Hadoop Questions and Answers – HCatalog with Hadoop – 1

This set of Basic Hadoop Questions & Answers focuses on “HCatalog with Hadoop – 1”.

1. __________ is a REST API for HCatalog.
a) WebHCat
b) WbHCat
c) InpHCat
d) None of the mentioned
View Answer

Answer: a
Explanation: REST stands for “representational state transfer”, a style of API based on HTTP verbs.

2. Point out the correct statement.
a) There is no guaranteed read consistency when a partition is dropped
b) Unpartitioned tables effectively have one default partition that must be created at table creation time
c) Once a partition is created, records cannot be added to it, removed from it, or updated in it
d) All of the mentioned
View Answer

Answer: d
Explanation: Partitioned tables have no partitions at create time.

3. With HCatalog _________ does not need to modify the table structure.
a) Partition
b) Columns
c) Robert
d) All of the mentioned
View Answer

Answer: c
Explanation: Without HCatalog, Robert must alter the table to add the required partition.

4. Sally in data processing uses __________ to cleanse and prepare the data.
a) Pig
b) Hive
c) HCatalog
d) Impala
View Answer

Answer: a
Explanation: Without HCatalog, Sally must be manually informed by Joe when data is available, or poll on HDFS.

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5. Point out the wrong statement.
a) The original name of WebHCat was Templeton
b) Robert in client management uses Hive to analyze his clients’ results
c) With HCatalog, HCatalog cannot send a JMS message that data is available
d) All of the mentioned
View Answer

Answer: c
Explanation: The Pig job can then be restarted after analyzing client.

6. For ___________ partitioning jobs, simply specifying a custom directory is not good enough.
a) static
b) semi cluster
c) dynamic
d) all of the mentioned
View Answer

Answer: c
Explanation: Since it writes to multiple destinations, and thus, instead of a directory specification, it requires a pattern specification.

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7. ___________ property allows us to specify a custom dir location pattern for all the writes, and will interpolate each variable.
a) hcat.dynamic.partitioning.custom.pattern
b) hcat.append.limit
c) hcat.pig.storer.external.location
d) hcatalog.hive.client.cache.expiry.time
View Answer

Answer: a
Explanation: hcat.append.limit allows an HCatalog user to specify a custom append limit.

8. HCatalog maintains a cache of _________ to talk to the metastore.
a) HiveServer
b) HiveClients
c) HCatClients
d) All of the mentioned
View Answer

Answer: b
Explanation: HCatalog manages a cache of 1 metastore client per thread, defaulting to an expiry of 120 seconds.

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9. On the write side, it is expected that the user pass in valid _________ with data correctly.
a) HRecords
b) HCatRecos
c) HCatRecords
d) None of the mentioned
View Answer

Answer: c
Explanation: In some cases where a user of HCat (such as some older versions of pig) does not support all the datatypes supported by hive, there are a few config parameters provided to handle data promotions/conversions to allow them to read data through HCatalog.

10. A float parameter, defaults to 0.0001f, which means we can deal with 1 error every __________ rows.
a) 1000
b) 10000
c) 1 million rows
d) None of the mentioned
View Answer

Answer: b
Explanation: hcat.input.bad.record.threshold property is throw out error on encountering bad record.

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Here’s the list of Best Books in Hadoop.

To practice basic questions on all areas of Hadoop, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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