From 2e280311b87ac95a765edd3cac05096e48c73545 Mon Sep 17 00:00:00 2001
From: "Wladimir J. van der Laan" <laanwj@gmail.com>
Date: Wed, 27 Aug 2014 09:20:33 +0200
Subject: [PATCH] Perform CVerifyDB on pcoinsdbview instead of pcoinsTip

Bypassing the main coins cache allows more thorough checking with the same
memory budget.

This has no effect on performance because everything ends up in the child
cache created by VerifyDB itself.

It has bugged me ever since #4675, which effectively reduced the
number of checked blocks to reduce peak memory usage.

- Pass the coinsview to use as argument to VerifyDB

- This also avoids that the first `pcoinsTip->Flush()` after VerifyDB
  writes a large slew of unchanged coin records back to the database.
---
 src/init.cpp          | 2 +-
 src/main.cpp          | 4 ++--
 src/main.h            | 2 +-
 src/rpcblockchain.cpp | 2 +-
 4 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/init.cpp b/src/init.cpp
index e972413c4b..7b1318654f 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -969,7 +969,7 @@ bool AppInit2(boost::thread_group& threadGroup)
                 }
 
                 uiInterface.InitMessage(_("Verifying blocks..."));
-                if (!CVerifyDB().VerifyDB(GetArg("-checklevel", 3),
+                if (!CVerifyDB().VerifyDB(pcoinsdbview, GetArg("-checklevel", 3),
                               GetArg("-checkblocks", 288))) {
                     strLoadError = _("Corrupted block database detected");
                     break;
diff --git a/src/main.cpp b/src/main.cpp
index 6567c77e93..de5730a388 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -3018,7 +3018,7 @@ CVerifyDB::~CVerifyDB()
     uiInterface.ShowProgress("", 100);
 }
 
-bool CVerifyDB::VerifyDB(int nCheckLevel, int nCheckDepth)
+bool CVerifyDB::VerifyDB(CCoinsView *coinsview, int nCheckLevel, int nCheckDepth)
 {
     LOCK(cs_main);
     if (chainActive.Tip() == NULL || chainActive.Tip()->pprev == NULL)
@@ -3031,7 +3031,7 @@ bool CVerifyDB::VerifyDB(int nCheckLevel, int nCheckDepth)
         nCheckDepth = chainActive.Height();
     nCheckLevel = std::max(0, std::min(4, nCheckLevel));
     LogPrintf("Verifying last %i blocks at level %i\n", nCheckDepth, nCheckLevel);
-    CCoinsViewCache coins(*pcoinsTip, true);
+    CCoinsViewCache coins(*coinsview, true);
     CBlockIndex* pindexState = chainActive.Tip();
     CBlockIndex* pindexFailure = NULL;
     int nGoodTransactions = 0;
diff --git a/src/main.h b/src/main.h
index e5357cbfdd..fae8990d20 100644
--- a/src/main.h
+++ b/src/main.h
@@ -942,7 +942,7 @@ class CVerifyDB {
 public:
     CVerifyDB();
     ~CVerifyDB();
-    bool VerifyDB(int nCheckLevel, int nCheckDepth);
+    bool VerifyDB(CCoinsView *coinsview, int nCheckLevel, int nCheckDepth);
 };
 
 /** An in-memory indexed chain of blocks. */
diff --git a/src/rpcblockchain.cpp b/src/rpcblockchain.cpp
index 58cab14045..b71d5a0804 100644
--- a/src/rpcblockchain.cpp
+++ b/src/rpcblockchain.cpp
@@ -430,7 +430,7 @@ Value verifychain(const Array& params, bool fHelp)
     if (params.size() > 1)
         nCheckDepth = params[1].get_int();
 
-    return CVerifyDB().VerifyDB(nCheckLevel, nCheckDepth);
+    return CVerifyDB().VerifyDB(pcoinsTip, nCheckLevel, nCheckDepth);
 }
 
 Value getblockchaininfo(const Array& params, bool fHelp)