fork of https://github.com/oxigraph/rocksdb and https://github.com/facebook/rocksdb for nextgraph and oxigraph
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
722 lines
23 KiB
722 lines
23 KiB
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
|
|
// This source code is licensed under both the GPLv2 (found in the
|
|
// COPYING file in the root directory) and Apache 2.0 License
|
|
// (found in the LICENSE.Apache file in the root directory).
|
|
//
|
|
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style license that can be
|
|
// found in the LICENSE file. See the AUTHORS file for names of contributors.
|
|
//
|
|
// Decodes the blocks generated by block_builder.cc.
|
|
|
|
#include "table/block.h"
|
|
#include <algorithm>
|
|
#include <string>
|
|
#include <unordered_map>
|
|
#include <vector>
|
|
|
|
#include "monitoring/perf_context_imp.h"
|
|
#include "port/port.h"
|
|
#include "port/stack_trace.h"
|
|
#include "rocksdb/comparator.h"
|
|
#include "table/block_prefix_index.h"
|
|
#include "table/format.h"
|
|
#include "util/coding.h"
|
|
#include "util/logging.h"
|
|
|
|
namespace rocksdb {
|
|
|
|
// Helper routine: decode the next block entry starting at "p",
|
|
// storing the number of shared key bytes, non_shared key bytes,
|
|
// and the length of the value in "*shared", "*non_shared", and
|
|
// "*value_length", respectively. Will not derefence past "limit".
|
|
//
|
|
// If any errors are detected, returns nullptr. Otherwise, returns a
|
|
// pointer to the key delta (just past the three decoded values).
|
|
struct DecodeEntry {
|
|
inline const char* operator()(const char* p, const char* limit,
|
|
uint32_t* shared, uint32_t* non_shared,
|
|
uint32_t* value_length) {
|
|
// We need 2 bytes for shared and non_shared size. We also need one more
|
|
// byte either for value size or the actual value in case of value delta
|
|
// encoding.
|
|
assert(limit - p >= 3);
|
|
*shared = reinterpret_cast<const unsigned char*>(p)[0];
|
|
*non_shared = reinterpret_cast<const unsigned char*>(p)[1];
|
|
*value_length = reinterpret_cast<const unsigned char*>(p)[2];
|
|
if ((*shared | *non_shared | *value_length) < 128) {
|
|
// Fast path: all three values are encoded in one byte each
|
|
p += 3;
|
|
} else {
|
|
if ((p = GetVarint32Ptr(p, limit, shared)) == nullptr) return nullptr;
|
|
if ((p = GetVarint32Ptr(p, limit, non_shared)) == nullptr) return nullptr;
|
|
if ((p = GetVarint32Ptr(p, limit, value_length)) == nullptr) {
|
|
return nullptr;
|
|
}
|
|
}
|
|
|
|
// Using an assert in place of "return null" since we should not pay the
|
|
// cost of checking for corruption on every single key decoding
|
|
assert(!(static_cast<uint32_t>(limit - p) < (*non_shared + *value_length)));
|
|
return p;
|
|
}
|
|
};
|
|
|
|
struct DecodeKey {
|
|
inline const char* operator()(const char* p, const char* limit,
|
|
uint32_t* shared, uint32_t* non_shared) {
|
|
uint32_t value_length;
|
|
return DecodeEntry()(p, limit, shared, non_shared, &value_length);
|
|
}
|
|
};
|
|
|
|
// In format_version 4, which is used by index blocks, the value size is not
|
|
// encoded before the entry, as the value is known to be the handle with the
|
|
// known size.
|
|
struct DecodeKeyV4 {
|
|
inline const char* operator()(const char* p, const char* limit,
|
|
uint32_t* shared, uint32_t* non_shared) {
|
|
// We need 2 bytes for shared and non_shared size. We also need one more
|
|
// byte either for value size or the actual value in case of value delta
|
|
// encoding.
|
|
if (limit - p < 3) return nullptr;
|
|
*shared = reinterpret_cast<const unsigned char*>(p)[0];
|
|
*non_shared = reinterpret_cast<const unsigned char*>(p)[1];
|
|
if ((*shared | *non_shared) < 128) {
|
|
// Fast path: all three values are encoded in one byte each
|
|
p += 2;
|
|
} else {
|
|
if ((p = GetVarint32Ptr(p, limit, shared)) == nullptr) return nullptr;
|
|
if ((p = GetVarint32Ptr(p, limit, non_shared)) == nullptr) return nullptr;
|
|
}
|
|
return p;
|
|
}
|
|
};
|
|
|
|
void DataBlockIter::Next() {
|
|
assert(Valid());
|
|
ParseNextDataKey();
|
|
}
|
|
|
|
void IndexBlockIter::Next() {
|
|
assert(Valid());
|
|
ParseNextIndexKey();
|
|
}
|
|
|
|
void IndexBlockIter::Prev() {
|
|
assert(Valid());
|
|
// Scan backwards to a restart point before current_
|
|
const uint32_t original = current_;
|
|
while (GetRestartPoint(restart_index_) >= original) {
|
|
if (restart_index_ == 0) {
|
|
// No more entries
|
|
current_ = restarts_;
|
|
restart_index_ = num_restarts_;
|
|
return;
|
|
}
|
|
restart_index_--;
|
|
}
|
|
SeekToRestartPoint(restart_index_);
|
|
do {
|
|
if (!ParseNextIndexKey()) {
|
|
break;
|
|
}
|
|
// Loop until end of current entry hits the start of original entry
|
|
} while (NextEntryOffset() < original);
|
|
}
|
|
|
|
// Similar to IndexBlockIter::Prev but also caches the prev entries
|
|
void DataBlockIter::Prev() {
|
|
assert(Valid());
|
|
|
|
assert(prev_entries_idx_ == -1 ||
|
|
static_cast<size_t>(prev_entries_idx_) < prev_entries_.size());
|
|
// Check if we can use cached prev_entries_
|
|
if (prev_entries_idx_ > 0 &&
|
|
prev_entries_[prev_entries_idx_].offset == current_) {
|
|
// Read cached CachedPrevEntry
|
|
prev_entries_idx_--;
|
|
const CachedPrevEntry& current_prev_entry =
|
|
prev_entries_[prev_entries_idx_];
|
|
|
|
const char* key_ptr = nullptr;
|
|
if (current_prev_entry.key_ptr != nullptr) {
|
|
// The key is not delta encoded and stored in the data block
|
|
key_ptr = current_prev_entry.key_ptr;
|
|
key_pinned_ = true;
|
|
} else {
|
|
// The key is delta encoded and stored in prev_entries_keys_buff_
|
|
key_ptr = prev_entries_keys_buff_.data() + current_prev_entry.key_offset;
|
|
key_pinned_ = false;
|
|
}
|
|
const Slice current_key(key_ptr, current_prev_entry.key_size);
|
|
|
|
current_ = current_prev_entry.offset;
|
|
key_.SetKey(current_key, false /* copy */);
|
|
value_ = current_prev_entry.value;
|
|
|
|
return;
|
|
}
|
|
|
|
// Clear prev entries cache
|
|
prev_entries_idx_ = -1;
|
|
prev_entries_.clear();
|
|
prev_entries_keys_buff_.clear();
|
|
|
|
// Scan backwards to a restart point before current_
|
|
const uint32_t original = current_;
|
|
while (GetRestartPoint(restart_index_) >= original) {
|
|
if (restart_index_ == 0) {
|
|
// No more entries
|
|
current_ = restarts_;
|
|
restart_index_ = num_restarts_;
|
|
return;
|
|
}
|
|
restart_index_--;
|
|
}
|
|
|
|
SeekToRestartPoint(restart_index_);
|
|
|
|
do {
|
|
if (!ParseNextDataKey()) {
|
|
break;
|
|
}
|
|
Slice current_key = key();
|
|
|
|
if (key_.IsKeyPinned()) {
|
|
// The key is not delta encoded
|
|
prev_entries_.emplace_back(current_, current_key.data(), 0,
|
|
current_key.size(), value());
|
|
} else {
|
|
// The key is delta encoded, cache decoded key in buffer
|
|
size_t new_key_offset = prev_entries_keys_buff_.size();
|
|
prev_entries_keys_buff_.append(current_key.data(), current_key.size());
|
|
|
|
prev_entries_.emplace_back(current_, nullptr, new_key_offset,
|
|
current_key.size(), value());
|
|
}
|
|
// Loop until end of current entry hits the start of original entry
|
|
} while (NextEntryOffset() < original);
|
|
prev_entries_idx_ = static_cast<int32_t>(prev_entries_.size()) - 1;
|
|
}
|
|
|
|
void DataBlockIter::Seek(const Slice& target) {
|
|
Slice seek_key = target;
|
|
PERF_TIMER_GUARD(block_seek_nanos);
|
|
if (data_ == nullptr) { // Not init yet
|
|
return;
|
|
}
|
|
uint32_t index = 0;
|
|
bool ok = BinarySeek<DecodeKey>(seek_key, 0, num_restarts_ - 1, &index,
|
|
comparator_);
|
|
|
|
if (!ok) {
|
|
return;
|
|
}
|
|
SeekToRestartPoint(index);
|
|
// Linear search (within restart block) for first key >= target
|
|
|
|
while (true) {
|
|
if (!ParseNextDataKey() || Compare(key_, seek_key) >= 0) {
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
void IndexBlockIter::Seek(const Slice& target) {
|
|
Slice seek_key = target;
|
|
if (!key_includes_seq_) {
|
|
seek_key = ExtractUserKey(target);
|
|
}
|
|
PERF_TIMER_GUARD(block_seek_nanos);
|
|
if (data_ == nullptr) { // Not init yet
|
|
return;
|
|
}
|
|
uint32_t index = 0;
|
|
bool ok = false;
|
|
if (prefix_index_) {
|
|
ok = PrefixSeek(target, &index);
|
|
} else if (value_delta_encoded_) {
|
|
ok = BinarySeek<DecodeKeyV4>(seek_key, 0, num_restarts_ - 1, &index,
|
|
active_comparator_);
|
|
} else {
|
|
ok = BinarySeek<DecodeKey>(seek_key, 0, num_restarts_ - 1, &index,
|
|
active_comparator_);
|
|
}
|
|
|
|
if (!ok) {
|
|
return;
|
|
}
|
|
SeekToRestartPoint(index);
|
|
// Linear search (within restart block) for first key >= target
|
|
|
|
while (true) {
|
|
if (!ParseNextIndexKey() || Compare(key_, seek_key) >= 0) {
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
void DataBlockIter::SeekForPrev(const Slice& target) {
|
|
PERF_TIMER_GUARD(block_seek_nanos);
|
|
Slice seek_key = target;
|
|
if (data_ == nullptr) { // Not init yet
|
|
return;
|
|
}
|
|
uint32_t index = 0;
|
|
bool ok = BinarySeek<DecodeKey>(seek_key, 0, num_restarts_ - 1, &index,
|
|
comparator_);
|
|
|
|
if (!ok) {
|
|
return;
|
|
}
|
|
SeekToRestartPoint(index);
|
|
// Linear search (within restart block) for first key >= seek_key
|
|
|
|
while (ParseNextDataKey() && Compare(key_, seek_key) < 0) {
|
|
}
|
|
if (!Valid()) {
|
|
SeekToLast();
|
|
} else {
|
|
while (Valid() && Compare(key_, seek_key) > 0) {
|
|
Prev();
|
|
}
|
|
}
|
|
}
|
|
|
|
void DataBlockIter::SeekToFirst() {
|
|
if (data_ == nullptr) { // Not init yet
|
|
return;
|
|
}
|
|
SeekToRestartPoint(0);
|
|
ParseNextDataKey();
|
|
}
|
|
|
|
void IndexBlockIter::SeekToFirst() {
|
|
if (data_ == nullptr) { // Not init yet
|
|
return;
|
|
}
|
|
SeekToRestartPoint(0);
|
|
ParseNextIndexKey();
|
|
}
|
|
|
|
void DataBlockIter::SeekToLast() {
|
|
if (data_ == nullptr) { // Not init yet
|
|
return;
|
|
}
|
|
SeekToRestartPoint(num_restarts_ - 1);
|
|
while (ParseNextDataKey() && NextEntryOffset() < restarts_) {
|
|
// Keep skipping
|
|
}
|
|
}
|
|
|
|
void IndexBlockIter::SeekToLast() {
|
|
if (data_ == nullptr) { // Not init yet
|
|
return;
|
|
}
|
|
SeekToRestartPoint(num_restarts_ - 1);
|
|
while (ParseNextIndexKey() && NextEntryOffset() < restarts_) {
|
|
// Keep skipping
|
|
}
|
|
}
|
|
|
|
template <class TValue>
|
|
void BlockIter<TValue>::CorruptionError() {
|
|
current_ = restarts_;
|
|
restart_index_ = num_restarts_;
|
|
status_ = Status::Corruption("bad entry in block");
|
|
key_.Clear();
|
|
value_.clear();
|
|
}
|
|
|
|
bool DataBlockIter::ParseNextDataKey() {
|
|
current_ = NextEntryOffset();
|
|
const char* p = data_ + current_;
|
|
const char* limit = data_ + restarts_; // Restarts come right after data
|
|
if (p >= limit) {
|
|
// No more entries to return. Mark as invalid.
|
|
current_ = restarts_;
|
|
restart_index_ = num_restarts_;
|
|
return false;
|
|
}
|
|
|
|
// Decode next entry
|
|
uint32_t shared, non_shared, value_length;
|
|
p = DecodeEntry()(p, limit, &shared, &non_shared, &value_length);
|
|
if (p == nullptr || key_.Size() < shared) {
|
|
CorruptionError();
|
|
return false;
|
|
} else {
|
|
if (shared == 0) {
|
|
// If this key dont share any bytes with prev key then we dont need
|
|
// to decode it and can use it's address in the block directly.
|
|
key_.SetKey(Slice(p, non_shared), false /* copy */);
|
|
key_pinned_ = true;
|
|
} else {
|
|
// This key share `shared` bytes with prev key, we need to decode it
|
|
key_.TrimAppend(shared, p, non_shared);
|
|
key_pinned_ = false;
|
|
}
|
|
|
|
if (global_seqno_ != kDisableGlobalSequenceNumber) {
|
|
// If we are reading a file with a global sequence number we should
|
|
// expect that all encoded sequence numbers are zeros and any value
|
|
// type is kTypeValue, kTypeMerge, kTypeDeletion, or kTypeRangeDeletion.
|
|
assert(GetInternalKeySeqno(key_.GetInternalKey()) == 0);
|
|
|
|
ValueType value_type = ExtractValueType(key_.GetKey());
|
|
assert(value_type == ValueType::kTypeValue ||
|
|
value_type == ValueType::kTypeMerge ||
|
|
value_type == ValueType::kTypeDeletion ||
|
|
value_type == ValueType::kTypeRangeDeletion);
|
|
|
|
if (key_pinned_) {
|
|
// TODO(tec): Investigate updating the seqno in the loaded block
|
|
// directly instead of doing a copy and update.
|
|
|
|
// We cannot use the key address in the block directly because
|
|
// we have a global_seqno_ that will overwrite the encoded one.
|
|
key_.OwnKey();
|
|
key_pinned_ = false;
|
|
}
|
|
|
|
key_.UpdateInternalKey(global_seqno_, value_type);
|
|
}
|
|
|
|
value_ = Slice(p + non_shared, value_length);
|
|
if (shared == 0) {
|
|
while (restart_index_ + 1 < num_restarts_ &&
|
|
GetRestartPoint(restart_index_ + 1) < current_) {
|
|
++restart_index_;
|
|
}
|
|
}
|
|
// else we are in the middle of a restart interval and the restart_index_
|
|
// thus has not changed
|
|
return true;
|
|
}
|
|
}
|
|
|
|
bool IndexBlockIter::ParseNextIndexKey() {
|
|
current_ = NextEntryOffset();
|
|
const char* p = data_ + current_;
|
|
const char* limit = data_ + restarts_; // Restarts come right after data
|
|
if (p >= limit) {
|
|
// No more entries to return. Mark as invalid.
|
|
current_ = restarts_;
|
|
restart_index_ = num_restarts_;
|
|
return false;
|
|
}
|
|
|
|
// Decode next entry
|
|
uint32_t shared, non_shared, value_length;
|
|
if (value_delta_encoded_) {
|
|
p = DecodeKeyV4()(p, limit, &shared, &non_shared);
|
|
value_length = 0;
|
|
} else {
|
|
p = DecodeEntry()(p, limit, &shared, &non_shared, &value_length);
|
|
}
|
|
if (p == nullptr || key_.Size() < shared) {
|
|
CorruptionError();
|
|
return false;
|
|
}
|
|
if (shared == 0) {
|
|
// If this key dont share any bytes with prev key then we dont need
|
|
// to decode it and can use it's address in the block directly.
|
|
key_.SetKey(Slice(p, non_shared), false /* copy */);
|
|
key_pinned_ = true;
|
|
} else {
|
|
// This key share `shared` bytes with prev key, we need to decode it
|
|
key_.TrimAppend(shared, p, non_shared);
|
|
key_pinned_ = false;
|
|
}
|
|
value_ = Slice(p + non_shared, value_length);
|
|
if (shared == 0) {
|
|
while (restart_index_ + 1 < num_restarts_ &&
|
|
GetRestartPoint(restart_index_ + 1) < current_) {
|
|
++restart_index_;
|
|
}
|
|
}
|
|
// else we are in the middle of a restart interval and the restart_index_
|
|
// thus has not changed
|
|
if (value_delta_encoded_) {
|
|
assert(value_length == 0);
|
|
DecodeCurrentValue(shared);
|
|
}
|
|
return true;
|
|
}
|
|
|
|
// The format:
|
|
// restart_point 0: k, v (off, sz), k, v (delta-sz), ..., k, v (delta-sz)
|
|
// restart_point 1: k, v (off, sz), k, v (delta-sz), ..., k, v (delta-sz)
|
|
// ...
|
|
// restart_point n-1: k, v (off, sz), k, v (delta-sz), ..., k, v (delta-sz)
|
|
// where, k is key, v is value, and its encoding is in parenthesis.
|
|
// The format of each key is (shared_size, non_shared_size, shared, non_shared)
|
|
// The format of each value, i.e., block hanlde, is (offset, size) whenever the
|
|
// shared_size is 0, which included the first entry in each restart point.
|
|
// Otherwise the format is delta-size = block handle size - size of last block
|
|
// handle.
|
|
void IndexBlockIter::DecodeCurrentValue(uint32_t shared) {
|
|
assert(value_delta_encoded_);
|
|
const char* limit = data_ + restarts_;
|
|
if (shared == 0) {
|
|
uint64_t o, s;
|
|
const char* newp = GetVarint64Ptr(value_.data(), limit, &o);
|
|
assert(newp);
|
|
newp = GetVarint64Ptr(newp, limit, &s);
|
|
assert(newp);
|
|
decoded_value_ = BlockHandle(o, s);
|
|
value_ = Slice(value_.data(), newp - value_.data());
|
|
} else {
|
|
uint64_t next_value_base =
|
|
decoded_value_.offset() + decoded_value_.size() + kBlockTrailerSize;
|
|
int64_t delta;
|
|
const char* newp = GetVarsignedint64Ptr(value_.data(), limit, &delta);
|
|
decoded_value_ =
|
|
BlockHandle(next_value_base, decoded_value_.size() + delta);
|
|
value_ = Slice(value_.data(), newp - value_.data());
|
|
}
|
|
}
|
|
|
|
// Binary search in restart array to find the first restart point that
|
|
// is either the last restart point with a key less than target,
|
|
// which means the key of next restart point is larger than target, or
|
|
// the first restart point with a key = target
|
|
template <class TValue>
|
|
template <typename DecodeKeyFunc>
|
|
bool BlockIter<TValue>::BinarySeek(const Slice& target, uint32_t left,
|
|
uint32_t right, uint32_t* index,
|
|
const Comparator* comp) {
|
|
assert(left <= right);
|
|
|
|
while (left < right) {
|
|
uint32_t mid = (left + right + 1) / 2;
|
|
uint32_t region_offset = GetRestartPoint(mid);
|
|
uint32_t shared, non_shared;
|
|
const char* key_ptr = DecodeKeyFunc()(
|
|
data_ + region_offset, data_ + restarts_, &shared, &non_shared);
|
|
if (key_ptr == nullptr || (shared != 0)) {
|
|
CorruptionError();
|
|
return false;
|
|
}
|
|
Slice mid_key(key_ptr, non_shared);
|
|
int cmp = comp->Compare(mid_key, target);
|
|
if (cmp < 0) {
|
|
// Key at "mid" is smaller than "target". Therefore all
|
|
// blocks before "mid" are uninteresting.
|
|
left = mid;
|
|
} else if (cmp > 0) {
|
|
// Key at "mid" is >= "target". Therefore all blocks at or
|
|
// after "mid" are uninteresting.
|
|
right = mid - 1;
|
|
} else {
|
|
left = right = mid;
|
|
}
|
|
}
|
|
|
|
*index = left;
|
|
return true;
|
|
}
|
|
|
|
// Compare target key and the block key of the block of `block_index`.
|
|
// Return -1 if error.
|
|
int IndexBlockIter::CompareBlockKey(uint32_t block_index, const Slice& target) {
|
|
uint32_t region_offset = GetRestartPoint(block_index);
|
|
uint32_t shared, non_shared;
|
|
const char* key_ptr =
|
|
value_delta_encoded_
|
|
? DecodeKeyV4()(data_ + region_offset, data_ + restarts_, &shared,
|
|
&non_shared)
|
|
: DecodeKey()(data_ + region_offset, data_ + restarts_, &shared,
|
|
&non_shared);
|
|
if (key_ptr == nullptr || (shared != 0)) {
|
|
CorruptionError();
|
|
return 1; // Return target is smaller
|
|
}
|
|
Slice block_key(key_ptr, non_shared);
|
|
return Compare(block_key, target);
|
|
}
|
|
|
|
// Binary search in block_ids to find the first block
|
|
// with a key >= target
|
|
bool IndexBlockIter::BinaryBlockIndexSeek(const Slice& target,
|
|
uint32_t* block_ids, uint32_t left,
|
|
uint32_t right, uint32_t* index) {
|
|
assert(left <= right);
|
|
uint32_t left_bound = left;
|
|
|
|
while (left <= right) {
|
|
uint32_t mid = (right + left) / 2;
|
|
|
|
int cmp = CompareBlockKey(block_ids[mid], target);
|
|
if (!status_.ok()) {
|
|
return false;
|
|
}
|
|
if (cmp < 0) {
|
|
// Key at "target" is larger than "mid". Therefore all
|
|
// blocks before or at "mid" are uninteresting.
|
|
left = mid + 1;
|
|
} else {
|
|
// Key at "target" is <= "mid". Therefore all blocks
|
|
// after "mid" are uninteresting.
|
|
// If there is only one block left, we found it.
|
|
if (left == right) break;
|
|
right = mid;
|
|
}
|
|
}
|
|
|
|
if (left == right) {
|
|
// In one of the two following cases:
|
|
// (1) left is the first one of block_ids
|
|
// (2) there is a gap of blocks between block of `left` and `left-1`.
|
|
// we can further distinguish the case of key in the block or key not
|
|
// existing, by comparing the target key and the key of the previous
|
|
// block to the left of the block found.
|
|
if (block_ids[left] > 0 &&
|
|
(left == left_bound || block_ids[left - 1] != block_ids[left] - 1) &&
|
|
CompareBlockKey(block_ids[left] - 1, target) > 0) {
|
|
current_ = restarts_;
|
|
return false;
|
|
}
|
|
|
|
*index = block_ids[left];
|
|
return true;
|
|
} else {
|
|
assert(left > right);
|
|
// Mark iterator invalid
|
|
current_ = restarts_;
|
|
return false;
|
|
}
|
|
}
|
|
|
|
bool IndexBlockIter::PrefixSeek(const Slice& target, uint32_t* index) {
|
|
assert(prefix_index_);
|
|
Slice seek_key = target;
|
|
if (!key_includes_seq_) {
|
|
seek_key = ExtractUserKey(target);
|
|
}
|
|
uint32_t* block_ids = nullptr;
|
|
uint32_t num_blocks = prefix_index_->GetBlocks(target, &block_ids);
|
|
|
|
if (num_blocks == 0) {
|
|
current_ = restarts_;
|
|
return false;
|
|
} else {
|
|
return BinaryBlockIndexSeek(seek_key, block_ids, 0, num_blocks - 1, index);
|
|
}
|
|
}
|
|
|
|
uint32_t Block::NumRestarts() const {
|
|
assert(size_ >= 2*sizeof(uint32_t));
|
|
return DecodeFixed32(data_ + size_ - sizeof(uint32_t));
|
|
}
|
|
|
|
Block::Block(BlockContents&& contents, SequenceNumber _global_seqno,
|
|
size_t read_amp_bytes_per_bit, Statistics* statistics)
|
|
: contents_(std::move(contents)),
|
|
data_(contents_.data.data()),
|
|
size_(contents_.data.size()),
|
|
restart_offset_(0),
|
|
num_restarts_(0),
|
|
global_seqno_(_global_seqno) {
|
|
if (size_ < sizeof(uint32_t)) {
|
|
size_ = 0; // Error marker
|
|
} else {
|
|
// Should only decode restart points for uncompressed blocks
|
|
if (compression_type() == kNoCompression) {
|
|
num_restarts_ = NumRestarts();
|
|
restart_offset_ =
|
|
static_cast<uint32_t>(size_) - (1 + num_restarts_) * sizeof(uint32_t);
|
|
if (restart_offset_ > size_ - sizeof(uint32_t)) {
|
|
// The size is too small for NumRestarts() and therefore
|
|
// restart_offset_ wrapped around.
|
|
size_ = 0;
|
|
}
|
|
}
|
|
}
|
|
if (read_amp_bytes_per_bit != 0 && statistics && size_ != 0) {
|
|
read_amp_bitmap_.reset(new BlockReadAmpBitmap(
|
|
restart_offset_, read_amp_bytes_per_bit, statistics));
|
|
}
|
|
}
|
|
|
|
template <>
|
|
DataBlockIter* Block::NewIterator(const Comparator* cmp, const Comparator* ucmp,
|
|
DataBlockIter* iter, Statistics* stats,
|
|
bool /*total_order_seek*/,
|
|
bool /*key_includes_seq*/,
|
|
bool /*value_is_full*/,
|
|
BlockPrefixIndex* /*prefix_index*/) {
|
|
DataBlockIter* ret_iter;
|
|
if (iter != nullptr) {
|
|
ret_iter = iter;
|
|
} else {
|
|
ret_iter = new DataBlockIter;
|
|
}
|
|
if (size_ < 2 * sizeof(uint32_t)) {
|
|
ret_iter->Invalidate(Status::Corruption("bad block contents"));
|
|
return ret_iter;
|
|
}
|
|
if (num_restarts_ == 0) {
|
|
// Empty block.
|
|
ret_iter->Invalidate(Status::OK());
|
|
return ret_iter;
|
|
} else {
|
|
ret_iter->Initialize(cmp, ucmp, data_, restart_offset_, num_restarts_,
|
|
global_seqno_, read_amp_bitmap_.get(), cachable());
|
|
if (read_amp_bitmap_) {
|
|
if (read_amp_bitmap_->GetStatistics() != stats) {
|
|
// DB changed the Statistics pointer, we need to notify read_amp_bitmap_
|
|
read_amp_bitmap_->SetStatistics(stats);
|
|
}
|
|
}
|
|
}
|
|
|
|
return ret_iter;
|
|
}
|
|
|
|
template <>
|
|
IndexBlockIter* Block::NewIterator(const Comparator* cmp,
|
|
const Comparator* ucmp, IndexBlockIter* iter,
|
|
Statistics* /*stats*/, bool total_order_seek,
|
|
bool key_includes_seq, bool value_is_full,
|
|
BlockPrefixIndex* prefix_index) {
|
|
IndexBlockIter* ret_iter;
|
|
if (iter != nullptr) {
|
|
ret_iter = iter;
|
|
} else {
|
|
ret_iter = new IndexBlockIter;
|
|
}
|
|
if (size_ < 2 * sizeof(uint32_t)) {
|
|
ret_iter->Invalidate(Status::Corruption("bad block contents"));
|
|
return ret_iter;
|
|
}
|
|
if (num_restarts_ == 0) {
|
|
// Empty block.
|
|
ret_iter->Invalidate(Status::OK());
|
|
return ret_iter;
|
|
} else {
|
|
BlockPrefixIndex* prefix_index_ptr =
|
|
total_order_seek ? nullptr : prefix_index;
|
|
ret_iter->Initialize(cmp, ucmp, data_, restart_offset_, num_restarts_,
|
|
prefix_index_ptr, key_includes_seq, value_is_full,
|
|
cachable());
|
|
}
|
|
|
|
return ret_iter;
|
|
}
|
|
|
|
size_t Block::ApproximateMemoryUsage() const {
|
|
size_t usage = usable_size();
|
|
#ifdef ROCKSDB_MALLOC_USABLE_SIZE
|
|
usage += malloc_usable_size((void*)this);
|
|
#else
|
|
usage += sizeof(*this);
|
|
#endif // ROCKSDB_MALLOC_USABLE_SIZE
|
|
if (read_amp_bitmap_) {
|
|
usage += read_amp_bitmap_->ApproximateMemoryUsage();
|
|
}
|
|
return usage;
|
|
}
|
|
|
|
} // namespace rocksdb
|
|
|