有关SQL server connection Keep Alive的几个问题解答-Mysql Tutorial-php.cn

Home

Database

Mysql Tutorial

有关SQL server connection Keep Alive的几个问题解答

WBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWB

Jun 07, 2016 pm 05:54 PM

sql serverquestion

1 、什么是SQL server TCP 连接的keep Alive ？简单说，keep alive 是SQL server在建立每一个TCP 连接的时候，指定了TCP 协议的keepaliveinterval 和keepalivetime参数。这样对每个TCP连接，如果该连接空闲时间（没有任何数据交互）超过keepalivetime，TCP

1、什么是SQL server TCP连接的keep Alive？

简单说，keep alive 是SQL server在建立每一个TCP 连接的时候，指定了TCP 协议的keepaliveinterval 和keepalivetime参数。这样对每个TCP连接，如果该连接空闲时间（没有任何数据交互）超过keepalivetime，TCP协议会自动发出keepalive 包检测连接存活与否。如果keepalive 检测次数超过注册表TcpMaxDataRetransmissions定义的值而对方还是没有回应，那么TCP就认为该连接有问题而关闭它。通过这样的机制SQL server能够检测出orphaned connection等问题。

SQL server 对每个TCP连接缺省指定keep alive 为30秒，keepaliveinterval为1秒。Windows TCP配置的TcpMaxDataRetransmissions缺省是5次。就是说，如果TCP连接idle了30秒，那么TCP会发送第一个keepalive检查。如果失败，那么TCP会每隔1秒重发keepalive 包，直到重发5次。如果第五次检测依然失败，则该连接就被close。所以，一个TCP连接如果出现异常问题，大概在35秒的时候就会被close。

2、在那里可以配置SQL server 的keep alive 配置？

SQL server 2000代码里面也有对TCP连接指定keep alive属性，但没有提供用户界面给用户定制修改。SQL server2005使用configuration manager可以修改keep alive值，但是不能修改keepalive interval。 Keepaliveinterval是hardcoded的1秒。

Configuration manager的界面如下：

该值保存在注册表如下位置：

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\MSSQL.?\MSSQLServer\SuperSocketNetLib\Tcp

注意SQL server的Native client也有类似配置，不要和server side 的TCP配置搞混了:

Native client的 keep alive 配置保存在如下位置:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSSQLServer\Client\SNI9.0\tcp

Statement

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

How do you handle database upgrades in MySQL?Apr 30, 2025 am 12:28 AM

The steps for upgrading MySQL database include: 1. Backup the database, 2. Stop the current MySQL service, 3. Install the new version of MySQL, 4. Start the new version of MySQL service, 5. Recover the database. Compatibility issues are required during the upgrade process, and advanced tools such as PerconaToolkit can be used for testing and optimization.

What are the different backup strategies you can use for MySQL?Apr 30, 2025 am 12:28 AM

MySQL backup policies include logical backup, physical backup, incremental backup, replication-based backup, and cloud backup. 1. Logical backup uses mysqldump to export database structure and data, which is suitable for small databases and version migrations. 2. Physical backups are fast and comprehensive by copying data files, but require database consistency. 3. Incremental backup uses binary logging to record changes, which is suitable for large databases. 4. Replication-based backup reduces the impact on the production system by backing up from the server. 5. Cloud backups such as AmazonRDS provide automation solutions, but costs and control need to be considered. When selecting a policy, database size, downtime tolerance, recovery time, and recovery point goals should be considered.

What is MySQL clustering?Apr 30, 2025 am 12:28 AM

MySQLclusteringenhancesdatabaserobustnessandscalabilitybydistributingdataacrossmultiplenodes.ItusestheNDBenginefordatareplicationandfaulttolerance,ensuringhighavailability.Setupinvolvesconfiguringmanagement,data,andSQLnodes,withcarefulmonitoringandpe

How do you optimize database schema design for performance in MySQL?Apr 30, 2025 am 12:27 AM

Optimizing database schema design in MySQL can improve performance through the following steps: 1. Index optimization: Create indexes on common query columns, balancing the overhead of query and inserting updates. 2. Table structure optimization: Reduce data redundancy through normalization or anti-normalization and improve access efficiency. 3. Data type selection: Use appropriate data types, such as INT instead of VARCHAR, to reduce storage space. 4. Partitioning and sub-table: For large data volumes, use partitioning and sub-table to disperse data to improve query and maintenance efficiency.

How can you optimize MySQL performance?Apr 30, 2025 am 12:26 AM

TooptimizeMySQLperformance,followthesesteps:1)Implementproperindexingtospeedupqueries,2)UseEXPLAINtoanalyzeandoptimizequeryperformance,3)Adjustserverconfigurationsettingslikeinnodb_buffer_pool_sizeandmax_connections,4)Usepartitioningforlargetablestoi

How to use MySQL functions for data processing and calculationApr 29, 2025 pm 04:21 PM

MySQL functions can be used for data processing and calculation. 1. Basic usage includes string processing, date calculation and mathematical operations. 2. Advanced usage involves combining multiple functions to implement complex operations. 3. Performance optimization requires avoiding the use of functions in the WHERE clause and using GROUPBY and temporary tables.

An efficient way to batch insert data in MySQLApr 29, 2025 pm 04:18 PM

Efficient methods for batch inserting data in MySQL include: 1. Using INSERTINTO...VALUES syntax, 2. Using LOADDATAINFILE command, 3. Using transaction processing, 4. Adjust batch size, 5. Disable indexing, 6. Using INSERTIGNORE or INSERT...ONDUPLICATEKEYUPDATE, these methods can significantly improve database operation efficiency.

Steps to add and delete fields to MySQL tablesApr 29, 2025 pm 04:15 PM

In MySQL, add fields using ALTERTABLEtable_nameADDCOLUMNnew_columnVARCHAR(255)AFTERexisting_column, delete fields using ALTERTABLEtable_nameDROPCOLUMNcolumn_to_drop. When adding fields, you need to specify a location to optimize query performance and data structure; before deleting fields, you need to confirm that the operation is irreversible; modifying table structure using online DDL, backup data, test environment, and low-load time periods is performance optimization and best practice.

See all articles