1. The minimum number of row versions to keep is configured per column family via _____________
a) HBaseDecriptor
b) HTabDescriptor
c) HColumnDescriptor
d) All of the mentioned
Answer: c
Clarification: The minimum number of row versions parameter is used together with the time-to-live parameter and can be combined with the number of row versions parameter.
2. Point out the correct statement.
a) The default for max versions is 1
b) It is recommended setting the number of max versions to an exceedingly high level
c) HBase does overwrite row values
d) All of the mentioned
Answer: a
Clarification: The number of max versions may need to be increased or decreased depending on application needs.
3. HBase supports a ____________ interface via Put and Result.
a) “bytes-in/bytes-out”
b) “bytes-in”
c) “bytes-out”
d) none of the mentioned
Answer: a
Clarification: Input could be strings, numbers, complex objects, or even images as long as they can rendered as bytes.
4. One supported data type that deserves special mention are ____________
a) money
b) counters
c) smallint
d) tinyint
Answer: b
Clarification: Synchronization on counters are done on the RegionServer, not in the client.
5. Point out the wrong statement.
a) Where time-ranges are very wide (e.g., year-long report) and where the data is voluminous, summary tables are a common approach
b) Coprocessors act like RDBMS triggers
c) HBase does not currently support ‘constraints’ in traditional (SQL) database parlance
d) None of the mentioned
Answer: c
Clarification: The advised usage for Constraints is in enforcing business rules for attributes in the table.
6. The _________ suffers from the monotonically increasing rowkey problem.
a) rowkey
b) columnkey
c) counterkey
d) all of the mentioned
Answer: a
Clarification: Attention must be paid to the number of buckets because this will require the same number of scans to return results.
7. __________ does re-write data and pack rows into columns for certain time-periods.
a) OpenTS
b) OpenTSDB
c) OpenTSD
d) OpenDB
Answer: b
Clarification: OpenTSDB is a very advanced processing technique.
8. Which command is used to disable all the tables matching the given regex?
a) remove all
b) drop all
c) disable_all
d) all of the mentioned
Answer: c
Clarification: The syntax for disable_all command is as follows : hbase> disable_all ‘r.*’
9. __________ command disables drops and recreates a table.
a) drop
b) truncate
c) delete
d) none of the mentioned
Answer: b
Clarification: The syntax of truncate is as follows: hbase> truncate ‘table name’.
10. Correct and valid syntax for count command is ____________
a) count ‘’
b) count ‘’
c) count ‘’
d) none of the mentioned
Answer: b
Clarification: You can count the number of rows of a table using the count command.