Ranking queries, also known as top-k queries, produce results that are ordered on some
computed score. Typically, these queries involve joins, where users are usually interested …

Systems for processing continuous monitoring queries over data streams must be adaptive
because data streams are often bursty and data characteristics may vary over time. We focus …

As our reliance on computers and computerized data has increased, we have come to
expect more from our computers. We no longer expect our computers to act as large …

The past decade has seen a wealth of research on time series representations, because the
manipulation, storage, and indexing of large volumes of raw time series data is impractical …

Dynamic plan migration is concerned with the on-the-fly transition from one continuous
query plan to a semantically equivalent yet more efficient plan. Migration is important for …

Today's database systems provide little feedback to the user/DBA on how much of a SQL
query's execution has been completed. For long running queries, such feedback can be very …

We introduce the hash-merge join algorithm (HMJ, for short); a new nonblocking join
algorithm that deals with data items from remote sources via unpredictable, slow, or bursty …

Ranking is an important property that needs to be fully supported by current relational query
engines. Recently, several rank-join query operators have been proposed based on rank …

We define a framework for static optimization of sliding window conjunctive queries over
infinite streams. When computational resources are sufficient, we propose that the goal of …

Many modern software systems provide progress indicators for long-running tasks. These
progress indicators make systems more user-friendly by helping the user quickly estimate …