1 research outputs found
Query Results over Ongoing Databases that Remain Valid as Time Passes By (Extended Version)
Ongoing time point now is used to state that a tuple is valid from the start
point onward. For database systems ongoing time points have far-reaching
implications since they change continuously as time passes by. State-of-the-art
approaches deal with ongoing time points by instantiating them to the reference
time. The instantiation yields query results that are only valid at the chosen
time and get invalidated as time passes by. We propose a solution that keeps
ongoing time points uninstantiated during query processing. We do so by
evaluating predicates and functions at all possible reference times. This
renders query results independent of a specific reference time and yields
results that remain valid as time passes by. As query results, we propose
ongoing relations that include a reference time attribute. The value of the
reference time attribute is restricted by predicates and functions on ongoing
attributes. We describe and evaluate an efficient implementation of ongoing
data types and operations in PostgreSQL.Comment: Extended version of ICDE pape