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## Problem The safekeeper migration code/logic slightly diverges from the initial RFC. This PR aims to address these differences. - Part of https://github.com/neondatabase/neon/issues/12192 ## Summary of changes - Adjust the RFC to reflect that we implemented the safekeeper reconciler with in-memory queue. - Add `sk_set_notified_generation` field to the `timelines` table in the RFC to address the "finish migration atomically" problem. - Describe how we are going to make the timeline migration handler fully retriable with in-memory reconciler queue. - Unify type/field/method names in the code and RFC. - Fix typos
Neon RFCs
Overview
This directory contains Request for Comments documents, or RFCs, for features or concepts that have been proposed. Alternative names: technical design doc, ERD, one-pager
To make a new proposal, create a new text file in this directory and open a Pull Request with it. That gives others a chance and a forum to comment and discuss the design.
When a feature is implemented and the code changes are committed, also include the corresponding RFC in this directory.
Some of the RFCs in this directory have been implemented in some form or another, while others are on the roadmap, while still others are just obsolete and forgotten about. So read them with a grain of salt, but hopefully even the ones that don't reflect reality give useful context information.
What
We use Tech Design RFC’s to summarize what we are planning to implement in our system. These RFCs should be created for large or not obvious technical tasks, e.g. changes of the architecture or bigger tasks that could take over a week, changes that touch multiple components or their interaction. RFCs should fit into a couple of pages, but could be longer on occasion.
Why
We’re using RFCs to enable early review and collaboration, reduce uncertainties, risk and save time during the implementation phase that follows the Tech Design RFC.
Tech Design RFCs also aim to avoid bus factor and are an additional measure to keep more peers up to date & familiar with our design and architecture.
This is a crucial part for ensuring collaboration across timezones and setting up for success a distributed team that works on complex topics.
Prior art
- Rust: https://github.com/rust-lang/rfcs/blob/master/0000-template.md
- React.js: https://github.com/reactjs/rfcs/blob/main/0000-template.md
- Google fuchsia: https://fuchsia.dev/fuchsia-src/contribute/governance/rfcs/TEMPLATE
- Apache: https://cwiki.apache.org/confluence/display/GEODE/RFC+Template / https://cwiki.apache.org/confluence/display/GEODE/Lightweight+RFC+Process
How
RFC lifecycle:
- Should be submitted in a pull request with and full RFC text in a committed markdown file and copy of the Summary and Motivation sections also included in the PR body.
- RFC should be published for review before most of the actual code is written. This isn’t a strict rule, don’t hesitate to experiment and build a POC in parallel with writing an RFC.
- Add labels to the PR in the same manner as you do Issues. Example TBD
- Request the review from your peers. Reviewing the RFCs from your peers is a priority, same as reviewing the actual code.
- The Tech Design RFC should evolve based on the feedback received and further during the development phase if problems are discovered with the taken approach
- RFCs stop evolving once the consensus is found or the proposal is implemented and merged.
- RFCs are not intended as a documentation that’s kept up to date after the implementation is finished. Do not update the Tech Design RFC when merged functionality evolves later on. In such situation a new RFC may be appropriate.
RFC template
Use template with YYYY-MM-DD-copy-me.md as a starting point. Timestamp prefix helps to avoid awkward 'id' collisions.
cp docs/rfcs/YYYY-MM-DD-copy-me.md docs/rfcs/$(date +"%Y-%m-%d")-<name>.md
Note, a lot of the sections are marked as ‘if relevant’. They are included into the template as a reminder and to help inspiration.