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Exam Certified Data Engineer Professional topic 1 question 14 discussion

Actual exam question from Databricks's Certified Data Engineer Professional
Question #: 14
Topic #: 1
[All Certified Data Engineer Professional Questions]

An hourly batch job is configured to ingest data files from a cloud object storage container where each batch represent all records produced by the source system in a given hour. The batch job to process these records into the Lakehouse is sufficiently delayed to ensure no late-arriving data is missed. The user_id field represents a unique key for the data, which has the following schema: user_id BIGINT, username STRING, user_utc STRING, user_region STRING, last_login BIGINT, auto_pay BOOLEAN, last_updated BIGINT
New records are all ingested into a table named account_history which maintains a full record of all data in the same schema as the source. The next table in the system is named account_current and is implemented as a Type 1 table representing the most recent value for each unique user_id.
Assuming there are millions of user accounts and tens of thousands of records processed hourly, which implementation can be used to efficiently update the described account_current table as part of each hourly batch job?

  • A. Use Auto Loader to subscribe to new files in the account_history directory; configure a Structured Streaming trigger once job to batch update newly detected files into the account_current table.
  • B. Overwrite the account_current table with each batch using the results of a query against the account_history table grouping by user_id and filtering for the max value of last_updated.
  • C. Filter records in account_history using the last_updated field and the most recent hour processed, as well as the max last_iogin by user_id write a merge statement to update or insert the most recent value for each user_id.
  • D. Use Delta Lake version history to get the difference between the latest version of account_history and one version prior, then write these records to account_current.
  • E. Filter records in account_history using the last_updated field and the most recent hour processed, making sure to deduplicate on username; write a merge statement to update or insert the most recent value for each username.
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Suggested Answer: C 🗳️


Chosen Answer:
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2 months ago
Selected Answer: E
We need to filter on last hours and deduplicate records, then merge. Do is not correct, filtering on max loggin_date makes no sense.
upvoted 1 times
1 week, 4 days ago
deduplication on username does not make sense, username is not PK.
upvoted 2 times
1 month, 3 weeks ago
If the "las log in" is the column that shows the lates version of the record then answer c is correct
upvoted 1 times
2 months, 3 weeks ago
correct answer is C
upvoted 1 times
3 months ago
Selected Answer: C
upvoted 3 times
Community vote distribution
A (35%)
C (25%)
B (20%)
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