Yi Pan (Data Infrastructure) created SAMZA-552:
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Summary: Tuple or time window semantics in physical operator
Key: SAMZA-552
URL: https://issues.apache.org/jira/browse/SAMZA-552
Project: Samza
Issue Type: Sub-task
Reporter: Yi Pan (Data Infrastructure)
The discussion is based on how to support tuple and/or time based window
operators in Samza physical operator layer.
Here are the few observations:
# Tuple represents the “physical ordering” of events while time-based window
has semantic meanings to users
# Total ordering between tuples are possible within Samza/Kafka given a
deterministic MessageSelector on all input streams and offsets within each
stream
# No matter whether tuple or time is used to measure the window size, the
window termination condition is needed to close a window to avoid the job to be
wedged forever
The following questions have to be answered to fully implement a window
operator:
# how to determine that a window is closed and no new tuples will be added?
## For tuple based, how do we close the window if messages do not come or get
delayed?
## For time based, how do we close the window if
### the messages are not strictly in order w/ the time?
### the message w/ timestamp greater than the window boundary does not come or
gets delayed?
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