项目
12/14/2010

查询活动收集器类型

“查询活动”收集器类型是“查询统计信息”收集组使用的自定义收集器类型，该收集组是一个预定义的系统数据收集组。

此收集器类型用于收集查询统计信息和查询活动信息，以及满足预定义条件的查询的查询计划和查询文本。如果使用此收集器类型创建自己的收集组，它将与“查询统计信息”收集组收集相同的信息。因此，建议您使用预定义的“查询统计信息”收集组。

体系结构和处理

“查询活动”收集器类型包含下列元素：

输入参数架构（内部）
用来收集数据的 SSIS 包 (QueryActivityCollect.dtsx)
用来上载数据的 SSIS 包 (QueryActivityUpload.dtsx)

此外，此收集器类型还利用自定义任务或转换来分析数据，并选择要存储在管理数据仓库中的数据。

“查询活动”收集器类型执行下列操作：

它收集 dm_exec_requests、dm_exec_sessions 以及选定的其他相关动态管理视图的示例。这是作为单个联接查询来实现的。数据收集按照为收集项指定的频率进行。
它按照与收集组上载频率相同的频率来收集 dm_exec_query_stats 动态管理视图的快照。默认情况下，“查询统计信息”收集组的上载频率为 15 分钟。

收集阶段

下表列出了在收集阶段使用的查询。此查询是在 QueryActivityCollect.dtsx SSIS 包中定义的。

收集频率

10 秒

查询

SET NOCOUNT ON
-- Get the collection time as UTC time
DECLARE @collection_time datetime
SET @collection_time = GETDATE()
SELECT
CONVERT(int, ROW_NUMBER() OVER (ORDER BY sess.session_id, ISNULL (req.request_id, -1), ISNULL (tasks.exec_context_id, -1)) ) AS row_id,
-- IDs and Blocking IDs
sess.session_id, 
ISNULL (req.request_id, -1) AS request_id, 
ISNULL (tasks.exec_context_id, -1) AS exec_context_id, 
ISNULL (req.blocking_session_id, 0) AS blocking_session_id,
CONVERT (bit, CASE 
                WHEN EXISTS (SELECT TOP 1 session_id FROM sys.dm_exec_requests bl WHERE bl.blocking_session_id = req.session_id) THEN 1
                ELSE 0
              END) AS is_blocking,
ISNULL (waits.blocking_exec_context_id, 0) AS blocking_exec_context_id, 
tasks.scheduler_id, 
DB_NAME(req.database_id) as database_name, 
req.[user_id], 
-- State information
LEFT (tasks.task_state, 10) AS task_state, 
LEFT (req.status, 15) AS request_status, 
LEFT (sess.status, 15) AS session_status,
req.executing_managed_code, 
-- Session information
sess.login_time, 
sess.is_user_process, 
LEFT (ISNULL (sess.[host_name], ''), 20) AS [host_name], 
LEFT (ISNULL (sess.[program_name], ''), 50) AS [program_name], 
LEFT (ISNULL (sess.login_name, ''), 30) AS login_name, 
-- Waits information
LEFT (ISNULL (req.wait_type, ''), 45) AS wait_type, 
LEFT (ISNULL (req.last_wait_type, ''), 45) AS last_wait_type, 
ISNULL (waits.wait_duration_ms, 0) AS wait_duration_ms, 
LEFT (ISNULL (req.wait_resource, ''), 50) AS wait_resource, 
LEFT (ISNULL (waits.resource_description, ''), 140) AS resource_description,
-- Transaction information
req.transaction_id, 
ISNULL(req.open_transaction_count, 0) AS open_transaction_count,
COALESCE(req.transaction_isolation_level, sess.transaction_isolation_level) AS transaction_isolation_level,
-- Request stats
req.cpu_time AS request_cpu_time, 
req.logical_reads AS request_logical_reads, 
req.reads AS request_reads, 
req.writes AS request_writes, 
req.total_elapsed_time AS request_total_elapsed_time, 
req.start_time AS request_start_time, 
-- Session stats
sess.memory_usage, 
sess.cpu_time AS session_cpu_time, 
sess.reads AS session_reads, 
sess.writes AS session_writes, 
sess.logical_reads AS session_logical_reads, 
sess.total_scheduled_time AS session_total_scheduled_time, 
sess.total_elapsed_time AS session_total_elapsed_time, 
sess.last_request_start_time, 
sess.last_request_end_time, 
req.open_resultset_count AS open_resultsets, 
sess.row_count AS session_row_count, 
sess.prev_error, 
tasks.pending_io_count, 
-- Text/Plan handles
ISNULL (req.command, 'AWAITING COMMAND') AS command,  
req.plan_handle, 
req.sql_handle, 
req.statement_start_offset, 
req.statement_end_offset,
@collection_time AS collection_time
FROM sys.dm_exec_sessions sess 
LEFT OUTER MERGE JOIN sys.dm_exec_requests req  ON sess.session_id = req.session_id
LEFT OUTER MERGE JOIN sys.dm_os_tasks tasks ON tasks.session_id = sess.session_id AND tasks.request_id = req.request_id AND tasks.task_address = req.task_address
LEFT OUTER MERGE JOIN sys.dm_os_waiting_tasks waits ON waits.session_id = sess.session_id AND waits.waiting_task_address = req.task_address
WHERE 
    sess.session_id <> @@SPID
    AND
    (
        (req.session_id IS NOT NULL AND (sess.is_user_process = 1 OR req.status COLLATE Latin1_General_BIN NOT IN ('background', 'sleeping')))-- active request
            OR 
        (sess.session_id IN (SELECT DISTINCT blocking_session_id FROM sys.dm_exec_requests WHERE blocking_session_id != 0))            -- not active, but head blocker
    )
OPTION (FORCE ORDER)

上载阶段

上载过程中，会分析所收集的数据，以确定哪些数据将保存在管理数据仓库中。此分析会确定一组需要保存的查询统计信息、查询计划和查询文本。

一个关键元素是用于选择打算保存在数据仓库中的查询和查询计划的算法。此算法的工作方式如下：

收集 sys.dm_exec_query_stats 的快照。按照与收集组上载频率相同的频率收集此快照。（默认情况下，上载频率为 15 分钟。）
检索最近（15 分钟内）的快照，以便与新快照进行比较。最近的快照缓存在本地，不必从管理数据仓库中检索。
使用下列指标从每个快照中选择前三个查询：
- 占用时间
- 工作线程时间
- 逻辑读取次数
- 逻辑写入次数
- 物理读取次数
- 执行计数
此过程提供 6 x 3 个 sql_handle 和 plan_handle。
标识唯一的 sql_handle 和 plan_handle。
将此结果与存储在数据仓库中的 sql_handle 和 plan_handle 进行求交运算。

对于新的 sql_handle 和 plan_handle，从服务器中获取计划和文本。如果找不到计划或文本（可能已经从本地缓存中删除），则将这些句柄存储在管理数据仓库中。
对于收集的每个 sql_handle 文本，将文本规范化（例如删除参数和文字信息）并计算规范化文本的唯一哈希值。将规范化文本、哈希值以及对原始 sql_handle 的映射存储到管理数据仓库中。

下表列出了用于获取快照以及分析数据并将数据上载到管理数据仓库的查询。此查询是在 QueryActivityUpload.dtsx SSIS 包中定义的。

查询

SET NOCOUNT ON
DECLARE @p1 datetime
SET @p1 = GETDATE()
SELECT 
    [sql_handle],
    statement_start_offset,
    statement_end_offset,
    -- Use ISNULL here and in other columns to handle in-progress queries that are not yet in sys.dm_exec_query_stats.  
    -- These values only come from sys.dm_exec_query_stats. If the plan does not show up in sys.dm_exec_query_stats 
    -- (first execution of a still-in-progress query, visible in sys.dm_exec_requests), these values will be NULL. 
    MAX (plan_generation_num) AS plan_generation_num,
    plan_handle,
    MIN (creation_time) AS creation_time, 
    MAX (last_execution_time) AS last_execution_time,
    SUM (execution_count) AS execution_count,
    SUM (total_worker_time) AS total_worker_time,
    MIN (min_worker_time) AS min_worker_time,           -- NULLable
    MAX (max_worker_time) AS max_worker_time,
    SUM (total_physical_reads) AS total_physical_reads,
    MIN (min_physical_reads) AS min_physical_reads,     -- NULLable
    MAX (max_physical_reads) AS max_physical_reads,
    SUM (total_logical_writes) AS total_logical_writes,
    MIN (min_logical_writes) AS min_logical_writes,     -- NULLable
    MAX (max_logical_writes) AS max_logical_writes,
    SUM (total_logical_reads) AS total_logical_reads,
    MIN (min_logical_reads) AS min_logical_reads,       -- NULLable
    MAX (max_logical_reads) AS max_logical_reads,
    SUM (total_clr_time) AS total_clr_time,
    MIN (min_clr_time) AS min_clr_time,                 -- NULLable
    MAX (max_clr_time) AS max_clr_time,
    SUM (total_elapsed_time) AS total_elapsed_time,
    MIN (min_elapsed_time) AS min_elapsed_time,         -- NULLable
    MAX (max_elapsed_time) AS max_elapsed_time,
    @p1 AS collection_time
FROM
(
    SELECT  
        [sql_handle],
        statement_start_offset,
        statement_end_offset,
        plan_generation_num,
        plan_handle,
        creation_time,
        last_execution_time,
        execution_count,
        total_worker_time,
        min_worker_time,
        max_worker_time,
        total_physical_reads,
        min_physical_reads,
        max_physical_reads,
        total_logical_writes,
        min_logical_writes,
        max_logical_writes,
        total_logical_reads,
        min_logical_reads,
        max_logical_reads,
        total_clr_time,
        min_clr_time,
        max_clr_time,
        total_elapsed_time,
        min_elapsed_time,
        max_elapsed_time 
    FROM sys.dm_exec_query_stats AS q
    UNION ALL 
    SELECT 
        r.[sql_handle],
        r.statement_start_offset,
        r.statement_end_offset,
        ISNULL (qs.plan_generation_num, 0) AS plan_generation_num,
        r.plan_handle,
        ISNULL (qs.creation_time, r.start_time) AS creation_time,
        r.start_time AS last_execution_time,
        1 AS execution_count,
        r.cpu_time AS total_worker_time,
        qs.min_worker_time,     -- min should not be influenced by in-progress queries
        r.cpu_time AS max_worker_time,
        r.reads AS total_physical_reads,
        qs.min_physical_reads,  -- min should not be influenced by in-progress queries
        r.reads AS max_physical_reads,
        r.writes AS total_logical_writes,
        qs.min_logical_writes,  -- min should not be influenced by in-progress queries
        r.writes AS max_logical_writes,
        r.logical_reads AS total_logical_reads,
        qs.min_logical_reads,   -- min should not be influenced by in-progress queries
        r.logical_reads AS max_logical_reads,
        qs.total_clr_time,      -- CLR time is not available in dm_exec_requests
        qs.min_clr_time,        -- CLR time is not available in dm_exec_requests
        qs.max_clr_time,        -- CLR time is not available in dm_exec_requests
        r.total_elapsed_time AS total_elapsed_time,
        qs.min_elapsed_time,    -- min should not be influenced by in-progress queries
        r.total_elapsed_time AS max_elapsed_time
    FROM sys.dm_exec_requests AS r 
    LEFT OUTER JOIN sys.dm_exec_query_stats AS qs ON r.plan_handle = qs.plan_handle AND r.statement_start_offset = qs.statement_start_offset 
        AND r.statement_end_offset = qs.statement_end_offset 
    WHERE r.sql_handle IS NOT NULL 
) AS query_stats 
OUTER APPLY sys.dm_exec_sql_text (sql_handle) AS sql
GROUP BY [sql_handle], plan_handle, statement_start_offset, statement_end_offset 
ORDER BY [sql_handle], plan_handle, statement_start_offset, statement_end_offset

查询输出

snapshots.query_stats、snapshots.notable_query_text 和 snapshots.notable_query_plan

更改历史记录

更新的内容
增加了“收集阶段”和“上载阶段”部分。
用 QueryActivityUpload.dtsx SSIS 包中定义的查询替换了规定上载过程中将哪些数据保存在管理数据仓库中的相关条件。