Can SQL Server Reclaim Identity Sequence Gaps After Transaction Rollbacks?

SQL Server Identity Column Gaps: Reclaiming Values After Rollbacks

SQL Server's identity columns automatically generate unique sequential numbers for each new table row. However, transactional rollbacks following inserts into identity columns can leave gaps in the sequence, resulting in unused numbers.

The question arises: can these gaps be recovered after a rollback? The answer is no. Making identity values transactional would severely impact concurrency, causing significant performance bottlenecks for other transactions.

When a transaction inserts multiple rows and subsequently rolls back due to an error, the allocated identity values are not automatically reused. This directly leads to gaps in the sequence for future inserts.

To maintain consistent, gapless sequential numbering, it's advisable to utilize alternative auto-numbering strategies. These could include a dedicated sequence table or a separate service responsible for generating and managing unique sequential identifiers. This approach bypasses the limitations of SQL Server's identity columns in transactional scenarios.

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