Practice Test 1 | Google Cloud Certified Professional Data Engineer | Dumps | Mock Test

Question 11

An e-payment service allows users to purchase online and transfer money securely. They log into the website to perform the transactions and they log out. The website needs to check if their sessions are idle for 10 minutes, means they did not perform any action or they opened a new link within the website. In case of idle session, the website ends their session for security purposes.

You need to build a Dataflow pipeline to aggregate session events received from the website and detect sessions idle more than 10 minutes to get their sessions expired.

Which windowing function you should choose to design the pipeline?

A. Fixed-time window with duration of 10 minutes.
B. Sliding-time window with duration of 10 minutes.
C. Per-session window with time gap duration of 10 minutes.
D. Single global window with time-based trigger of 10 minutes.

Answer

Answer: C.

A session window function defines windows around areas of concentration in the data. Session windowing is useful for data that is irregularly distributed with respect to time; for example, a data stream representing user mouse activity may have long periods of idle time interspersed with high concentrations of clicks. Session windowing groups the high concentrations of data into separate windows and filters out the idle sections of the data stream. Note that session windowing applies on a per-key basis: That is, grouping into sessions only takes into account data that has the same key. Each key in your data collection will therefore be grouped into disjoint windows of differing sizes.