feat: Implement idempotent DB writes for event processing

[cypriannwokolo2-creator]

Description

All DB writes from event processing must be idempotent to prevent duplicates.

Requirements

• Use INSERT ON CONFLICT for all writes
• Add transaction hash deduplication
• Add event IDempotency keys
• Test idempotency with replay scenarios

Acceptance Criteria

• All writes idempotent
• Duplicates rejected gracefully
• Transaction hash deduplication working
• Tests verify idempotency

Priority

High

[Akintobidavid]

@Akintobidavid has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

I’ve reviewed the issue and it aligns with my backend and database experience. I can make event-processing writes idempotent using conflict-safe inserts, transaction-hash and event-ID deduplication, and add replay tests to verify duplicates are handled safely.

Please assign this to me, you won’t be disappointed, thank you.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Akintobidavid to this issue.

[Komelove]

@Komelove has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

I’d be happy to take this issue. I’ve looked through the requirements and have a plan for approaching the implementation. I’ll investigate the existing code and dependencies, make the required changes, verify the behaviour with tests, and provide a concise PR explaining what was changed. I can start immediately and will communicate any blockers during development.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Komelove to this issue.

[Timmmytunner]

@Timmmytunner has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hello Maintainer, I’ve reviewed the issue and understand the requirements. I’m confident I can handle the task effectively and would appreciate the opportunity to work on it.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Timmmytunner to this issue.

[codewithzubair07]

@codewithzubair07 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

i would like to work on this issue

ℹ️ Repo Maintainers: To accept this application, review their application or assign @codewithzubair07 to this issue.

[webdevayo]

@webdevayo has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hi maintainer I have thoroughly read the description to this issue and I can resolve this according to the description required ensuring it meet all the acceptance criteria kindly assign..

ℹ️ Repo Maintainers: To accept this application, review their application or assign @webdevayo to this issue.

[Swissnificient]

@Swissnificient has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hi maintaner, please allow me to work and fix this issue as I strongly understand idempotency and the issue requirements.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Swissnificient to this issue.

[ybmahq]

@ybmahq has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hello, I'd like to pick this issue up.

I've worked on blockchain and Web3 projects, including Stellar and Soroban smart contracts, alongside traditional full-stack web development. I'm comfortable moving between frontend, backend, and on-chain work.

I've looked into this issue closely and I'm confident in my ability to deliver a high-quality implementation here.

Looking forward to contributing — please assign this issue to me.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @ybmahq to this issue.

[linesofcodes0-cloud]

@linesofcodes0-cloud has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

I'm a full-stack developer and I'd like to take this issue.
I understand the requirements and will follow the existing project structure, keep the implementation clean, and include proper tests where applicable.

ETA: 1–3 days (depending on scope)

ℹ️ Repo Maintainers: To accept this application, review their application or assign @linesofcodes0-cloud to this issue.

[drips-wave]

Congratulations, @linesofcodes0-cloud! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on August 31, 2026.

🧑‍💻 @linesofcodes0-cloud: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

Warning

When opening a PR, please link it to this issue to ensure it gets tracked accurately. Points are awarded when this issue is marked as completed by the maintainer.

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🌊 Happy Wave 🌊