Session重叠问题学习(五)--最优化

发布时间：2020-08-10 15:34:05 来源：ITPUB博客阅读：111 作者：壹頁書栏目：MySQL数据库

周五晚上10点了.
这一周连续优化Session合并和拆分问题.每天都比前一天提升性能一倍以上.
终于在今天,用独创的小花狸Session合并算法达到了最优级别.

令人振奋的1.5秒到2秒级别.

时间已经很晚了,思路也有些不清晰了.先把代码贴出来.下周再仔细解释一下这个奇妙算法。

DELIMITER $$
CREATE DEFINER=`root`@`localhost` PROCEDURE `p`()
BEGIN
declare done int default 0;
declare v_roomid bigint;
declare v_time timestamp(6);
declare v_cur_type smallint;
declare v_before_roomid bigint default -1;
declare v_before_type smallint default -1;
declare v_before_time timestamp(6) ;
declare v_num bigint default 0;
declare cur_test CURSOR for select roomid,type,timepoint from tmp_time_point order by roomid,timepoint,type ;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
drop table if exists t1;
drop table if exists t2;
drop table if exists tmp_time_point;
drop table if exists tmp_result;
drop table if exists tmp_min_range;
CREATE temporary TABLE `t1` (
`roomid` int(11) NOT NULL DEFAULT '0',
`userid` bigint(20) NOT NULL DEFAULT '0',
`s` timestamp(6),
`e` timestamp(6),
primary KEY `roomid` (`roomid`,`s`,`e`,`userid`)
) ENGINE=memory;
CREATE temporary TABLE `t2` (
`roomid` int(11) NOT NULL DEFAULT '0',
`s` timestamp(6),
`e` timestamp(6),
primary KEY `roomid` (`roomid`,`s`,`e`)
) ENGINE=memory;
CREATE temporary TABLE `tmp_min_range` (
`roomid` int(11) NOT NULL DEFAULT '0',
`s` timestamp(6),
`e` timestamp(6),
primary KEY `roomid` (`roomid`,`s`,`e`),
key(roomid,e)
) ENGINE=memory;
create temporary table tmp_time_point(
roomid bigint,
timepoint timestamp(6),
type smallint,
key(roomid,timepoint)
) engine=memory;
create temporary table tmp_result(
roomid bigint,
timepoint timestamp(6),
c int
) engine=memory;
SET @A=0;
SET @B=0;
insert into t1(roomid,userid,s,e)
select distinct
roomid, userid,
if(date(s)!=date(e) and id>1,date(s+interval id-1 date(s+interval id-1 date(e) ,e,date_format(s+interval id-1 '%Y-%m-%d 23:59:59')) e
from (
SELECT x.roomid,x.userid,s,e
FROM
(
(
SELECT @B:=@B+1 AS id,roomid,userid,s
FROM (
SELECT DISTINCT roomid, userid, roomstart AS s
FROM u_room_log a
WHERE NOT EXISTS (SELECT *
FROM u_room_log b
WHERE a.roomid = b.roomid
AND a.userid = b.userid
AND a.roomstart > b.roomstart
AND a.roomstart <= b.roomend)
) AS p
) AS x,
(
SELECT @A:=@A+1 AS id,roomid,userid,e
FROM
(
SELECT DISTINCT roomid, userid, roomend AS e
FROM u_room_log a
WHERE NOT EXISTS (SELECT *
FROM u_room_log b
WHERE a.roomid = b.roomid
AND a.userid = b.userid
AND a.roomend >= b.roomstart
AND a.roomend < b.roomend)
) AS o
) AS y
)
WHERE x.id = y.id AND x.roomid = y.roomid AND x.userid = y.userid
) t1 ,
nums
where nums.id<=datediff(e,s)+1
;
insert into t2 (roomid,s,e)
select roomid,
s+interval startnum/1000000 second s,
e-interval endnum/1000000 second e
from (
select
roomid,
s,e,
startnum,
when @eflag=eflag then @rn:=@rn+1 when @eflag:=eflag then @rn else @rn end endnum
from (
select * from (
select when @sflag=sflag then @rn:=@rn+1 when @sflag:=sflag then @rn else @rn end startnum,roomid,s,e,sflag,eflag from
(
select * from
(
select t1.*,concat('[',roomid,'],',s) sflag,concat('[',roomid,'],',e) eflag from t1 order by roomid ,sflag
)a,(select @sflag:='',@rn:=0,@eflag:='') vars
) b
) bb order by roomid,eflag
) c
) d ;
insert into tmp_time_point(roomid,timepoint,type) select roomid,s,1 from t2;
insert into tmp_time_point(roomid,timepoint,type) select roomid,e,0 from t2;
insert into tmp_min_range(roomid,s,e)
select distinct roomid,starttime starttime, endtime endtime from (
select
if(@roomid=roomid,@d,'') as starttime,@d:=str_to_date(timepoint,'%Y-%m-%d %H:%i:%s.%f'),@roomid:=roomid,p.roomid,str_to_date(timepoint,'%Y-%m-%d %H:%i:%s.%f') endtime
from tmp_time_point p,(select @d:='',@roomid:=-1) vars
order by roomid,timepoint
) v4 where starttime!='' and date(starttime)=date(endtime);
open cur_test;
repeat
fetch cur_test into v_roomid,v_cur_type,v_time;
if done !=1 then
-- 第一行或者每个房间的第一行
if v_before_roomid=-1 or v_roomid!=v_before_roomid then
set v_before_roomid:=v_roomid;
set v_before_type:=1;
set v_before_time:='0000-00-00 00:00:00';
set v_num:=0;
end if;
if v_before_type=1 then
set v_num:=v_num+1;
insert into tmp_result(roomid,timepoint,c) values(v_roomid,v_time,v_num);
end if;
if v_before_type=0 then
set v_num:=v_num-1;
insert into tmp_result(roomid,timepoint,c) values(v_roomid,v_time,v_num);
end if;
set v_before_roomid:=v_roomid;
set v_before_type:=v_cur_type;
set v_before_time:=v_time;
end if;
until done end repeat;
close cur_test;
select roomid,date(s) dt,round(second,date_format(s,'%Y-%m-%d %H:%i:%s'),date_format(e,'%Y-%m-%d %H:%i:%s')))/60) ts,max(c)-1 c from (
select a.roomid,a.s,a.e,r.c,r.timepoint from tmp_result r
inner join
tmp_min_range a on( r.timepoint=a.e and r.roomid=a.roomid)
where c>2
) a group by roomid,date(s);
END

和之前的算法比较,结果一致。基本上都在1.6秒左右.

向AI问一下细节

Session重叠问题学习(五)--最优化

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