Question

SQL Server 2008（不是R2），远程托管数据库。 SSMS 2008R2。

对于一些非常简单的查询，我经历了极长的查询时间，例如在这种情况下需要77秒才完成的查询 UPDATE Balances SET InUse WHERE BalanceId = 6;

问题是非常零星的，因为我可以一次又一次地运行相同的查询，并且它将在不到一秒的时间内运行，但偶尔会花费过多的时间来完成。以下是使用SET STATISTICS TIME ON和SET STATISTICS IO ON从上述查询输出的消息。

SQL Server parse and compile time: 
   CPU time = 0 ms, elapsed time = 0 ms.
SQL Server parse and compile time: 
   CPU time = 0 ms, elapsed time = 0 ms.
Table 'Balances'. Scan count 1, logical reads 38, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
SQL Server parse and compile time: 
   CPU time = 0 ms, elapsed time = 0 ms.

 SQL Server Execution Times:
   CPU time = 0 ms,  elapsed time = 0 ms.
Table 'BalanceRevisionsAuto'. Scan count 10, logical reads 267106, physical reads 77634, read-ahead reads 80251, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.

 SQL Server Execution Times:
   CPU time = 2312 ms,  elapsed time = 77219 ms.

 SQL Server Execution Times:
   CPU time = 0 ms,  elapsed time = 0 ms.

 SQL Server Execution Times:
   CPU time = 0 ms,  elapsed time = 0 ms.
Table 'BalanceRevisionsAuto'. Scan count 0, logical reads 1, physical reads 0, read ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Assets'. Scan count 0, logical reads 2, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Balances'. Scan count 1, logical reads 38, physical reads 2, read-ahead reads 18, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.

 SQL Server Execution Times:
   CPU time = 0 ms,  elapsed time = 61 ms.

(1 row(s) affected)

 SQL Server Execution Times:
   CPU time = 2312 ms,  elapsed time = 77300 ms.

(1 row(s) affected)

我对以下几点感到困惑：

为什么其他表“BalanceRevisionsAuto”，“Assets”在此查询中显示为对它们执行了逻辑读取？表之间没有外键关系，因此在更新期间需要检查其他关系。
在SQL Server执行时间下，经过时间= 77300ms是什么意思？我read“经过的时间包括这些元素：
- 信号等待时间
- 等待时间完成IO操作和
- 将输出传输到客户端所需的时间这最后一项是否包括网络传输时间？
“已用时间”是否包括将数据恢复到请求计算机的时间？似乎我引用的文章说它确实如此。有没有办法把这个时间分开？
为什么“SQL Server执行时间”会出现六次？这些是查询计划的每个部分吗？

解释SET STATISTICS TIME的输出，特别是执行时间：经过时间

0 个答案: