Wiki Article · Cinematic

At-least-once delivery

At-least-once delivery ek messaging / distributed-systems guarantee (concept) hai jiska simple…

Overview

At-least-once delivery — Quick Facts

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Field: Value

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Topic type: Distributed systems / messaging…

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Primary guarantee: message will be delivered 1+ times…

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Typical mechanism: retries + acknowledgements (acks)…

Topic 1

Infobox

📚 | Field | Value | |---|---| | Topic type | Distributed systems / messaging semantics…

Topic 2

Overview

💡 At-least-once delivery ka goal reliability hota hai: agar network glitch ho, consumer…

Topic 3

What does "delivery" mean? (concept)

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Delivered: message consumer side…

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Processed: consumer ne message ka…

Topic 4

At-most-once vs at-least-once vs exactly-once (concept)

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At-most-once: duplicate nahi…

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At-least-once: message drop hone…

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Exactly-once: na drop, na…

Topic 5

Why duplicates happen (concept)

🔑 Duplicates usually retries ki wajah se aate hain: 1) Consumer ne message receive kiya 2)…

Topic 6

Acknowledgements and retries (concept)

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broker message deliver karta

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consumer process karta

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consumer ack bhejta

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broker ack ke baad message ko…

Topic 7

Idempotency and deduplication (concept)

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Idempotency: same message ko 2…

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Deduplication: consumer messageId…

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payment capture: idempotency key…

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email sending: "sent" log + unique…

Topic 8

Ordering, offsets, and checkpoints (concept)

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At-least-once ka focus duplicates…

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Ordering ka focus: messages kis…

Topic 9

Failure scenarios (concept)

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Network partition: ack broker tak…

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Consumer crash: processing mid-way…

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Broker restart: in-flight state…

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Slow consumer: timeouts trigger,…

Topic 10

Operational practices (concept)

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DLQ (dead-letter queue): poison…

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Retry policy: exponential backoff…

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Observability: duplicate rate,…

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Idempotency coverage: critical…

Topic 11

Comparison tables (table)

Topic 12

Glossary

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Message: data packet/event sent…

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Producer: message publish karne…

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Broker/Queue: message…

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Consumer: message receive/process…

Comparison

Comparison tables (table)

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At-most-once: 0 or 1 delivery

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At-least-once: 1+ delivery

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Exactly-once: 1 delivery (ideal)

Diagram

Visual Flow

📊 Diagram visualization — details in narration

Quiz — Question 1

At-least-once delivery ka sabse sahi definition kya hai?

Quick Quiz

Quiz — Question 2

At-least-once delivery ka 'Topic type' kya hai?

Complete! 🎉

At-least-once delivery Complete!

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