System Activity Monitoring

Automatic monitoring and corrective actions

You can use the administration API, the scheduler, and information stored in the sysadmin database to manage automatic maintenance, monitoring, and administrative tasks. These components of Dynamic Server enable you to simplify the collection of information and maintenance of the server in complex systems.

Administration API

The SQL administration API enables you to perform remote administration using various, specific SQL commands for tasks such as managing spaces, managing configuration, running routine jobs, and system validation.

The scheduler

The scheduler enables the database server to execute database functions and procedures at predefined times or as determined internally by the server. The functions and procedures collect information, and monitor and adjust the server, using an SQL-based administrative system and a set of tasks.

The scheduler manages and executes scheduled maintenance, monitoring, and administration tasks. This tool enables you to monitor activities (for example, space management or automatically backing up any new log data at timed intervals since the last log backup) and create corrective actions that run automatically.

The scheduler manages:

  • Tasks, which provide the means for running a specific job at a specific time or interval.
  • Sensors, which collect and save information.
  • Startup tasks, which run only once when the database server starts.
  • Startup sensors, which run only once when the database starts.

The system-monitoring interface

The system-monitoring interface (SMI) tables are special tables managed by the database server that contain dynamic information about the state of the database server. You can use SELECT statements on them to determine almost anything you might want to know about your database server.

The sysmaster database

The sysmaster database is described as a pseudo database. That means most of its tables are not normal tables on disk, but pointers to shared memory structures in the IDS engine. The sysmaster database contains over 120 tables. Only some of these tables are documented in the Informix Dynamic Server Administrators Guide. The rest are undocumented and meant to be as such for internal use.

The onstat utility

The onstat utility provides a way to monitor database server shared memory from the command line. The onstat utility reads data from shared memory and reports statistics that are accurate for the instant during which the command executes. That is, onstat provides information that changes dynamically during processing, including changes in buffers, locks, indexes, and users.
More on the Section Informix online utilities.
Also in The onstat utility.

The oncheck utility

The oncheck utility displays information about the database disk configuration and usage, such as the number of pages used for a table, the contents of the reserved pages, and the number of extents in a table.
More on the Section Informix online utilities.

The oncheck utility can repair the following types of disk structures:

  • Partition-page statistics
  • Bitmap pages
  • Partition blobpages
  • Blobspace blobpages
  • Indexes
  • Sbspace pages
  • Metadata partitions for sbspaces

Message log

The database server message log is an operating system file. The messages contained in the database server message log do not usually require immediate action.

Location

The location is specified by the parameter MSGPATH.

Monitoring message log

The command onstat -m is used to obtain the name of the message log and the 20 most recent entries.

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