Many applications need the generation of sequence numbers for each transaction to function properly. If a sequence counter is locked in a two-phase fashion, it has the potential to create a bottleneck...

Many applications need the generation of sequence numbers for each transaction to function properly.

1. If a sequence counter is locked in a two-phase fashion, it has the potential to create a bottleneck for concurrent operations. Explain why you believe this is the case.

The majority of database systems offer built-in sequence counters that are not locked in a two-phase manner; instead, when a transaction requests a sequence number, the counter is locked, increased, and unlocked in the same transaction.

1. Describe how such counters may help to increase concurrency.

Provide an explanation for why there may be gaps in the sequence numbers associated with the final set of committed transactions.