# Synopsis Structure

**DOI:**https://doi.org/10.1007/978-1-4614-8265-9_383

## Synonyms

Synopsis

## Definition

A *synopsis structure* for a dataset *S* is any summary of *S* whose size is substantively smaller than *S*. Formally, its size is at most *O*(|*S*|^{ε}), where |*S*| is the size (in bytes) of *S*, for some constant ε < 1.

## Key Points

Synopsis structures are small, often statistical summaries of a data set. The term serves as an umbrella for any summarization structure of sufficiently small size, such as random samples, histograms, wavelets, sketches, top-k summaries, etc.

Synopsis structures are most commonly used in conjunction with data streams. The goal is to construct, in one pass over the data stream, a synopsis structure that can be used to answer any query from a prespecified class of queries. That is, at any point, a user may pose a query *Q* on the data stream thus far, and a (typically approximate) answer to *Q*must be produced using only the current synopsis structure. Two key advantages of using a synopsis structure to answer queries are that the space overhead is...

## Recommeded Reading

- 1.Gibbons PB, Matias Y. Synopsis data structures for massive data sets. DIMACS Series in Discrete Mathematics and Theoretical Computer Science: External Memory Algorithms. 1999.Google Scholar