Data Conversion Errors for the last week

Question

We've been running a simple Stream Analytics job for little over a month now with a very light workload. Input is Event hub and output SQL Server. We noticed today that we haven't received anything into SQL Server since 2014-12-08 (we don't receive events
every day so we only know that everything still worked on the 8th of December), so we checked the job's logs. It seems that job is failing to process all the messages: The value of "Data Conversion Errors" is high.
I wonder what could have happened? We haven't touched the client since we started the job so it's still sending the messages in same format. And we haven't touched the job's query either.
Has there been an update to either to Stream Analytics or to Events Hub which could cause the issue we're seeing?

Answer 1

I've followed word for word the TollApp Instructions (except the thing with NamespaceType "Messaging" that has been added to New-AzureSBNamespace).
I have 0 line in output, and this is the service log:
Correlation ID:
e94f5b9e-d755-4160-b49e-c8225ceced0c
Error:
Message:
After deserialization, 0 rows have been found. Possible reasons could be a missing header or malformed CSV input.
Message Time:
2015-01-21 10:35:15Z
Microsoft.Resources/EventNameV2:
sharedNode92F920DE-290E-4B4C-861A-F85A4EC01D82.entrystream_0_c76f7247_25b7_4ca6_a3b6_c7bf192ba44a#0.output
Microsoft.Resources/Operation:
Information
Microsoft.Resources/ResourceUri:
/subscriptions/eb880f80-0028-49db-b956-464f8439270f/resourceGroups/StreamAnalytics-Default-West-Europe/providers/Microsoft.StreamAnalytics/streamingjobs/TollData
Type:
CsvParserError
Then I stopped the job, and connected to the event hub with a console app and received that:
Message received. Partition: '11', Data: 'TollId,EntryTime,LicensePlate,State,Make,Model,VehicleType,VehicleWeight,Toll,Tag
85,21/01/2015 10:24:56,QBQ 1188,OR,Toyota,4x4,1,0,4,361203677
Message received. Partition: '11', Data: 'TollId,EntryTime,LicensePlate,State,Make,Model,VehicleType,VehicleWeight,Toll,Tag
33,21/01/2015 10:25:42,BSE 3166,PA,Toyota,Rav4,1,0,6,603558073
Message received. Partition: '11', Data: 'TollId,EntryTime,LiMessage received. Partition: '10', Data: 'TollId,EntryTime,LicensePlate,State,Make,Model,VehicleType,VehicleWeight,Toll,Tag
59,21/01/2015 10:23:59,AXD 1469,CA,Toyota,Camry,1,0,6,150568526
Message received. Partition: '10', Data: 'TollId,EntryTime,LicensePlate,State,Make,Model,VehicleType,VehicleWeight,Toll,Tag
25,21/01/2015 10:24:17,OLW 6671,NJ,Honda,Civic,1,0,5,729503344
Message received. Partition: '10', Data: 'TollId,EntryTime,LicensePlate,State,Make,Model,VehicleType,VehicleWeight,Toll,Tag
51,21/01/2015 10:24:23,LTV 6699,CA,Honda,CRV,1,0,5,169341662
Note the bug on the 3rd message. In my opinion it's unrelated, it could be the writeline that can't keep up with the stream in the console application. And at worst it's in the stream, but then I should see at least some lines in output for the correctly
formatted messages.