Unit 5 - Practice Quiz

1 What is Apache HBase primarily classified as?

2 Which underlying file system does Apache HBase typically use to store its data?

3 Which centralized service is used by HBase to maintain configuration information and distributed synchronization?

4 In the HBase architecture, which node is responsible for monitoring RegionServers and assigning regions to them?

5 Which component in HBase actually handles the read and write requests from the clients?

6 What uniquely identifies a specific row in an HBase table?

7 In HBase, columns are grouped into logical and physical sets called what?

8 Which of the following MUST be predefined when creating an HBase table?

9 Apache HBase is written in which programming language?

10 Does Apache HBase natively support SQL queries out of the box?

11 What is an HBase 'Region'?

12 According to the CAP theorem, which two properties does HBase primarily guarantee?

13 How does HBase handle multiple versions of data stored in the same cell?

14 Which API operation is used to insert or update data in an HBase table?

15 Which API operation is used to fetch a single, specific row of data from HBase?

16 In HBase, what is a Column Qualifier?

17 If an HMaster node fails in a highly available HBase cluster, what happens?

18 Why would a system choose HBase over plain HDFS?

19 Which operation is used to iterate over a range of rows in an HBase table?

20 Which famous Google technology paper inspired the creation of Apache HBase?

21 In an HBase cluster, how is the state and configuration of the distributed environment maintained to ensure high availability?

22 If a user needs to retrieve a specific version of a value in an HBase table, which combination of coordinates is required?

23 What happens automatically when an HBase table's region grows beyond its configured maximum file size?

24 Which of the following scenarios is a valid reason to choose Apache HBase over directly storing files in HDFS?

25 Why is it generally recommended to keep the number of column families in an HBase table small (typically 1 to 3)?

26 When a client sends a write request to a RegionServer, what is the correct operational sequence before the server acknowledges the write as successful?

27 How are rows physically sorted within an HBase table?

28 In the event of a RegionServer crash, which HBase component is responsible for reassigning its regions to other healthy RegionServers?

29 What is the key difference between Minor Compaction and Major Compaction in HBase?

30 A developer is inserting sequential time-series data into HBase using the timestamp as the row key. What performance issue is likely to occur?

31 During a read request, if a RegionServer does not find the requested data in the BlockCache or MemStore, what does it do to optimize the search on disk?

32 Which of the following guarantees does Apache HBase provide in the context of the CAP Theorem?

33 What is the primary purpose of the Write-Ahead Log (WAL) located on a RegionServer?

34 How does an HBase client initially discover the location of the hbase:meta table to perform read/write operations?

35 How does Apache HBase internally store data types such as Strings, Integers, or custom objects?

36 Which of the following is NOT a responsibility of the HMaster in HBase?

37 To solve the region hotspotting problem caused by sequentially increasing row keys, which technique involves adding a deterministic prefix based on the original key?

38 In HBase, when a cell is updated or deleted, what physically happens to the old data immediately?

39 What is the primary function of the BlockCache in a RegionServer?

40 If an HBase table defines a Column Family named metrics, which of the following represents a valid column qualifier creation process?

41 A telecommunications company uses Apache HBase to store call detail records (CDRs). They initially designed the RowKey as [Timestamp]-[CallerID]. They are experiencing severe write bottlenecks on a single RegionServer during peak hours. Which of the following RowKey redesign strategies effectively eliminates this 'hot-spotting' while maintaining optimal performance for time-range queries?

42 During a high-throughput write operation in HBase, a RegionServer crashes immediately after writing a batch of mutations to the MemStore and appending them to the Write-Ahead Log (WAL), but before a flush to an HFile occurs. How does HBase ensure data durability and consistency in this scenario?

43 An HBase cluster is experiencing high disk I/O and CPU utilization due to frequent major compactions. A data engineer proposes disabling major compactions entirely and relying solely on minor compactions. What is the primary negative consequence of this approach?

44 When an HBase client performs a Get request for a newly introduced RowKey for the very first time after the cluster has been restarted, what is the exact sequence of network interactions it performs to locate the correct RegionServer?

45 HBase provides strong consistency for row-level operations. Which internal mechanism guarantees that concurrent reads do not see partial updates from a parallel write operation to the same row?

46 In a highly available HBase cluster, the Active HMaster node suddenly crashes due to a hardware failure. Assuming the Zookeeper ensemble and all RegionServers remain healthy, what is the immediate impact on client applications executing heavy read and write (DML) workloads?

47 An HBase administrator configures hbase.regionserver.global.memstore.size to 0.5 (50% of heap) and hfile.block.cache.size to 0.4 (40% of heap) on a RegionServer with a 32GB heap. During a sustained, mixed read/write workload, the RegionServer repeatedly crashes with OutOfMemoryError. What is the fundamental architectural constraint violated here?

48 HBase achieves data locality by ensuring HFiles are written to HDFS DataNodes residing on the same physical machine as the RegionServer. Under which of the following circumstances is data locality temporarily lost, and how is it subsequently restored?

49 A developer configures a ROWCOL Bloom Filter on an HBase column family to optimize high-latency read queries. For which of the following access patterns will this specific Bloom Filter provide the most significant performance improvement?

50 Consider an HBase table where a client inserts a cell at RowKey R1, Column Family CF1, Qualifier Q1, with a specific timestamp . Later, the client issues a Delete operation for R1:CF1:Q1 without specifying a timestamp. Assuming default behavior, what exactly does HBase write to the storage engine?

51 In the context of the CAP theorem, Apache HBase is classified as a CP (Consistent and Partition Tolerant) system. In the event of a network partition separating the HMaster and several RegionServers from Zookeeper, how does HBase sacrifice Availability to maintain Consistency?

52 A data science team needs to calculate the real-time sum of a specific numerical column across millions of rows in an HBase table. Retrieving all rows to the client application is too slow due to network overhead. Which HBase feature provides the most efficient, distributed execution for this aggregation directly on the RegionServers?

53 HFiles use a block-based format (default 64KB block size) to store data on HDFS. Within the HFile structure, how does the Read Path rapidly locate a specific RowKey without scanning the entire file?

54 A developer heavily uses reverse scans (Scan.setReversed(true)) to fetch the most recent records from a time-series HBase table where RowKeys are monotonically increasing timestamps. They observe significant performance degradation compared to forward scans. What is the fundamental architectural reason for this degradation?

55 To improve write throughput on a massive HBase cluster, the administration enables the MultiWAL feature. What is the specific bottleneck this feature aims to resolve?

56 A column family CF1 is configured with VERSIONS => 3 and MIN_VERSIONS => 1, and a TTL (Time-To-Live) of 86400 seconds (1 day). If 5 updates are made to a specific cell within the last hour, and 1 update was made 2 days ago, what will a major compaction retain?

57 HBase relies on a Log-Structured Merge-Tree (LSM-Tree) architecture rather than a traditional B-Tree. Which of the following best describes the primary advantage of this choice for Big Data workloads?

58 Zookeeper tracks the status of RegionServers using ephemeral nodes in a specific directory (e.g., /hbase/rs). What edge-case occurs if a RegionServer experiences a severe Java "Stop-The-World" Garbage Collection pause lasting longer than the Zookeeper session timeout?

59 You are pre-splitting an HBase table to prevent initial hot-spotting. The RowKeys are MD5 hashes represented as 32-character hexadecimal strings (0-9, a-f). You want to pre-split the table into exactly 16 regions. Which of the following represents the optimal set of split keys?

60 Which of the following scenarios natively requires distributed transaction management libraries (like Apache Phoenix or Tephra) because it violates HBase's out-of-the-box ACID guarantees?