Database locking coordinates clustered background tasks by allowing only one application instance to handle a trigger and run its associated job. section 34.3.3
In a clustered Quartz.NET deployment:
- Quartz.NET persists jobs and triggers in a shared database and uses its locking primitives to prevent duplicate handling. section 34.3.3
- SQLite can store persistence data but cannot provide the locking primitives required for clustering. section 34.3.3
- The required Quartz.NET tables must be created separately, using supplied database scripts or an EF Core migration. section 34.3.3
Listing 34.13 Enabling persistence and clustering for Quartz.NET
using Quartz;
IHost host = Host.CreateDefaultBuilder(args)
.ConfigureServices((hostContext, services) => #1
{
var connectionString = Configuration #2
.GetConnectionString("DefaultConnection"); #2
services.AddQuartz(q =>
{
q.SchedulerId = "AUTO"; #3
q. UseMicrosoftDependencyInjectionJobFactory();
q.UsePersistentStore(s => #4
{
s.UseSqlServer(connectionString); #5
s.UseClustering(); #6
s.UseProperties = true; #7
s.UseJsonSerializer(); #7
});
var jobKey = new JobKey("Update_exchange_rates");
q.AddJob<UpdateExchangeRatesJob>(opts =>
opts.WithIdentity(jobKey));
q.AddTrigger(opts => opts
.ForJob(jobKey)
.WithIdentity(jobKey.Name + " trigger")
.StartNow()
.WithSimpleSchedule(x => x
.WithInterval(TimeSpan.FromMinutes(5))
.RepeatForever())
);
});
services.AddQuartzHostedService(
q => q.WaitForJobsToComplete = true);
})
.Build();
host.Run();
#1 Configuration is identical for both ASP.NET Core apps and worker services.
#2 Obtains the connection string for your database from configuration
#3 Each instance of your app must have a unique SchedulerId. AUTO takes care of this for you.
#4 Enables database persistence for the Quartz.NET scheduler data
#5 Stores the scheduler data in a SQL Server (or LocalDb) database
#6 Enables clustering between multiple instances of your app
#7 Adds the recommended configuration for job persistence
Shows the Quartz.NET configuration that combines a persistent SQL Server store with clustering. section 34.3.3
