Etherscan 是如何工作的？

據我了解，區塊鏈並未針對搜尋過去的交易進行優化。Etherscan 是否將數據下載到另一個數據庫以進行更高性能的查詢？如果是這樣，它如何下載數據以及它使用什麼查詢呢？

如果你想做分析，訣竅是將整個區塊鏈廢棄到索引數據庫中。我的建議是你得到一個 SQL 數據庫，並編寫一個程序，逐個查詢節點的塊，然後你得到交易和交易收據，你可以再次查詢更多數據。取決於您最感興趣的欄位，以及您希望對其應用正確索引的欄位。

這是塊的結構

來自https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_getblockbyhash

// Request
curl -X POST --data '{"jsonrpc":"2.0","method":"eth_getBlockByHash","params":["0xe670ec64341771606e55d6b4ca35a1a6b75ee3d5145a99d05921026d1527331", true],"id":1}'

// Result
{
"id":1,
"jsonrpc":"2.0",
"result": {
   "number": "0x1b4", // 436
   "hash": "0xe670ec64341771606e55d6b4ca35a1a6b75ee3d5145a99d05921026d1527331",
   "parentHash": "0x9646252be9520f6e71339a8df9c55e4d7619deeb018d2a3f2d21fc165dde5eb5",
   "nonce": "0xe04d296d2460cfb8472af2c5fd05b5a214109c25688d3704aed5484f9a7792f2",
   "sha3Uncles": "0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347",
   "logsBloom": "0xe670ec64341771606e55d6b4ca35a1a6b75ee3d5145a99d05921026d1527331",
   "transactionsRoot": "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
   "stateRoot": "0xd5855eb08b3387c0af375e9cdb6acfc05eb8f519e419b874b6ff2ffda7ed1dff",
   "miner": "0x4e65fda2159562a496f9f3522f89122a3088497a",
   "difficulty": "0x027f07", // 163591
   "totalDifficulty":  "0x027f07", // 163591
   "extraData": "0x0000000000000000000000000000000000000000000000000000000000000000",
   "size":  "0x027f07", // 163591
   "gasLimit": "0x9f759", // 653145
   "gasUsed": "0x9f759", // 653145
   "timestamp": "0x54e34e8e" // 1424182926
   "transactions": [{...},{ ... }]
   "uncles": ["0x1606e5...", "0xd5145a9..."]
 }
}

然後你得到交易的雜湊值，你可以為每個查詢執行兩個查詢

https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_gettransactionbyhash

// Request
curl -X POST --data '{"jsonrpc":"2.0","method":"eth_getTransactionByHash","params":["0xb903239f8543d04b5dc1ba6579132b143087c68db1b2168786408fcbce568238"],"id":1}'

// Result
{
"id":1,
"jsonrpc":"2.0",
"result": {
   "hash":"0xc6ef2fc5426d6ad6fd9e2a26abeab0aa2411b7ab17f30a99d3cb96aed1d1055b",
   "nonce":"0x",
   "blockHash": "0xbeab0aa2411b7ab17f30a99d3cb9c6ef2fc5426d6ad6fd9e2a26a6aed1d1055b",
   "blockNumber": "0x15df", // 5599
   "transactionIndex":  "0x1", // 1
   "from":"0x407d73d8a49eeb85d32cf465507dd71d507100c1",
   "to":"0x85h43d8a49eeb85d32cf465507dd71d507100c1",
   "value":"0x7f110" // 520464
   "gas": "0x7f110" // 520464
   "gasPrice":"0x09184e72a000",
   "input":"0x603880600c6000396000f300603880600c6000396000f3603880600c6000396000f360",
 }
}

https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_gettransactionreceipt

// Request
curl -X POST --data '{"jsonrpc":"2.0","method":"eth_getTransactionReceipt","params":["0xb903239f8543d04b5dc1ba6579132b143087c68db1b2168786408fcbce568238"],"id":1}'

// Result
{
"id":1,
"jsonrpc":"2.0",
"result": {
    transactionHash: '0xb903239f8543d04b5dc1ba6579132b143087c68db1b2168786408fcbce568238',
    transactionIndex:  '0x1', // 1
    blockNumber: '0xb', // 11
    blockHash: '0xc6ef2fc5426d6ad6fd9e2a26abeab0aa2411b7ab17f30a99d3cb96aed1d1055b',
    cumulativeGasUsed: '0x33bc', // 13244
    gasUsed: '0x4dc', // 1244
    contractAddress: '0xb60e8dd61c5d32be8058bb8eb970870f07233155' // or null, if none was created
    logs: [{
        // logs as returned by getFilterLogs, etc.
    }, ...]
 }
}

引用自：https://ethereum.stackexchange.com/questions/12425