index: Implement block filter index with write operations.

This commit is contained in:
Jim Posen 2018-08-27 17:01:24 -07:00
parent 2ad2338ef9
commit 75a76e3619
3 changed files with 337 additions and 0 deletions

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@ -133,6 +133,7 @@ BITCOIN_CORE_H = \
httprpc.h \ httprpc.h \
httpserver.h \ httpserver.h \
index/base.h \ index/base.h \
index/blockfilterindex.h \
index/txindex.h \ index/txindex.h \
indirectmap.h \ indirectmap.h \
init.h \ init.h \
@ -253,6 +254,7 @@ libbitcoin_server_a_SOURCES = \
httprpc.cpp \ httprpc.cpp \
httpserver.cpp \ httpserver.cpp \
index/base.cpp \ index/base.cpp \
index/blockfilterindex.cpp \
index/txindex.cpp \ index/txindex.cpp \
interfaces/chain.cpp \ interfaces/chain.cpp \
interfaces/handler.cpp \ interfaces/handler.cpp \

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@ -0,0 +1,282 @@
// Copyright (c) 2018 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include <map>
#include <index/blockfilterindex.h>
#include <util/system.h>
#include <validation.h>
/* The index database stores three items for each block: the disk location of the encoded filter,
* its dSHA256 hash, and the header. Those belonging to blocks on the active chain are indexed by
* height, and those belonging to blocks that have been reorganized out of the active chain are
* indexed by block hash. This ensures that filter data for any block that becomes part of the
* active chain can always be retrieved, alleviating timing concerns.
*
* The filters themselves are stored in flat files and referenced by the LevelDB entries. This
* minimizes the amount of data written to LevelDB and keeps the database values constant size. The
* disk location of the next block filter to be written (represented as a FlatFilePos) is stored
* under the DB_FILTER_POS key.
*
* Keys for the height index have the type [DB_BLOCK_HEIGHT, uint32 (BE)]. The height is represented
* as big-endian so that sequential reads of filters by height are fast.
* Keys for the hash index have the type [DB_BLOCK_HASH, uint256].
*/
constexpr char DB_BLOCK_HASH = 's';
constexpr char DB_BLOCK_HEIGHT = 't';
constexpr char DB_FILTER_POS = 'P';
constexpr unsigned int MAX_FLTR_FILE_SIZE = 0x1000000; // 16 MiB
/** The pre-allocation chunk size for fltr?????.dat files */
constexpr unsigned int FLTR_FILE_CHUNK_SIZE = 0x100000; // 1 MiB
namespace {
struct DBVal {
uint256 hash;
uint256 header;
FlatFilePos pos;
ADD_SERIALIZE_METHODS;
template <typename Stream, typename Operation>
inline void SerializationOp(Stream& s, Operation ser_action) {
READWRITE(hash);
READWRITE(header);
READWRITE(pos);
}
};
struct DBHeightKey {
int height;
DBHeightKey() : height(0) {}
DBHeightKey(int height_in) : height(height_in) {}
template<typename Stream>
void Serialize(Stream& s) const
{
ser_writedata8(s, DB_BLOCK_HEIGHT);
ser_writedata32be(s, height);
}
template<typename Stream>
void Unserialize(Stream& s)
{
char prefix = ser_readdata8(s);
if (prefix != DB_BLOCK_HEIGHT) {
throw std::ios_base::failure("Invalid format for block filter index DB height key");
}
height = ser_readdata32be(s);
}
};
struct DBHashKey {
uint256 hash;
DBHashKey(const uint256& hash_in) : hash(hash_in) {}
ADD_SERIALIZE_METHODS;
template <typename Stream, typename Operation>
inline void SerializationOp(Stream& s, Operation ser_action) {
char prefix = DB_BLOCK_HASH;
READWRITE(prefix);
if (prefix != DB_BLOCK_HASH) {
throw std::ios_base::failure("Invalid format for block filter index DB hash key");
}
READWRITE(hash);
}
};
}; // namespace
BlockFilterIndex::BlockFilterIndex(BlockFilterType filter_type,
size_t n_cache_size, bool f_memory, bool f_wipe)
: m_filter_type(filter_type)
{
const std::string& filter_name = BlockFilterTypeName(filter_type);
if (filter_name.empty()) throw std::invalid_argument("unknown filter_type");
fs::path path = GetDataDir() / "indexes" / "blockfilter" / filter_name;
fs::create_directories(path);
m_name = filter_name + " block filter index";
m_db = MakeUnique<BaseIndex::DB>(path / "db", n_cache_size, f_memory, f_wipe);
m_filter_fileseq = MakeUnique<FlatFileSeq>(std::move(path), "fltr", FLTR_FILE_CHUNK_SIZE);
}
bool BlockFilterIndex::Init()
{
if (!m_db->Read(DB_FILTER_POS, m_next_filter_pos)) {
// Check that the cause of the read failure is that the key does not exist. Any other errors
// indicate database corruption or a disk failure, and starting the index would cause
// further corruption.
if (m_db->Exists(DB_FILTER_POS)) {
return error("%s: Cannot read current %s state; index may be corrupted",
__func__, GetName());
}
// If the DB_FILTER_POS is not set, then initialize to the first location.
m_next_filter_pos.nFile = 0;
m_next_filter_pos.nPos = 0;
}
return BaseIndex::Init();
}
bool BlockFilterIndex::CommitInternal(CDBBatch& batch)
{
const FlatFilePos& pos = m_next_filter_pos;
// Flush current filter file to disk.
CAutoFile file(m_filter_fileseq->Open(pos), SER_DISK, CLIENT_VERSION);
if (file.IsNull()) {
return error("%s: Failed to open filter file %d", __func__, pos.nFile);
}
if (!FileCommit(file.Get())) {
return error("%s: Failed to commit filter file %d", __func__, pos.nFile);
}
batch.Write(DB_FILTER_POS, pos);
return BaseIndex::CommitInternal(batch);
}
size_t BlockFilterIndex::WriteFilterToDisk(FlatFilePos& pos, const BlockFilter& filter)
{
assert(filter.GetFilterType() == GetFilterType());
size_t data_size =
GetSerializeSize(filter.GetBlockHash(), CLIENT_VERSION) +
GetSerializeSize(filter.GetEncodedFilter(), CLIENT_VERSION);
// If writing the filter would overflow the file, flush and move to the next one.
if (pos.nPos + data_size > MAX_FLTR_FILE_SIZE) {
CAutoFile last_file(m_filter_fileseq->Open(pos), SER_DISK, CLIENT_VERSION);
if (last_file.IsNull()) {
LogPrintf("%s: Failed to open filter file %d\n", __func__, pos.nFile);
return 0;
}
if (!TruncateFile(last_file.Get(), pos.nPos)) {
LogPrintf("%s: Failed to truncate filter file %d\n", __func__, pos.nFile);
return 0;
}
if (!FileCommit(last_file.Get())) {
LogPrintf("%s: Failed to commit filter file %d\n", __func__, pos.nFile);
return 0;
}
pos.nFile++;
pos.nPos = 0;
}
// Pre-allocate sufficient space for filter data.
bool out_of_space;
m_filter_fileseq->Allocate(pos, data_size, out_of_space);
if (out_of_space) {
LogPrintf("%s: out of disk space\n", __func__);
return 0;
}
CAutoFile fileout(m_filter_fileseq->Open(pos), SER_DISK, CLIENT_VERSION);
if (fileout.IsNull()) {
LogPrintf("%s: Failed to open filter file %d\n", __func__, pos.nFile);
return 0;
}
fileout << filter.GetBlockHash() << filter.GetEncodedFilter();
return data_size;
}
bool BlockFilterIndex::WriteBlock(const CBlock& block, const CBlockIndex* pindex)
{
CBlockUndo block_undo;
uint256 prev_header;
if (pindex->nHeight > 0) {
if (!UndoReadFromDisk(block_undo, pindex)) {
return false;
}
std::pair<uint256, DBVal> read_out;
if (!m_db->Read(DBHeightKey(pindex->nHeight - 1), read_out)) {
return false;
}
uint256 expected_block_hash = pindex->pprev->GetBlockHash();
if (read_out.first != expected_block_hash) {
return error("%s: previous block header belongs to unexpected block %s; expected %s",
__func__, read_out.first.ToString(), expected_block_hash.ToString());
}
prev_header = read_out.second.header;
}
BlockFilter filter(m_filter_type, block, block_undo);
size_t bytes_written = WriteFilterToDisk(m_next_filter_pos, filter);
if (bytes_written == 0) return false;
std::pair<uint256, DBVal> value;
value.first = pindex->GetBlockHash();
value.second.hash = filter.GetHash();
value.second.header = filter.ComputeHeader(prev_header);
value.second.pos = m_next_filter_pos;
if (!m_db->Write(DBHeightKey(pindex->nHeight), value)) {
return false;
}
m_next_filter_pos.nPos += bytes_written;
return true;
}
static bool CopyHeightIndexToHashIndex(CDBIterator& db_it, CDBBatch& batch,
const std::string& index_name,
int start_height, int stop_height)
{
DBHeightKey key(start_height);
db_it.Seek(key);
for (int height = start_height; height <= stop_height; ++height) {
if (!db_it.GetKey(key) || key.height != height) {
return error("%s: unexpected key in %s: expected (%c, %d)",
__func__, index_name, DB_BLOCK_HEIGHT, height);
}
std::pair<uint256, DBVal> value;
if (!db_it.GetValue(value)) {
return error("%s: unable to read value in %s at key (%c, %d)",
__func__, index_name, DB_BLOCK_HEIGHT, height);
}
batch.Write(DBHashKey(value.first), std::move(value.second));
db_it.Next();
}
return true;
}
bool BlockFilterIndex::Rewind(const CBlockIndex* current_tip, const CBlockIndex* new_tip)
{
assert(current_tip->GetAncestor(new_tip->nHeight) == new_tip);
CDBBatch batch(*m_db);
std::unique_ptr<CDBIterator> db_it(m_db->NewIterator());
// During a reorg, we need to copy all filters for blocks that are getting disconnected from the
// height index to the hash index so we can still find them when the height index entries are
// overwritten.
if (!CopyHeightIndexToHashIndex(*db_it, batch, m_name, new_tip->nHeight, current_tip->nHeight)) {
return false;
}
// The latest filter position gets written in Commit by the call to the BaseIndex::Rewind.
// But since this creates new references to the filter, the position should get updated here
// atomically as well in case Commit fails.
batch.Write(DB_FILTER_POS, m_next_filter_pos);
if (!m_db->WriteBatch(batch)) return false;
return BaseIndex::Rewind(current_tip, new_tip);
}

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@ -0,0 +1,53 @@
// Copyright (c) 2018 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#ifndef BITCOIN_INDEX_BLOCKFILTERINDEX_H
#define BITCOIN_INDEX_BLOCKFILTERINDEX_H
#include <blockfilter.h>
#include <chain.h>
#include <flatfile.h>
#include <index/base.h>
/**
* BlockFilterIndex is used to store and retrieve block filters, hashes, and headers for a range of
* blocks by height. An index is constructed for each supported filter type with its own database
* (ie. filter data for different types are stored in separate databases).
*
* This index is used to serve BIP 157 net requests.
*/
class BlockFilterIndex final : public BaseIndex
{
private:
BlockFilterType m_filter_type;
std::string m_name;
std::unique_ptr<BaseIndex::DB> m_db;
FlatFilePos m_next_filter_pos;
std::unique_ptr<FlatFileSeq> m_filter_fileseq;
size_t WriteFilterToDisk(FlatFilePos& pos, const BlockFilter& filter);
protected:
bool Init() override;
bool CommitInternal(CDBBatch& batch) override;
bool WriteBlock(const CBlock& block, const CBlockIndex* pindex) override;
bool Rewind(const CBlockIndex* current_tip, const CBlockIndex* new_tip) override;
BaseIndex::DB& GetDB() const override { return *m_db; }
const char* GetName() const override { return m_name.c_str(); }
public:
/** Constructs the index, which becomes available to be queried. */
explicit BlockFilterIndex(BlockFilterType filter_type,
size_t n_cache_size, bool f_memory = false, bool f_wipe = false);
BlockFilterType GetFilterType() const { return m_filter_type; }
};
#endif // BITCOIN_INDEX_BLOCKFILTERINDEX_H