Raise Block Limits to 50M

proposals/0207-raise-block-limits-to-50M.md

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+---
+simd: '0207'
+title: Raise Block Limits to 50M CUs
+authors:
+  - Andrew Fitzgerad (Anza)
+category: Standard
+type: Core
+status: Review
+created: 2024-12-05
+feature:
+supersedes:
+superseded-by:
+extends:
+---
+
+## Summary
+
+Raise the block limit from 48M to 50M CUs.
+
+## Motivation
+
+Current block limits are set to 48M CUs.
+Block limits's primary purpose is to make sure that the vast majority of
+network participants are able to keep up with the network, by restricting the
+amount of work a leader is allowed to pack into a block.
+However, current main net beta traffic is largely not constrained by large
+block execution times.
+This proposal aims a modest increase in block limits to 50M CUs, in order to
+give some additional capacity to the network, and client implementations ready
+for future increases as the performance of the network improves.
+
+## New Terminology
+
+No new terms, but the following definitions are given for clarity:
+
+- Max Block Units - The maximum number of CUs that can be included in a block.
+- Max Writable Account Units - The maximum number of CUs that can be used to
+  write any given account in a block.
+- Max Vote Units - The maximum number of CUs that can be used by simple votes
+  in a block.
+- Max Block Accounts Data Size Delta - The maximum size of the accounts data
+  size delta in a block.
+
+## Detailed Design
+
+The following table shows the current block limits and the proposed block
+limits:
+
+| Type | Current Block Limit | Proposed Block Limit |
+|------|----------------------|----------------------|
+| Max Block Units | 48M | 50M |
+| Max Writable Account Units | 12M | 12M |
+| Max Vote Units | 36M | 36M |
+| Max Block Accounts Data Size Delta | 100MB | 100MB |
+
+This proposal only changes the `Max Block Units` limit.
+The purpose is to increase capacity for non-vote transactions.
+The `Max Writable Account Units` is left unchanged since there is no specific
+push to increase the capacity for individual accounts at this time.
+Keeping `Max Writeable Account Units` unchanged while raising the
+`Max Block Units` , allows for additional parallel capacity.
+
+## Alternatives Considered
+
+- Leave the block limits as they are
+  - This leaves capacity on the table, we want to get ready for future
+    increases.
+- Double limit to 96M CUs
+  - Viewed as too aggressive at this time, and may cause unforeseen issues
+    particularly in infrastructure supporting the network users.
+  - We instead plan to increase the limits incrementally as the network
+    performance improves.
+
+## Impact
+
+- More transactions can be included per block.
+
+## Security Considerations
+
+- Blocks may take longer to execute, slowing down network progress.
+
+## Drawbacks
+
+- Larger blocks may cause unforseen issues in infrastructure beyond the
+  validators.
+
+## Backwards Compatibility
+
+- All previously valid blocks are still valid, since limits are only
+  increasing.
+- Blocks produced after the change may be rejected by previous versions that do
+  not support the new limits.