Don't log warnings regarding scheduler parallelism too often

Author: odinserj

src/Hangfire.Core/BackgroundJobServer.cs

@@ -213,7 +213,14 @@ private IEnumerable<IBackgroundProcessDispatcherBuilder> GetRequiredProcesses(
 
             if (!_options.IsLightweightServer)
             {
-                processes.Add(new DelayedJobScheduler(_options.SchedulePollingInterval, stateChanger).UseBackgroundPool(1));
+                processes.Add(
+                    new DelayedJobScheduler(_options.SchedulePollingInterval, stateChanger)
+                    {
+                        TaskScheduler = _options.TaskScheduler,
+                        MaxDegreeOfParallelism = _options.MaxDegreeOfParallelismForSchedulers
+                    }
+                    .UseBackgroundPool(1));
+
                 processes.Add(
                     new RecurringJobScheduler(factory, _options.SchedulePollingInterval, timeZoneResolver)
                         {

src/Hangfire.Core/Server/DelayedJobScheduler.cs

@@ -81,6 +81,7 @@ public class DelayedJobScheduler : IBackgroundProcess
         private readonly IBackgroundJobStateChanger _stateChanger;
         private readonly IProfiler _profiler;
         private readonly TimeSpan _pollingDelay;
+        private bool _parallelismIssueLogged;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="DelayedJobScheduler"/>
@@ -234,9 +235,10 @@ private int EnqueueNextScheduledJobs(BackgroundProcessContext context)
                 }
                 else
                 {
-                    if (MaxDegreeOfParallelism > 1)
+                    if (MaxDegreeOfParallelism > 1 && !_parallelismIssueLogged)
                     {
                         _logger.Warn("Parallel execution is configured but can't be used, because current storage implementation doesn't support batching.");
+                        _parallelismIssueLogged = true;
                     }
 
                     for (var i = 0; i < BatchSize; i++)

src/Hangfire.Core/Server/RecurringJobScheduler.cs

@@ -78,6 +78,7 @@ public class RecurringJobScheduler : IBackgroundProcess
         private readonly ITimeZoneResolver _timeZoneResolver;
         private readonly TimeSpan _pollingDelay;
         private readonly IProfiler _profiler;
+        private bool _parallelismIssueLogged;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="RecurringJobScheduler"/>
@@ -252,9 +253,10 @@ private int EnqueueNextRecurringJobs(BackgroundProcessContext context)
                 }
                 else
                 {
-                    if (MaxDegreeOfParallelism > 1)
+                    if (MaxDegreeOfParallelism > 1 && !_parallelismIssueLogged)
                     {
                         _logger.Warn("Parallel execution is configured but can't be used, because current storage implementation doesn't support batching.");
+                        _parallelismIssueLogged = true;
                     }
 
                     for (var i = 0; i < BatchSize; i++)