The Read method cannot be called

Robert Riley 21

Hello,
I am having an issue with the npgsql connector to postgres. Error message below:

'Type=Npgsql.NpgsqlException,Message=Exception while reading from stream,Source=Npgsql,''Type=System.NotSupportedException,Message=The Read method cannot be called when another read operation is pending.,Source=System,'

This is coming from a look up query to a managed postgres instance, the query is a simple nested query like:

SELECT * FROM table1 t1 WHERE t1.id IN (SELECT t2.id from Table2 t2)

I am unable to find anything from npgsql or adf in regards to this error.

Please advise!

HimanshuSinha-msft 19,376 Reputation points Microsoft Employee

2021-01-21T01:05:25.37+00:00
Hello @Robert Riley ,
Thanks for using the forum .

i am assuming that you are using ADF look up to run the query which you mentioned above . On running the lookup activity you are getting the error . I must accept that at this time I do not have the environment to test this , but can you please check

When you run the query mentioned outside ADF , use some other IDE / application ,do you get the same error ?

Can you please run a simple query eg (SELECT * FROM table1 t1 ) in the lookup activity and see if that works . The idea is to find if its the query itself which is the culprit .

From the error message it looks like it is coming from Postgre itself but I could be wrrong .
Let me know how it goes .

Thanks
Himamshu
Robert Riley 21 Reputation points

2021-01-21T13:23:05.153+00:00

The query is part of a bigger design I developed using pgAdmin4, so I validated the return of the query in pgAdmin, so it does work. Have run both queries in a look up activity and there is no problem. I'm curious if it has to do with any settings in the connection string. I noticed yesterday that this only happens in a new LinkedService/Dataset that I created, where I modified a connection string:
"connectionString": "host=@{host};port=5432;database=@{Name};uid=@{UserName};EncryptionMethod=1;ValidateServerCertificate=0;Timeout=60;CommandTimeout=60;Keepalive=30;"

Could it be something here? I have altered the timeout and command timeout since I was unable to run any where that took longer than 30 second to complete (via ADF, no problems in Postgres itself).
HimanshuSinha-msft 19,376 Reputation points Microsoft Employee

2021-02-02T17:37:47.847+00:00

@Robert Riley : My apoloziges for the delay in response here . For a deeper investigation and immediate assistance on this issue, if you have a support plan you may file a support ticket, else could you please send an email to azcommunity@microsoft.com with the below details, so that we can create a one-time-free support ticket for you to work closely on this matter.

Thread URL:

Subscription ID:

Subject : Attn Himanshu

Please let me know once you have done the same

Thanks
Himanshu
Robert Riley 21 Reputation points

2021-02-02T17:57:29.783+00:00

Thank you, I believe we have a support plan, I will reach out and inquire on my end.