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Limit the impact of reorganisations on the database

Sometimes a new block arrives in a new chain that was already the
best valid one, but wasn't marked that way. This happens for example
when network rules change to recover after a fork.

In this case, it is not necessary to do the entire reorganisation
inside a single db commit. These can become huge, and exceed the
objects/lockers limits in bdb. This patch limits the blocks the
actual reorganisation is applied to, and adds the next blocks
afterwards in separate db transactions.
pull/1/head
Pieter Wuille 11 years ago
parent
commit
d68dcf741e
  1. 78
      src/main.cpp
  2. 3
      src/main.h

78
src/main.cpp

@ -1457,6 +1457,32 @@ runCommand(std::string strCommand) @@ -1457,6 +1457,32 @@ runCommand(std::string strCommand)
printf("runCommand error: system(%s) returned %d\n", strCommand.c_str(), nErr);
}
bool CBlock::SetBestChainInner(CTxDB& txdb, CBlockIndex *pindexNew)
{
assert(pindexNew->pprev == pindexBest);
uint256 hash = GetHash();
// Adding to current best branch
if (!ConnectBlock(txdb, pindexNew) || !txdb.WriteHashBestChain(hash))
{
txdb.TxnAbort();
InvalidChainFound(pindexNew);
return false;
}
if (!txdb.TxnCommit())
return error("SetBestChain() : TxnCommit failed");
// Add to current best branch
pindexNew->pprev->pnext = pindexNew;
// Delete redundant memory transactions
BOOST_FOREACH(CTransaction& tx, vtx)
tx.RemoveFromMemoryPool();
return true;
}
bool CBlock::SetBestChain(CTxDB& txdb, CBlockIndex* pindexNew)
{
uint256 hash = GetHash();
@ -1471,32 +1497,50 @@ bool CBlock::SetBestChain(CTxDB& txdb, CBlockIndex* pindexNew) @@ -1471,32 +1497,50 @@ bool CBlock::SetBestChain(CTxDB& txdb, CBlockIndex* pindexNew)
}
else if (hashPrevBlock == hashBestChain)
{
// Adding to current best branch
if (!ConnectBlock(txdb, pindexNew) || !txdb.WriteHashBestChain(hash))
if (!SetBestChainInner(txdb, pindexNew))
return error("SetBestChain() : SetBestChainInner failed");
}
else
{
// the first block in the new chain that will cause it to become the new best chain
CBlockIndex *pindexIntermediate = pindexNew;
// list of blocks that need to be connected afterwards
std::vector<CBlockIndex*> vpindexSecondary;
// Reorganize is costly in terms of db load, as it works in a single db transaction.
// Try to limit how much needs to be done inside
while (pindexIntermediate->pprev && pindexIntermediate->pprev->bnChainWork > pindexBest->bnChainWork)
{
txdb.TxnAbort();
InvalidChainFound(pindexNew);
return error("SetBestChain() : ConnectBlock failed");
vpindexSecondary.push_back(pindexIntermediate);
pindexIntermediate = pindexIntermediate->pprev;
}
if (!txdb.TxnCommit())
return error("SetBestChain() : TxnCommit failed");
// Add to current best branch
pindexNew->pprev->pnext = pindexNew;
if (!vpindexSecondary.empty())
printf("Postponing %i reconnects\n", vpindexSecondary.size());
// Delete redundant memory transactions
BOOST_FOREACH(CTransaction& tx, vtx)
tx.RemoveFromMemoryPool();
}
else
{
// New best branch
if (!Reorganize(txdb, pindexNew))
// Switch to new best branch
if (!Reorganize(txdb, pindexIntermediate))
{
txdb.TxnAbort();
InvalidChainFound(pindexNew);
return error("SetBestChain() : Reorganize failed");
}
// Connect futher blocks
BOOST_REVERSE_FOREACH(CBlockIndex *pindex, vpindexSecondary)
{
CBlock block;
if (!block.ReadFromDisk(pindex))
{
printf("SetBestChain() : ReadFromDisk failed\n");
break;
}
txdb.TxnBegin();
// errors now are not fatal, we still did a reorganisation to a new chain in a valid way
if (!block.SetBestChainInner(txdb, pindex))
break;
}
}
// Update best block in wallet (so we can detect restored wallets)

3
src/main.h

@ -1030,6 +1030,9 @@ public: @@ -1030,6 +1030,9 @@ public:
bool AddToBlockIndex(unsigned int nFile, unsigned int nBlockPos);
bool CheckBlock() const;
bool AcceptBlock();
private:
bool SetBestChainInner(CTxDB& txdb, CBlockIndex *pindexNew);
};

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