SQL API gives non-intuitive error if skipfields contains non-existent field

[andy-esch]

For instance, in this call, the column phony doesn't exist:

http://eschbacher.cartodb.com/api/v2/sql?q=select%20*%20from%20all_month_3&format=csv&skipfields=cartodb_id,the_geom,the_geom_webmercator,phony

The error reported is:

{
  "error": [
    "ERROR 4: Failed to create \/mnt\/exports\/sqlapi-24723-CSV:cartodb_user_6b304b59-2c86-4d7b-a8a2-dc98a5a35d48_db:cartodb_publicuser_86b53c46-b187-440c-b0b6-f2a1fb7512df::afa43b735e2f56ace98db372c38b5537:17c6b40802e327c70a8ba7fa772ec5e7:phony:cartodb_id:the_geom:the_geom_webmercator:cartodb-query.csv:"
  ]
}

What's strange is that it seems to work if any of the other field names are taken away (e.g., the_geom,the_geom_webmercatory,phony seems to work just fine).

[rochoa]

It seems related to the filename length, which usually is 255 chars. If you just remove a couple of characters from phony it also works.