SIMD-0231: Disable account rent epoch field updates

proposals/0175-disable-partitioned-rent-collection.md

@@ -4,8 +4,9 @@ title: Disable Partitioned Rent Updates
 authors: Justin Starry (Anza)
 category: Standard
 type: Core
-status: Accepted
+status: Withdrawn
 created: 2024-09-25
+superseded-by: https://github.com/solana-foundation/solana-improvement-documents/pull/231
 feature: (fill in with feature tracking issues once accepted)
 ---
 

proposals/0231-disable-account-rent-epoch-updates.md

@@ -0,0 +1,72 @@
+---
+simd: '0231'
+title: Disable Account Rent Epoch Updates
+authors: Justin Starry (Anza)
+category: Standard
+type: Core
+status: Draft
+created: 2025-01-23
+supersedes: https://github.com/solana-foundation/solana-improvement-documents/pull/175
+feature: (fill in with feature tracking issues once accepted)
+---
+
+## Summary
+
+Rent fee collection has been disabled in SIMD-0084 but that proposal did not
+disable account rent epoch updates. In order to fully disable rent collection,
+this SIMD proposes disabling all rent epoch field updates.
+
+## Motivation
+
+Since the rent epoch field is no longer necessary for tracking when accounts are
+rent exempt or last had rent collected, we no longer need to keep this field
+updated. By not updating this field, validators no longer need to waste time
+scanning accounts for partitioned rent collection.
+
+## New Terminology
+
+NA
+
+## Detailed Design
+
+New accounts MUST no longer have their rent epoch field updated to `u64::MAX`
+upon creation. The default value for this field in new accounts will be `0`.
+This includes new builtin accounts like new sysvars and precompiles which should
+already have their initial rent epoch field set to `0`.
+
+Existing accounts MUST not have their rent epoch field updated when loaded as
+writable by an executable transaction OR during partitioned rent collection.
+
+Since existing accounts will no longer have their rent epoch field update
+updated, partioned rent collection will no longer have any effect and can be
+safely disabled and removed.
+
+## Alternatives Considered
+
+NA
+
+## Impact
+
+Improved block processing performance by removing the need to load all accounts
+once per epoch for partitioned rent collection. Note that the epoch accounts
+hash calculation similarly loads all accounts once per epoch but serves the
+important role of ensuring that all validators have the same set of account
+state.
+
+After this proposal has been applied and activated, new accounts will be
+distinguishable from old accounts because they will have a different rent epoch
+field. This will be observable both onchain and offchain until the rent epoch
+field is fully deprecated in a future proposal.
+
+## Security Considerations
+
+Rent related code changes often come along with a lot of edge cases to consider
+so changes should be made carefully to avoid introducing any bugs.
+
+## Drawbacks *(Optional)*
+
+Why should we not do this?
+
+## Backwards Compatibility *(Optional)*
+
+Changes require feature gates for activation to avoid any backwards incompatiblity