Submission Details
Impact:
Likelihood:
Storage Optimization via Struct Packing
Author Revealed upon completion
Why it matters
The Transaction struct utilizes 6 storage slots per proposal. By packing fields, this can be reduced to 3 slots, saving ~6000 gas per proposal (3x SSTORE) and reducing gas on reads.
Suggested Optimization
Pack confirmations, proposedAt, executed (and potentially to) into a single slot.
Current:
struct Transaction {
address to; // Slot 0 (20 bytes)
uint256 value; // Slot 1 (32 bytes)
bytes data; // Slot 2 (32 bytes - ptr)
uint256 confirmations; // Slot 3 (32 bytes)
uint256 proposedAt; // Slot 4 (32 bytes)
bool executed; // Slot 5 (1 byte)
}
Proposed:
struct Transaction {
address to; // Slot 0 (20 bytes)
uint64 proposedAt; // Slot 0 (8 bytes) - sufficient for timestamp
uint8 confirmations; // Slot 0 (1 byte) - sufficient for max 5
bool executed; // Slot 0 (1 byte)
// Total Slot 0: 30 bytes
uint256 value; // Slot 1 (32 bytes)
bytes data; // Slot 2
}
Estimated Savings
~6000 gas per transaction proposed.
Rewards breakdown
nSLOC
205This contest has a flat reward structure with the following payouts:
100 EXP
20 EXP
2 EXP
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