MySQL的 - 優化「使用臨時」引發的ORDER BY

Question

下面是該查詢

SELECT * FROM ProductReviews 
INNER JOIN RatingActions USING(RatingActionID) 
LEFT JOIN ProductRatingVotes USING(RatingActionID) 
WHERE ProductReviews.ProductID="200129" AND ProductReviewStatus="1" 
ORDER BY RatingActionTimestamp DESC; 

這裏是執行計劃

*************************** 1. row *************************** 
      id: 1 
    select_type: SIMPLE 
     table: ProductReviews 
     type: ref 
possible_keys: FK_ProductReview_ProductID,FK_ProductReviews_RatingActionID 
      key: FK_ProductReview_ProductID 
     key_len: 4 
      ref: const 
     rows: 1 
     Extra: Using where; Using temporary; Using filesort 
*************************** 2. row *************************** 
      id: 1 
    select_type: SIMPLE 
     table: ProductRatingVotes 
     type: ref 
possible_keys: FK_ProductRatingVotes_RatingActionID 
      key: FK_ProductRatingVotes_RatingActionID 
     key_len: 4 
      ref: scart.ProductReviews.RatingActionID 
     rows: 1 
     Extra: 
*************************** 3. row *************************** 
      id: 1 
    select_type: SIMPLE 
     table: RatingActions 
     type: eq_ref 
possible_keys: PRIMARY 
      key: PRIMARY 
     key_len: 4 
      ref: scart.ProductReviews.RatingActionID 
     rows: 1 
     Extra: 
3 rows in set (0.00 sec) 

雖然它的掃描只有一個排，using temporary殺死它，它需要3-4秒才能完成（一個非常繁忙的服務器;在我的本地主機上0.004秒，與沒有排序的版本相比，仍然是6倍慢）。

據我所知，using temporary是由於order by列不在第一個表中。

有沒有一種方法來優化此查詢，或者我應該將Timestamp複製到ProductReviews表中？

UPDATE 表：

CREATE TABLE `ProductReviews` (
`ProductReviewID` int(10) unsigned NOT NULL AUTO_INCREMENT, 
`ProductID` int(10) unsigned NOT NULL DEFAULT '0', 
`RatingActionID` int(10) unsigned NOT NULL DEFAULT '0', 
`ProductReviewText` text NOT NULL, 
`ProductReviewStatus` tinyint(3) unsigned NOT NULL DEFAULT '0', 
PRIMARY KEY (`ProductReviewID`), 
KEY `FK_ProductReview_ProductID` (`ProductID`), 
KEY `FK_ProductReviews_RatingActionID` (`RatingActionID`), 
CONSTRAINT `FK_ProductReviews_RatingActionID` FOREIGN KEY (`RatingActionID`) REFERENCES `ratingactions` (`RatingActionID`) ON DELETE CASCADE ON UPDATE CASCADE, 
CONSTRAINT `FK_ProductReview_ProductID` FOREIGN KEY (`ProductID`) REFERENCES `products` (`ProductID`) ON DELETE CASCADE ON UPDATE CASCADE 
) ENGINE=InnoDB AUTO_INCREMENT=66 DEFAULT CHARSET=utf8 

CREATE TABLE `ratingactions` (
`RatingActionID` int(10) unsigned NOT NULL AUTO_INCREMENT, 
`RatingActionTimestamp` int(10) unsigned NOT NULL DEFAULT '0', 
`CustomerID` int(10) unsigned DEFAULT NULL, 
`RatingActionIPAddress` int(10) unsigned NOT NULL DEFAULT '0', 
`RatingActionInputName` varchar(255) NOT NULL DEFAULT '', 
PRIMARY KEY (`RatingActionID`), 
KEY `FK_RatingActions_CustomerID` (`CustomerID`), 
CONSTRAINT `FK_RatingActions_CustomerID` FOREIGN KEY (`CustomerID`) REFERENCES `customers` (`CustomerID`) ON DELETE SET NULL ON UPDATE CASCADE 
) ENGINE=InnoDB AUTO_INCREMENT=142 DEFAULT CHARSET=utf8 

CREATE TABLE `ProductRatingVotes` (
`ProductRatingVoteID` int(10) unsigned NOT NULL AUTO_INCREMENT, 
`ProductID` int(10) unsigned NOT NULL DEFAULT '0', 
`RatingActionID` int(10) unsigned NOT NULL DEFAULT '0', 
`ProductRatingVoteValue` tinyint(3) unsigned NOT NULL DEFAULT '0', 
`ProductRatingVoteStatus` tinyint(3) unsigned NOT NULL DEFAULT '0', 
PRIMARY KEY (`ProductRatingVoteID`), 
KEY `FK_ProductRatingVotes_ProductID` (`ProductID`), 
KEY `FK_ProductRatingVotes_RatingActionID` (`RatingActionID`), 
CONSTRAINT `FK_ProductRatingVotes_ProductID` FOREIGN KEY (`ProductID`) REFERENCES 
`products` (`ProductID`) ON DELETE CASCADE ON UPDATE CASCADE, 
CONSTRAINT `FK_ProductRatingVotes_RatingActionID` FOREIGN KEY 
(`RatingActionID`) REFERENCES `ratingactions` (`RatingActionID`) ON 
DELETE CASCADE ON UPDATE CASCADE) 
ENGINE=InnoDB AUTO_INCREMENT=142 
DEFAULT CHARSET=utf8 

Answer 1

看來，其中一個表包含文本或BLOB字段和ORDER BY被迫使用磁盤排序。一種解決方案可能是在沒有子查詢中的字段的情況下進行排序，並再次與其餘列進行連接。

Answer 2

試試這個：

SELECT /*STRAIGHT_JOIN*/ ProductReviews.ProductID, RatingActionTimestamp 
FROM ratingactions 
join ProductReviews USING(RatingActionID) 
LEFT JOIN ProductRatingVotes USING(RatingActionID) 
WHERE ProductReviews.ProductID=200129 AND ProductReviewStatus=1 
order by RatingActionTimestamp desc; 

這應該消除了使用臨時使用文件排序額外的步驟。如果沒有，請嘗試取消註釋STRAIGHT_JOIN。

Answer 3

與所有其他不起作用的明顯的東西，我會然後提供以下...將產品評論移動到第一個位置作爲一個select/from本身...然後應用連接

SELECT STRAIGHT_JOIN 
     PR.ProductID, 
     RA.RatingActionTimestamp 
    FROM 
     (select PR1.ProductID, 
       PR1.RatingActionID 
      FROM ProductReviews PR1 
      WHERE 
       PR1.ProductID = 200129 
      AND PR1.ProductReviewStatus = 1) PR 
     JOIN rating actions RA 
      on PR.RatingActionID = RA.RatingActionID 
     LEFT JOIN ProductRatingVotes PRV 
      on PR.RatingActionID = PRV.RatingActionID 
    order by 
     RA.RatingActionTimestamp desc; 

這樣，它應該與您的預期，加盟評級行動。產品條用戶，讓那些有資格的條目有問題的獨特產品的單排造成的內部查詢開始，然後繼續參加了到評級行動的評級和評級表...