Pipelining
How pipelining is organised between two operators:
- blocks execute "concurrently" as producer/consumer pairs
- first operator acts as producer; second as consumer
- structured as interacting iterators (open; while(next); close)
Advantage:
- no requirement for disk access
(results passed via memory buffers)
Disadvantage:
- higher-level operators access inputs via linear scan, or
- requires sufficient memory buffers to hold all outputs
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