SQL bcp The semaphore timeout period has expired - sql

Question

I'm making a bulk copy onto a file of a select in my database.
DECLARE #cmd varchar(1000)
DECLARE #sql varchar(8000)
SET #cmd='"select * from [MyDB].[dbo].MyTable"'
SELECT #sql = 'bcp '+#cmd+' queryout C:\myfile.txt -c -t -T -S MyServer -U user -P password';
exec xp_cmdshell #sql;
If I change the parameters and I execute the same command on the database test on my machine it works, but on the database server I get this error:
Msg 121, Level 20, State 0, Line 0
A transport-level error has occurred when receiving results from the server. (provider: TCP Provider, error: 0 - The semaphore timeout period has expired.)
I check server name, user, password, table name and they are correct, so I cannot understand what I'm doing wrong.
Can someone help me with this issue?
thanks

Answer 1

Increase timeout seconds in connection string.
private static void OpenSqlConnection() {
string connectionString = GetConnectionString();
using(SqlConnection connection = new SqlConnection(connectionString)) {
connection.Open();
Console.WriteLine("State: {0}", connection.State);
Console.WriteLine("ConnectionTimeout: {0}",
connection.ConnectionTimeout);
}
}
static private string GetConnectionString() {
// To avoid storing the connection string in your code,
// you can retrieve it from a configuration file, using the
// System.Configuration.ConfigurationSettings.AppSettings property
return "Data Source=(local);Initial Catalog=AdventureWorks;" + "Integrated Security=SSPI;Connection Timeout=30";
}

Answer 2

I had the same error. A third-party tool was connecting to the database to extract data for import into a business intelligence system. Each extract/import would run for about 1 hour and there would be something like 10 to 15 separate queries in the process. Fortunately we had logging in place - so we knew at what time each of those queries was starting and ending. The extract/import process was saying that it was completing successfully after 30 minutes - rather than taking about 1 hour. I was able to isolate the query during which the process was failing. When I ran that query in SSMS I got the same error you've given in the question.
However, when I ran that query in another environment, I got an error that a subquery cannot return more than one row.
Sure enough, when I commented out my subqueries in the prod environment, the query ran without any error.
So ultimately, the root cause for me was a subquery returning more than one row - and the issue only appeared because for some reason, "bad data" got into the database - ie. that particular subquery should never have found a scenario where there is more than one row, and hence too, the error just began to appear one day. (For other people who are experiencing this error intermittently - it could be because it is only some of your queries - or one of your queries - that is failing).