CCB-400 Online Practice Questions and Answers

The cells in a given row have versions that range from 1000 to 2000. You execute a delete specifying the value 3000 for the version. What is the outcome?

A. The delete fails with an error.

B. Only cells equal to the Specified version are deleted.

C. The entire row is deleted.

D. Nothing in the row is deleted.

You have an "Employees" table in HBase. The Row Keys are the employees' IDs. You would like to retrieve all employees who have an employee ID between 'user_100' and 'user_110'. The shell command you would use to complete this is:

A. scan'Employees', {STARTROW =>'user_100', STOPROW =>'user_111'}

B. get'Employees', {STARTROW =>'user_100', STOPROW =>'user_110'}

C. scan'Employees', {STARTROW =>'user_100', SLIMIT => 10}

D. scan'Employees', {STARTROW =>'user_100', STOPROW =>'user_110'}

You have two standbys and one primary HMaster. Your primary HMaster fails. Which of the remaining HMasters becomes the new primary?

A. Whichever HMaster first responds to ZooKeeper

B. Whichever HMasterZooKeeper randomly selects

C. Whichever HMastercreates the znode first

D. Whichever HMaster has the lower IP address

You have a table with the following rowkeys:

r1, r2, r3, r10, r15, r20, r25, r30, r35

In which order will these rows be retrieved from a scan?

A. r35,r30,r3,r25,r20,r2,r15,r10,r1

B. r1,r2,r3,r10,r15,r20, r25,r30,r35

C. r1,r10,r15,r2,r20,r25,r3,r30,r35

D. r35,r30,r25,r20,r15,r10,r3,r2,r1

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

Yon are storing page view data for a large number of Web sites, each of which has many subdomains (www.example.com, archive.example.com, beta.example.com, etc.) Your reporting tool needs to retrieve the total number of page views for a given subdomain of a Web site. Which of the following rowkeys should you use?

A. The reverse domain name (e.g., com.example.beta)

B. The domain name followed by the URL

C. The URL

D. The URL followed by the reverse domain name

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

You want to do mostly full table scans on your data. In order to improve performance you increase your block size. Why does this improve your scan performance?

A. It does not. Increasing block size does not improve scan performance.

B. It does not. Increasing block size means that fewer blocks fit into your block cache. This requires HBase to read each block from disk rather than cache for each scan, thereby decreasing scan performance.

C. Increasing block size requires HBase to readfrom disk fewer times, thereby increasing scan performance.

D. Increasing block size means fewer block indexes that need to be read from disk, therebyincreasing scan performance.

Your client application needs to write a row to a region that has, recently split. Where will the row be written?

A. One of the daughter regions

B. The original region

C. The .META. table

D. The HMaster