๐๐ฎ๐ณ๐ธ๐ฎ + ๐๐ฑ๐ฒ๐บ๐ฝ๐ผ๐๐ฒ๐ป๐ฐ๐
Most distributed systems don’t fail loudly.They fail silently with duplicate processing.
I learned this the hard way.
In event-driven systems, retries are inevitable:
• Consumer crashes
• Network glitches
• Reprocessing
๐ Result: Same event processed multiple times
The fix is not “prevent retries”
The fix is design for idempotency
Simple rules:
• Use unique event IDs
• Maintain processed state
• Make operations repeat-safe
If your system breaks on duplicate events,
it’s not fault-tolerant yet.
๐ฅ๐ฒ๐ฎ๐น ๐๐ฐ๐ฎ๐น๐ฎ๐ฏ๐ถ๐น๐ถ๐๐ ๐๐๐ฎ๐ฟ๐๐ ๐๐ต๐ฒ๐ป ๐ฑ๐๐ฝ๐น๐ถ๐ฐ๐ฎ๐๐ฒ๐ ๐๐๐ผ๐ฝ ๐ต๐๐ฟ๐๐ถ๐ป๐ด ๐๐ผ๐.
Even if producer retries sending same message multiple times, system handle duplicates by using the simple rules stated, aka ๐๐ฒ๐๐ถ๐ด๐ป ๐ณ๐ผ๐ฟ ๐๐ฑ๐ฒ๐บ๐ฝ๐ผ๐๐ฒ๐ป๐ฐ๐