Any help with this impala error is much appreciated:
I think it was probably unable to get enough memory because of other concurrently executing queries.
This is somewhat counterintuitive, but if you set the mem_limit query option to an amount of memory that the query can reliably obtain, e.g. 2GB, then when it hits that limit spill-to-disk will kick in and the query should be able to complete (albeit slow than running fully in-memory).
We generally recommend that all queries run with a mem_limit set. You can configure a default mem_limit via the "default query options" config or by setting up memory-based admission control. We have some good docs about how to set up memory-based admission control here: https://www.cloudera.com/documentation/enterprise/latest/topics/impala_admission.html#admission_memo...
We're actively working on improving this so that it's more hands-off.