How does PostgreSQL ensure transaction isolation and prevent conflicting operations?

PostgreSQL provides transaction isolation through the MVCC (Multiversion Concurrency Control) mechanism. This means that each transaction sees its own "snapshot" of the database at the moment it starts, which helps avoid read locks and ensures data consistency.

Key points:

• When data is modified, new row versions are created, while old ones remain for other transactions.
• Transactions do not block each other during reads, increasing performance.
• To prevent conflicts during writes, locking systems and version checks are used.

Thus, PostgreSQL allows multiple transactions to run concurrently, providing isolation levels (Read Committed, Repeatable Read, Serializable) and preventing conflicting operations through MVCC and locking mechanisms.