CCB-400 Online Practice Questions and Answers

You have an average key-value pair size of 100 bytes. Your primary access is random needs on the table. Which of the following actions will speed up random reading performance on your cluster?

A. Turn off WAL on puts

B. Increase the number of versions kept

C. Decrease the block size

D. Increase the block size

Under default settings, which feature of HBase ensures that data won't be lost in the event of a RegionServer failure?

A. AllHBase activity is written to the WAL, which is stored in HDFS

B. All operations are logged on theHMaster.

C. HBase is ACID compliant, which guarantees that itis Durable.

D. Data is stored on the local filesystem of the RegionServer.

Data is written to the HLog in which of the following orders?

A. In order of writes

B. In order of writes, separated by region

C. Ascending first by region and second by row key

D. Descending first by region and second by row key

Given that following is your entire dataset:

100 column=Managers:Name, timestamp=13313141762084, value=Steve 100 column=Manage:Salary, timestamp=13313141762086, value=80000 100 column=Skills:Skill_1, timestamp=13313141762089, value=Hadoop 100 column=Skills:Skill_2, timestamp=13313141762092, value=HBase How many sets of physical files will be read during a scan of the entire dataset immediately following a major compaction?

A. Two

B. One

C. Three

D. Four

Your client application if; writing data to a Region. By default, where is the data saved first?

A. StoreFile

B. WAL

C. MemStore

D. Local disk on theRegionServer

Given that the following is your entire dataset:

100 column=Managers:Name, timestamp=13313141762084, value=Steve 100 column=Manage:Salary, timestamp=13313141762086, value=80000 100 column=Skills:Skill_1, timestamp=13313141762089, value=Hadoop 100 column=Skills:Skill_2, timestamp=13313141762092, value=HBase

How many regions will be read during a scan of the entire dataset?

A. Four

B. Two

C. One

D. Three

Your client is writing to a region when the RegionServer crashes. At what point in the write is your data secure?

A. From the moment the RegionServer wrote to the WAL (write-ahead log)

B. From the moment the RegionServer returned the call

C. From the moment the RegionServer received the call

D. From the moment the RegionServer wrote to the MemStore

Given the following HBase dataset, which is labeled with row numbers. . .

Row # ROW KEY COLUMN+CELL 1 BB002 Column=Comments:C_Author, timestamp=001, value=Diana Mears 2 BB002 Column=Comments:C_Title, timestamp=001, value=Thanks 3 BB001 Column=INFO:Title, timestamp=005, value=HBsase+Hadoop 4 BB001 Column=INFO:Author,timestamp=005,value=Lars George 5 BB002 Column=Comments:C_Text, timestamp=001, value=Any tips on ... 6 BB001 Column=INFO:Text, timestamp=005, value=Some of the ...

Which of the following lists of row numbers is the correct order that HBase would store this data?

A. 1, 5, 2, 4, 3, 6

B. 4, 1, 2, 6, 3, 5

C. 4, 6, 3, 1, 5, 2

D. 3, 4, 6, 1, 2, 5

From within an HBase application, you want to retrieve two versions of a row, if they exist. Where your application should configure the maximum number of versions to be retrieved?

A. HTableDescriptor

B. HTable

C. Get or scan

D. HColumnDescriptor

You have tin linage table live in production. The table users as the rowkey. You want to change the existing rowkeys to . Which of the following should you do?

A. Modify the client application to write to both the old table and a new table while migrating the old data separately

B. Use theALTERtable command to modify the rowkeys

C. Use theASSIGNcommand to modify the rowkeys

D. Add a new columnto store the userid