Gas and Execution Issues

Back to Troubleshooting

Insufficient GAS at Runtime

error: execution failed: insufficient GAS

Cause: The transaction's system fee doesn't cover the execution cost.

Diagnosis:

1. Check gas consumption with gasleft():

   function expensiveOperation() external {
       uint256 gasBefore = gasleft();
       // ... operation ...
       uint256 gasUsed = gasBefore - gasleft();
       Runtime.log(string(abi.encodePacked("Gas used: ", gasUsed)));
   }

2. Use the withGasLimit modifier from FrameworkBase:

   function criticalOp() external withGasLimit(50000000) {
       // Reverts early if < 0.5 GAS remaining
   }

Common gas-heavy operations:

Operation	Approximate Cost
System.Storage.Put (new key)	200,000+ GAS units
System.Storage.Put (update)	100,000+ GAS units
System.Contract.Call	32,768 GAS units
CryptoLib.verifyWithECDsa	1,000,000+ GAS units
Large array iteration	Scales with array size

WARNING

Neo GAS uses 10^8 decimals (not 10^18 like Ethereum). 1 GAS = 100,000,000 fractional units. Adjust your constants accordingly.

---