Why does GCD backup & BQ load create RECORD with "string" and "provided" fields?

[Andrey Fedorov via StackOverflow]

I have half a dozen tables backing up and loading into BigQuery without any issues, but just one string field of dozens seems to translate into a RECORD field with with "string" and "provided" fields: BQ table details.

Why could this be? I'm not seeing these fields mentioned in my code in any way, and the backup & load jobs are all Google's code.

Please DO NOT REPLY directly to this email but go to StackOverflow:
http://stackoverflow.com/questions/43987559/why-does-gcd-backup-bq-load-create-record-with-string-and-provided-fields

[Andrey Fedorov via StackOverflow]

Looks like when a String is long enough it gets stored as a Blob in the datastore, and BigQuery does not support those, so they instead show up as base64encoded strings in the GCD Console and end up as:

{"d_3_string": null, "d_3_provided": null}

in BigQuery tables.

Please DO NOT REPLY directly to this email but go to StackOverflow:

http://stackoverflow.com/questions/43987559/why-does-gcd-backup-bq-load-create-record-with-string-and-provided-fields/43988394#43988394