A single Foundry call is limited to returning less that one million rows or 1GB.

[phil-moura]

The UEC extract failed when adding a new metric and this was because the additional rows contributed by the new metric broke the 1 million rows Foundry limit. This meant the entire call failed and NO rows were returned. Either the Foundry wrapper needs to manage chunking up the query itself or users of the API need to be made aware that they might need to create separate queries (I know this is solutionising but it's Friday so sue me).