Pessimistic Offline Lock Design Pattern

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What is the Pessimistic Offline Lock Pattern?

The Pessimistic Offline Lock is a core pattern in enterprise application architecture used to handle concurrency. It prevents conflicts between concurrent business transactions by allowing only one business transaction at a time to access and edit specific data.

Unlike database-level transactions that last only milliseconds, business transactions often span multiple requests (for example, a user opening an edit screen, entering details, and submitting). Pessimistic locking assumes that conflicts are very likely to happen, so it locks the record upfront before anyone else can touch it.

Real-World Example: Step-by-Step

Let's take a simple Customer database table with columns like CustomerID, Name, and a dedicated Lock column:

• Initial State: The record has Lock = 'N' (No lock applied).
• User A (Martin) Enters: Martin requests Customer #129. The system immediately sets Lock = 'Y' in the table. Martin now has exclusive ownership of the record.
• User B (David) Enters: A few seconds later, David requests Customer #129. The application checks the Lock column, sees it is already set to 'Y', and rejects the edit request, informing David that the record is locked.
• Completion: Once Martin finishes his updates and submits, the lock is released back to 'N'.

When Should You Use It?

Choose Pessimistic Offline Locking when:

• The probability of two users editing the same data at the same time is high.
• Discarding a user's work due to a conflict would cause frustration or financial loss.
• You want an immediate guarantee that once an edit session starts, it will succeed without collision.

Watch Related Design Pattern Tutorials:

• 👉 Optimistic Offline Lock Design Pattern Explained
• 👉 Implicit Lock Design Pattern Explained
• 👉 Coarse-Grained Lock Design Pattern Explained

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Pessimistic Offline Lock Design Pattern