log: update progress calculations for background validation
What the developer wrote
Authored by Pol Espinasa
log: update progress calculations for background validation
updates estimations to the block snapshot instead of the main chain tip as it will stop validation after reaching that height
What changed, and why it matters
This commit only changes how Bitcoin Core calculates and prints a progress percentage in log messages during a special background validation mode (used with the assume-utxo feature). It does not change consensus rules, network behavior, wallet handling, or any security-critical logic. The old code could show a misleading progress number; the new code makes the log estimate more accurate. There is no security vulnerability here.
No security action required. Treat as a normal logging/UX improvement. Reviewers may optionally verify that the new progress fraction is bounded (it is, by construction, since pindex is at or before target_block).
Security signals we found
No changes to consensus, cryptography, networking, or transaction validation rules
Change is confined to logging/progress estimation code paths
No input parsing, memory allocation, or privilege boundary changes
No bug fixes, bounds checks, or hardening patterns present
Evidence from the diff
The patch adds a new ChainstateManager::GetBackgroundVerificationProgress() helper and a background_validation flag to UpdateTipLog(). When logging progress for the historical/background chainstate in an assume-utxo setup, it now divides the current block’s m_chain_tx_count by the snapshot target block’s m_chain_tx_count instead of by the live chain tip’s transaction count. This fixes a cosmetic/log-only miscalculation where background validation progress could appear to jump near 100% before historical validation was actually complete. GuessVerificationProgress() remains unchanged for normal use.
Changed components
src/validation.cpp logging helper UpdateTipLog()src/validation.cpp Chainstate::UpdateTip()src/validation.cpp ChainstateManager::GetBackgroundVerificationProgress()src/validation.h ChainstateManager method declarationsInspect captured patch +25 / −5
diff --git a/src/validation.cpp b/src/validation.cpp
index 1efe109b..59654c9d 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -2858,7 +2858,8 @@ static void UpdateTipLog(
const CBlockIndex* tip,
const std::string& func_name,
const std::string& prefix,
- const std::string& warning_messages) EXCLUSIVE_LOCKS_REQUIRED(::cs_main)
+ const std::string& warning_messages,
+ const bool background_validation) EXCLUSIVE_LOCKS_REQUIRED(::cs_main)
{
AssertLockHeld(::cs_main);
@@ -2869,7 +2870,7 @@ static void UpdateTipLog(
tip->GetBlockHash().ToString(), tip->nHeight, tip->nVersion,
log(tip->nChainWork.getdouble()) / log(2.0), tip->m_chain_tx_count,
FormatISO8601DateTime(tip->GetBlockTime()),
- chainman.GuessVerificationProgress(tip),
+ background_validation ? chainman.GetBackgroundVerificationProgress(*tip) : chainman.GuessVerificationProgress(tip),
coins_tip.DynamicMemoryUsage() * (1.0 / (1 << 20)),
coins_tip.GetCacheSize(),
!warning_messages.empty() ? strprintf(" warning='%s'", warning_messages) : "");
@@ -2886,7 +2887,7 @@ void Chainstate::UpdateTip(const CBlockIndex* pindexNew)
// Only log every so often so that we don't bury log messages at the tip.
constexpr int BACKGROUND_LOG_INTERVAL = 2000;
if (pindexNew->nHeight % BACKGROUND_LOG_INTERVAL == 0) {
- UpdateTipLog(m_chainman, coins_tip, pindexNew, __func__, "[background validation] ", "");
+ UpdateTipLog(m_chainman, coins_tip, pindexNew, __func__, "[background validation] ", "", /*background_validation=*/true);
}
return;
}
@@ -2909,7 +2910,7 @@ void Chainstate::UpdateTip(const CBlockIndex* pindexNew)
}
}
UpdateTipLog(m_chainman, coins_tip, pindexNew, __func__, "",
- util::Join(warning_messages, Untranslated(", ")).original);
+ util::Join(warning_messages, Untranslated(", ")).original, /*background_validation=*/false);
}
/** Disconnect m_chain's tip.
@@ -5520,6 +5521,19 @@ double ChainstateManager::GuessVerificationProgress(const CBlockIndex* pindex) c
return std::min<double>(pindex->m_chain_tx_count / fTxTotal, 1.0);
}
+double ChainstateManager::GetBackgroundVerificationProgress(const CBlockIndex& pindex) const
+{
+ AssertLockHeld(GetMutex());
+ Assert(HistoricalChainstate());
+ auto target_block = HistoricalChainstate()->TargetBlock();
+
+ if (pindex.m_chain_tx_count == 0 || target_block->m_chain_tx_count == 0) {
+ LogDebug(BCLog::VALIDATION, "[background validation] Block %d has unset m_chain_tx_count. Unable to estimate verification progress.", pindex.nHeight);
+ return 0.0;
+ }
+ return static_cast<double>(pindex.m_chain_tx_count) / static_cast<double>(target_block->m_chain_tx_count);
+}
+
Chainstate& ChainstateManager::InitializeChainstate(CTxMemPool* mempool)
{
AssertLockHeld(::cs_main);
diff --git a/src/validation.h b/src/validation.h
index 729cdbaa..cee0dd72 100644
--- a/src/validation.h
+++ b/src/validation.h
@@ -1194,9 +1194,15 @@ public:
/** Check whether we are doing an initial block download (synchronizing from disk or network) */
bool IsInitialBlockDownload() const noexcept;
- /** Guess verification progress (as a fraction between 0.0=genesis and 1.0=current tip). */
+ /** Guess verification progress (as a fraction between 0.0=genesis and 1.0=current tip).
+ * This is also the case in the assumeutxo context, meaning that the progress reported for
+ * the snapshot chainstate may suggest that all historical blocks have already been verified
+ * even though that may not actually be the case. */
double GuessVerificationProgress(const CBlockIndex* pindex) const EXCLUSIVE_LOCKS_REQUIRED(GetMutex());
+ /** Guess background verification progress in case assume-utxo was used (as a fraction between 0.0=genesis and 1.0=snapshot blocks). */
+ double GetBackgroundVerificationProgress(const CBlockIndex& pindex) const EXCLUSIVE_LOCKS_REQUIRED(GetMutex());
+
/**
* Import blocks from an external file
*
Why this scored 19/100
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