During big (~5GB) INSERT INTO ... SELECT statement execution I always get "Connection has been idle for longer than system defined threshold." error.

What could be the reason for that?

most likely, it's been throttled.

you might want to break down your insert into smaller chunks.

• Proposed as answer by Sofiya LiMicrosoft contingent staff, Moderator Wednesday, December 11, 2013 3:54 AM

most likely, it's been throttled.

you might want to break down your insert into smaller chunks.

• Proposed as answer by Sofiya LiMicrosoft contingent staff, Moderator Wednesday, December 11, 2013 3:54 AM

most likely, it's been throttled.

you might want to break down your insert into smaller chunks.

• Proposed as answer by Sofiya LiMicrosoft contingent staff, Moderator Wednesday, December 11, 2013 3:54 AM

Hi Eugene,

According to your description, we need to verify the edition of your SQL Azure database, and if the size of the database reaches its MAXSIZE, you cannot insert or update data. In addition, when databases encounter resource shortages, they will trigger connection-loss.  There are some throttling limits, you need to notice them. Such as, worker threads, sessions, database size,  physical database space, type of requests throttled and so on. In this case, I recommend you can reduce the size of data in the transaction, and split the operation into multiple transactions.

For more information, see: Windows Azure SQL Database Connection Management, and Inserting Large Amounts of Data Into Windows Azure SQL Database.

Thanks,
Sofiya Li