I have a case where I want to enqueue hundreds of jobs in a batch, and the enqueued jobs contain database operations on the same database server as the one Hangfire runs on.
The problem is that after starting the batch, the Hangfire dashboard becomes unresponsive, and I start getting lots of errors like this:
Error occurred during execution of 'Worker #d726f5b8' process. Execution will be retried (attempt 1 of 2147483647) in 00:00:00 seconds.
System.InvalidOperationException: Timeout expired. The timeout period elapsed prior to obtaining a connection from the pool. This may have occurred because all pooled connections were in use and max pool size was reached. at System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, DbConnectionInternal& connection) at System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions) at System.Data.ProviderBase.DbConnectionClosed.TryOpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions) at System.Data.SqlClient.SqlConnection.TryOpenInner(TaskCompletionSource`1 retry) at System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1 retry) at System.Data.SqlClient.SqlConnection.Open() at Hangfire.SqlServer.SqlServerStorage.CreateAndOpenConnection() at Hangfire.SqlServer.SqlServerStorage.UseConnection[T](Func`2 func) at Hangfire.SqlServer.SqlServerStorage.UseTransaction[T](Func`3 func, Nullable`1 isolationLevel) at Hangfire.SqlServer.SqlServerStorage.UseTransaction(Action`2 action) at Hangfire.SqlServer.SqlServerWriteOnlyTransaction.Commit() at Hangfire.Batches.BatchJobSupportAttribute.OnStateApplied(ApplyStateContext context, IWriteOnlyTransaction outerTransaction) at Hangfire.States.StateMachine.ApplyState(ApplyStateContext initialContext) at Hangfire.States.BackgroundJobStateChanger.ChangeState(StateChangeContext context, BackgroundJob backgroundJob, IState toState, String oldStateName) at Hangfire.States.BackgroundJobStateChanger.ChangeState(StateChangeContext context) at Hangfire.Server.Worker.Execute(BackgroundProcessContext context) at Hangfire.Server.ServerProcessExtensions.Execute(IServerProcess process, BackgroundProcessContext context) at Hangfire.Server.AutomaticRetryProcess.Execute(BackgroundProcessContext context)
It would seem the batching of the jobs causes some kind of connection pool shortage.
These errors do not appear if I queue the jobs up normally.
Using Hangfire 1.6.3 with Hangfire Pro 1.4.7.
Any idea how to fix this?