查询运行快，但在存储过程中运行慢 [英] Query runs fast, but runs slow in stored procedure

问题描述

我正在使用 SQL 2005 分析器进行一些测试.

I am doing some tests using the SQL 2005 profiler.

我有一个存储过程，它只运行一个 SQL 查询.

I have a stored procedure which simply runs one SQL query.

当我运行存储过程时，它需要很长时间并执行 800,000 次磁盘读取.

When I run the stored procedure, it takes a long time and performs 800,000 disk reads.

当我在存储过程之外运行相同的查询时，它会读取 14,000 次磁盘.

When I run the same query separate to the stored procedure, it does 14,000 disk reads.

我发现，如果我使用 OPTION(重新编译)运行相同的查询，则需要 800,000 次磁盘读取.

I found that if I run the same query with OPTION(recompile), it takes 800,000 disk reads.

由此，我做出(可能是错误的)假设，即存储过程每次都在重新编译，这就是问题所在.

From this, I make the (possibly erroneous) assumption that the stored procedure is recompiling each time, and that's causing the problem.

有人可以对此有所了解吗?

Can anyone shed some light onto this?

我已将 ARITHABORT 设为 ON.(这在stackoverflow上解决了类似的问题，但没有解决我的)

I have set ARITHABORT ON. (This solved a similar problem on stackoverflow, but didn't solve mine)

这里是整个存储过程:

CREATE PROCEDURE [dbo].[GET_IF_SETTLEMENT_ADJUSTMENT_REQUIRED]
 @Contract_ID int,
 @dt_From smalldatetime,
 @dt_To smalldatetime,
 @Last_Run_Date datetime
AS
BEGIN
 DECLARE @rv int


 SELECT @rv = (CASE WHEN EXISTS
 (
  select * from 
  view_contract_version_last_volume_update
  inner join contract_version
  on contract_version.contract_version_id = view_contract_version_last_volume_update.contract_version_id
  where contract_version.contract_id=@Contract_ID
  and volume_date >= @dt_From
  and volume_date < @dt_To
  and last_write_date > @Last_Run_Date
 )
 THEN 1 else 0 end)

 -- Note that we are RETURNING a value rather than SELECTING it.
 -- This means we can invoke this function from other stored procedures
 return @rv
END

这是我运行的演示问题的脚本:

Here's a script I run that demonstrates the problem:

DECLARE 
 @Contract_ID INT,
 @dt_From smalldatetime,
 @dt_To smalldatetime,
 @Last_Run_Date datetime,
    @rv int


SET @Contract_ID=38
SET @dt_From='2010-09-01'
SET @dt_To='2010-10-01'
SET @Last_Run_Date='2010-10-08 10:59:59:070'


-- This takes over fifteen seconds
exec GET_IF_SETTLEMENT_ADJUSTMENT_REQUIRED @Contract_ID=@Contract_ID,@dt_From=@dt_From,@dt_To=@dt_To,@Last_Run_Date=@Last_Run_Date

-- This takes less than one second!
SELECT @rv = (CASE WHEN EXISTS
(
 select * from 
 view_contract_version_last_volume_update
 inner join contract_version
 on contract_version.contract_version_id = view_contract_version_last_volume_update.contract_version_id
 where contract_version.contract_id=@Contract_ID
 and volume_date >= @dt_From
 and volume_date < @dt_To
 and last_write_date > @Last_Run_Date
)
THEN 1 else 0 end)


-- With recompile option. Takes 15 seconds again!
SELECT @rv = (CASE WHEN EXISTS
(
 select * from 
 view_contract_version_last_volume_update
 inner join contract_version
 on contract_version.contract_version_id = view_contract_version_last_volume_update.contract_version_id
 where contract_version.contract_id=@Contract_ID
 and volume_date >= @dt_From
 and volume_date < @dt_To
 and last_write_date > @Last_Run_Date
)
THEN 1 else 0 end) OPTION(recompile)

推荐答案

好的，我们之前也遇到过类似的问题.

OK, we have had similar issues like this before.

我们解决这个问题的方法是在 SP 内部设置局部参数，这样

The way we fixed this, was by making local parameters inside the SP, such that

DECLARE @LOCAL_Contract_ID int, 
        @LOCAL_dt_From smalldatetime, 
        @LOCAL_dt_To smalldatetime, 
        @LOCAL_Last_Run_Date datetime

SELECT  @LOCAL_Contract_ID = @Contract_ID, 
        @LOCAL_dt_From = @dt_From, 
        @LOCAL_dt_To = @dt_To, 
        @LOCAL_Last_Run_Date = @Last_Run_Date

然后我们使用 SP 内部的本地参数而不是传入的参数.

We then use the local parameters inside the SP rather than the parameters that was passed in.

这通常为我们解决了问题.

This typically fixed the issue for Us.

我们认为这是由于参数嗅探引起的，但没有任何证据，抱歉...X-)

We believe this to be due to parameter sniffing, but do not have any proof, sorry... X-)

看看不同纠正 SQL Server 参数嗅探的方法，了解一些有见地的示例、解释和修复.

Have a look at Different Approaches to Correct SQL Server Parameter Sniffing for some insightful examples, explanations and fixes.

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