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Omoreira
Asked: 2015-09-22 10:21:58 +0800 CST

使用 IsolationLevel 读取未提交和支持 TransactionOption 的 SSIS 阻塞自身

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我的项目组件有IsolationLevel = ReadUncommitted和TransactionOption = supported。

我的查询是对表 Y 的选择，验证表 X 中是否不存在，并将结果写入表 X。

SSIS 在 SQL Server 中打开两个 id，一个 select 和一个 bulk。批量被选择阻止。

我尝试使用NOLOCK，SET ISOLATION LEVEL READ UNCOMMITTED但它们不起作用。

我能够通过检查“OLEDB Destination”上的“Check Constraint”来解决这个问题，但我不知道为什么。

堵塞

ssis ssis-2012

1 个回答

  1. Best Answer

    检查您打开了多少笔交易

    select @@opentran

    如果您只想不受阻塞的影响-并且您知道可能的副作用-脏读-

    您可以 在选择之前添加此行：

    set transaction isolation level read uncommitted

    或者在您的选择 中，您可以使用 WITH (NOLOCK) 提示，例如：

    select a,b,c, from mytable with (nolock)

    而不是 sp_who 请运行以下代码，并在此处发布结果：

    SET NOCOUNT ON
SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED

SELECT es.session_id AS session_id
,COALESCE(es.original_login_name, 'No Info') AS login_name
,COALESCE(es.host_name,'No Info') AS hostname
,COALESCE(es.last_request_end_time,es.last_request_start_time) AS last_batch
,es.status
,COALESCE(er.blocking_session_id,0) AS blocked_by
,COALESCE(er.wait_type,'MISCELLANEOUS') AS waittype
,COALESCE(er.wait_time,0) AS waittime
,COALESCE(er.last_wait_type,'MISCELLANEOUS') AS lastwaittype
,COALESCE(er.wait_resource,'') AS waitresource
,coalesce(db_name(er.database_id),'No Info') as dbid
,COALESCE(er.command,'AWAITING COMMAND') AS cmd
,sql_text=st.text
,transaction_isolation =
    CASE es.transaction_isolation_level
        WHEN 0 THEN 'Unspecified'
        WHEN 1 THEN 'Read Uncommitted'
        WHEN 2 THEN 'Read Committed'
        WHEN 3 THEN 'Repeatable'
        WHEN 4 THEN 'Serializable'
        WHEN 5 THEN 'Snapshot'
    END
,COALESCE(es.cpu_time,0) 
    + COALESCE(er.cpu_time,0) AS cpu
,COALESCE(es.reads,0) 
    + COALESCE(es.writes,0) 
    + COALESCE(er.reads,0) 
    + COALESCE(er.writes,0) AS physical_io
,COALESCE(er.open_transaction_count,-1) AS open_tran
,COALESCE(es.program_name,'') AS program_name
,es.login_time
FROM sys.dm_exec_sessions es
    LEFT OUTER JOIN sys.dm_exec_connections ec ON es.session_id = ec.session_id
    LEFT OUTER JOIN sys.dm_exec_requests er ON es.session_id = er.session_id
    LEFT OUTER JOIN sys.server_principals sp ON es.security_id = sp.sid
    LEFT OUTER JOIN sys.dm_os_tasks ota ON es.session_id = ota.session_id
    LEFT OUTER JOIN sys.dm_os_threads oth ON ota.worker_address = oth.worker_address
    CROSS APPLY sys.dm_exec_sql_text(er.sql_handle) AS st

where es.is_user_process = 1 
  and es.session_id <> @@spid

UNION 

SELECT es.session_id AS session_id
,COALESCE(es.original_login_name, 'No Info') AS login_name
,COALESCE(es.host_name,'No Info') AS hostname
,COALESCE(es.last_request_end_time,es.last_request_start_time) AS last_batch
,es.status
,COALESCE(er.blocking_session_id,0) AS blocked_by
,COALESCE(er.wait_type,'MISCELLANEOUS') AS waittype
,COALESCE(er.wait_time,0) AS waittime
,COALESCE(er.last_wait_type,'MISCELLANEOUS') AS lastwaittype
,COALESCE(er.wait_resource,'') AS waitresource
,coalesce(db_name(er.database_id),'No Info') as dbid
,COALESCE(er.command,'AWAITING COMMAND') AS cmd
,sql_text=st.text
,transaction_isolation =
    CASE es.transaction_isolation_level
        WHEN 0 THEN 'Unspecified'
        WHEN 1 THEN 'Read Uncommitted'
        WHEN 2 THEN 'Read Committed'
        WHEN 3 THEN 'Repeatable'
        WHEN 4 THEN 'Serializable'
        WHEN 5 THEN 'Snapshot'
    END
,COALESCE(es.cpu_time,0) 
    + COALESCE(er.cpu_time,0) AS cpu
,COALESCE(es.reads,0) 
    + COALESCE(es.writes,0) 
    + COALESCE(er.reads,0) 
    + COALESCE(er.writes,0) AS physical_io
,COALESCE(er.open_transaction_count,-1) AS open_tran
,COALESCE(es.program_name,'') AS program_name
,es.login_time
FROM sys.dm_exec_sessions es
    INNER JOIN sys.dm_exec_requests ec2 ON es.session_id = ec2.blocking_session_id
    LEFT OUTER JOIN sys.dm_exec_connections ec ON es.session_id = ec.session_id
    LEFT OUTER JOIN sys.dm_exec_requests er ON es.session_id = er.session_id
    LEFT OUTER JOIN sys.server_principals sp ON es.security_id = sp.sid
    LEFT OUTER JOIN sys.dm_os_tasks ota ON es.session_id = ota.session_id
    LEFT OUTER JOIN sys.dm_os_threads oth ON ota.worker_address = oth.worker_address
    CROSS APPLY sys.dm_exec_sql_text(ec.most_recent_sql_handle) AS st
where es.is_user_process = 1 
  and es.session_id <> @@spid

    这将向您展示实际导致阻塞的原因。这段代码来自这里：

    如何找到阻塞其他进程的睡眠会话的 T-SQL？

    • 0

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