What is an ArcSDE service?
An ArcSDE service, also known as an application server or a three-tiered architecture, conveys spatial data between GIS applications and a geodatabase.
The database may be any of the supported database management systems (DBMSs)—Oracle, SQL Server, Informix, DB2, or PostgreSQL.
Defining properties of the ArcSDE service
The giomgr process
This is the ArcSDE service monitor. Each ArcSDE service has one giomgr process. This process listens for user application connection requests, spawns gsrvr processes, and cleans up disconnected user processes. The giomgr will not start if a valid server license has not been installed.
The gsrvr process
The giomgr process spawns a gsrvr process for each application connected to the ArcSDE service. The gsrvr process is dedicated to a single user/application connection. It communicates with the database on behalf of the connected application. The gsrvr process responds to the queries and edit requests the application sends to the database.
The TCP/IP service name and port number
The ArcSDE service, through the giomgr process, listens for application connection requests on a dedicated Transmission Control Protocol/Internet Protocol (TCP/IP) service name and port number. The gsrvr process, in turn, communicates with the application on the same TCP/IP service and port number. These are stored in the services.sde file, the operating system's service file, and, on Windows, in the Windows Registry.