how to avoid deadlock in sql server

(X) lock to update. A deadlock occurs because two transactions are converted to exclusive (X) locks, and each transaction waits for another transaction to release the shared-mode lock.To avoid this potential deadlock problem, use the update (U) lock. Only one transaction at a time can obtain an update (U) lock on the resource. If the transaction modifies the res

SQL Server concurrent processing, update solution discussion, SQL Server Preface In this section, we will talk about the most common situation of concurrency, that is, update. If no row record exists in concurrency, insert it. At this time, it is very easy to insert duplicate keys, this article describes the seven solu

) lock to update. A deadlock occurs because two transactions are converted to exclusive (X) locks, and each transaction waits for another transaction to release the shared-mode lock.To avoid this potential deadlock problem, use the update (U) lock. Only one transaction at a time can obtain an update (U) lock on the resource. If the transaction modifies the resour

exclusive (X) lock to update. A deadlock occurs because two transactions are converted to exclusive (X) locks, and each transaction waits for another transaction to release the shared-mode lock.To avoid this potential deadlock problem, use the update (U) lock. Only one transaction at a time can obtain an update (U) lock on the resource. If the transaction modifi

returned, the stored procedure is used.　　 42. Do not use the same function repeatedly in one sentence, waste resources, and put the result in a variable before calling it faster.　　 43. The efficiency of select count (*) is low. Try to change the method while exists is fast. Note the difference: Select count (FieldOf null) from table and select count (field of not null) from tableThe returned values are different !!!　　 44. When the server has enough m

I. Introduction to SQL Profiler ToolsSQL Profiler is a graphical interface and a set of system stored procedures that function as follows: Graphical monitoring of SQL Server queries; Collect query information in the background; Analyze performance; Diagnosing a problem like a deadlock; Debug T-

instead of a shared lock, which is persisted to this statement or to the end of the entire transaction, using UPDLOCK to allow the user to read the data first (and not to block other users from reading the data), and ensure that the data is not modified by other users for a period of time when the data is later updated.Visible from the above, in SQL Server can be flexible and diverse for

Tags: SQL Server 2014 log shipping13.2.4 Deploying log shipping with Management StudioUse SQL Server Management Studio to deploy the log shipping steps as follows:(1) Open the Properties page for the primary database DB01 as log shipping in the primary server SQLSVR1, and th

Ms SQL Server ODBC driver SQL Server listing Stack Overflow Vulnerability Created:Article attributes: originalSource: http://www.xfocus.netArticle submitted: flashsky (flashsky1_at_sina.com) Indicate the author and security focusAuthor: flashskySite: www. xfocus. netMail: flashsky@xfocus.org An overflow vulnerability e

SQL Server Query SQL Execution time, Enter the following content in the query Analyzer: Set statistics profile onSet statistics Io onSet statistics time onGoGoSet statistics profile offSet statistics Io offSet statistics time off Check the SQL statement in the project and find something different from your

@ IntCountProperties = Count (*), @ intCounter = 1 from # tmp_lock_whoIF @ ERROR 'No blocking and deadlock information' As message -- start loop while @ intCounter @ Spid = spid, @ bl = blfrom # tmp_lock_who where id = @ intCounter beginif @ spid = 0 select 'The cause of database deadlock is: '+ CAST (@ bl as varchar (10) +' process number, Its SQL syntax is

uniqueness of the row. The following is the constraint with the primary key. ALTER TABLE dbo.BlogsADD CONSTRAINT pk_constraint_blogId PRIMARY KEY(BlogId) In the key folder, the constraint on column BlogId is generated to upgrade to the primary key, as shown below: When you insert duplicate data into a primary key, a message is displayed, indicating that duplicate keys cannot be inserted, which violates the constraints. To enforce the uniqueness of logical primary key constraints,

so, did not think of its impact This parameter is a data-level option that can be set up to refer to 　　 What is the automatic parameterization of the case? In a simple parameterized mode, SQL Server automatically parameterize a adhoc SQL statement with only one execution mode, thus achieving the purpose of reusing the execution plan.What types of

SQL server databases are the most widely used relational databases. However, in actual application, many databases need to be optimized. When the data volume is particularly large, we must rely on the optimization of our team's database. Such as creating indexes, table partitions, database shards, and table shards. This article summarizes some optimization methods. Address of this Article There are many rea

not think of its impactThis parameter is a data-level option that can be set up to refer to　　What is the automatic parameterization of the case?In a simple parameterized mode, SQL Server automatically parameterize a adhoc SQL statement with only one execution mode, thus achieving the purpose of reusing the execution plan.What types of

see, SQL Server is simpler for the manager of the heap. It is also more fragile in algorithm capability. Not talking about performance, light from the data storage management, it is difficult to manage a large table with heaps. So in SQL Server, a clustered index is built on all large, frequently used tables. Because

cursor. If a large result is returned, the stored procedure is used.42. Do not use the same function repeatedly in one sentence, waste resources, and put the result in a variable before calling it faster.43. The efficiency of select count (*) is low. Try to change his writing style as much as possible, while exists is fast. note the difference: the return values of select count (field of null) from table and select count (field of not null) from table are different !!!44. When the

45. Access your table in a certain order. If you lock table A and table B first, lock them in this order in all stored procedures. If you first lock table B in A stored procedure and then lock Table A, this may lead to A deadlock. If the lock sequence is not designed in detail in advance, it is difficult to find deadlocks. 46. Monitor the load of the corresponding hardware through SQL

compromise. Note that when you use the Enterprise Manager for the preceding settings, the files, registries, and ACLs on user rights are processed at the same time.5. determine all SQL server data, and the system file is mounted to the NTFS partition, and appropraite ACLs is applied. If someone gets access to the system, this level of permission can prevent intruders from damaging data and

, you do not allow any other transaction to manipulate the resource until the exclusive lock is released, preventing multiple operations on the same resource at the same time. Update Lock (U): Prevent deadlock in the lock mode, two transactions to a data resource read first in the case of modification, use of shared and exclusive locks sometimes deadlock phenomenon, and the use of update locks can