Cloudera HBase Certification Questions and Answers (Dumps and Practice Questions)

Question : What is true about HLog..




1. One HLog instance per RegionServer
2. Stored in HDFS in /hbase/.logs with subdirectories per region
3. Access Mostly Uused Products by 50000+ Subscribers
4. Both 1 and 2 are wrong


Correct Answer : Get Lastest Questions and Answer :

HLog is the WAL implementation
- One HLog instance per RegionServer
- Stored in HDFS in /hbase/.logs with subdirectories per region




Question : In case of RegionServer update (Puts and Deletes)..

1. Added to WAL (write ahead log) before written to MemCache
2. It Ensures Durable writes
3. Access Mostly Uused Products by 50000+ Subscribers
4. Both 1 and 2 are wrong

Correct Answer : Get Lastest Questions and Answer :

RegionServer update (Puts, Deletes)
- Added to WAL before written to MemStore
- Ensures durable writes




Question :

In case of RegionServer Crach


1. Recent changes would still be in MemStore
2. HLog is used to reapply the recent changes
3. Access Mostly Uused Products by 50000+ Subscribers
4. All 1,2 and 3 are correct
5. Only 1 and 2 are correct

Correct Answer : Get Lastest Questions and Answer :

In case of RegionServer Crash
MemStore is in memory and its data is lost

Recent changes would still be in MemStore
HLog is used to reapply the recent changes

Region StoreFiles (HFiles) are stored in HDFS

Master notices that Regions are not being served
Master splits the Hlog into a per-region log
Reassigns Regions to another RegionServer
RegionServer automatically applies the log

Related Questions

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Question : You have network servers producing timeseries data from network traffic logs.
You want to attain high write throughput for storing this data in an HBase table.
Which of these should you choose for a row key to maximize your write throughput?

1. (hashCode(centralServerGeneratedSequenceID)>(timestamp>
2. (timestamp>

3. Access Mostly Uused Products by 50000+ Subscribers

4. (Long.MAX_VALUE - timestamp>




Question : If you have more than one tables in RDBMS which are frequently joined to fetch the data, now you want migrate these tables in HBase.
Please select correct statement from below..

1. Create all the tables each with multiple column families in HBASE
2. Create a single table with as many column families
as tables
3. Access Mostly Uused Products by 50000+ Subscribers
for all the tables
4. Any of the above will fine




Question : You have a table with the following rowkeys based on the date:
21012010, 22012010, 23012010,21052010,28012010,24012010,29012010
In which order will these rows be retrieved from a scan?

1. 21012010, 22012010, 23012010, 21052010, 28012010, 24012010, 29012010
2. 21012010, 21052010, 22012010, 23012010, 24012010, 28012010, 29012010
3. Access Mostly Uused Products by 50000+ Subscribers
4. It could be in any random order



Question : You want to store clickstream data in HBase. Your data consists of the following:
the source id
the name of the cluster
the url of the click
the datetimestamp for each click
Which rowkey should you use if you want to retrieve the source ids with a scan and sorted with the most recent first?

1. (source_id)(Long.MAX_VALUE - (Long)datetimestamp)
2. ((Long)datetimestamp)(source_id)

3. Access Mostly Uused Products by 50000+ Subscribers
4. (source_id)(datetimestamp)(Long.MAX_VALUE)



Question : Given the following HBase code:
byte [] rowKey = Bytes.toBytes(65);
Put put = new Put(rowKey);
put.add("info".getBytes(), "FirstName".getBytes(), "Kimberly".getBytes());
put.add("info".getBytes(), "LastName".getBytes(), "Grant".getBytes());
What does "info" represent?


1. Primary key of the row
2. Column family name
3. Access Mostly Uused Products by 50000+ Subscribers
4. Column value



Question : Given the following HBase code:
byte [] rowKey = Bytes.toBytes(65);
Put put = new Put(rowKey);
put.add("info".getBytes(), "FirstName".getBytes(), "Kimberly".getBytes());
put.add("info".getBytes(), "LastName".getBytes(), "Grant".getBytes());
What does "FirstName" represent?


1. Primary key of the row
2. Column family name
3. Access Mostly Uused Products by 50000+ Subscribers
4. Column value