Locking terminology: what do we call the “size” or scope of a lock (for example, row-level vs. page-level vs. table-level)?
-
Aimplicit lock
-
Block granularity
-
Cexclusive lock
-
Dshared lock
Answer
Correct Answer: lock granularity
Explanation
Introduction / Context:Locking can occur at different scopes, from fine-grained (row) to coarse-grained (table). Understanding the term for this scope helps reason about performance and contention.
Given Data / Assumptions:
- Locks may apply to rows, pages/blocks, partitions, or entire tables.
- The question asks for the standard term for this scope/size.
Concept / Approach:Lock granularity refers to the amount of data covered by a lock. Finer granularity increases concurrency but may raise overhead; coarser granularity lowers overhead but can increase contention.
Step-by-Step Solution:
Identify the concept of scope/size of locked data.Associate this with the term “granularity.”Choose “lock granularity.”Verification / Alternative check:DBMS tuning guides consistently use “granularity” to describe row/page/table lock scope.
Why Other Options Are Wrong:
- Implicit/exclusive/shared: describe acquisition method or mode, not size.
Common Pitfalls:Assuming coarser locks always perform better; they reduce overhead but may dramatically lower concurrency.
Final Answer:lock granularity