What is "Connect Timeout" in sql server connection string?

Solution 1:

That is the timeout to create the connection, NOT a timeout for commands executed over that connection.

See for instance http://www.connectionstrings.com/all-sql-server-connection-string-keywords/ (note that the property is "Connect Timeout" (or "Connection Timeout"), not just "Timeout")

From the comments:

It is not possible to set the command timeout through the connection string. However, the SqlCommand has a CommandTimeout property (derived from DbCommand) where you can set a timeout (in seconds) per command.

Do note that when you loop over query results with Read(), the timeout is reset on every read. The timeout is for each network request, not for the total connection.

Solution 2:

Connect Timeout=30 means, within 30second sql server should establish the connection.other wise current connection request will be cancelled.It is used to avoid connection attempt to waits indefinitely.

Solution 3:

Connection Timeout=30 means that the database server has 30 seconds to establish a connection.

Connection Timeout specifies the time limit (in seconds), within which the connection to the specified server must be made, otherwise an exception is thrown i.e. It specifies how long you will allow your program to be held up while it establishes a database connection.

DataSource=server;
InitialCatalog=database;
UserId=username;
Password=password;
Connection Timeout=30

SqlConnection.ConnectionTimeout. specifies how many seconds the SQL Server service has to respond to a connection attempt. This is always set as part of the connection string.

Notes:

• The value is expressed in seconds, not milliseconds.

• The default value is 30 seconds.

• A value of 0 means to wait indefinitely and never time out.

In addition, SqlCommand.CommandTimeout specifies the timeout value of a specific query running on SQL Server, however this is set via the SqlConnection object/setting (depending on your programming language), and not in the connection string i.e. It specifies how long you will allow your program to be held up while the command is run.