ACID vs BASE Transactions

Consistency Models

ACID and BASE represent opposing philosophies for database consistency. ACID guarantees strict consistency while BASE prioritizes availability.

ACID Properties

Atomicity, Consistency, Isolation, Durability:

-- ACID transaction example

BEGIN TRANSACTION;

UPDATE accounts SET balance = balance - 100 WHERE account_id = 1;

UPDATE accounts SET balance = balance + 100 WHERE account_id = 2;

COMMIT;

BASE Properties

Basically Available, Soft state, Eventual consistency:

class EventualConsistentLedger:

def __init__(self):

self.pending = []

def transfer(self, sender, recipient, amount):

self.pending.append({

"sender": sender, "recipient": recipient,

"amount": amount, "timestamp": time.time()

})

return {"status": "accepted"}

def reconcile(self):

for tx in self.pending:

self.apply_transaction(tx)

When to Relax ACID

| Requirement | ACID | BASE | |-------------|------|------| | Consistency | Strong | Eventual | | Availability | Lower | Higher | | Latency | Higher | Lower | | Use case | Financial | Analytics |

Conclusion

Choose ACID where correctness is critical and BASE where scale matters. Modern databases increasingly blur the line. Understand your consistency requirements and choose accordingly.