Responding to a query in a data processing system

A data processing system comprising:

• at least one processor;
• a plurality of processing stages to apply respective operations on data;
• and
• a query processing engine executable on the at least one processor to:
• receive a query;
• in response to the query, access a membership structure to determine whether partially processed data produced by a particular one of the processing stages potentially contains data responsive to the query;
• and
• provide an output in response to the query, wherein the output has an indication regarding whether the output is potentially out-of-date, according to the determining performed based on accessing the membership structure.

An article comprising at least one non-transitory machine-readable storage medium storing instructions that upon execution cause a data processing system having a processor to:

• produce an output structure by a particular one of a plurality of processing stages, wherein the processing stages perform respective different operations on data received by the data processing system, and wherein the output structure contains partially processed data produced by the particular processing stage;
• associate a Bloom filter with the output structure produced by the particular processing stage;
• and
• in response to a query received from a query client after the output structure has been produced by the particular processing stage, access the Bloom filter to determine whether the Bloom filter indicates that data responsive to the query is present in the partially processed data in the output structure.