There are 3 SPJobLockType available:
1. SPJobLockType.None -- if you set it none, the
instance will run in all the available servers in the Farm (e.g. Application
Server Timer Job)
If you have to develop a job, you have to first
decide on the type of lock you need for your job.
E.g. If your job does something with the files in the Web-Frontend server you
might want to use a ContentDatabase lock.. or if you have something that
manipulates the data in a list.. you will have to use Job lock.
Note: If you use other types of locks to manipulate the data in a list.. the
multiple job instances will run simultaneously and cause Data Update conflict
errors.
Note: If for any reason you re-deploy your job.. either put the dll directly in
GAC or deploysolution.. make sure you restart the 'Windows Sharepoint Services
Timer' service. (OWSTIMER.EXE)Note: The account used by the Timer service
should have access to the Content Database.
Here are some sample code(s) of a custom timer job
definition:
[Guid("{62FF3B87-654E-41B8-B997-A1EA6720B127}")]
class MyTimerJob1 : SPJobDefinition
{
public MyTimerJob1()
: base()
{ }
public MyTimerJob1(string name, SPService service,
SPServer server,
SPJobLockType lockType) : base(name, service, server, lockType)
{ }
public MyTimerJob1(string name, SPWebApplication
webApplication, SPServer server,
SPJobLockType lockType) : base(name, webApplication, server, lockType)
{ }
public override void Execute(Guid targetInstanceId)
{
//Execute Timer Job Tasks
}
}
Remember that the different server roles that we can find on a
Sharepoint farm are:
- Database
Server:
the server that hosts the Microsoft SQL Server database for the farm.
Since Sharepoint Foundation is not typically installed in this server, no
jobs will run here.
- Web
Front End Server:
server where the Microsoft SharePoint Foundation Web Application
service is running on.
- Application
Server:
Any other Sharepoint server.
Here are a couple of examples on where the jobs will run depending
on the parameters passed to the constructor:
//Job associated with a web app, no server in particular and none lock: // will run on all fron end servers. var jobRunningOnAllFrontEndServers = new MyTimerJob1("mytimerjob", SPWebApplication.Lookup(webAppURI), null, SPJobLockType.None); //Job associated with a web app, one front end server and job lock: // will run only in the frontEndServer1 server. var jobRunningOnAParticularFronEndServer = new MyTimerJob1("mytimerjob", SPWebApplication.Lookup(webAppURI), fronEndServer1, SPJobLockType.Job); //Job associated with a webApp, and an app server and lock type job: // it won't run on any server since the server specified is NOT running // the Web Application Service var jobRunningOnNoServer = new MyTimerJob1("mytimerjob", SPWebApplication.Lookup(webAppURI), appServer1, SPJobLockType.Job); //Job associated with the timer service, a particular app server and none lock: // will run on the appServer1 server only. var jobRunningOnAppServer = new MyTimerJob1("mytimerjob", SPFarm.Local.TimerService, appServer1, SPJobLockType.None);
