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$$CREATEDEFINER=`root`@`localhost`PROCEDURE`p`() BEGIN declaredoneintdefault0; declarev_roomidbigint; declarev_timetimestamp(6); declarev_cur_typesmallint;declarev_before_roomidbigintdefault-1; declarev_before_typesmallintdefault-1; declarev_before_timetimestamp(6);declarev_numbigintdefault0; declarecur_testCURSORforselectroomid,type,timepointfromtmp_time_pointorderbyroomid,timepoint,type; DECLARECONTINUEHANDLERFORNOTFOUNDSETdone=1; droptableifexistst1; droptableifexistst2; droptableifexiststmp_time_point; droptableifexiststmp_result; droptableifexiststmp_min_range;CREATEtemporaryTABLE`t1`( `roomid`int(11)NOTNULLDEFAULT'0', `userid`bigint(20)NOTNULLDEFAULT'0', `s`timestamp(6), `e`timestamp(6), primaryKEY`roomid`(`roomid`,`s`,`e`,`userid`) )ENGINE=memory;CREATEtemporaryTABLE`t2`( `roomid`int(11)NOTNULLDEFAULT'0', `s`timestamp(6), `e`timestamp(6), primaryKEY`roomid`(`roomid`,`s`,`e`) )ENGINE=memory;CREATEtemporaryTABLE`tmp_min_range`( `roomid`int(11)NOTNULLDEFAULT'0', `s`timestamp(6), `e`timestamp(6), primaryKEY`roomid`(`roomid`,`s`,`e`), key(roomid,e) )ENGINE=memory;createtemporarytabletmp_time_point( roomidbigint, timepointtimestamp(6), typesmallint, key(roomid,timepoint) )engine=memory;createtemporarytabletmp_result( roomidbigint, timepointtimestamp(6), cint )engine=memory;SET@A=0; SET@B=0; insertintot1(roomid,userid,s,e) selectdistinct roomid,userid, if(date(s)!=date(e)andid>1,date(s+intervalid-1date(s+intervalid-1date(e),e,date_format(s+intervalid-1'%Y-%m-%d23:59:59'))e from( SELECTx.roomid,x.userid,s,e FROM ( ( SELECT@B:=@B+1ASid,roomid,userid,s FROM( SELECTDISTINCTroomid,userid,roomstartASs FROMu_room_loga WHERENOTEXISTS(SELECT* FROMu_room_logb WHEREa.roomid=b.roomid ANDa.userid=b.userid ANDa.roomstart>b.roomstart ANDa.roomstart<=b.roomend) )ASp )ASx, ( SELECT@A:=@A+1ASid,roomid,userid,e FROM ( SELECTDISTINCTroomid,userid,roomendASe FROMu_room_loga WHERENOTEXISTS(SELECT* FROMu_room_logb WHEREa.roomid=b.roomid ANDa.userid=b.userid ANDa.roomend>=b.roomstart ANDa.roomend<b.roomend) )ASo )ASy ) WHEREx.id=y.idANDx.roomid=y.roomidANDx.userid=y.userid )t1, nums wherenums.id<=datediff(e,s)+1 ;insertintot2(roomid,s,e) selectroomid, s+intervalstartnum/1000000seconds, e-intervalendnum/1000000seconde from( select roomid, s,e, startnum, when@eflag=eflagthen@rn:=@rn+1when@eflag:=eflagthen@rnelse@rnendendnum from( select*from( selectwhen@sflag=sflagthen@rn:=@rn+1when@sflag:=sflagthen@rnelse@rnendstartnum,roomid,s,e,sflag,eflagfrom ( select*from ( selectt1.*,concat('[',roomid,'],',s)sflag,concat('[',roomid,'],',e)eflagfromt1orderbyroomid,sflag )a,(select@sflag:='',@rn:=0,@eflag:='')vars )b )bborderbyroomid,eflag )c )d;insertintotmp_time_point(roomid,timepoint,type)selectroomid,s,1fromt2; insertintotmp_time_point(roomid,timepoint,type)selectroomid,e,0fromt2;insertintotmp_min_range(roomid,s,e) selectdistinctroomid,starttimestarttime,endtimeendtimefrom( select if(@roomid=roomid,@d,'')asstarttime,@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 fromtmp_time_pointp,(select@d:='',@roomid:=-1)vars orderbyroomid,timepoint )v4wherestarttime!=''anddate(starttime)=date(endtime);opencur_test; repeat fetchcur_testintov_roomid,v_cur_type,v_time; ifdone!=1then --第一行或者每个房间的第一行 ifv_before_roomid=-1orv_roomid!=v_before_roomidthen setv_before_roomid:=v_roomid; setv_before_type:=1; setv_before_time:='0000-00-0000:00:00'; setv_num:=0; endif; ifv_before_type=1thensetv_num:=v_num+1;insertintotmp_result(roomid,timepoint,c)values(v_roomid,v_time,v_num); endif;ifv_before_type=0thensetv_num:=v_num-1;insertintotmp_result(roomid,timepoint,c)values(v_roomid,v_time,v_num); endif;setv_before_roomid:=v_roomid; setv_before_type:=v_cur_type; setv_before_time:=v_time; endif; untildoneendrepeat; closecur_test;selectroomid,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)-1cfrom( selecta.roomid,a.s,a.e,r.c,r.timepointfromtmp_resultr innerjoin tmp_min_rangeaon(r.timepoint=a.eandr.roomid=a.roomid) wherec>2 )agroupbyroomid,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.