What potential negative consequences can arise from changing the transaction isolation level in a database management system?

Changing the transaction isolation level in a DBMS affects the behavior of concurrent transactions and can lead to the following negative consequences:

• Data integrity loss: At low isolation levels (e.g., Read Uncommitted), dirty reads are possible, where a transaction reads data that may be rolled back.
• Phantom reads and non-repeatable reads: At medium isolation levels (Read Committed, Repeatable Read), situations may occur where data changes between reads within a single transaction.
• Locks and reduced performance: High isolation levels (Serializable) require holding locks longer, which can lead to deadlocks and decreased throughput.
• Increased response time: Due to waiting for locks to be released, transactions may take longer to execute.

Thus, changing the isolation level is a trade-off between data integrity and system performance.