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  • 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

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  • 原文地址:https://www.cnblogs.com/yfceshi/p/6805244.html
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