how to avoid deadlock in sql server

transactions so that another transaction can be successfully completed. Generally, it is to undo the transaction that modifies the amount of data, so the cost of rolling back is less. A database that uses row-level locks rarely has this problem, since two users are less likely to modify the same record at the same time, and there are fewer locks due to the extremely accidental modification of the data. Also, the database uses a lock timeout to avoid

AJAX. 6. Database The database is the focus of my optimization. Because it is a database of SQL Server 2000, there is no DMV, no performance monitor for SSMS, no indexes included ...... There are too many useful functions, which is very inconvenient. In general, I think the optimization of database performance is mainly in three directions: Optimize the index and create the index to Remove unused index

really too high (it must be a serialized isolation level to be completely isolated, a bit of concurrency ...). Therefore, SQL Server's default read commited is a good choice to strike a balance between isolation and concurrency. SQL Server passes the lock, just like a traffic light at a crossroads, to tell all concurrent connections that at the same time those r

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

RAID0, and SQL2000 is not supported. The larger the data size (size), the more important it is to increase I/O.2. vertical and horizontalSplit the table to reduce the table size.(Sp_spaceuse)3. upgrade hardware4,Create indexes, optimize indexes, and optimize access methods based on query Conditions,Limit the data size of the result set. Note:Fill factor should be appropriate(It is best to use the default value 0 ). The index should be as small as possible,Index Using a column with a small numbe

Label: SQL Server Query optimization method The reasons for the slow query are many, the following are common 1, no index or no index (this is the most common problem of slow query, is the defect of program design)2, I/O throughput is small, forming a bottleneck effect3. No computed column created causes query not to be optimized4. Insufficient memory5. Slow network speed6, the amount of data queried is too

of shared and exclusive locks sometimes deadlock phenomenon, and the use of update locks can avoid the occurrence of deadlocks. A resource's update lock can only be assigned to one transaction at a time, and if the resource needs to be modified, the update lock becomes an exclusive lock, or it becomes a shared lock. Intent Lock: SQL

that SQL Server listens on:( SQL Server 2000 Server-side Network Configuration tool )(SQL Server 2005/2008 Configuration Manager)This shows the TCP/IP port that

related issues (problems with column correlations) 16th Week cardinality estimates in SQL Server 2014 (cardinality estimation in SQL Server 2014) 5th Month: Lock, block, deadlock As a developer or database administrator so far, your life is still pea

, you will need to select the Crosstab table (intersection table) as the underlying table, which is the table referenced by the other tables For example: The EMP table describes the intersection of the location table and the category table SELECT * from LOCATION L, CATEGORY C, EMP E WHERE e.emp_no BETWEEN 1000 and e.cat_no = C.cat_ NO will be more efficient than the following SQL SELECT * from EMP E, LOCATION L, CATEGO

If you are in charge of a SQL Server-based project or you have just been in touch with SQL Server, you may have to face some database performance problems, this article will provide you with some useful guidance (most of which can also be used for other DBMS ). Here, I am not going to introduce the tips for using

several minutes to several hours. If the waiting task is in an I/O process, this type does not indicate a problem.Bad_page_processWhen the background error page recorder is trying to avoid running at more than five seconds.Broker_receive_waitforIt appears when receive waitfor is waiting. This status usually appears if no message is to be received.Broker_transmitterWhen SQL

Operator: indicates failure ann A full operator that, if the message cannot reach the specified operator for an indeterminate reason, the SQL Server Agent passes the message to the failed-safe operator; (5) Select the Job System tab, as shown in Figure 17-4; Job History log: This area specifies the size of the log and the maximum number of rows per piece of work to

Many people do not know how SQL statements are executed in SQL Server, fearing that their written SQL statements will be misunderstood by SQL Server. Like what: SELECT * FROM table1 where name= ' Zhangsan ' and TID > 10000 and i

right window and select Properties from the context menu. 3 Select "Enable AlwaysOn availability Group" in the pop-up window by selecting the "AlwaysOn High Availability" tab. Click "Confirm". 4 in the Pop-up Warning dialog box prompts the changes need to restart the SQL Server Database engine service to take effect, click OK. 5 Again, right click SQL

result rows immediately. If the application does not extract all the result rows, the lock may stay on the table and block other users. If you use an application that will Transact-SQL statements are transparently submitted to the server, the application must fetch all the result rows. If the application does not do this (if it cannot be configured to do so), the blocking problem may not be resolved. To

Label:1. Four properties of a transaction Atomic Atomicity, consistency consistency, isolation isolation, persistent durability, acid properties. atomicity : A transaction must be a unit of complete work, either fully executed or not executed at all. consistency : At the end of the transaction, all internal data is correct. isolation : When multiple transactions are concurrent, each transaction does not interfere with internal data, and it processes data that is before or after another transacti

the deadlock, whether we have deadlock-causing performance problems in the application.Step 1:Right-select "Properties" on the previous "Deadlock_monitor" session. Select the Events page to add the Lock_deadlock and Lock_deadlock_chain event classes to the right-selected event list.650) this.width=650; "title=" clip_image014 "style=" Border-top:0px;border-right:0px;border-bottom:0px;border-left : 0px; "alt

no longer to be promoted in order to avoid sweeping. But the running time is mainly the following: Execution plan, statistics, index.Performance Wait Problem analysis:Wait time: Lock wait, latch wait.About resource waits, here are three articles,SQL Server Performance tuning wait Event,SQL

database. If an error is prompted, stop the SQL Service and restart it, as for the above other errors, you can change the content of the errors to restore them. Iii. Database shrinking In general, SQL database contraction does not greatly reduce the database size. Its main function is to shrink the log size, this operation should be performed on a regular basis to a