Filling in missing values

[sparkz_alot]

You need to post the relevant code relating to your question. For instance, you mention an "isnull" function, yet I do not see it in your code and a variable "bfill", again not present in the code you posted. Ideally, you should also post a small sample of the json file that shows an example of what you mean by 'backfill' as well as what you consider a complete line. For information on how to properly ask a question, thereby increasing the chance of a quick and correct answer, refer to our Help/Info document.