Gas optimization for L2 in Blockchain / Solidity - Step-by-Step Execution

Concept Flow - Gas optimization for L2

Start Transaction

↓

Check L2 Gas Costs

↓

Apply Optimizations?

No→Pay Full Gas

Yes↓

Use Batch Calls

↓

Compress Data

↓

Minimize Storage Writes

↓

Calculate Reduced Gas

↓

Submit Transaction

↓

End

The flow shows starting a transaction on L2, checking gas costs, applying optimizations like batching and compression, then submitting with reduced gas.

Execution Sample

Blockchain / Solidity

function sendBatchTx(transactions) {
  let gasUsed = 0;
  for (let tx of transactions) {
    gasUsed += estimateGas(tx) * 0.8; // 20% optimization
  }
  return gasUsed;
}

This code estimates gas for a batch of transactions applying a 20% gas saving per transaction.

Execution Table

Iteration	Transaction	Estimated Gas	Optimized Gas (80%)	Running Total Gas
1	tx1	21000	16800	16800
2	tx2	30000	24000	40800
3	tx3	15000	12000	52800
Exit	-	-	-	All transactions processed, total gas 52800

💡 All transactions processed with 20% gas optimization applied per transaction.

Variable Tracker

Variable	Start	After 1	After 2	After 3	Final
gasUsed	0	16800	40800	52800	52800

Key Moments - 2 Insights

Why do we multiply estimated gas by 0.8 in each iteration?

Multiplying by 0.8 applies a 20% gas saving per transaction, as shown in the 'Optimized Gas (80%)' column in the execution_table.

What happens if we don't batch transactions?

Without batching, each transaction pays full gas separately, increasing total gas cost. The execution_table shows savings by batching.

Visual Quiz - 3 Questions

Look at the execution_table, what is the running total gas after processing the second transaction?

A 40800

B 24000

C 16800

D 52800

💡 Hint

Check the 'Running Total Gas' column at iteration 2 in the execution_table.

At which iteration does the total gas used reach 52800?

A After 1

B After 2

C After 3

D Exit

💡 Hint

Look at the 'Running Total Gas' column and find when it reaches 52800.

If the optimization factor changed from 0.8 to 0.9, how would the total gas after 3 transactions change?

A It would decrease

B It would increase

C It would stay the same

D It would be zero

💡 Hint

Higher factor means less gas saving, so total gas increases; check how 'Optimized Gas' is calculated in execution_table.

Concept Snapshot

Gas optimization on L2 reduces transaction costs by batching calls, compressing data, and minimizing storage writes.
Estimate gas per transaction, apply optimization factor (e.g., 0.8 for 20% savings), sum optimized gas.
Batching multiple transactions reduces overhead.
Compression lowers calldata size, saving gas.
Minimize storage writes as they are costly.
Submit optimized transaction to save gas fees.

Full Transcript

This visual execution traces gas optimization for Layer 2 blockchain transactions. Starting with zero gas used, each transaction's estimated gas is multiplied by 0.8 to apply a 20% saving. The running total gas accumulates these optimized values. After processing three transactions, total gas used is 52800, less than full cost without optimization. Key points include why the 0.8 factor applies savings, the benefit of batching transactions, and how changing optimization affects total gas. This helps beginners see step-by-step how gas optimization reduces costs on L2.