10. The system of claim 7 , wherein the instructions, when executed by the one or more processors, cause the one or more processors to: identify a partitioning attribute, other than a row number, of a query that references the relational data items; group the relational data items into different sets of relational data items, each relational data item in a given set sharing the same value for the partitioning attribute; and use the partitioning attribute as a progress attribute for the stream engine.
7. A system comprising: one or more processors; and one or more computer-readable storage media comprising instructions which, when executed by the one or more processors, cause the one or more processors to: access relational data items from a relational data table that lacks an explicit temporal attribute for ordering the relational data items of the relational data table; and adapt the relational data items for processing by a stream engine by associating explicit temporal data with the relational data items.