postLivecommentHandler の N+1

[Ryoga]

livecomment_handler.go の postLivecommentHandler

isucon13/go/livecomment_handler.go

Lines 205 to 222 in 71acd86

 	var hitSpam int 
 	for _, ngword := range ngwords { 
 		query := ` 
 		SELECT COUNT(*) 
 		FROM 
 		(SELECT ? AS text) AS texts 
 		INNER JOIN 
 		(SELECT CONCAT('%', ?, '%')	AS pattern) AS patterns 
 		ON texts.text LIKE patterns.pattern; 
 		` 
 		if err := tx.GetContext(ctx, &hitSpam, query, req.Comment, ngword.Word); err != nil { 
 			return echo.NewHTTPError(http.StatusInternalServerError, "failed to get hitspam: "+err.Error()) 
 		} 
 		c.Logger().Infof("[hitSpam=%d] comment = %s", hitSpam, req.Comment) 
 		if hitSpam >= 1 { 
 			return echo.NewHTTPError(http.StatusBadRequest, "このコメントがスパム判定されました") 
 		} 
 	} 

[Ryoga]

N+1 ではなく、SQL を正規表現エンジンとして使ってしまっているあれだ