Redigeeri

Jagamisviis:

CONTEXT_INFO (Transact-SQL)

  • Artikkel

Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance

This function returns the context_info value either set for the current session or batch, or derived through use of the SET CONTEXT_INFO statement.

Transact-SQL syntax conventions

Syntax

CONTEXT_INFO()

Return value

The context_info value.

If context_info was not set:

  • SQL Server returns NULL.
  • SQL Database returns a unique session-specific GUID.

Remarks

The Multiple Active Result Sets (MARS) feature enables applications to run multiple batches, or requests, at the same time, on the same connection. When one of the MARS connection batches runs SET CONTEXT_INFO, the CONTEXT_INFO function returns the new context value, when the CONTEXT_INFO function runs in the same batch as the SET statement. If the CONTEXT_INFO function runs in one or more of the other connection batches, the CONTEXT_INFO function does not return the new value unless those batches started after completion of the batch that ran the SET statement.

Permissions

Requires no special permissions. The following system views store the context information, but querying these views directly requires SELECT and VIEW SERVER STATE permissions:

  • sys.dm_exec_requests
  • sys.dm_exec_sessions
  • sys.sysprocesses

Examples

This simple example sets the context_info value to 0x1256698456, and then uses the CONTEXT_INFO function to retrieve the value.

SET CONTEXT_INFO 0x1256698456;  
GO  
SELECT CONTEXT_INFO();  
GO

See also

SET CONTEXT_INFO (Transact-SQL) SESSION_CONTEXT (Transact-SQL)
sp_set_session_context (Transact-SQL)