May 14, 2013
VoltDB has a csv loading utility. One path is to dump data from SQL Server to CSV files (comma separated values), then use the csv utility to load that data into VoltDB. You could also write a client program to connect to SQL Server and VoltDB - have the client pull data from SQL Server then insert it into VoltDB.
As a general rule, you should avoid long-running/blocking operations *within* a Stored Procedure (such as file I/O, network I/O, etc) because VoltDB executes stored procedures serially, so any blocking operations (like I/O) will stall the execution of other stored procedures, potentially significantly slowing down the throughput of the system.