Data Unload

To unload data, create an external table and insert the data into it, or select data from an internal table into an external file.

To unload data in parallel, initiate a query that runs in parallel and writes its output to multiple files. The unload job uses a round-robin technique to equalize the number of rows in the output files.

To direct the output to a specific external table, run a separate SELECT statement for each coserver and use the LOCAL keyword for the source table and specify only data files on that coserver.

If multiple data files reside on a coserver and a data file fills up its disk, the unload task redirects the data to the remaining data files on that coserver. If all of the data files on a single coserver fill up, the unloading task fails. The redirection works only on a single coserver, not across coservers. No similar redirection capability exists for named pipes.