इडेम्पोटेंसी म्हणजे एक ऑपरेशन एकदा किंवा अनेक वेळा केल्यास समान परिणाम तयार करते. वितरित प्रणालींमध्ये ही महत्वाची आहे कारण रिट्राई आणि डुप्लिकेट संदेश अपरिहार्य आहेत — इडेम्पोटेंट ऑपरेशन्स हे सुरक्षित बनवतात.
इडेम्पोटेंसी म्हणजे काय
An operation is IDEMPOTENT if doing it MULTIPLE times has the SAME effect as doing it ONCE:
→ "set balance to 100" → idempotent (same result however many times)
→ "add 100 to balance" → NOT idempotent (each call changes it → wrong if duplicated!)
→ in HTTP: GET, PUT, DELETE are idempotent; POST typically is NOT
वितरित प्रणालींमध्ये ते का महत्वाचे आहे
Retries and duplicates are INEVITABLE in distributed systems:
→ a request times out → the client RETRIES → but the original may have succeeded →
the operation runs TWICE (e.g. a payment charged twice! an order placed twice!)
→ message queues often guarantee AT-LEAST-ONCE delivery → duplicates happen
→ network issues, failures → operations get retried
→ if operations are IDEMPOTENT, duplicates/retries are SAFE (no harm from repeating)
→ this is essential for correctness and safe retries.
