Connection states

If an application process executes a CONNECT statement, and the server name is known to the application requester but is not in the set of existing connections for the application process: (i) the current connection is placed into the dormant connection state, the server name is added to the set of connections, and the new connection is placed into both the current connection state and the held connection state.

If the server name is already in the set of existing connections for the application process, and the application is precompiled with the SQLRULES(STD) option, an error (SQLSTATE 08002) is raised.

Held and release-pending states. The RELEASE statement controls whether a connection is in the held or the release-pending state. The release-pending state means that a disconnect is to occur at the next successful commit operation. (A rollback has no effect on connections.) The held state means that a disconnect is not to occur at the next commit operation.

All connections are initially in the held state and can be moved to the release-pending state using the RELEASE statement. Once in the release-pending state, a connection cannot be moved back to the held state. A connection remains in release-pending state across unit of work boundaries if a ROLLBACK statement is issued, or if an unsuccessful commit operation results in a rollback operation.

Even if a connection is not explicitly marked for release, it might still be disconnected by a commit operation if the commit operation satisfies the conditions of the DISCONNECT precompiler option.

Current and dormant states. Regardless of whether a connection is in the held state or the release-pending state, it can also be in the current state or the dormant state. A connection in the current state is the connection being used to execute SQL statements while in this state. A connection in the dormant state is a connection that is not current.

The only SQL statements that can flow on a dormant connection are COMMIT, ROLLBACK, DISCONNECT, or RELEASE. The SET CONNECTION and CONNECT statements change the connection state of the specified server to current, and any existing connections are placed or remain in dormant state. At any point in time, only one connection can be in current state. If a dormant connection becomes current in the same unit of work, the state of all locks, cursors, and prepared statements is the same as the state they were in the last time that the connection was current.

When a connection ends

When a connection ends, all resources that were acquired by the application process through the connection, and all resources that were used to create and maintain the connection are de-allocated. For example, if the application process executes a RELEASE statement, any open cursors are closed when the connection ends during the next commit operation.

A connection can also end because of a communications failure. If this connection is in current state, the application process is placed in unconnected state.

All connections for an application process end when the process ends.