Which of the following descriptions about the HBase storage model is correct? (Multiple choice)

Question

Options

• AEach KeyValue has a Qualifier logo
• BThe same key value key is associated with multiple values
• CKeyValue has key information such as timestamp and type
• DEven if there are multiple KeyValues with the same key value and the same Qualifier, there may

• A
  100% (52)

Explanation

All four options correctly describe HBase's internal KeyValue storage model. In HBase, every cell (KeyValue) is physically stored with a composite key containing the row key, column family, column qualifier (A), timestamp, and type (C - types include Put, Delete, DeleteColumn, etc.), plus the actual value. Because HBase supports multi-version concurrency (MVCC), a single row key + column family + qualifier triple can map to multiple timestamped values (B), meaning the same qualifier can appear many times with different timestamps representing different versions (D - even with identical row key and qualifier, multiple KeyValues can coexist).

Since this is an all-correct multiple-choice question, there are no incorrect distractors - the trap is assuming some options contradict each other (e.g., thinking B and D are redundant and one must be wrong), when in fact they reinforce each other.

Memory tip: Think of an HBase KeyValue key as a 5-tuple - Row + Family + Qualifier + Timestamp + Type ("RFQ Two T's") - and remember that HBase is a versioned store, so the same RFQ can repeat with different timestamps, giving you multiple values per logical cell.

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