User's Guide

Part III. Using SQL Anywhere

Chapter 29. Running Programs as Services

This section describes some topic specific to running more than one service at a time.

Service dependencies

In some circumstances you may wish to run more than one executable as a service, and these executables may depend on each other. For example, you may wish to run a SQL Anywhere Client and also a SQL Remote Message Agent or SQL Anywhere Log Transfer Manager to assist in replication.

In cases such as these, it is important that the services start in the proper order. If a SQL Remote Message Agent service starts up before the SQL Anywhere Client has started, it will fail because it cannot find the server.

You can prevent these problems using service groups. You can manage the service groups from Sybase Central.

Service groups overview

You can assign each service on your system to be a member of a service group. By default, each service belongs to a group, as listed in the following table.

Service	Default group
Network server	SQLANYServer
Standalone engine	SQLANYEngine
Client	SQLANYClient
SQL Remote Message Agent	SQLANYRemote
Replication Agent	SQLANYLTM
Open Server Gateway	SQLANYOSG

Before you can configure your services to ensure that they start in the correct order, you must check that your service is a member of an appropriate group. You can check which group a service belongs to, and change this group, from Sybase Central.

To check which group a service belongs to:

1. In Sybase Central, open the Services folder.
2. Right-click the icon of the service you wish to start, and select Properties from the popup menu.
3. Click the Dependencies tab. The top text box displays the name of the group to which the service belongs.

To change which group a service belongs to:

1. In Sybase Central, open the Services folder.
2. Right-click the icon of the service you wish to start, and select Properties from the popup menu.
3. Click the Dependencies tab. Click Look Up to display a list of available groups on your system.
4. Select one of the groups, or type a name of a new group, and click OK to assign the service to that group.

Managing service dependencies

With Sybase Central you can ensure that at least one member of a each of a list of service groups, and each of a list of services, has started before the current service. The members of these lists are called dependencies.

For example, you may wish to ensure that a particular network server has started before a SQL Remote Message Agent that is to run against that server starts.

To add a service or group to a list of dependencies:

1. In Sybase Central, open the Services folder.
2. Right-click the icon of the service you wish to start, and select Properties from the popup menu.
3. Click the Dependencies tab. Click Add Service or Add Group to add a service or group to the list of dependencies..
4. Select one of the services or groups from the list, and click OK to add the service or group to the list of dependencies.

Possible problems running more than one server as a service

You may experience problems if you run more than one SQL Anywhere network server as a service at a time. Under some circumstances, it cannot be guaranteed that the correct service will respond to a client that sends a request to the database server as a broadcast. Broadcasts are typically used if you are using the TCP/IP protocol, or the IPX protocol on a Novell network without using the bindery. The broadcast is only used to find the server during startup.

We recommend that you not run more than one SQL Anywhere network server service at a time.