSE
          EXECUTE 'SELECT SUM(saleqtypermt) FROM customernotorderdb_temp WHERE dealer LIKE ''%'||dealerName||'%'' AND month IN (to_char( now() - interval ''3 month'', ''YYYYMM''),to_char( now() - interval ''4 month'', ''YYYYMM''),to_char( now() - interval ''5 month'', ''YYYYMM''),to_char( now() - interval ''6 month'', ''YYYYMM''),to_char( now() - interval ''7 month'', ''YYYYMM''),to_char( now() -interval ''8 month'', ''YYYYMM''),to_char( now() - interval ''9 month'', ''YYYYMM''),to_char( now() - interval ''10 month'', ''YYYYMM''),to_char( now() - interval ''11 month'', ''YYYYMM''),to_char( now() - interval ''12 month'', ''YYYYMM''),to_char( now() - interval ''13 month'', ''YYYYMM''),to_char( now() - interval ''14 month'', ''YYYYMM''))' INTO var_sum_of_quantity;
          EXECUTE 'SELECT SUM(basic_value-rate_diff) FROM customernotorderdb_temp WHERE dealer LIKE ''%'||dealerName||'%'' AND month IN (to_char( now() - interval ''3 month'', ''YYYYMM''),to_char( now() - interval ''4 month'', ''YYYYMM''),to_char( now() - interval ''5 month'', ''YYYYMM''),to_char( now() - interval ''6 month'', ''YYYYMM''),to_char( now() - interval ''7 month'', ''YYYYMM''),to_char( now() -interval ''8 month'', ''YYYYMM''),to_char( now() - interval ''9 month'', ''YYYYMM''),to_char( now() - interval ''10 month'', ''YYYYMM''),to_char( now() - interval ''11 month'', ''YYYYMM''),to_char( now() - interval ''12 month'', ''YYYYMM''),to_char( now() - interval ''13 month'', ''YYYYMM''),to_char( now() - interval ''14 month'', ''YYYYMM''))' INTO var_net_value;
          EXECUTE 'SELECT SUM(avgpricensr) FROM customernotorderdb_temp WHERE dealer LIKE ''%'||dealerName||'%'' AND month IN (to_char( now() - interval ''3 month'', ''YYYYMM''),to_char( now() - interval ''4 month'', ''YYYYMM''),to_char( now() - interval ''5 month'', ''YYYYMM''),to_char( now() - interval ''6 month'', ''YYYYMM''),to_char( now() - interval ''7 month'', ''YYYYMM''),to_char( now() -interval ''8 month'', ''YYYYMM''),to_char( now() - interval ''9 month'', ''YYYYMM''),to_char( now() - interval ''10 month'', ''YYYYMM''),to_char( now() - interval ''11 month'', ''YYYYMM''),to_char( now() - interval ''12 month'', ''YYYYMM''),to_char( now() - interval ''13 month'', ''YYYYMM''),to_char( now() - interval ''14 month'', ''YYYYMM''))' INTO var_average_price_nsr;
          --RAISE NOTICE 'B [ %  % ]', dealername,var_net_value;
          UPDATE LOM SET sum_of_quantity=var_sum_of_quantity,net_value=var_net_value,average_price_nsr=var_average_price_nsr WHERE dealer_name=var_loop1.dealer;
      END IF;         
 END LOOP;
END;
$BODY$
  LANGUAGE plpgsql VOLATILE

首先，看起来您将月份存储为字符串，并手动使用字符串进行日期比较。那会减慢速度的。你能用Postgres日期类型或整数来代替吗

对于其他方面，如果不了解数据库布局和统计信息，我就无法确定，但以下是优化查询的基本方法：

使用psql或其他方法打开新连接

设置enable_seqscan=off

，这将仅为此会话禁用查询计划器中的seq scan（除非完全必要）

在查询之前运行

EXPLAIN

，查看哪些查询被强制扫描大型表。如果您看到任何

SEQ SCAN

s，请添加索引

“解释分析选择lastonemonth（）；st=0.00..0.26行=1宽度=0）（实际时间=16959.720..16959.721行=1循环=1）”“总运行时间：16959.734毫秒”非常感谢，现在代码的效率是解释分析选择lastonemonth（）；“结果（成本=0.00..0.26行=1宽度=0）（实际时间=2783.845..2783.845行=1循环=1）”“总运行时间：2783.859毫秒”不错。你改变了什么？您没有发布解释生成的查询计划。1。删除通配符%2。添加了显式索引。3.在if块下，将三个execute语句合并为一个4。修改了postgresql.conf文件设置5。从函数6中删除了“CREATE”和“DROP”语句。删除了减速部分中的一个变量，但没有在表格上运行分析。较新的drop temp表，将其截断。然后你可以使用静态SQL，你不需要函数；您不需要循环，也不需要plpgsql。该函数有效地将

插入LOM（…）选择经销商名称、金额（xxx0）。。。根据上述建议，从CustomerMotorDerDB_temp GROUP BY dealer_name

（加上一些其他聚合和选择）中选择以下代码：

其中dealer喜欢“%”| | dealerName | |“%”

为什么在这里使用通配符？你在同一张桌子上找到了dealername！