You can create user-defined table operators, which accept one or more tables or table expressions as input and generate a table as output. A table operator is a form of UDF that can only be specified in the FROM clause of a SELECT statement.
You can define a table operator that reads input tables, performs operations on the tables such as partitioning or aggregation, then writes output rows. The table operator can accept an arbitrary row format for each input table or table expression and based on the operation and input row types, it can produce an arbitrary output row format.
Table functions and table operators cannot execute against fallback data when an AMP is down. Once the AMP returns to service, the query can be submitted.