查找占用更多 CPU 的当前正在运行的查询

Question

如何获取有关使用更多 CPU 的当前正在运行的查询的详细信息。

Answer 1

有几种方法可以找到导致 CPU 使用率高的查询，最常见的方法是：

方法 1：使用内置 SQL 服务器报告查找 CPU 时间较长的查询。

方法 2：使用以下查询：

查询1：获取CPU使用率从高到低的所有语句

SELECT
       -- using statement_start_offset and
       -- statement_end_offset we get the query text
       -- from inside the entire batch
       SUBSTRING(qt.TEXT, (qs.statement_start_offset/2)+1,
                           ((CASE qs.statement_end_offset
                                        WHEN -1 THEN DATALENGTH(qt.TEXT)
                                        ELSE qs.statement_end_offset
                           END
                           - qs.statement_start_offset)/2)+1)
                           as [Text],
qs.execution_count,
qs.total_logical_reads, qs.last_logical_reads,
qs.total_logical_writes, qs.last_logical_writes,
qs.total_worker_time,
qs.last_worker_time,
-- converting microseconds to seconds
qs.total_elapsed_time/1000000 total_elapsed_time_in_S,
qs.last_elapsed_time/1000000 last_elapsed_time_in_S,
qs.last_execution_time,
qp.query_plan
FROM sys.dm_exec_query_stats qs
       -- Retrieve the query text
       CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) qt
       -- Retrieve the query plan
       CROSS APPLY sys.dm_exec_query_plan(qs.plan_handle) qp
ORDER BY qs.total_worker_time DESC -- CPU time

查询 2：缓存中存在计划的前 3 个占用 CPU 的查询

SELECT TOP 3
total_worker_time ,
execution_count ,
total_worker_time / execution_count AS [Avg CPU Time] ,
CASE WHEN deqs.statement_start_offset = 0
AND deqs.statement_end_offset = -1
THEN '-- see objectText column--'
ELSE '-- query --' + CHAR(13) + CHAR(10)
+ SUBSTRING(execText.text, deqs.statement_start_offset / 2,
( ( CASE WHEN deqs.statement_end_offset = -1
THEN DATALENGTH(execText.text)
ELSE deqs.statement_end_offset
END ) - deqs.statement_start_offset ) / 2)
END AS queryText
FROM sys.dm_exec_query_stats deqs
CROSS APPLY sys.dm_exec_sql_text(deqs.plan_handle) AS execText
ORDER BY deqs.total_worker_time DESC ;

查询 3：获取核心使用量以及 CPU 时间（注意此查询还有很多其他用途，例如桌面 I/O）

SELECT TOP 50
    [Avg. MultiCore/CPU time(sec)] = qs.total_worker_time / 1000000 / qs.execution_count,
    [Total MultiCore/CPU time(sec)] = qs.total_worker_time / 1000000,
    [Avg. Elapsed Time(sec)] = qs.total_elapsed_time / 1000000 / qs.execution_count,
    [Total Elapsed Time(sec)] = qs.total_elapsed_time / 1000000,
    qs.execution_count,
    [Avg. I/O] = (total_logical_reads + total_logical_writes) / qs.execution_count,
    [Total I/O] = total_logical_reads + total_logical_writes,
    Query = SUBSTRING(qt.[text], (qs.statement_start_offset / 2) + 1,
        (
            (
                CASE qs.statement_end_offset
                    WHEN -1 THEN DATALENGTH(qt.[text])
                    ELSE qs.statement_end_offset
                END - qs.statement_start_offset
            ) / 2
        ) + 1
    ),
    Batch = qt.[text],
    [DB] = DB_NAME(qt.[dbid]),
    qs.last_execution_time,
    qp.query_plan
FROM sys.dm_exec_query_stats AS qs
CROSS APPLY sys.dm_exec_sql_text(qs.[sql_handle]) AS qt
CROSS APPLY sys.dm_exec_query_plan(qs.plan_handle) AS qp
where qs.execution_count > 5    --more than 5 occurences
ORDER BY [Total MultiCore/CPU time(sec)] DESC

编辑
以下排序过程也很有帮助

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