SQL命令运行缓慢。需要帮助识别缓慢

Question

我有一个SQL查询需要几个小时才能运行。基本上，我期待在我们的“页面”表格中找到具有特殊字符的文档（PDF）。我在PDFFile表中找到这些PDF。执行第一个AND子句将在16秒内返回。添加第二个子句使SQL花费3小时。试图找出我做错了什么。任何帮助是极大的赞赏。

查询：

select b.bookletname, b.trackingID, b.[version], s.name 
from page p 
inner join section s on s.id = p.sectionid 
inner join booklet b on b.id = s.bookletid 
INNER JOIN [user] u ON b.CreatedBy = u.id 
INNER JOIN client c ON c.id = u.clientID 
WHERE u.clientID = 2 
AND p.[filename] IN (
    SELECT DISTINCT pdf.[FileName] 
    FROM PDFFile pdf 
    WHERE pdf.fileName LIKE '%\<%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\>%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\"%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\%%' ESCAPE '\' 
    OR pdf.fileName LIKE '%''%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\*%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\+%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\\%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\/%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\:%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\?%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\[%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\]%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\|%' ESCAPE '\' 
) 
OR p.[PDF_File_Name] IN (
    SELECT DISTINCT pdf.[FileName] 
    FROM PDFFile pdf 
    WHERE pdf.fileName LIKE '%\<%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\>%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\"%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\%%' ESCAPE '\' 
    OR pdf.fileName LIKE '%''%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\*%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\+%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\\%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\/%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\:%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\?%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\[%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\]%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\|%' ESCAPE '\' 
) 
OR p.[PDFName] IN (
    SELECT DISTINCT pdf.[FileName] 
    FROM PDFFile pdf 
    WHERE pdf.fileName LIKE '%\<%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\>%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\"%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\%%' ESCAPE '\' 
    OR pdf.fileName LIKE '%''%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\*%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\+%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\\%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\/%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\:%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\?%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\[%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\]%' ESCAPE '\' 
    OR pdf.fileName LIKE '%\|%' ESCAPE '\' 
) 

Answer 1

用exists重写这个，并简化like s。 SQL Server允许你在模式中有字符列表，并且你所拥有的大部分字符都不需要转义（我希望我的结果模式完全正确）。

我会建议：

select b.bookletname, b.trackingID, b.[version], s.name 
from page p inner join 
    section s 
    on s.id = p.sectionid inner join 
    booklet b 
    on b.id = s.bookletid inner join 
    [user] u 
    on b.CreatedBy = u.id inner join 
    client c 
    on c.id = u.clientID 
where u.clientID = 2 and 
     (exists (select 1 
       from PDFFile pdf 
       where pdf.fileName LIKE '%[<>"''*+\\/:?\[\]|]%' ESCAPE '\' and 
        pdf.fileName = p.filename 
      ) or 
     exists (select 1 
       from PDFFile pdf 
       where pdf.fileName LIKE '%[<>"''*+\\/:?\[\]|]%' ESCAPE '\' and 
        pdf.fileName = p.PDF_File_Name 
      ) or 
     exists (select 1 
       from PDFFile pdf 
       where pdf.fileName LIKE '%[<>"''*+\\/:?\[\]|]%' ESCAPE '\' and 
        pdf.fileName = p.PDFName 
      ) 
    ); 

你要确保你的PDFFile(fileName)性能有一个索引。

我也改变了逻辑。您的原始逻辑像where A and B or C or D这被解析为where (A and B) or C or C。我将其更改为where A and (B or C or D)。这也可能是导致性能瓶颈的原因。

Answer 2

尝试取出三次表命中，并将该选择到临时表，因为你使用的是相同的选择要检查三列。所以你可以在任何情况下使用临时表。

SELECT DISTINCT pdf.[FileName] 
INTO #temp 
FROM PDFFile pdf 
WHERE pdf.fileName LIKE '%\<%' ESCAPE '\' 
     OR pdf.fileName LIKE '%\>%' ESCAPE '\' 
     OR pdf.fileName LIKE '%\"%' ESCAPE '\' 
     OR pdf.fileName LIKE '%\%%' ESCAPE '\' 
     OR pdf.fileName LIKE '%''%' ESCAPE '\' 
     OR pdf.fileName LIKE '%\*%' ESCAPE '\' 
     OR pdf.fileName LIKE '%\+%' ESCAPE '\' 
     OR pdf.fileName LIKE '%\\%' ESCAPE '\' 
     OR pdf.fileName LIKE '%\/%' ESCAPE '\' 
     OR pdf.fileName LIKE '%\:%' ESCAPE '\' 
     OR pdf.fileName LIKE '%\?%' ESCAPE '\' 
     OR pdf.fileName LIKE '%\[%' ESCAPE '\' 
     OR pdf.fileName LIKE '%\]%' ESCAPE '\' 
     OR pdf.fileName LIKE '%\|%' ESCAPE '\' 

SELECT b.bookletname, 
     b.trackingID, 
     b.[version], 
     s.NAME 
FROM page p 
     INNER JOIN section s 
       ON s.id = p.sectionid 
     INNER JOIN booklet b 
       ON b.id = s.bookletid 
     INNER JOIN [user] u 
       ON b.CreatedBy = u.id 
     INNER JOIN client c 
       ON c.id = u.clientID 
WHERE u.clientID = 2 
     AND p.[filename] IN (SELECT * 
          FROM #temp) 
     OR p.[PDF_File_Name] IN (SELECT * 
           FROM #temp) 
     OR p.[PDFName] IN (SELECT * 
          FROM #temp)