mysql开发之---使用游标双层嵌套对总表进行拆分为帖子表和回复表

注意点：

（1）进行拆分的总表表名是不同的。所以创建暂时表，把总表的数据先插入暂时表

（2）为了避免最外层游标轮询数据结束时，抛出 not found 退出程序，不会运行关闭游标等兴许操作，定义continue handler。 declare continue handler for not found set done1=1;

1.1、外部存储过程调用主存储过程

CREATE PROCEDURE `bbs_split_thread_post_outer`(IN `in_tabname` varchar(128))

BEGIN

declare v_row_count int(11);

declare v_sql varchar(200);



-- 必须清空暂时表bbs_fromask_importask_tmp

select sysdate();

truncate table bbs_fromask_importask_tmp;





set @sql=concat('insert into bbs_fromask_importask_tmp select * from ',in_tabname,';');

prepare stmt from @sql;

execute stmt;



call bbs_split_thread_post();





select sysdate();

END

CREATE PROCEDURE `bbs_split_thread_post`()

BEGIN

declare v_source_count int(11);

declare v_thread_pkid int(11);

declare v_thread_pkid_uni_count int(11);

  declare done1,done2 int default 0;

declare v_cur_thread_pkid cursor for select pkid,count(*) from bbs_fromask_importask_tmp group by pkid;

declare continue handler for not found set done1=1;





-- 清空暂时表

truncate table pre_data_thread_tmp;

truncate table pre_data_post_tmp;



-- 推断原表是否有数据，没有什么也不做

select count(*) into v_source_count from bbs_fromask_importask_tmp;

if v_source_count>0 then

    select ifnull(max(id),0) into @thread_max_id from yaolanbbs.pre_data_thread; -- 可做改动

  select @thread_max_id;

 

  -- 打开游标

  open v_cur_thread_pkid;

  repeat

  fetch v_cur_thread_pkid into v_thread_pkid,v_thread_pkid_uni_count;

  -- 每次fetch最大id自增1

  if not done1 then

  set @thread_max_id=@thread_max_id+1;

  insert into pre_data_thread_tmp(id,title,age,rule,param)

  select @thread_max_id,t1.qtitle,t1.age,'age',t1.age from bbs_fromask_importask_tmp t1 where t1.pkid=v_thread_pkid limit 1;

  -- 依据pkid对一组数据进行处理

  begin

  declare v_post_answer text;

  declare v_cur_post_record cursor for select t1.answer from bbs_fromask_importask_tmp t1 where t1.pkid=v_thread_pkid;

  declare exit handler for not found close v_cur_post_record;

  -- declare continue handler for not found set done2=1;

 

  insert into pre_data_post_tmp(tid,text,sort)

  select @thread_max_id,t1.qdesc,1 from bbs_fromask_importask_tmp t1 where t1.pkid=v_thread_pkid limit 1;

 

  set @sort=2; ######设置值

  open v_cur_post_record;

  repeat 

  fetch v_cur_post_record into v_post_answer;

   -- select @sort;

  -- select v_post_answer;

  insert into pre_data_post_tmp(tid,text,sort) values(@thread_max_id,v_post_answer,@sort);

  -- insert into testincre values(@sort,v_post_answer);

  set @sort=@sort+1;

  until 0 end repeat;

  -- select curdate(); 不会运行的原因。定义exit handler

  close v_cur_post_record;

  end;

  end if;

  until done1 end repeat;

  -- 关闭游标

  close v_cur_thread_pkid;

  -- select curdate();

  /*-- 导入终于表

  insert into pre_data_thread(id,title,create_time,age,rule,param)

  select id,title,create_time,age,rule,param from pre_data_thread_tmp;

  insert into pre_data_post(tid,text,sort,create_time)

  select tid,text,sort,create_time from pre_data_post_tmp;

*/

end if;

END

总结：

（1）30G内存没有负载的情况下。8488276行拆为两个表共10500000行用时39分钟

drop procedure if exists if_var_inner_updated_swap;

create procedure `if_var_inner_updated_swap`()

begin



declare ind int (8);



declare update_status char (10);



declare swap_status char (10);





select

id

from

datalogic_var_inner_update_swap_log

where

task_name = "datalogic_var_inner_apply_hist_uuid_01_backup"

and task_date = curdate() into ind;



select

task_update_status

from

datalogic_var_inner_update_swap_log

where

id = ind into update_status;



select

task_swap_status

from

datalogic_var_inner_update_swap_log

where

id = ind into swap_status;



if (

update_status = 'finished'

and swap_status =0

) then

rename table datalogic_var_inner_apply_hist_uuid_01 to datalogic_var_inner_apply_hist_uuid_01_temp,

datalogic_var_inner_apply_hist_uuid_01_backup to datalogic_var_inner_apply_hist_uuid_01,

datalogic_var_inner_apply_hist_uuid_01_temp to datalogic_var_inner_apply_hist_uuid_01_backup;



update datalogic_var_inner_update_swap_log

set task_swap_status = '1'

where

id = ind;

end if;



end