Optimisation du RPC Solana : Pratiques de Performance & Coût

const testTransaction = new VersionedTransaction(/* your transaction */);
const simulation = await connection.simulateTransaction(testTransaction, {
  replaceRecentBlockhash: true,
  sigVerify: false
});
const unitsConsumed = simulation.value.unitsConsumed;

const computeUnitLimit = Math.ceil(unitsConsumed * 1.1);
const computeUnitIx = ComputeBudgetProgram.setComputeUnitLimit({ 
  units: computeUnitLimit 
});
instructions.unshift(computeUnitIx); // Add at beginning

const response = await fetch(`https://mainnet.helius-rpc.com/?api-key=${API_KEY}`, {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({
    method: 'getPriorityFeeEstimate',
    params: [{
      accountKeys: ['11111111111111111111111111111112'], // System Program
      options: { recommended: true }
    }]
  })
});
const { priorityFeeEstimate } = await response.json().result;

const priorityFeeIx = ComputeBudgetProgram.setComputeUnitPrice({ 
  microLamports: priorityFeeEstimate 
});
instructions.unshift(priorityFeeIx);

// ❌ Old approach - could timeout with large datasets
const allAccounts = await connection.getProgramAccounts(programId, {
  encoding: 'base64',
  filters: [{ dataSize: 165 }]
});

// ✅ New approach - paginated with better performance
let allAccounts = [];
let paginationKey = null;

do {
  const response = await fetch(`https://mainnet.helius-rpc.com/?api-key=${API_KEY}`, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({
      jsonrpc: '2.0',
      id: '1',
      method: 'getProgramAccountsV2',
      params: [
        programId,
        {
          encoding: 'base64',
          filters: [{ dataSize: 165 }],
          limit: 5000,
          ...(paginationKey && { paginationKey })
        }
      ]
    })
  });
  
  const data = await response.json();
  allAccounts.push(...data.result.accounts);
  paginationKey = data.result.paginationKey;
} while (paginationKey);

// Get only accounts modified since a specific slot
const incrementalUpdate = await fetch(`https://mainnet.helius-rpc.com/?api-key=${API_KEY}`, {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({
    jsonrpc: '2.0',
    id: '1',
    method: 'getProgramAccountsV2',
    params: [
      programId,
      {
        encoding: 'jsonParsed',
        limit: 1000,
        changedSinceSlot: lastProcessedSlot // Only get recent changes
      }
    ]
  })
});

// Parsed USDC transfers received by a wallet - no manual parsing needed
const response = await fetch(`https://mainnet.helius-rpc.com/?api-key=${API_KEY}`, {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({
    jsonrpc: '2.0',
    id: 1,
    method: 'getTransfersByAddress',
    params: [
      address, // Wallet owner address, not a token account
      {
        mint: 'EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v', // USDC
        direction: 'in',
        limit: 100
      }
    ]
  })
});
// Each transfer includes parsed sender, recipient, amount, decimals, and uiAmount

// Monitor specific program accounts with filters
connection.onProgramAccountChange(
  programId,
  (accountInfo, context) => {
    // Handle program account changes
  },
  'confirmed',
  {
    filters: [
      { dataSize: 1024 },
      { memcmp: { offset: 0, bytes: ACCOUNT_DISCRIMINATOR }}
    ],
    encoding: 'base64'
  }
);

// Subscribe to transaction logs for real-time monitoring
const ws = new WebSocket(`wss://mainnet.helius-rpc.com/?api-key=${API_KEY}`);

ws.on('open', () => {
  ws.send(JSON.stringify({
    jsonrpc: '2.0',
    id: 1,
    method: 'logsSubscribe',
    params: [
      { mentions: [programId] },
      { commitment: 'confirmed' }
    ]
  }));
});

ws.on('message', (data) => {
  const message = JSON.parse(data);
  if (message.params) {
    const signature = message.params.result.value.signature;
    // Process transaction signature
  }
});

class RetryManager {
  private backoff = new ExponentialBackoff({
    min: 100,
    max: 5000,
    factor: 2,
    jitter: 0.2
  });

  async executeWithRetry<T>(operation: () => Promise<T>): Promise<T> {
    while (true) {
      try {
        return await operation();
      } catch (error) {
        if (error.message.includes('429')) {
          // Rate limit - wait and retry
          await this.backoff.delay();
          continue;
        }
        throw error;
      }
    }
  }
}

// Process large datasets in chunks
function chunk<T>(array: T[], size: number): T[][] {
  return Array.from({ length: Math.ceil(array.length / size) }, (_, i) =>
    array.slice(i * size, i * size + size)
  );
}

// Process program accounts in batches
const allAccounts = await connection.getProgramAccounts(programId, {
  dataSlice: { offset: 0, length: 32 }
});

const chunks = chunk(allAccounts, 100);
for (const batch of chunks) {
  const detailedAccounts = await connection.getMultipleAccountsInfo(
    batch.map(acc => acc.pubkey)
  );
  // Process batch...
}

class ConnectionPool {
  private connections: Connection[] = [];
  private currentIndex = 0;

  constructor(rpcUrls: string[]) {
    this.connections = rpcUrls.map(url => new Connection(url));
  }

  getConnection(): Connection {
    const connection = this.connections[this.currentIndex];
    this.currentIndex = (this.currentIndex + 1) % this.connections.length;
    return connection;
  }
}

const pool = new ConnectionPool([
  'https://mainnet.helius-rpc.com/?api-key=YOUR_API_KEY',
  'https://mainnet-backup.helius-rpc.com/?api-key=YOUR_API_KEY'
]);

class RPCMonitor {
  private metrics = {
    calls: 0,
    errors: 0,
    totalLatency: 0
  };

  async monitoredCall<T>(operation: () => Promise<T>): Promise<T> {
    const start = Date.now();
    this.metrics.calls++;
    
    try {
      const result = await operation();
      this.metrics.totalLatency += Date.now() - start;
      return result;
    } catch (error) {
      this.metrics.errors++;
      throw error;
    }
  }

  getStats() {
    return {
      ...this.metrics,
      averageLatency: this.metrics.totalLatency / this.metrics.calls,
      errorRate: this.metrics.errors / this.metrics.calls
    };
  }
}

// Implement robust error handling
async function robustRPCCall<T>(operation: () => Promise<T>): Promise<T> {
  try {
    return await operation();
  } catch (error) {
    if (error.code === -32602) {
      // Invalid params - fix request
      throw new Error('Invalid RPC parameters');
    } else if (error.code === -32005) {
      // Node behind - retry with different node
      throw new Error('Node synchronization issue');
    } else if (error.message.includes('429')) {
      // Rate limit - implement backoff
      throw new Error('Rate limited');
    }
    throw error;
  }
}