Azure SQL: Invalid operation. The connection is closed

Dear fellow easymorph (em) users,

We have an em package, scheduled as task from the server, running every 15 mins,

The reason I reach out to you is…, sometimes we have a strange error.

The step that fails is the ‘import from database’, the database is actually an Azure SQL Database.
The import is just a simple table, around 50k rows.
We did some logging on the database and the load is around 1-4% and there are no heavy queries running at the time our em package fails.

The error produced is:
Invalid operation. The connection is closed.
Location: action “Import from database”, module “FinYears”,
(We use the default logging from the scheduler.)

This happens only ad random. Mostly in the evening.
Furthermore, at first sight, we can not spot any rarities in the network at the time of the error.

Someone has an idea what can be the problem OR how we can troubleshoot this better ?

Many thanks in advance

Hi Laurens and welcome to the Community!

What’s your EasyMorph version?

Hi Dmitry,

Thanks! Happy to be a part of it - as of today.

Client version is (5.3 is ready to be installed)
Server version:

Hi Laurens,

Can you please turn on the Diagnostics Log for that task (on the task’s Options tab), wait for the next occurrence of that error, and send the created Diagnostics Log to our support email? Please don’t forget to turn off the Diagnostics Log for that task afterward.

Hi Andrew,

Thanks for your reply. Please find below an extract, the most important part, of the error, taken from the diagnostic log file.
I have sent the full log to the support email address as well.

Just one slight thing we noticed:

Could it be possible easymorph uses the ‘old’ sql dataclient?

The log mentions the ‘System.Data.SqlClient’ whereas the new(est) client is ‘Microsoft.Data.SqlClient’

Thank you.

02/10/2022 XX:15:43    000216            ERROR     Source: action "Import from database", module "Main", table "PREMAP | Extant dbo.Relations"
02/10/2022 XX:15:43    000217            ERROR     
02/10/2022 XX:15:43    000218            ERROR     Exception: 
02/10/2022 XX:15:43    000219            ERROR     InvalidOperationException
02/10/2022 XX:15:43    000220            ERROR     Invalid operation. The connection is closed.
02/10/2022 XX:15:43    000221            ERROR     Call stack:
02/10/2022 XX:15:43    000222            ERROR        at System.Data.SqlClient.TdsParserStateObject.ReadSniSyncOverAsync()
02/10/2022 XX:15:43    000223            ERROR        at System.Data.SqlClient.TdsParserStateObject.TryReadNetworkPacket()
02/10/2022 XX:15:43    000224            ERROR        at System.Data.SqlClient.TdsParserStateObject.TryPrepareBuffer()
02/10/2022 XX:15:43    000225            ERROR        at System.Data.SqlClient.TdsParserStateObject.TryReadUInt32(UInt32& value)
02/10/2022 XX:15:43    000226            ERROR        at System.Data.SqlClient.TdsParserStateObject.TryReadPlpLength(Boolean returnPlpNullIfNull, UInt64& lengthLeft)
02/10/2022 XX:15:43    000227            ERROR        at System.Data.SqlClient.TdsParser.TrySkipPlpValue(UInt64 cb, TdsParserStateObject stateObj, UInt64& totalBytesSkipped)
02/10/2022 XX:15:43    000228            ERROR        at System.Data.SqlClient.TdsParser.TrySkipValue(SqlMetaDataPriv md, Int32 columnOrdinal, TdsParserStateObject stateObj)
02/10/2022 XX:15:43    000229            ERROR        at System.Data.SqlClient.TdsParser.TrySkipRow(_SqlMetaDataSet columns, Int32 startCol, TdsParserStateObject stateObj)
02/10/2022 XX:15:43    000230            ERROR        at System.Data.SqlClient.SqlDataReader.TryCleanPartialRead()
02/10/2022 XX:15:43    000231            ERROR        at System.Data.SqlClient.SqlDataReader.TryReadInternal(Boolean setTimeout, Boolean& more)
02/10/2022 XX:15:43    000232            ERROR        at System.Data.SqlClient.SqlDataReader.Read()
02/10/2022 XX:15:43    000233            ERROR        at Morph.DataDrivers.Database.DataReaders.DataReaderBase._ReadDbRows(DbDataReader reader, CancellationToken cancellationToken)
02/10/2022 XX:15:43    000234            ERROR        at Morph.DataDrivers.Database.DataReaders.DataReaderBase.(DbCommand , String , CancellationToken )
02/10/2022 XX:15:43    000235            ERROR        at Morph.DataDrivers.Database.DataReaders.DataReaderBase.RunQuery(String sql, CancellationToken token)
02/10/2022 XX:15:43    000236            ERROR        at Morph.DataDrivers.Database.DatabaseImportDriver..MoveNext()
02/10/2022 XX:15:43    000237            ERROR     --- End of stack trace from previous location where exception was thrown ---
02/10/2022 XX:15:43    000238            ERROR        at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
02/10/2022 XX:15:43    000239            ERROR        at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
02/10/2022 XX:15:43    000240            ERROR        at Morph.DataDrivers.Database.DatabaseImportDriver..MoveNext()
02/10/2022 XX:15:43    000241            INFO      cleanUp called

Please also consider following resource: Fixes "InvalidOperationException" errors by performing async operations in SemaphoreSlim by cheenamalhotra · Pull Request #796 · dotnet/SqlClient · GitHub

Hi Laurens,

Yes, EasyMorph uses System.Data.SqlClient, which quite possibly may be the source of the error in question.

We will test EasyMorph with Microsoft.Data.SqlClient and release an updated version if everything is OK.

Hi Andrew,

Great to see your alertness.
Glad we could help. Do not hesitate to let me know via this topic or via pm when the new version can be tested (possible through Beta)

Thank you

Hello Andrew,

is there any news on this?

Thanks and kind regards


Hello David,

We tested EasyMorph with Microsoft.Data.SqlClient and our test SQL Server. And it seems that everything is OK, so we are planning to switch to that client.

We expect this fix to be released with the next EasyMorph version in 1 or 2 weeks,
but we are still resolving some issues with the new client package, so I can’t make any promises.

Hello Andrew,

great news, thanks for this. We’re looking forward to the next release then :slight_smile:

Kind regards,

Hello @andrew.rybka

Hope you are well.
Could you tell us whether the switch to the Microsoft.Data.SqlClient was implemented in v5.3.1 ? If not, what would be the timeline for the next release? We’re relying more and more on our Azure DB connectors, and this leads to more and more instances of the same ‘Connection is closed’ error. So any improvement on this would be great :slight_smile:


Hi @David,

Yes, it was implemented. Version 5.3.1 was released yesterday.

1 Like

Great, thanks! We’ll upgrade asap and will let you know whether the error we encouter(ed) was fixed.

Hello dgudkov,

We still get the (same) error very often, I fear it hasn’t changed with the recent EasyMorph update:
“Invalid operation. The connection is closed.”

I have attached the log from one of the errors of today.
This is the result of the diagnostic logging on the Server.
EM_DiagnosticLog_20221205_part.txt (4.9 KB)

Is there anything else you can advise us to do ? Thank you in advance.