type TxPool struct { config TxPoolConfig // 交易池配置 chainconfig *params.ChainConfig // 区块链配置 chain blockChain // 定义blockchain接口 gasPrice *big.Int txFeed event.Feed //时间流 scope event.SubscriptionScope // 订阅范围 signer types.Signer //签名 mu sync.RWMutex istanbul bool // Fork indicator whether we are in the istanbul stage. currentState *state.StateDB // 当前头区块对应的状态 pendingNonces *txNoncer // Pending state tracking virtual nonces currentMaxGas uint64 // Current gas limit for transaction caps locals *accountSet // Set of local transaction to exempt from eviction rules journal *txJournal // Journal of local transaction to back up to disk pending map[common.Address]*txList // All currently processable transactions queue map[common.Address]*txList // Queued but non-processable transactions beats map[common.Address]time.Time // Last heartbeat from each known account all *txLookup // All transactions to allow lookups priced *txPricedList // All transactions sorted by price chainHeadCh chan ChainHeadEvent chainHeadSub event.Subscription reqResetCh chan *txpoolResetRequest reqPromoteCh chan *accountSet queueTxEventCh chan *types.Transaction reorgDoneCh chan chan struct{} reorgShutdownCh chan struct{} // requests shutdown of scheduleReorgLoop wg sync.WaitGroup // tracks loop, scheduleReorgLoop}
if pool.all.Get(hash) != nil { log.Trace("Discarding already known transaction", "hash", hash) knownTxMeter.Mark(1) return false, fmt.Errorf("known transaction: %x", hash) }
②：如果交易没通过验证也要丢弃，这里的重点是验证函数：
validateTx: 主要做了以下几件事- 交易大小不能超过32kb- 交易金额不能为负- 交易gas值不能超出当前交易池设定的gaslimit- 交易签名必须正确- 如果交易为远程交易，则需验证其gasprice是否小于交易池gasprice最小值，如果是本地，优先打包，不管gasprice- 判断当前交易nonce值是否过低- 交易所需花费的转帐手续费是否大于帐户余额 cost == V + GP * GL- 判断交易花费gas是否小于其预估花费gas
③：如果交易池已满，丢弃价格过低的交易
if uint64(pool.all.Count()) >= pool.config.GlobalSlots+pool.config.GlobalQueue { if !local && pool.priced.Underpriced(tx, pool.locals) { ... } drop := pool.priced.Discard(pool.all.Count()-int(pool.config.GlobalSlots+pool.config.GlobalQueue-1), pool.locals) for _, tx := range drop { ... pool.removeTx(tx.Hash(), false) } }
if list := pool.pending[from]; list != nil && list.Overlaps(tx) { // Nonce already pending, check if required price bump is met inserted, old := list.Add(tx, pool.config.PriceBump) if !inserted { pendingDiscardMeter.Mark(1) return false, ErrReplaceUnderpriced } // New transaction is better, replace old one if old != nil { pool.all.Remove(old.Hash()) pool.priced.Removed(1) pendingReplaceMeter.Mark(1) } pool.all.Add(tx) pool.priced.Put(tx) pool.journalTx(from, tx) pool.queueTxEvent(tx) log.Trace("Pooled new executable transaction", "hash", hash, "from", from, "to", tx.To()) return old != nil, nil } // New transaction isn't replacing a pending one, push into queue replaced, err = pool.enqueueTx(hash, tx)
inserted, old := list.Add(tx, pool.config.PriceBump) if !inserted { // An older transaction was better, discard this // 老的交易更好，删除这个交易 pool.all.Remove(hash) pool.priced.Removed(1) pendingDiscardMeter.Mark(1) return false } // Otherwise discard any previous transaction and mark this // 现在这个交易更好，删除旧的交易 if old != nil { pool.all.Remove(old.Hash()) pool.priced.Removed(1) pendingReplaceMeter.Mark(1) } else { ... }
注：间隙的出现通常是因为交易余额问题导致的。假如原规范链 A 上交易m花费10，分叉后该账户又在分叉链B发出一个交易m花费20，这就导致该账户余额本来可以支付A链上的某笔交易，但在B链上可能就不够了。这个余额不足的交易在B如果是n+3，那么在A链上n+2，n+4号交易之间就出现了空隙，这就导致从n+3开始往后所有的交易都要降级；
if oldHead != nil && oldHead.Hash() != newHead.ParentHash {}
②：如果新头区块和旧头区块相差大于64，则所有交易不必回退到交易池
if depth := uint64(math.Abs(float64(oldNum) - float64(newNum))); depth > 64 { log.Debug("Skipping deep transaction reorg", "depth", depth)}
③：如果旧链的头区块大于新链的头区块高度，旧链向后退并回收所有回退的交易
for rem.NumberU64() > add.NumberU64() { discarded = append(discarded, rem.Transactions()...) if rem = pool.chain.GetBlock(rem.ParentHash(), rem.NumberU64()-1); rem == nil { log.Error("Unrooted old chain seen by tx pool", "block", oldHead.Number, "hash", oldHead.Hash()) return } }
④：如果新链的头区块大于旧链的头区块，新链后退并回收交易
for add.NumberU64() > rem.NumberU64() { included = append(included, add.Transactions()...) if add = pool.chain.GetBlock(add.ParentHash(), add.NumberU64()-1); add == nil { log.Error("Unrooted new chain seen by tx pool", "block", newHead.Number, "hash", newHead.Hash()) return } }
⑤：当新旧链到达同一高度的时候同时回退，知道找到共同的父节点
for rem.Hash() != add.Hash() { discarded = append(discarded, rem.Transactions()...) if rem = pool.chain.GetBlock(rem.ParentHash(), rem.NumberU64()-1); rem == nil { log.Error("Unrooted old chain seen by tx pool", "block", oldHead.Number, "hash", oldHead.Hash()) return } included = append(included, add.Transactions()...) if add = pool.chain.GetBlock(add.ParentHash(), add.NumberU64()-1); add == nil { log.Error("Unrooted new chain seen by tx pool", "block", newHead.Number, "hash", newHead.Hash()) return } }
