mysql 存储过程批量删除重复数据

雨点打透心脏的1/2处 2024-03-30 14:32 13阅读 0赞

## mysql 存储过程批量删除重复数据 ##

表结构：

![44d63e08be9b9640e55d7a86eb4c7099.png][]

LOAD DATA INFILE '/usr/local/phone\_imsi\_12' replace INTO TABLE tbl\_imsi2number\_new FIELDS TERMINATED BY '\\t' ENCLOSED BY '' (number,imsi);

先用SQL语句来进行去重操作：

delete from tbl\_imsi2number\_new where imsi in (select imsi from (select imsi from tbl\_imsi2number\_new group by imsi having count(imsi) > 1) a) and number not in (select \* from (select min(number) from tbl\_imsi2number\_new group by imsi having count(imsi) > 1 ) b);

因为数据量太大(共计3亿多数据)，所以：

将开发那边拿过来的数据load data infile到大表里，不进行任何去重操作，没有任何约束。然后将这些数据分成几十个小文件，再load进几十个小表中，用这几十个小表去对比大表去重。得到去重后的小表。去重以后的小表，根据字段进行hash算出后两位数字（mod(conv(right(md5(imsi),2),16,10),100)）进行批量插入。

存储过程如下（去重）：

DELIMITER //

/\*tblname 动态控制表名\*/  
CREATE PROCEDURE create\_imsi(IN tblname varchar(200))  
begin  
declare age int default 1;  
declare done int(1) default 0;  
declare v\_imsi varchar(200);

/\*定义游标\*/  
declare cur\_l cursor for select imsi from sqlstr;

/\*定义异常\*/  
DECLARE CONTINUE HANDLER FOR SQLSTATE '02000' set done=1;  
drop view if exists sqlstr;

/\*定义视图\*/  
set @tbl = CONCAT("create view sqlstr as select a.imsi from tbl\_new a,(select imsi from phone\_",tblname," group by imsi having count(imsi) > 1) b where a.imsi = b.imsi group by imsi");

/\*执行视图语句\*/

PREPARE stmt FROM @tbl;  
EXECUTE stmt;  
DEALLOCATE PREPARE stmt;  
OPEN cur\_l;  
FETCH cur\_l INTO v\_imsi;  
while (done <> 1)  
do

/\*对比大表数据，删除小表中的重复数据\*/  
set @del = CONCAT("delete from phone\_",tblname," where imsi=",v\_imsi);  
PREPARE stmt1 FROM @del;  
EXECUTE stmt1;  
DEALLOCATE PREPARE stmt1;  
FETCH cur\_l INTO v\_imsi;  
end while;  
close cur\_l;  
end//

DELIMITER ;

2、根据hash算法插入新表：

DELIMITER //  
CREATE PROCEDURE insert\_imsi(IN tblname varchar(20))  
begin  
declare age int default 1;  
declare done int(1) default 0;  
declare done1 int(1) default 0;  
declare v\_imsi varchar(200);  
declare v\_e varchar(2000);  
declare v\_number varchar(3000);  
declare v\_ctype varchar(2000);  
declare cur\_l cursor for select split from sqlstr;  
DECLARE CONTINUE HANDLER FOR SQLSTATE '02000' set done=1;  
DECLARE CONTINUE HANDLER FOR 1146 set done1=3;  
DECLARE CONTINUE HANDLER FOR SQLSTATE '23000' set done1=1;  
DECLARE CONTINUE HANDLER FOR SQLSTATE '42000' set done1=2;  
DECLARE CONTINUE HANDLER FOR SQLSTATE 'HY000' set done1=3;  
drop view if exists sqlstx;  
drop view if exists sqlstr;  
set @sqlstx = CONCAT("create view sqlstr as SELECT imsi,number,ctype,mod(conv(right(md5(imsi),2),16,10),100) split from imsi\_phone\_",tblname);  
PREPARE stmt1 FROM @sqlstx;  
EXECUTE stmt1;  
DEALLOCATE PREPARE stmt1;  
OPEN cur\_l;  
WHILE done <> 1  
DO  
　　FETCH cur\_l INTO v\_e;  
　　set @ins = concat("insert into imsi\_",v\_e,"(imsi,number,ctype) select imsi,number,ctype from sqlstr where split = '",v\_e,"'");  
　　PREPARE stmt3 FROM @ins;  
　　EXECUTE stmt3;  
END WHILE;  
close cur\_l;  
end//

DELIMITER ;

报错：1、ERROR 1243 (HY000) at line 1: Unknown prepared statement handler (stmt3) given to EXECUTE

2、ERROR 1054 (42S22) at line 1: Unknown column '000cdc41b2a02518' in 'where clause'

由于set @dat = concat("insert into imsi\_",v\_e,"(imsi,number,ctype) select imsi,number,ctype from imsi\_phone\_",tblname," where imsi=‘’",v\_imsi，“‘’”);没有在（=）那里加单引号，因为字段里有字母。

参数优化：

由于建表使用innodb引擎，所以此优化是针对innodb引擎的：

1、innodb\_flush\_log\_at\_trx\_commit参数设置为1，减少刷新。  
2、set sql\_log\_bin=0　　暂时不产生二进制日志  
3、sync\_binlog　　设置为0，减少刷新  
4、innodb\_buffer\_pool\_size　　　　尽可能设置最大  
5、set foreign\_key\_checks=0　　去除外键检查  
6、减少不必要的索引，有重复数据的话，主键是必须要的  
7、innodb\_change\_buffer\_max\_size　　　　上限为50，这里我设置为40，因为load是插入数据，所以设置插入缓冲  
8、binlog\_cache\_size　　如果必须要开启二进制日志，设置此参数尽可能大，因为sync\_binlog设置为0，所以缓冲应该大  
9、innodb\_flush\_method　　　　刷新模式，设置为O\_DIRECT  
10、innodb\_io\_capacity　　　　刷新脏页，根据你的硬盘设置，SAS设置800--900  
11、innodb\_log\_buffer\_size与innodb\_sort\_buffer\_size　　尽可能设置最大  
12、unique\_checks　　设置为不检查：set unique\_checks=0;  
13、alter table tablename disable keys;设置表忽略索引，如果有。

14、设置自动提交为0，减少日志刷新：SET autocommit=0;

15、设置`innodb_autoinc_lock_mode=2`

16、设置主键，聚簇索引，按照主键顺序插入会更快

[44d63e08be9b9640e55d7a86eb4c7099.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/30/7147e0e8fd6247f3978cb89a6d7e114c.png