Glossary

• Ingestion – reading one new item from the stream and storing or discarding it.
• Lookup – calculating the original stream index at which a stored item arrived.
• S – shorthand for surface size, i.e. the number of storage sites available.
• Site – a location in memory where one item may be stored.
• Steady – downsample distribution maintaining uniform spacing between retained items.
• Stretched – distribution that thins proportionally to depth in the stream, emphasizing older data.
• T – count of elapsed items in the stream.
• Tilted – distribution that thins proportionally to age, emphasizing recent data.
• Surface – data structure comprising dstream-structured data in fixed-capacity buffer, with counter for number of items ingested.
• hybrid algorithm – algorithm combining multiple distributions by partitioning the surface among them.
• primed algorithm – algorithm filling surface left-to-right before delegating to another algorithm.