Engineering Questions with Answers - Multiple Choice Questions
Hadoop MCQs
1 - Question
1. _________________ property allow users to override the expiry time specified.
a) hcat.desired.partition.num.splits
b) hcatalog.hive.client.cache.expiry.time
c) hcatalog.hive.client.cache.disabled
d) hcat.append.limit
View Answer
Answer: b
Explanation: This property is an int, and specifies number of seconds.
2 - Question
2. Point out the correct statement.
a) The HCatLoader and HCatStorer interfaces are used with Pig scripts to read and write data in HCatalog-managed tables
b) HCatalog is not thread safe
c) HCatLoader is used with Pig scripts to read data from HCatalog-managed tables.
d) All of the mentioned
View Answer
Answer: d
Explanation: HCatLoader is accessed via a Pig load statement.
Explanation: HCatLoader is accessed via a Pig load statement.
3 - Question
3. ____________ is used with Pig scripts to write data to HCatalog-managed tables.
a) HamaStorer
b) HCatStam
c) HCatStorer
d) All of the mentioned
View Answer
Answer: c
Explanation: HCatStorer is accessed via a Pig store statement.
4 - Question
4. Hive does not have a data type corresponding to the ____________ type in Pig.
a) decimal
b) short
c) biginteger
d) datetime
View Answer
Answer: c
Explanation: Hive 0.12.0 and earlier releases support writing Pig primitive data types with HCatStorer.
5 - Question
5. Point out the wrong statement.
a) The Hive metastore lets you create tables without specifying a database
b) Restrictions apply to the types of columns HCatLoader can read from HCatalog-managed tables
c) If the table is partitioned, you can indicate which partitions to scan by immediately following the load statement with a partition filter statement
d) None of the mentioned
View Answer
Answer: d
Explanation: If you created tables using metastore, then the database name is ‘default’ and is not required when specifying the table for HCatLoader.
6 - Question
6. _______________ method is used to include a projection schema, to specify the output fields.
a) OutputSchema
b) setOut
c) setOutputSchema
d) none of the mentioned
View Answer
Answer: c
Explanation: If a schema is not specified, all the columns in the table will be returned.
7 - Question
7. The first call on the HCatOutputFormat must be ____________
a) setOutputSchema
b) setOutput
c) setOut
d) OutputSchema
View Answer
Answer: b
Explanation: Any other call will throw an exception saying the output format is not initialized.
8 - Question
8. ___________ is the type supported for storing values in HCatalog tables.
a) HCatRecord
b) HCatColumns
c) HCatValues
d) All of the mentioned
View Answer
Answer: a
Explanation: The types in an HCatalog table schema determine the types of objects returned for different fields in HCatRecord.
9 - Question
9. The output descriptor for the table to be written is created by calling ____________
a) OutputJobInfo.describe
b) OutputJobInfo.create
c) OutputJobInfo.put
d) None of the mentioned
View Answer
Answer: b
Explanation: The implementation of Map takes HCatRecord as an input and the implementation of Reduce produces it as an output.
10 - Question
10. Which of the following Hive commands is not supported by HCatalog?
a) ALTER INDEX … REBUILD
b) CREATE VIEW
c) SHOW FUNCTIONS
d) DROP TABLE
View Answer
Answer: a
Explanation: Any command which is not supported throws an exception with the message “Operation Not Supported”.