Database Server Operating Modes

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Database Server Operating Modes

You can determine the current database server mode by executing the onstat utility from the command line. The onstat header displays the mode.

Table 15 shows the principal modes of operation of the database server.

Table 15. Operating Modes
Operating Mode	Description	Users Allowed Access
Offline mode	The database server is not running. Shared memory is not allocated.	Only the administrator (user informix) can change from this mode to another mode.
Quiescent mode	Database-server processes are running and shared-memory resources are allocated. Administrators use this mode to perform maintenance functions that do not require the execution of SQL and DDL statements.	Only the administrator (user informix) can access the database server. Other users can view database-server status information, but they cannot access the database server.
Single-User mode	This mode is an intermediary mode between Quiescent mode and Online mode. Administrators use this mode to perform any maintenance task, including tasks requiring the execution of SQL and DDL statements. Administrators can also perform all other functions available in Online mode.	Only the administrator (user informix) can access the database server. Other users can view database-server status information, but they cannot access the database server.
Online mode	This is the normal operating mode of the database server.	Any authorized user can connect with the database server and perform all database activities. User informix or user root can use the command-line utilities to change many database server ONCONFIG parameter values.

In addition, the database server can also be in one of the following modes:

Read-only mode is used by the secondary database server in an HDR pair. An application can query a database server that is in read-only mode, but the application cannot write to a read-only database.
Recovery mode is transitory. It occurs when the database server performs fast recovery or recovers from a system archive or system restore. Recovery occurs during the change from offline to quiescent mode.
Shutdown mode is transitory. It occurs when the database server is moving from online to quiescent mode or from online (or quiescent) to offline mode. Current users access the system, but no new users are allowed access.
After shutdown mode is initiated, it cannot be cancelled.