From 63d1ae5556ea40dde0cca20addda4bba40005496 Mon Sep 17 00:00:00 2001
From: Pieter Wuille <pieter.wuille@gmail.com>
Date: Tue, 25 Nov 2014 16:26:20 +0100
Subject: [PATCH] Do all block index writes in a batch

---
 src/chain.h  |  2 +-
 src/main.cpp | 31 +++++++++++++++----------------
 src/txdb.cpp | 25 ++++++++++++-------------
 src/txdb.h   |  4 +---
 4 files changed, 29 insertions(+), 33 deletions(-)

diff --git a/src/chain.h b/src/chain.h
index c01240665d..e76d5a3d9a 100644
--- a/src/chain.h
+++ b/src/chain.h
@@ -293,7 +293,7 @@ public:
         hashPrev = 0;
     }
 
-    explicit CDiskBlockIndex(CBlockIndex* pindex) : CBlockIndex(*pindex) {
+    explicit CDiskBlockIndex(const CBlockIndex* pindex) : CBlockIndex(*pindex) {
         hashPrev = (pprev ? pprev->GetBlockHash() : 0);
     }
 
diff --git a/src/main.cpp b/src/main.cpp
index 88fb31980f..832d7747f8 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1784,24 +1784,23 @@ bool static FlushStateToDisk(CValidationState &state, FlushStateMode mode) {
         // First make sure all block and undo data is flushed to disk.
         FlushBlockFile();
         // Then update all block file information (which may refer to block and undo files).
-        bool fileschanged = false;
-        for (set<int>::iterator it = setDirtyFileInfo.begin(); it != setDirtyFileInfo.end(); ) {
-            if (!pblocktree->WriteBlockFileInfo(*it, vinfoBlockFile[*it])) {
-                return state.Abort("Failed to write to block index");
+        {
+            std::vector<std::pair<int, const CBlockFileInfo*> > vFiles;
+            vFiles.reserve(setDirtyFileInfo.size());
+            for (set<int>::iterator it = setDirtyFileInfo.begin(); it != setDirtyFileInfo.end(); ) {
+                vFiles.push_back(make_pair(*it, &vinfoBlockFile[*it]));
+                setDirtyFileInfo.erase(it++);
+            }
+            std::vector<const CBlockIndex*> vBlocks;
+            vBlocks.reserve(setDirtyBlockIndex.size());
+            for (set<CBlockIndex*>::iterator it = setDirtyBlockIndex.begin(); it != setDirtyBlockIndex.end(); ) {
+                vBlocks.push_back(*it);
+                setDirtyBlockIndex.erase(it++);
+            }
+            if (!pblocktree->WriteBatchSync(vFiles, nLastBlockFile, vBlocks)) {
+                return state.Abort("Files to write to block index database");
             }
-            fileschanged = true;
-            setDirtyFileInfo.erase(it++);
         }
-        if (fileschanged && !pblocktree->WriteLastBlockFile(nLastBlockFile)) {
-            return state.Abort("Failed to write to block index");
-        }
-        for (set<CBlockIndex*>::iterator it = setDirtyBlockIndex.begin(); it != setDirtyBlockIndex.end(); ) {
-             if (!pblocktree->WriteBlockIndex(CDiskBlockIndex(*it))) {
-                 return state.Abort("Failed to write to block index");
-             }
-             setDirtyBlockIndex.erase(it++);
-        }
-        pblocktree->Sync();
         // Finally flush the chainstate (which may refer to block index entries).
         if (!pcoinsTip->Flush())
             return state.Abort("Failed to write to coin database");
diff --git a/src/txdb.cpp b/src/txdb.cpp
index 0731d843f3..29ef350374 100644
--- a/src/txdb.cpp
+++ b/src/txdb.cpp
@@ -66,23 +66,10 @@ bool CCoinsViewDB::BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock) {
 CBlockTreeDB::CBlockTreeDB(size_t nCacheSize, bool fMemory, bool fWipe) : CLevelDBWrapper(GetDataDir() / "blocks" / "index", nCacheSize, fMemory, fWipe) {
 }
 
-bool CBlockTreeDB::WriteBlockIndex(const CDiskBlockIndex& blockindex)
-{
-    return Write(make_pair('b', blockindex.GetBlockHash()), blockindex);
-}
-
-bool CBlockTreeDB::WriteBlockFileInfo(int nFile, const CBlockFileInfo &info) {
-    return Write(make_pair('f', nFile), info);
-}
-
 bool CBlockTreeDB::ReadBlockFileInfo(int nFile, CBlockFileInfo &info) {
     return Read(make_pair('f', nFile), info);
 }
 
-bool CBlockTreeDB::WriteLastBlockFile(int nFile) {
-    return Write('l', nFile);
-}
-
 bool CBlockTreeDB::WriteReindexing(bool fReindexing) {
     if (fReindexing)
         return Write('R', '1');
@@ -152,6 +139,18 @@ bool CCoinsViewDB::GetStats(CCoinsStats &stats) const {
     return true;
 }
 
+bool CBlockTreeDB::WriteBatchSync(const std::vector<std::pair<int, const CBlockFileInfo*> >& fileInfo, int nLastFile, const std::vector<const CBlockIndex*>& blockinfo) {
+    CLevelDBBatch batch;
+    for (std::vector<std::pair<int, const CBlockFileInfo*> >::const_iterator it=fileInfo.begin(); it != fileInfo.end(); it++) {
+        batch.Write(make_pair('f', it->first), *it->second);
+    }
+    batch.Write('l', nLastFile);
+    for (std::vector<const CBlockIndex*>::const_iterator it=blockinfo.begin(); it != blockinfo.end(); it++) {
+        batch.Write(make_pair('b', (*it)->GetBlockHash()), CDiskBlockIndex(*it));
+    }
+    return WriteBatch(batch, true);
+}
+
 bool CBlockTreeDB::ReadTxIndex(const uint256 &txid, CDiskTxPos &pos) {
     return Read(make_pair('t', txid), pos);
 }
diff --git a/src/txdb.h b/src/txdb.h
index 9a98fcc41b..f81fc62689 100644
--- a/src/txdb.h
+++ b/src/txdb.h
@@ -48,11 +48,9 @@ private:
     CBlockTreeDB(const CBlockTreeDB&);
     void operator=(const CBlockTreeDB&);
 public:
-    bool WriteBlockIndex(const CDiskBlockIndex& blockindex);
+    bool WriteBatchSync(const std::vector<std::pair<int, const CBlockFileInfo*> >& fileInfo, int nLastFile, const std::vector<const CBlockIndex*>& blockinfo);
     bool ReadBlockFileInfo(int nFile, CBlockFileInfo &fileinfo);
-    bool WriteBlockFileInfo(int nFile, const CBlockFileInfo &fileinfo);
     bool ReadLastBlockFile(int &nFile);
-    bool WriteLastBlockFile(int nFile);
     bool WriteReindexing(bool fReindex);
     bool ReadReindexing(bool &fReindex);
     bool ReadTxIndex(const uint256 &txid, CDiskTxPos &pos);