MYSQL查詢掛起發送狀態

Question

我有mysql查詢掛起發送數據階段。當分析慢查詢日誌

Rows_sent：176975081
Rows_examined：408406766個

行的這些數字是比的行數大於存在於表中。

下面是該查詢

select md.Event_id,db.Listing_ID,db.original_date, 
    DATE_FORMAT(ed.event_date, '%m-%d-%Y') AS 'EventDate', 
    datediff(ed.event_date,db.original_date), 
    zn.zonename, 
    sn.sectionname, 
    rn.Row_Name, 
    db.original_price, 
    db.last_date, 
    db.last_price, 
    (1 - (original_price/Last_Price)) as 'PercentChange' 


    from market_data as md 

    inner join id_result as db 

    on db.id=md.id 
    left join 
    zonename zn ON md.zn_id = zn.zoneId 
    inner JOIN 
    rowname rn ON md.RN_ID = rn.RN_ID 
    inner JOIN 
    sectionname sn ON md.SN_ID = sn.SN_ID 
    inner JOIN 
    event_data ed ON md.Event_id = ed.Event_id 
    where md.dirtyTicketInd=0 

下面是表結構

'CREATE TABLE `id_result` (
`id` int(11) NOT NULL, 
`listing_id` int(20) DEFAULT NULL, 
`original_date` date DEFAULT NULL, 
`original_price` decimal(10,2) DEFAULT NULL, 
`last_date` date DEFAULT NULL, 
`last_price` decimal(10,2) DEFAULT NULL, 
PRIMARY KEY (`id`), 
KEY `listing_id` (`listing_id`) 
) ENGINE=MyISAM DEFAULT CHARSET=latin1' 


'CREATE TABLE `market_data` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT, 
`currentPrice` varchar(10) NOT NULL DEFAULT ''0'', 
`SN_ID` int(11) NOT NULL, 
`quantity` tinyint(2) NOT NULL DEFAULT ''0'', 
`seatNumbers` varchar(60) NOT NULL DEFAULT ''0'', 
`ZN_ID` int(11) NOT NULL, 
`listingAttributeList` varchar(15) NOT NULL DEFAULT ''0'', 
`listingAttributeCategoryList` varchar(15) NOT NULL DEFAULT ''0'', 
`deliveryTypeList` varchar(15) NOT NULL DEFAULT ''0'', 
`ticketClass` varchar(15) NOT NULL DEFAULT ''0'', 
`dirtyTicketInd` tinyint(4) NOT NULL DEFAULT ''0'', 
`splitOption` tinyint(2) NOT NULL DEFAULT ''0'', 
`ticketSplit` tinyint(3) NOT NULL DEFAULT ''0'', 
    `splitVector` varchar(40) NOT NULL DEFAULT ''0'', 
    `sellerOwnInd` tinyint(3) NOT NULL DEFAULT ''0'', 
    `faceValue` varchar(25) NOT NULL DEFAULT ''0'', 
    `serviceFee` varchar(15) NOT NULL DEFAULT ''0'', 
    `deliveryFee` varchar(12) NOT NULL DEFAULT ''0'', 
    `totalCost` varchar(25) NOT NULL DEFAULT ''0'', 
    `score` decimal(12,7) NOT NULL DEFAULT ''0.0000000'', 
    `seller_price` decimal(10,5) NOT NULL DEFAULT ''0.00000'', 
    `Event_id` int(11) DEFAULT NULL, 
    `RN_ID` int(11) NOT NULL, 
    `SSN_ID` int(11) NOT NULL, 
    `LI_ID` int(11) NOT NULL, 
    `TS_ID` int(11) NOT NULL, 
    PRIMARY KEY (`id`), 
    KEY `SSN_ID` (`SSN_ID`), 
    KEY `SN_ID` (`SN_ID`), 
    KEY `ZN_ID` (`ZN_ID`), 
    KEY `event_id` (`Event_id`), 
    KEY `ts_id` (`TS_ID`), 
    KEY `LI_ID` (`LI_ID`) 
) ENGINE=MyISAM AUTO_INCREMENT=218909923 DEFAULT CHARSET=utf16' 

這是explain Plan

Answer 1

你有一個JOIN。它需要'檢查'兩個表中的行，所以計數很高。而且，由於您需要行的組合，「發送」比任何一個表都大。

（無關的註釋...）

utf16？我認爲我沒有聽說過有人使用過這個。謹慎加入字符串，特別是如果他們有不同的CHARACTER SETs。

費用和費用VARCHARs？很難算術或排序。