What type of lock does SAP HANA use during transactions?

SAP HANA primarily uses row-level locks during transactions, which allows for a high degree of concurrency and performance. This locking mechanism is particularly beneficial in environments where multiple transactions occur simultaneously. By locking only the specific rows that are being modified rather than the entire table, SAP HANA enables other transactions to continue interacting with the remaining rows. This minimizes contention and improves the overall efficiency of the database.

In contrast, table-level locks would restrict access to an entire table, which can lead to significant performance bottlenecks, especially in multi-user scenarios. Database-level locks would implement a similar restrictive approach at the level of the entire database. The idea of using no locks in a transactional context would not ensure data integrity, as concurrent transactions might interfere with each other, leading to inconsistent results. Therefore, row-level locking strikes a balance by providing necessary protection for data while maintaining optimal performance and concurrency.