Storage organization terms In file/page storage, the “blocking factor” refers to:
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AA group of fields stored contiguously in a single column family.
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BThe number of physical records that fit on one page or block.
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CAttributes grouped by the same primary key across relations.
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DAttributes grouped by the same secondary key across indexes.
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EThe average number of indexes attached to a table.
Answer
Correct Answer: The number of physical records that fit on one page or block.
Explanation
Introduction / Context:On-disk layout influences performance. Many DBMSs store data in fixed-size pages or blocks. The blocking factor captures how densely records pack into those pages, directly affecting I/O costs for scans and lookups. This question checks your recall of that definition.
Given Data / Assumptions:
- Data is stored in fixed-size pages/blocks (e.g., 8 KB).
- Each row has a physical length including overhead.
- Free space and fragmentation can reduce effective packing.
Concept / Approach:
Blocking factor = floor(page_size / record_size_with_overhead). Higher values mean more rows per I/O and typically better sequential scan efficiency. Very wide rows reduce the factor and can increase I/O per query.
Step-by-Step Solution:
1) Identify page size and average record size.2) Compute how many complete records fit → the blocking factor.3) Recognize its impact on buffer hits and disk reads.Verification / Alternative check:
Database storage references and file-organization texts define the term exactly this way; it is not about keys or logical grouping but about physical packing density.
Why Other Options Are Wrong:
- Primary/secondary key groupings describe logical design, not page packing.
- “Column family” applies to certain NoSQL models and is unrelated to classic blocking factor.
- Number of indexes has no direct definition link here.
Common Pitfalls:
- Ignoring row overhead (headers, alignment) when estimating packing.
- Assuming larger pages always help; they can hurt random access.
Final Answer:
The number of physical records that fit on one page or block.