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Question 21

How can you convert a stream into a table in KSQL?

  • A. CREATE TABLE table_name AS SELECT * FROM stream_name;
  • B. INSERT INTO table_name SELECT * FROM stream_name;
  • C. CREATE TABLE table_name FROM stream_name;
  • D. CONVERT STREAM stream_name TO TABLE table_name;

Explanation: The correct syntax to convert a stream into a table in KSQL is CREATE TABLE table_name AS SELECT * FROM stream_name;.

  • B, C, and D are incorrect because they are not valid syntaxes for this operation in KSQL.

Answer: A

Question 22

What is the purpose of the AVRO format in KSQL?

  • A. To provide a human-readable format for data
  • B. To enable complex data types and schema evolution
  • C. To ensure data is stored as plain text
  • D. To simplify data parsing

Explanation: The AVRO format in KSQL is used to enable complex data types and schema evolution. It is a binary serialization format that supports rich data structures and efficient data encoding.

  • A, C, and D are incorrect because they do not accurately describe the purpose and capabilities of the AVRO format.

Answer: B

Question 23

Which KSQL function is used to extract the year from a timestamp?

  • A. EXTRACTYEAR()
  • B. GETYEAR()
  • C. YEAR()
  • D. EXTRACT(YEAR FROM timestamp)

Explanation: The EXTRACT(YEAR FROM timestamp) function in KSQL is used to extract the year from a timestamp.

  • A, B, and C are incorrect because they are not valid KSQL functions for this operation.

Answer: D

Question 24

How do you handle null values in KSQL?

  • A. Use the IS NULL and IS NOT NULL predicates
  • B. Use the NULLIFY() function
  • C. Replace null values with default values using COALESCE()
  • D. Both A and C

Explanation: In KSQL, you can handle null values using the IS NULL and IS NOT NULL predicates to filter records, and the COALESCE() function to replace null values with default values.

  • B is incorrect because NULLIFY() is not a valid KSQL function. Combining A and C provides comprehensive handling of null values.

Answer: D

Question 25

Which KSQL function calculates the total sum of a column's values?

  • A. SUM()
  • B. TOTAL()
  • C. ADD()
  • D. AGGREGATE()

Explanation: The SUM() function in KSQL calculates the total sum of a column's values.

  • B, C, and D are incorrect because they are not valid KSQL functions for this operation.

Answer: A

Question 26

What is the default retention period for KSQL streams?

  • A. 7 days
  • B. 1 day
  • C. 1 week
  • D. 2 days

Explanation:

In KSQL, streams are abstractions over Kafka topics. By default, the retention period for Kafka topics—and therefore KSQL streams—is 7 days. This means that the data in a KSQL stream is retained for 7 days before it is eligible for deletion, unless you configure a different retention period when creating the stream or alter the topic settings.

Key Points:

  • Default Retention Period: 7 days.
  • Inheritance from Kafka: KSQL streams inherit the retention settings from the underlying Kafka topics.
  • Configuration: You can adjust the retention period by setting the RETENTION property when creating a stream or by modifying the topic configuration directly.

Example of Setting Retention Period:

CREATE STREAM my_stream (
  ...
) WITH (
  kafka_topic='my_topic',
  value_format='JSON',
  retention='168 HOURS'  -- Retention period of 7 days
);

Other Options Explained:

  • B. 1 day: Not the default retention period but can be set manually.
  • C. 1 week: Equivalent to 7 days, but the default is specified in days.
  • D. 2 days: Not the default retention period but can be configured if needed.

A. 7 days

Question 27

How can you filter records in a KSQL stream?

  • A. By using the FILTER clause
  • B. By using the WHERE clause
  • C. By using the HAVING clause
  • D. By using the LIMIT clause

Explanation: Records in a KSQL stream can be filtered using the WHERE clause, which allows you to specify conditions that records must meet to be included in the query results.

  • A, C, and D are incorrect because they are not valid clauses for filtering records in a KSQL stream.

Answer: B

Question 28

Which KSQL function can be used to format timestamps?

  • A. FORMAT_TIMESTAMP()
  • B. TO_TIMESTAMP()
  • C. DATE_FORMAT()
  • D. TIMESTAMP_FORMAT()

Explanation: The DATE_FORMAT() function in KSQL can be used to format timestamps. It allows you to specify a pattern for formatting the date and time.

  • A, B, and D are incorrect because they are not valid KSQL functions for formatting timestamps.

Answer: C