From f8fbbcfe298d725a8a4eccffea7f0167414902f9 Mon Sep 17 00:00:00 2001
From: Martin Boehm <martin.boehm@1mbsoftware.net>
Date: Thu, 1 Mar 2018 00:32:40 +0100
Subject: [PATCH] Connect blocks in parallel without getting block header -
 optimization

---
 bchain/bitcoinrpc.go | 19 +++++++++++++++++++
 blockbook.go         | 16 ++++++++++------
 2 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/bchain/bitcoinrpc.go b/bchain/bitcoinrpc.go
index 1e874def..28c221c1 100644
--- a/bchain/bitcoinrpc.go
+++ b/bchain/bitcoinrpc.go
@@ -287,6 +287,25 @@ func (b *BitcoinRPC) GetBlock(hash string) (*Block, error) {
 	return block, nil
 }
 
+// GetBlockWithoutHeader is an optimization - it does not call GetBlockHeader to get prev, next hashes
+// instead it sets to header only block hash and height passed in parameters
+func (b *BitcoinRPC) GetBlockWithoutHeader(hash string, height uint32) (*Block, error) {
+	if b.Parser == nil {
+		return b.GetBlockFull(hash)
+	}
+	data, err := b.GetBlockRaw(hash)
+	if err != nil {
+		return nil, err
+	}
+	block, err := b.Parser.ParseBlock(data)
+	if err != nil {
+		return nil, err
+	}
+	block.BlockHeader.Hash = hash
+	block.BlockHeader.Height = height
+	return block, nil
+}
+
 // GetBlockRaw returns block with given hash as bytes.
 func (b *BitcoinRPC) GetBlockRaw(hash string) ([]byte, error) {
 	glog.V(1).Info("rpc: getblock (verbosity=0) ", hash)
diff --git a/blockbook.go b/blockbook.go
index 63a9fb44..1be2acc5 100644
--- a/blockbook.go
+++ b/blockbook.go
@@ -480,17 +480,21 @@ func connectBlocksParallel(
 	higher uint32,
 	numWorkers int,
 ) error {
+	type hashHeight struct {
+		hash   string
+		height uint32
+	}
 	var err error
 	var wg sync.WaitGroup
-	hch := make(chan string, numWorkers)
+	hch := make(chan hashHeight, numWorkers)
 	running := make([]bool, numWorkers)
 	work := func(i int) {
 		defer wg.Done()
-		for hash := range hch {
+		for hh := range hch {
 			running[i] = true
-			block, err := chain.GetBlock(hash)
+			block, err := chain.GetBlockWithoutHeader(hh.hash, hh.height)
 			if err != nil {
-				glog.Error("Connect block ", hash, " error ", err)
+				glog.Error("Connect block ", hh.height, " ", hh.hash, " error ", err)
 				running[i] = false
 				continue
 			}
@@ -500,7 +504,7 @@ func connectBlocksParallel(
 			}
 			err = index.ConnectBlock(block)
 			if err != nil {
-				glog.Error("Connect block ", hash, " error ", err)
+				glog.Error("Connect block ", hh.height, " ", hh.hash, " error ", err)
 			}
 			running[i] = false
 		}
@@ -516,7 +520,7 @@ func connectBlocksParallel(
 		if err != nil {
 			break
 		}
-		hch <- hash
+		hch <- hashHeight{hash, h}
 		if h > 0 && h%1000 == 0 {
 			glog.Info("connecting block ", h, " ", hash)
 		}