SQL Server, Why doesn't my update come to an end? a light post!

Hi guys,

Today i present to you a light post at base level but however very useful!

There are questions that come back often.
For example:

Why doesn't my update come to an end?
Why I am not be able to drop an index?
The answer is always the same: Something is blocking!

Enjoy the reading!

Find who is locking!

Have you an update that doesn't come to an end?
Are you trying to drop and index but is not possible?
Well, your T-SQL statement is blocked by another T-SQL statement.

In this case you can run this command: 


Sp_who2

This command display a list of processes (called SPID).

From this list you can identify your process through the command column.



In our example we are the SPID 106 and we are executing a DROP INDEX command.

Now look at the blkBy (blocked by)) columns.
A value in this column is the process id (SPID) of the command that is blocking.

So now we konow that is the SPID 90 that is blocking our drop index command.

If you kill it though the Kill command


Kill 90

Your command will come to and end.


That's all for today people!
See you soo and feel free to ask me any questions or problems you have! 

Luca Biondi @ SQLServerPerformance blog!



 

 

 

 

 

Next Post: SQL Server, How to find deadlocks: the easy way DBCC TRACEON (1204, 1222,-1)

Previuos post: Your biggest customer can’t work! It is stuck due to a SQL Server randomly crash? And now?

A song with the mood of the day: Here we go

Comments

Post a Comment

I Post più popolari

SQL Server, execution plan and the lazy spool (clearly explained)

Image
Hi Guys, Welcome back! In one of the last posts we talked about Table Spool . We had explained what Spool are for by telling the somewhat curious story of the halloween problem . Here we specifically talked about a type of spool called Eager Spool   You can look to the execution plan below where the eager Spool is used to avoid the halloween problem in classic query of the "salary increase".. i suggest Well, if the story of the eager spool intrigued you, today instead we will speak about another type of Spool, the Lazy Spool . The Lazy spool Let's take a small step back. So, what is a Spool operation?  As we have already understood a spool operation is simply a temporary storage of data . Data are read from a source table and stored inside a worktable in the Tempdb database . While an Eager Spool is used to prevent the Halloween problem, the Lazy Spool is instead used to store data that will later be needed again when running a query . So, when a Lazy spool is used?    I
Read more

SQL Server, datetime vs. datetime2

Image
Hi guys, This time, in this post we will speak about datetime and datetime2 datatypes. We will talk about the pros and cons. We will talk about all the differences between the two types of data. Write me in the comments which type of data do you prefer between the two. Enjoy the reading!     Datetime Vs. Datetime2 First of all, it must be said that the datatype datetime is certainly the best known native format for storing a date in SQL Server. However, Microsoft has also been introducing a new type of data for many years now, also used to manage dates. It is in fact from SQL server 2008 that it is present in datetime2 data type. This "new" type of data was born primarily to have higher accuracy . Let's in fact talk about ... precision ! Datetime Certainly the datetime data type is not very precise and certainly there are many cases in which its precision is simply not sufficient. Let's see it with an example. Open the SQL Management studio (SSMS) and write the fo
Read more

La clausola NOLOCK. Approfondiamo e facciamo chiarezza!

Image
Ehi ragazzi! La domanda è di quelle importanti! Siete pronti per scoprire tutto ma proprio tutto sulla clausola NOLOCK?   Se la riposta è si, allora seguitemi! Oggi ne spiegheremo il funzionamento in maniera approfondita. Faremo una introduzione al concetto di tipi di LOCK Ed infine vedremo come mai una SELECT ne può bloccare un'altra. Non vi nascondo che il motivo di questo articolo è fare chiarezza. Su questo argomento si sentono spesso affermazioni “curiose” ma tra le tante questa è la prima: “ uso la SELECT con l’opzione WITH(LOCK) così non blocco le altre tabelle ”.   Ma, è proprio vero quanto affermato? Beh oggi facciamo il punto!   Buona lettura!     La clausola NOLOCK Diciamo subito per iniziare che cos’è la NOLOCK. NOLOCK è il nome di una clausola che è possibile specificare all’interno di uno statement di tipo SELECT utilizzando la seguente sintassi: SELECT * FROM TABELLA WITH (NOLOCK) Si noti che non possiamo utilizzare questa cl
Read more