I have a large table without any indexes on it, about 27.5m rows.
I tried to delete about half of those using using BEGIN TRAN.
I then tried canceling the querie, but because it was taking long I decided to just close the Management Studio.
Now when I try to look into that table, it does not return anything, just keeps running.
When I run SELECT TOP 10 * FROM Tbl it just executes without returning anything.
But when I run SELECT TOP 10 * FROM Tbl(NOLOCK) it return 10 rows.
This tells me that it is waiting on a Rollback/Commit from my BEGIN TRAN.
I thought it would rollback automatically after closing the session and Management Studio.
How do I fix this issue?
Thanks.
Execute SP: SP_LOCK
In Results you will get SPID, DBID, OBJID, INDID, TYPE, RESOURCE,
MODE, STATUS
Now check the status column, if it is showing wait then
kill that SPID. To kill a particular SPID Execute SP: Kill 65 (Where
65 is SPID)
MSDN Forum
Apparently, this worked:
Terminate/Close connection to the database would solve this. To close connection you can try terminating sqlserver.exe from Task Manager or Activity Monitor if you have a Mac.
Related
We are using azure data flows and we are trying to load the data in one particular table in sql server. however our data flow keeps running for hours for smaller set of data.
when we tried to truncate or drop the table, our request times out.
how can we force drop and recreate the table.
What I checked
We don't have any foreign constraints that may avoid the drop
Getting this error when i tried to truncate
Failed to execute query. Error: A severe error occurred on the current command. The results, if any, should be discarded.
I also ran this query and found this
Query -
SELECT session_id
,blocking_session_id
,wait_time
,wait_type
,last_wait_type
,wait_resource
,transaction_isolation_level
,lock_timeout
FROM sys.dm_exec_requests
WHERE blocking_session_id <> 0
Is this causing the issue
How can I fix this issue
i found this after running
exec sp_who 88
What can i do on it
find out more about blocking session 88 , run exec sp_who 88 , seems like this is the session that is blocking , find out more about blocking stuff , if you are allowed to add a proc to the database , go get and install sp_whoisactive which gives you more information
then you can run : dbcc inputnuffer(88) to find out which main proc or process is executing that select query.
if this is safe to kill that process, you can kill that session by
kill 88
before killing that session make sure that session id is still running the same process
Say I have a query like this:
BEGIN Transaction
UPDATE Person SET Field=1
Rollback
There are one hundred million people. I stopped the query after twenty minutes. Will SQL Server rollback the records updated?
A single update will not update some rows. It will either update all or 0.
So, if you cancel the query, nothing will be updated.
This is atomicity database systems which SQL Server follows.
In other words, you don't have to do that rollback at the end, nothing was committed anyway.
When you cancel a query, it will still hold locks until everything is rolled back so no need to panic.
You could test it yourself, execute the long query, cancel it and you will notice that it takes a while before the process really end.
While the update statement will not complete, the transaction will still be open, so make sure you rollback manually or close out the window to kill the transaction. You can test this by including two statements in your transaction, where the first one finishes and you cancel while it's running the second - you can still commit the transaction after stopping it, and then get the first half of your results.
BEGIN Transaction
UPDATE Person SET Field=1 WHERE Id = 1
UPDATE Person SET Field=1
Rollback
If you start this, give it enough time for the first line to finish, hit the Stop button in SSMS, then execute commit transaction, you'll see that the first change did get applied. Since you obviously don't want part of a transaction to succeed, I'd just kill the whole window after you've stopped it so you can be sure everything's rolled back.
Since you have opened the Transaction, Stoping the Query manually does not completes the transaction, This transaction will still be open and all the subsequent requests to this table will be blocked.
You can do any one of following options
Kill the Connection using the command KILL SPID (SPID is the process ID of your connection)
Note: This will auto rollback the changes you made, you can monitor the rollback status with command KILL SPID WITH STATUSONLY (After killing)
run the ROLLBACK command manually
** SPID is your request id, you can find it from sys.sysprocesses table/ you can also find it on Management Studio query Window the number which is within brackets / also you can find it at bottom right corner of your management studio beside the login name.
Example SQLQuery2.sql... (161) -- 161 is your spid.
I have a SQL Server 2008 R2 Enterprise database with a view on it called vw_Users.
-Running (Select * from vw_users) takes less than a second to complete.
-Running the SQL inside of the view takes less than a second to complete.
-Running (drop view vw_Users) just hangs and never actually completes. I let it run for about 10 minutes before I cancelled it.
I restarted the SQL Server Agent, then tried again, but it's still occurring.
This is a brand new issue, this server and this database have been running fine for over a year.
There are no indices on the view. I'm not sure what the problem is, but any help would be very appreciated.
Thanks
Someone or something has an open connection accessing that view and you are being blocked.
You can check this by starting your DROP, then in another window in SSMS running:
sp_who2 active
You should see a row with your spid, and the blocked_by field will have another spid number in it. Find that spid to see what is blocking you.
If it can be safely terminated, either close the process manually or from within SSMS run:
kill x
...where x is the spid of the blocking process.
So I'm trying to monitor the longest living lock in my database. The idea is that if a lock has been held for a certain amount of time, I will receive a warning in my application.
But for the life of I can't find the creation time of the locks.
I have used:
exec msdb..sp_lock
exec msdb..sp_who2
SELECT * FROM sys.dm_tran_locks
select * from sys.syslockinfo
select cmd, * from sys.sysprocesses where blocked > 0
But none of these seem to have the information I need.
Any ideas?
G
A long running transaction makes more sense which you can do by looking at database_transaction_begin_time column in sys.dm_tran_database_transactions
I've never known anyone to try and monitor locks... which is possibly why there is no start date/time information for them...
The Lock:Acquired EventClass in SQL Profiler has StartTime and EndTime. You might want to check that
I have a simple query like this
SELECT * FROM MY_TABLE;
When I run it, SQL Server Management Studio hangs.
Other tables and views are working fine.
What can cause this? I've had locks while running UPDATE statements before, and I know how to approach those. But what could cause a SELECT to lock?
I have run the "All Blocking Transactions" report, and it says there are none.
It is probably not the select that is locking up, but some other process that is editing (udpate/delete/insert) the table that is causing the locks.
You can view which process is blocking by runing exec sp_who2 on your SQL Server.
Alternatively, if you are OK with dirty reads, you can do one of two things
SELECT * FROM Table WITH (NOLOCK)
OR
SET Transaction Isolation Level Read Uncommitted
SELECT * FROM Table
If there's a lot of other activity going on, something else might be causing locks, and your SELECT might be the deadlock victim. if you run the following
SELECT * FROM my_table WITH(nolock)
you're telling the database that you're ok to read dirty (uncomitted) data, and that locks caused by other activity can be safely ignored.
Also, if a query like that causes management studio to hang, your table might use some optimization
Use this:
SELECT * FROM MY_TABLE with (NOLOCK)
Two possibilities:
Its a really massive table, and you're trying to return 500m rows.
Some other process has a lock on the table, preventing your select from going through until that lock is released.
MY_TABLE could be also locked up by some uncommitted transaction -- i.e. script/stored procedure running (or failed while running) in another MSMM window.