Locking terminology: Is the “lock granularity” the size or scope of the lock (for example, row-level vs. page-level vs. table-level)?

Introduction / Context:
Locking granularity affects concurrency and overhead. Finer granularity (row) increases concurrency but may require more locks; coarser granularity (table) reduces overhead but can block more operations. This question checks the definition of “lock granularity.”

Given Data / Assumptions:

• Various resources can be locked: rows, keys, pages/blocks, partitions, or entire tables.
• Lock types (shared, exclusive, intent) are orthogonal to granularity.
• Granularity influences contention and performance.

Concept / Approach:
“Granularity” literally describes the size or scope of a lockable unit. Databases often support hierarchical locking with intent locks to combine coarse and fine-grained locks safely. Tuning granularity is a trade-off between throughput and overhead.

Step-by-Step Solution:

Verification / Alternative check:
Examine DBMS documentation for lock modes and levels; they explicitly refer to lock levels as granularity choices.

Why Other Options Are Wrong:

• Granularity is not limited to shared or exclusive locks; it applies to both.
• “Incorrect” conflicts with standard terminology.

Common Pitfalls:
Assuming finer granularity is always better. More locks mean more overhead and potential deadlock complexity.

Final Answer:
Correct