long sql優化例項 todo

create table `hbt_messageflow` (

`id` int(11) not null auto_increment,
`shopid` int(11) default null,
`receive` varchar(50) not null comment '接收方',
`configid` int(11) default null comment '配置資訊模版id',
`reftype` int(11) not null comment '型別',
`refid` varchar(50) not null comment '型別值',
`sendstatus` int(11) not null comment '傳送狀態',
`meno` varchar(200) not null comment 'meno',
`content` varchar(1000) not null comment '引數內容',
`addtime` datetime not null,
`updatetime` timestamp not null default current_timestamp on update current_timestamp comment '更新時間',
primary key (`id`),
key `ix_addtime` (`addtime`),
key `ix_updatetime` (`updatetime`),
key `ix_receive` (`receive`),
key `ix_reftype` (`reftype`),
key `ix_refid` (`refid`)
) engine=innodb auto_increment=1384415 default charset=utf8 comment='傳送訊息記錄表'

created: 2016-09-12

engine: innodb

rows: 815558

size: 282 mib

encoding: utf8_general_ci

auto-increment: 1384415

原始long-sql

explain select id ,shopid,receive, configid, reftype, refid, sendstatus, meno, content,addtime from hbt_messageflow where configid = 13 and receive = '18358169297' and sendstatus = 200 order by addtime desc limit 1

idselect_type

table

type

possible_keys

keykey_len

refrows

extra

1******

hbt_messageflow

index

ix_receive

ix_addtime566

using where

增加limit

explain select id ,shopid,receive, configid, reftype, refid, sendstatus, meno, content,addtime from hbt_messageflow where configid = 13 and receive = '18358169297' and sendstatus = 200 order by addtime desc limit 10

idselect_type

table

type

possible_keys

keykey_len

refrows

extra

1******

hbt_messageflow

index

ix_receive

ix_addtime

5663

using where

explain select id ,shopid,receive, configid, reftype, refid, sendstatus, meno, content,addtime from hbt_messageflow where configid = 13 and receive = '18358169297' and sendstatus = 200 order by addtime desc limit 184

idselect_type

table

type

possible_keys

keykey_len

refrows

extra

1******

hbt_messageflow

refix_receive

ix_receive

152const

12192

using index condition; using where; using filesort

去除desc

explain select id ,shopid,receive, configid, reftype, refid, sendstatus, meno, content,addtime from hbt_messageflow where configid = 13 and receive = '18358169297' and sendstatus = 200 order by addtime limit 1

select_type

table

type

possible_keys

keykey_len

refrows

extra

1******

hbt_messageflow

index

ix_receive

ix_addtime566

using where

更改order列

explain select id ,shopid,receive, configid, reftype, refid, sendstatus, meno, content,addtime from hbt_messageflow where configid = 13 and receive = '18358169297' and sendstatus = 200 order by id desc limit 1

select_type

table

type

possible_keys

keykey_len

refrows

extra

1******

hbt_messageflow

refix_receive

ix_receive

152const

12192

using where

刪除sendstatus和configid條件

explain select id ,shopid,receive, configid, reftype, refid, sendstatus, meno, content,addtime from hbt_messageflow where receive = '18358169297'  order by addtime desc limit 1

idselect_type

table

type

possible_keys

keykey_len

refrows

extra

1******

hbt_messageflow

index

ix_receive

ix_addtime566

using where

更改receive條件為15901736035(特徵：首次命中記錄的id靠前)

explain select id ,shopid,receive, configid, reftype, refid, sendstatus, meno, content,addtime from hbt_messageflow where configid = 13 and receive = '15901736035' and sendstatus = 200 order by addtime desc limit 1

idselect_type

table

type

possible_keys

keykey_len

refrows

extra

1******

hbt_messageflow

refix_receive

ix_receive

152const

184using index condition; using where; using filesort

receive + addtime聯合查詢

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