从SQL Server中的Sproc返回到ADO.NET应用程序的最大数据量是多少

Question

We have a windows service that needs to retrieve all the Orders of a Customer. There can be cases where a customer can have large number of Orders. So wanted to know if there was a known limit on the size of data that can be returned from a sproc in SQL Server to ADO.NET application. I can then calculate the average size of row in the table and provide the max Orders per customer limit. Thanks.

Answer 1

Since you are using ADO.NET, DataReader supports the max data types. You will have to use a batching strategy if you are dealing with massive result sets.

Large object (LOB) data types are those that exceed the maximum row size of 8 kilobytes (KB). SQL Server provides a max specifier for varchar, nvarchar, and varbinary data types to allow storage of values as large as 2^32 bytes. Table columns and Transact-SQL variables may specify varchar(max), nvarchar(max), or varbinary(max) data types. In ADO.NET, the max data types can be fetched by a DataReader , and can also be specified as both input and output parameter values without any special handling. For large varchar data types, data can be retrieved and updated incrementally.

https://msdn.microsoft.com/en-us/library/bb399384(v=vs.110).aspx

I just found following SO post which is also relevant.

SQL Server and SqlDataReader - Trillion Records - Memory

Answer 2

Apparently I cannot repeat this enough: There is no row limit.

The maximum size of a SQL Server database is, if I recall correctly apprx 500,000 terabytes . You are nowhere near that, plus, there is no limit to the number of rows returned . Your interface method might have a limit, but if you are using a .Net streaming method like a datareader , the only limit is your time and patience (and your client's memory or storage if you are trying to retain them all at once).