SQL Server查询运行速度非常慢

以下通过SQL Server Management Studio执行的查询非常缓慢。SQL Server查询运行速度非常慢

输入表tbl_sb12_bhs约有40000条记录，一小时后只处理40条记录。

在这里可以改变什么使其运行速度更快？

DECLARE @bsrange INT 

SET @bsrange = 0 

WHILE @bsrange <= (SELECT max([p_a_l_out]) 
        FROM [DB001].[FD\f7].[tbl_sb12_bhs]) 
    BEGIN 
     INSERT INTO [FD\f7].tbl_sb13_b_lin1 
        (aId, 
        p_a_l_out, 
        bs_id, 
        bs_db, 
        bs_tbl, 
        bs_column, 
        Int1, 
        cd1, 
        Hop1, 
        Int2, 
        cd2, 
        Hop2, 
        Int3, 
        cd3, 
        Hop3, 
        Int4, 
        cd4, 
        Hop4, 
        Int5, 
        cd5, 
        Hop5, 
        Int6, 
        cd6, 
        Hop6, 
        Int7, 
        cd7, 
        Hop7, 
        Int8, 
        cd8, 
        Hop8, 
        Int9, 
        cd9, 
        Hop9, 
        Int10, 
        cd10, 
        Hop10, 
        Int11, 
        cd11, 
        Hop11, 
        Int12, 
        cd12, 
        Hop12, 
        Int13, 
        cd13, 
        Hop13, 
        Int14, 
        cd14, 
        Hop14, 
        Int15, 
        cd15, 
        Hop15, 
        Int16, 
        cd16, 
        Hop16) 
     SELECT DISTINCT tbl_sb12_bhs.aId, 
         tbl_sb12_bhs.p_a_l_out, 
         tbl_sb12_bhs.bs_id, 
         tbl_sb12_bhs.bs_db, 
         tbl_sb12_bhs.bs_tbl, 
         tbl_sb12_bhs.bs_column, 
         tbl_rpt_val_pt_crl.pt_el_Int AS Int1, 
         tbl_rpt_val_pt_crl.user_cd  AS cd1, 
         tbl_rpt_val_pt_crl.cfk_upel  AS Hop1, 
         tbl_rpt_val_pt_crl_1.pt_el_Int AS Int2, 
         tbl_rpt_val_pt_crl_1.user_cd AS cd2, 
         tbl_rpt_val_pt_crl_1.cfk_upel AS Hop2, 
         tbl_rpt_val_pt_crl_2.pt_el_Int AS Int3, 
         tbl_rpt_val_pt_crl_2.user_cd AS cd3, 
         tbl_rpt_val_pt_crl_2.cfk_upel AS Hop3, 
         tbl_rpt_val_pt_crl_3.pt_el_Int AS Int4, 
         tbl_rpt_val_pt_crl_3.user_cd AS cd4, 
         tbl_rpt_val_pt_crl_3.cfk_upel AS Hop4, 
         tbl_rpt_val_pt_crl_4.pt_el_Int AS Int5, 
         tbl_rpt_val_pt_crl_4.user_cd AS cd5, 
         tbl_rpt_val_pt_crl_4.cfk_upel AS Hop5, 
         tbl_rpt_val_pt_crl_5.pt_el_Int AS Int6, 
         tbl_rpt_val_pt_crl_5.user_cd AS cd6, 
         tbl_rpt_val_pt_crl_5.cfk_upel AS Hop6, 
         tbl_rpt_val_pt_crl_6.pt_el_Int AS Int7, 
         tbl_rpt_val_pt_crl_6.user_cd AS cd7, 
         tbl_rpt_val_pt_crl_6.cfk_upel AS Hop7, 
         tbl_rpt_val_pt_crl_7.pt_el_Int AS Int8, 
         tbl_rpt_val_pt_crl_7.user_cd AS cd8, 
         tbl_rpt_val_pt_crl_7.cfk_upel AS Hop8, 
         tbl_rpt_val_pt_crl_8.pt_el_Int AS Int9, 
         tbl_rpt_val_pt_crl_8.user_cd AS cd9, 
         tbl_rpt_val_pt_crl_8.cfk_upel AS Hop9, 
         tbl_rpt_val_pt_crl_9.pt_el_Int AS Int10, 
         tbl_rpt_val_pt_crl_9.user_cd AS cd10, 
         tbl_rpt_val_pt_crl_9.cfk_upel AS Hop10, 
         tbl_rpt_val_pt_crl_10.pt_el_Int AS Int11, 
         tbl_rpt_val_pt_crl_10.user_cd AS cd11, 
         tbl_rpt_val_pt_crl_10.cfk_upel AS Hop11, 
         tbl_rpt_val_pt_crl_11.pt_el_Int AS Int12, 
         tbl_rpt_val_pt_crl_11.user_cd AS cd12, 
         tbl_rpt_val_pt_crl_11.cfk_upel AS Hop12, 
         tbl_rpt_val_pt_crl_12.pt_el_Int AS Int13, 
         tbl_rpt_val_pt_crl_12.user_cd AS cd13, 
         tbl_rpt_val_pt_crl_12.cfk_upel AS Hop13, 
         tbl_rpt_val_pt_crl_13.pt_el_Int AS Int14, 
         tbl_rpt_val_pt_crl_13.user_cd AS cd14, 
         tbl_rpt_val_pt_crl_13.cfk_upel AS Hop14, 
         tbl_rpt_val_pt_crl_14.pt_el_Int AS Int15, 
         tbl_rpt_val_pt_crl_14.user_cd AS cd15, 
         tbl_rpt_val_pt_crl_14.cfk_upel AS Hop15, 
         tbl_rpt_val_pt_crl_15.pt_el_Int AS Int16, 
         tbl_rpt_val_pt_crl_15.user_cd AS cd16, 
         tbl_rpt_val_pt_crl_15.cfk_upel AS Hop16 
     FROM (SELECT DISTINCT pk_a AS aId, 
           p_a_l_out, 
           bs_id, 
           bs_db, 
           bs_tbl, 
           bs_column, 
           hop_pt_id_1, 
           hop_pt_id_2, 
           hop_pt_id_3, 
           hop_pt_id_4, 
           hop_pt_id_5, 
           hop_pt_id_6, 
           hop_pt_id_7, 
           hop_pt_id_8, 
           hop_pt_id_9, 
           hop_pt_id_10, 
           hop_pt_id_11, 
           hop_pt_id_12, 
           hop_pt_id_13, 
           hop_pt_id_14, 
           hop_pt_id_15, 
           hop_pt_id_16 
       FROM [FD\f7].tbl_sb12_bhs 
       WHERE [p_a_l_out] >= @bsrange 
        AND [p_a_l_out] < (@bsrange + 1)) AS tbl_sb12_bhs 
      LEFT JOIN tbl_rpt_val_pt_crl 
       ON tbl_sb12_bhs.hop_pt_id_1 = tbl_rpt_val_pt_crl.sk_el_pt 
      LEFT JOIN tbl_rpt_val_pt_crl AS tbl_rpt_val_pt_crl_1 
       ON tbl_sb12_bhs.hop_pt_id_2 = tbl_rpt_val_pt_crl_1.sk_el_pt 
      LEFT JOIN tbl_rpt_val_pt_crl AS tbl_rpt_val_pt_crl_2 
       ON tbl_sb12_bhs.hop_pt_id_3 = tbl_rpt_val_pt_crl_2.sk_el_pt 
      LEFT JOIN tbl_rpt_val_pt_crl AS tbl_rpt_val_pt_crl_3 
       ON tbl_sb12_bhs.hop_pt_id_4 = tbl_rpt_val_pt_crl_3.sk_el_pt 
      LEFT JOIN tbl_rpt_val_pt_crl AS tbl_rpt_val_pt_crl_4 
       ON tbl_sb12_bhs.hop_pt_id_5 = tbl_rpt_val_pt_crl_4.sk_el_pt 
      LEFT JOIN tbl_rpt_val_pt_crl AS tbl_rpt_val_pt_crl_5 
       ON tbl_sb12_bhs.hop_pt_id_6 = tbl_rpt_val_pt_crl_5.sk_el_pt 
      LEFT JOIN tbl_rpt_val_pt_crl AS tbl_rpt_val_pt_crl_6 
       ON tbl_sb12_bhs.hop_pt_id_7 = tbl_rpt_val_pt_crl_6.sk_el_pt 
      LEFT JOIN tbl_rpt_val_pt_crl AS tbl_rpt_val_pt_crl_7 
       ON tbl_sb12_bhs.hop_pt_id_8 = tbl_rpt_val_pt_crl_7.sk_el_pt 
      LEFT JOIN tbl_rpt_val_pt_crl AS tbl_rpt_val_pt_crl_8 
       ON tbl_sb12_bhs.hop_pt_id_9 = tbl_rpt_val_pt_crl_8.sk_el_pt 
      LEFT JOIN tbl_rpt_val_pt_crl AS tbl_rpt_val_pt_crl_9 
       ON tbl_sb12_bhs.hop_pt_id_10 = tbl_rpt_val_pt_crl_9.sk_el_pt 
      LEFT JOIN tbl_rpt_val_pt_crl AS tbl_rpt_val_pt_crl_10 
       ON tbl_sb12_bhs.hop_pt_id_11 = tbl_rpt_val_pt_crl_10.sk_el_pt 
      LEFT JOIN tbl_rpt_val_pt_crl AS tbl_rpt_val_pt_crl_11 
       ON tbl_sb12_bhs.hop_pt_id_12 = tbl_rpt_val_pt_crl_11.sk_el_pt 
      LEFT JOIN tbl_rpt_val_pt_crl AS tbl_rpt_val_pt_crl_12 
       ON tbl_sb12_bhs.hop_pt_id_13 = tbl_rpt_val_pt_crl_12.sk_el_pt 
      LEFT JOIN tbl_rpt_val_pt_crl AS tbl_rpt_val_pt_crl_13 
       ON tbl_sb12_bhs.hop_pt_id_14 = tbl_rpt_val_pt_crl_13.sk_el_pt 
      LEFT JOIN tbl_rpt_val_pt_crl AS tbl_rpt_val_pt_crl_14 
       ON tbl_sb12_bhs.hop_pt_id_15 = tbl_rpt_val_pt_crl_14.sk_el_pt 
      LEFT JOIN tbl_rpt_val_pt_crl AS tbl_rpt_val_pt_crl_15 
       ON tbl_sb12_bhs.hop_pt_id_16 = tbl_rpt_val_pt_crl_15.sk_el_pt 

     SET @bsrange = @bsrange + 1 
    END

来源

2013-05-01 user2337289

规范化表有16行每实体上tbl_rpt_val_pt_crl参加一次，而不是16列上tbl_rpt_val_pt_crl加入了16倍。 – HardCode 2013-05-01 19:19:02

想想如何在没有循环的情况下运行单个插入quey。 – 2013-05-01 19:34:19

你可以（尝试）将结果扔到#temp表中......然后插入？ – granadaCoder 2013-05-01 19:34:36

我最好的猜测是它速度很慢，因为你一次做一些密集的操作。没有任何样本数据很难，但我可以尝试提出一些建议。

从你所说的只有一小时后才能处理40条记录，这是循环内部正在发生的事情，正在减慢你的速度。

SELECT DISTINCT并不便宜，因为它必须比较所有数据，并且您还比较了很多列。如果可以的话，如果将列数限制为明确选择所需的最小值，然后将其自动加入到原始表中，则运行速度可能会更快。它应该足够简单，以便对其余部分进行单独测试，以确保获得相同的结果以及是否更快。

此外，您拥有的联接越多，性能越差越好......我们为标准化付出的代价。

无论如何，我会退一步尝试将其分解成最小的工作单元，然后您可以单独测试每个单元，直到找到罪魁祸首。这样做，你可能会想到一个更好的方法来做到这一点。再次，没有任何样本数据，这对我来说很难帮助。

来源

2013-05-01 19:43:21 ubercam

那么，如果你有一个或多个目标索引，那么SQL将重新索引每一行。我会禁用目标表上的任何索引，然后在插入完成时将它们重新命名。 Id批处理插入inro范围（说）5k记录，所以任何阻塞将减少，或者我会创建一个临时文件作为select和bcp结果中的结果。因为每次在插入一条记录之前，你都要做这个可怕的左连接。 SQL只能优化大约7或8个左右连接。我的猜测是，表中插入的索引很少或没有索引，从这意味着每个联接的表扫描或对插入的每个行的大约17个表扫描。对不起，但这种方法在每个阶段都是错误的。或者你可以让你的老板给你买一个datecentre ....

来源

2013-05-01 19:39:02

您可能想要做的另一件事是最初将连接加入临时表中，然后引用该连接。你不必每次都做独特或加入。只需添加bsrange的where子句即可。

因此，这将是这样的：

Create temporary table with as much of the joins/distinct as you can. 
while..... 
    insert into [FD\f7].tbl_sb13_b_lin1 
     select * from temptable where [p_a_l_out] >= @bsrange 
        AND [p_a_l_out] < (@bsrange + 1)

来源

2013-05-02 12:22:15

SQL Server查询运行速度非常慢

回答

相关问题