问题
while processing a CSV file, I am getting an error about maximum string size. "String size exceeds the maximum allowed size".
回答1:
Currently the maximum allowed size for a string in U-SQL is 128 KB.
If you need to handle larger sizes than that for now, then use the byte[] type instead when reading from the CSV file. Later, as the rowsets are processed in the script in the body of some C# code you can transform the byte[] into a string and do whatever string operations you need in the C# code.
NOTE: Rows in U-SQL also have a maximum size (Currently 4MB). And this technique is also subject to that limitation.
If you are interested in scenarios that support a string size that is greater than 128 KB, please vote on the feature request here, adding your scenario as comments would be super helpful as well.. https://feedback.azure.com/forums/327234-data-lake/suggestions/13416093-usql-string-data-type-has-a-size-limit-of-128kb
来源：https://stackoverflow.com/questions/36937965/what-is-the-maximum-allowed-size-for-string-in-u-sql