core: make reorg use less memory

core/blockchain.go

@@ -1934,8 +1934,13 @@ func mergeLogs(logs [][]*types.Log, reverse bool) []*types.Log {
 // Note the new head block won't be processed here, callers need to handle it
 // externally.
 func (bc *BlockChain) reorg(oldBlock, newBlock *types.Block) error {
+	type block struct {
+		hash   common.Hash
+		number uint64
+	}
+
 	var (
-		newChain    types.Blocks
+		newChain    []block
 		oldChain    types.Blocks
 		commonBlock *types.Block
 
@@ -1961,7 +1966,7 @@ func (bc *BlockChain) reorg(oldBlock, newBlock *types.Block) error {
 	} else {
 		// New chain is longer, stash all blocks away for subsequent insertion
 		for ; newBlock != nil && newBlock.NumberU64() != oldBlock.NumberU64(); newBlock = bc.GetBlock(newBlock.ParentHash(), newBlock.NumberU64()-1) {
-			newChain = append(newChain, newBlock)
+			newChain = append(newChain, block{hash: newBlock.Hash(), number: newBlock.NumberU64()})
 		}
 	}
 	if oldBlock == nil {
@@ -1987,7 +1992,7 @@ func (bc *BlockChain) reorg(oldBlock, newBlock *types.Block) error {
 		if len(logs) > 0 {
 			deletedLogs = append(deletedLogs, logs)
 		}
-		newChain = append(newChain, newBlock)
+		newChain = append(newChain, block{hash: newBlock.Hash(), number: newBlock.NumberU64()})
 
 		// Step back with both chains
 		oldBlock = bc.GetBlock(oldBlock.ParentHash(), oldBlock.NumberU64()-1)
@@ -2008,14 +2013,14 @@ func (bc *BlockChain) reorg(oldBlock, newBlock *types.Block) error {
 			logFn = log.Warn
 		}
 		logFn(msg, "number", commonBlock.Number(), "hash", commonBlock.Hash(),
-			"drop", len(oldChain), "dropfrom", oldChain[0].Hash(), "add", len(newChain), "addfrom", newChain[0].Hash())
+			"drop", len(oldChain), "dropfrom", oldChain[0].Hash(), "add", len(newChain), "addfrom", newChain[0].hash)
 		blockReorgAddMeter.Mark(int64(len(newChain)))
 		blockReorgDropMeter.Mark(int64(len(oldChain)))
 		blockReorgMeter.Mark(1)
 	} else if len(newChain) > 0 {
 		// Special case happens in the post merge stage that current head is
 		// the ancestor of new head while these two blocks are not consecutive
-		log.Info("Extend chain", "add", len(newChain), "number", newChain[0].NumberU64(), "hash", newChain[0].Hash())
+		log.Info("Extend chain", "add", len(newChain), "number", newChain[0].number, "hash", newChain[0].hash)
 		blockReorgAddMeter.Mark(int64(len(newChain)))
 	} else {
 		// len(newChain) == 0 && len(oldChain) > 0
@@ -2026,15 +2031,17 @@ func (bc *BlockChain) reorg(oldBlock, newBlock *types.Block) error {
 	// taking care of the proper incremental order.
 	for i := len(newChain) - 1; i >= 1; i-- {
 		// Insert the block in the canonical way, re-writing history
-		bc.writeHeadBlock(newChain[i])
+		block := bc.GetBlock(newChain[i].hash, newChain[i].number)
+
+		bc.writeHeadBlock(block)
 
 		// Collect reborn logs due to chain reorg
-		logs := bc.collectLogs(newChain[i].Hash(), false)
+		logs := bc.collectLogs(block.Hash(), false)
 		if len(logs) > 0 {
 			rebirthLogs = append(rebirthLogs, logs)
 		}
 		// Collect the new added transactions.
-		addedTxs = append(addedTxs, newChain[i].Transactions()...)
+		addedTxs = append(addedTxs, block.Transactions()...)
 	}
 	// Delete useless indexes right now which includes the non-canonical
 	// transaction indexes, canonical chain indexes which above the head.