A blocking SQL command prevents other reading or writing operations while it is being executed.

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Blocked Process Report -two updates causing a long block

I have a .NET application which is getting SQL update timeouts and I believe that some sort of blocking/locking is taking place which is causing this. I have ran a blocking process report on the ...
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2answers
102 views

Blocked Process Report SQL Server 31 hour duration

I have an application (.NET EF 6 ) which is getting timeouts when submitting/reading data from the database. Whilst trying to diagnose the problem I used Blocked Process Reports from SQL server ...
2
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0answers
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Locks while stream reading and deleting/inserting involving the same tables?

I have a question regarding a potential block/lock situation: I am reading data using a select command, which is then modified externally and uploaded to a temporary table. A stored procedure will ...
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0answers
40 views

In Sql Server, is there a way to check if a selected group of rows are locked or not?

We are attempting to update/delete a large number of records in a multi-billion row table. Since this is a popular table, there is a lot of activity in different sections of this table. Any large ...
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1answer
54 views

SQL Blocking causing timeouts

We have a long running transaction (with nested trans), it runs for about 2min. In this time it does a heap of insert, update and selects. At the same time users still need to be able to use the ...
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1answer
156 views

SSRS Blocking Processes

We have a busy SSRS Reporting server (SQL Server 2008 R2) on which we see frequent blocking between the below processes: [dbo].[CheckSessionLock] [dbo].[WriteLockSession] We are aware that some ...
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48 views

Postgresql: Update or insert stuck

I'm running update-or-insert query on a table of approximatelly 3mln rows, 4 columns. Query is part of every day process, and for same days, the query stucks forever. It's just blocked. It's ...
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1answer
177 views

SQL Server 2012 merge replication blocks other insert/updates during sync

I have a merge replication setup between two SQL Server 2012 databases via Pull method. There are several merge replications affecting different table sets (3 sets 2-5 tables each, actually). There ...
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0answers
46 views

Trying to add a NULLable column to a table with over 90 million rows takes a very long time

I have been trying to add a NULLable column to a table with over 90 million rows. ALTER TABLE <TableName> ADD <FieldName> INT NULL; It is taking a very long time (been running for over ...
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3answers
84 views

Why is sql server waiting for acknowledgment?

I have an application that often request a big set of rows [about 20K] from a sql view, in the mean time other applications can't update the table from where the data comes from, the update query's ...
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0answers
10 views

CLR UDT SCH-M blocking

I’m hoping someone can provide some guidance on a problem I’m having with schema locking on C# CLR UDT’s. I’ve been on the Internet for an extended period of time researching my problem without ...
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54 views

Sleeping queries blocking rebuild index and update statistics job in Always on

At one of your client sides we have configured Always on with synchronous mode.Also we have schedule rebuild index and update statistics job which runs in night every alternate day. the issue is ...
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1answer
110 views

What happens if two mySQL queries both try to lock the same row at the same time?

So this isn't exactly my strong suit, but here's my basic understanding of the situation: If two threads of the same application both try to execute the same query at the same time, mySQL will ...
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70 views

When does SQL Server acquire locks?

The list of isolation levels in SQL Server found here states that write locks acquired within a transaction are retained until the end of the transaction. However it doesn't mention anything about ...
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1answer
37 views

My connection to a Mysql DB has been blocked after spamming queries, for how long?

I am creating a web application that depends on querying a legacy DB without an API. It's MySql. Off course the lack of an API eventually got me in trouble. A feedback loop while testing the app ...
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0answers
144 views

Renaming a column with sp_rename hangs SQL Server 2012

I was attempting to remove a column from a table within SQL Server 2012 for one of our developers. As a precaution, before dropping the column, we rename them to make sure that everything continues ...
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1answer
81 views

How to determine which statement is blocking an update in SQL Server

We have an UPDATE statement running in a large J2EE application that is getting blocked by some other statement. The update is using the primary key, so it should affect only one row. The isolation ...
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1answer
78 views

Resource cost of a blocked query

I'm currently reviewing a case where an SSRS server is experiencing frequent blocking and deadlocking. The reports are not business-critical, and they are frequently killed to alleviate the blocking. ...
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0answers
155 views

LCK_M_SCH_M Blocking

I have 2 stored procedures (one vendor, one third party) that are constantly (monthly) stepping on each other. They both (for some reason) acquire a schema lock when all they are doing is updating ...
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57 views

How can I obtain concurrent deletes for this table?

We have a program that is currently doing something to the effect of: SET TRANSACTION ISOLATION LEVEL READ COMMITTED BEGIN TRANSACTION UPDATE [Source].[dbo].[SourceTable] SET [ProcessedOn] = ...
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64 views

PostgreSQL: How can I identify the connections which is blocking ALTER TABLE?

I would like to add some fields to a table in all testing and production DBs, all of which are stored in PostgreSQL 9.3 on Amazon RDS. ALTER TABLE users DROP COLUMN IF EXISTS device_language; ALTER ...
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1answer
106 views

TempDB Query being Blocked

I have been monitoring Blocking issues on our SQL Server database. Very often the below query is running on tempdb and is blocked with LCK_M_S What is this query used for and why does it run ...
4
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1answer
239 views

Why is SQL Server's online indexing causing blocking?

My understanding is that online indexing acquires locks at the beginning (Preparation) and end (Final) phases. However, we see a lot of DML queries blocked during the Build phase. A sampling of the ...
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1answer
38 views

Getting null block_st.text when querying for blocks

We are using the blocking query from this article which queries sys.dm_tran_locks. http://simplesqlserver.com/2013/05/21/blocking-capturing-and-monitoring/ The issue we've ran into is that often ...
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1answer
3k views

why a session becomes a head blocker

I am troubleshooting a problem that seems to be random The problem is sometimes an application (dynamics SL) is freezing When the application is freezing , I notice there is a blocked by in SQL ...
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1answer
691 views

Alter table add column query blocking a table or taking so much time

I'm trying to add a new column to an existing table but it takes so much time or the query is blocking the table, I'm really confused about what's happening exactly. ALTER TABLE MYTABLE1 ADD ...
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1answer
330 views

How can a blocking_session_id be negative?

I have a case where a query I'm running is taking a long time. When I checked sys.dm_exec_requests the blocking_session_id is a negative value, -2 to be specific. The wait is a LCK_M_X and the ...
3
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1answer
183 views

Why am I getting blocked when I call OBJECT_NAME(object_id, database_id) from sys.dm_tran_locks?

I'm working on a query to tell what objects have locks from a given session and I'm running into some blocking issues. Here is my basic query: SELECT request_session_id AS session_id, ...
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0answers
395 views

Excessive compile blocking on sp_procedure_params_90_rowset

A resurgence of this question Blocked-process-report: what is this waitresource "OBJECT: 32767:124607697:0 [COMPILE] on MSDN: I have caught these statements in Profiler. They all have durations over ...
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2answers
1k views

Why did my UPDATE statement not complete?

Running SQL Server 2008; Mgmt Studio 2008. I am working with a MS SQL job that we have created for our MS CRM 4.0 implementation. For anyone familiar with CRM, this job purges the aSyncOperationBase ...