OpenEdge Getting Started: Installation and Configuration - Product ...

Appendix F: Configuration Models
The sections that follow explain the components of the architecture.
Broker
The initial database server process is identified as the broker (_mprosrv). The broker
process manages shared resources and starts servers for remote users, as needed.
OpenEdge Database Monitor utility
The OpenEdge Database Monitor utility (_dbagent) displays performance and usage
information about database status and activity.
For more information about the Database Monitor utility, see the description of the
PROMON utility in OpenEdge Data Management: Database Administration.
OpenEdge Watchdog utility
If a process terminates improperly, it can maintain a lock on a record or shared-memory
structure. This can impact database concurrency. The OpenEdge Watchdog utility
detects processes that have terminated improperly and cleans up after them.
At regular intervals, the Watchdog utility checks for processes that have terminated
unexpectedly. If it finds one, it releases any locks or shared-memory structures that the
process might hold.
The Watchdog utility checks for inactive processes approximately once every 10
seconds. It also checks for self-service clients that are no longer active, releases all the
appropriate record locks, backs out of any live transactions, and releases any
shared-memory locks. If a server process terminates unexpectedly, the Watchdog
utility disconnects and cleans up the server’s remote clients.
For more information about the Watchdog utility, see the description and other details
about the PROWDOG utility in OpenEdge Data Management: Database Administration.
Background writers
The OpenEdge Enterprise RDBMS offers three background writer processes that
improve performance. These processes continually perform certain housekeeping
functions in the background. Because these functions are performed regularly by the
dedicated background writer processes, client and server processes rarely have to wait
for these functions to be performed.
The three types of background writers, asynchronous page writers, before-image
writers, and after-image writers, are described in the “Processes on Windows and
UNIX platforms” section on page 201 and in the “Processes on UNIX platforms” section
on page 206. The AdminService starts the background writers if the AdminService has
been configured to do this by OpenEdge Management or OpenEdge Explorer. For
more information about background writers, see OpenEdge Data Management:
Database Administration.
508 OpenEdge Getting Started: Installation and Configuration