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rocksdb/db/dbformat.h

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// 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.
#pragma once
#include <stdio.h>
#include <memory>
#include <optional>
#include <string>
#include <utility>
#include "rocksdb/comparator.h"
#include "rocksdb/slice.h"
#include "rocksdb/slice_transform.h"
#include "rocksdb/types.h"
#include "util/coding.h"
#include "util/user_comparator_wrapper.h"
namespace ROCKSDB_NAMESPACE {
// The file declares data structures and functions that deal with internal
// keys.
// Each internal key contains a user key, a sequence number (SequenceNumber)
// and a type (ValueType), and they are usually encoded together.
// There are some related helper classes here.
class InternalKey;
// Value types encoded as the last component of internal keys.
// DO NOT CHANGE THESE ENUM VALUES: they are embedded in the on-disk
// data structures.
// The highest bit of the value type needs to be reserved to SST tables
// for them to do more flexible encoding.
enum ValueType : unsigned char {
kTypeDeletion = 0x0,
kTypeValue = 0x1,
kTypeMerge = 0x2,
kTypeLogData = 0x3, // WAL only.
kTypeColumnFamilyDeletion = 0x4, // WAL only.
kTypeColumnFamilyValue = 0x5, // WAL only.
kTypeColumnFamilyMerge = 0x6, // WAL only.
kTypeSingleDeletion = 0x7,
kTypeColumnFamilySingleDeletion = 0x8, // WAL only.
kTypeBeginPrepareXID = 0x9, // WAL only.
kTypeEndPrepareXID = 0xA, // WAL only.
kTypeCommitXID = 0xB, // WAL only.
kTypeRollbackXID = 0xC, // WAL only.
kTypeNoop = 0xD, // WAL only.
kTypeColumnFamilyRangeDeletion = 0xE, // WAL only.
kTypeRangeDeletion = 0xF, // meta block
kTypeColumnFamilyBlobIndex = 0x10, // Blob DB only
kTypeBlobIndex = 0x11, // Blob DB only
// When the prepared record is also persisted in db, we use a different
// record. This is to ensure that the WAL that is generated by a WritePolicy
// is not mistakenly read by another, which would result into data
// inconsistency.
kTypeBeginPersistedPrepareXID = 0x12, // WAL only.
// Similar to kTypeBeginPersistedPrepareXID, this is to ensure that WAL
// generated by WriteUnprepared write policy is not mistakenly read by
// another.
kTypeBeginUnprepareXID = 0x13, // WAL only.
kTypeDeletionWithTimestamp = 0x14,
kTypeCommitXIDAndTimestamp = 0x15, // WAL only
kTypeWideColumnEntity = 0x16,
kTypeColumnFamilyWideColumnEntity = 0x17, // WAL only
kTypeValuePreferredSeqno = 0x18, // Value with a unix write time
kTypeColumnFamilyValuePreferredSeqno = 0x19, // WAL only
kTypeMaxValid, // Should be after the last valid type, only used for
// validation
kMaxValue = 0x7F // Not used for storing records.
};
// Defined in dbformat.cc
extern const ValueType kValueTypeForSeek;
extern const ValueType kValueTypeForSeekForPrev;
// A range of user keys used internally by RocksDB. Also see `Range` used by
// public APIs.
struct UserKeyRange {
// In case of user_defined timestamp, if enabled, `start` and `limit` should
// include user_defined timestamps.
Slice start;
Slice limit;
UserKeyRange() = default;
UserKeyRange(const Slice& s, const Slice& l) : start(s), limit(l) {}
};
// A range of user keys used internally by RocksDB. Also see `RangePtr` used by
// public APIs.
struct UserKeyRangePtr {
// In case of user_defined timestamp, if enabled, `start` and `limit` should
// point to key with timestamp part.
// An optional range start, if missing, indicating a start before all keys.
std::optional<Slice> start;
// An optional range end, if missing, indicating an end after all keys.
std::optional<Slice> limit;
UserKeyRangePtr(const std::optional<Slice>& s, const std::optional<Slice>& l)
: start(s), limit(l) {}
};
// Checks whether a type is an inline value type
// (i.e. a type used in memtable skiplist and sst file datablock).
inline bool IsValueType(ValueType t) {
return t <= kTypeMerge || kTypeSingleDeletion == t || kTypeBlobIndex == t ||
kTypeDeletionWithTimestamp == t || kTypeWideColumnEntity == t ||
kTypeValuePreferredSeqno == t;
}
// Checks whether a type is from user operation
// kTypeRangeDeletion is in meta block so this API is separated from above
// kTypeMaxValid can be from keys generated by
// TruncatedRangeDelIterator::start_key()
inline bool IsExtendedValueType(ValueType t) {
return IsValueType(t) || t == kTypeRangeDeletion || t == kTypeMaxValid;
}
// We leave eight bits empty at the bottom so a type and sequence#
// can be packed together into 64-bits.
static const SequenceNumber kMaxSequenceNumber = ((0x1ull << 56) - 1);
static const SequenceNumber kDisableGlobalSequenceNumber =
std::numeric_limits<uint64_t>::max();
constexpr uint64_t kNumInternalBytes = 8;
// Defined in dbformat.cc
extern const std::string kDisableUserTimestamp;
// The data structure that represents an internal key in the way that user_key,
// sequence number and type are stored in separated forms.
struct ParsedInternalKey {
Slice user_key;
SequenceNumber sequence;
ValueType type;
ParsedInternalKey()
: sequence(kMaxSequenceNumber),
type(kTypeDeletion) // Make code analyzer happy
{} // Intentionally left uninitialized (for speed)
// u contains timestamp if user timestamp feature is enabled.
ParsedInternalKey(const Slice& u, const SequenceNumber& seq, ValueType t)
: user_key(u), sequence(seq), type(t) {}
std::string DebugString(bool log_err_key, bool hex,
const Comparator* ucmp = nullptr) const;
void clear() {
user_key.clear();
sequence = 0;
type = kTypeDeletion;
}
void SetTimestamp(const Slice& ts) {
assert(ts.size() <= user_key.size());
const char* addr = user_key.data() + user_key.size() - ts.size();
memcpy(const_cast<char*>(addr), ts.data(), ts.size());
}
Slice GetTimestamp(size_t ts_sz) {
assert(ts_sz <= user_key.size());
const char* addr = user_key.data() + user_key.size() - ts_sz;
return Slice(const_cast<char*>(addr), ts_sz);
}
};
// Return the length of the encoding of "key".
inline size_t InternalKeyEncodingLength(const ParsedInternalKey& key) {
return key.user_key.size() + kNumInternalBytes;
}
// Pack a sequence number and a ValueType into a uint64_t
inline uint64_t PackSequenceAndType(uint64_t seq, ValueType t) {
assert(seq <= kMaxSequenceNumber);
// kTypeMaxValid is used in TruncatedRangeDelIterator, see its constructor.
assert(IsExtendedValueType(t) || t == kTypeMaxValid);
return (seq << 8) | t;
}
// Given the result of PackSequenceAndType, store the sequence number in *seq
// and the ValueType in *t.
inline void UnPackSequenceAndType(uint64_t packed, uint64_t* seq,
ValueType* t) {
*seq = packed >> 8;
*t = static_cast<ValueType>(packed & 0xff);
// Commented the following two assertions in order to test key-value checksum
// on corrupted keys without crashing ("DbKvChecksumTest").
// assert(*seq <= kMaxSequenceNumber);
// assert(IsExtendedValueType(*t));
}
const uint64_t kRangeTombstoneSentinel =
PackSequenceAndType(kMaxSequenceNumber, kTypeRangeDeletion);
EntryType GetEntryType(ValueType value_type);
// Append the serialization of "key" to *result.
//
// input [internal key]: <user_key | seqno + type>
// output before: empty
// output: <user_key | seqno + type>
void AppendInternalKey(std::string* result, const ParsedInternalKey& key);
// Append the serialization of "key" to *result, replacing the original
// timestamp with argument ts.
//
// input [internal key]: <user_provided_key | original_ts | seqno + type>
// output before: empty
// output after: <user_provided_key | ts | seqno + type>
void AppendInternalKeyWithDifferentTimestamp(std::string* result,
const ParsedInternalKey& key,
const Slice& ts);
// Append the user key to *result, replacing the original timestamp with
// argument ts.
//
// input [user key]: <user_provided_key | original_ts>
// output before: empty
// output after: <user_provided_key | ts>
void AppendUserKeyWithDifferentTimestamp(std::string* result, const Slice& key,
const Slice& ts);
// Serialized internal key consists of user key followed by footer.
// This function appends the footer to *result, assuming that *result already
// contains the user key at the end.
//
// output before: <user_key>
// output after: <user_key | seqno + type>
void AppendInternalKeyFooter(std::string* result, SequenceNumber s,
ValueType t);
// Append the key and a minimal timestamp to *result
//
// input [user key without ts]: <user_provided_key>
// output before: empty
// output after: <user_provided_key | min_ts>
void AppendKeyWithMinTimestamp(std::string* result, const Slice& key,
size_t ts_sz);
// Append the key and a maximal timestamp to *result
//
// input [user key without ts]: <user_provided_key>
// output before: empty
// output after: <user_provided_key | max_ts>
void AppendKeyWithMaxTimestamp(std::string* result, const Slice& key,
size_t ts_sz);
// `key` is a user key with timestamp. Append the user key without timestamp
// and the minimum timestamp to *result.
//
// input [user key]: <user_provided_key | original_ts>
// output before: empty
// output after: <user_provided_key | min_ts>
void AppendUserKeyWithMinTimestamp(std::string* result, const Slice& key,
size_t ts_sz);
// `key` is a user key with timestamp. Append the user key without timestamp
// and the maximal timestamp to *result.
//
// input [user key]: <user_provided_key | original_ts>
// output before: empty
// output after: <user_provided_key | max_ts>
void AppendUserKeyWithMaxTimestamp(std::string* result, const Slice& key,
size_t ts_sz);
// `key` is an internal key containing a user key without timestamp. Create a
// new key in *result by padding a min timestamp of size `ts_sz` to the user key
// and copying the remaining internal key bytes.
//
// input [internal key]: <user_provided_key | seqno + type>
// output before: empty
// output after: <user_provided_key | min_ts | seqno + type>
void PadInternalKeyWithMinTimestamp(std::string* result, const Slice& key,
size_t ts_sz);
// `key` is an internal key containing a user key without timestamp. Create a
// new key in *result by padding a max timestamp of size `ts_sz` to the user key
// and copying the remaining internal key bytes.
//
// input [internal key]: <user_provided_key | seqno + type>
// output before: empty
// output after: <user_provided_key | max_ts | seqno + type>
void PadInternalKeyWithMaxTimestamp(std::string* result, const Slice& key,
size_t ts_sz);
// `key` is an internal key containing a user key with timestamp of size
// `ts_sz`. Create a new internal key in *result by stripping the timestamp from
// the user key and copying the remaining internal key bytes.
//
// input [internal key]: <user_provided_key | original_ts | seqno + type>
// output before: empty
// output after: <user_provided_key | seqno + type>
void StripTimestampFromInternalKey(std::string* result, const Slice& key,
size_t ts_sz);
// `key` is an internal key containing a user key with timestamp of size
// `ts_sz`. Create a new internal key in *result while replace the original
// timestamp with min timestamp.
//
// input [internal key]: <user_provided_key | original_ts | seqno + type>
// output before: empty
// output after: <user_provided_key | min_ts | seqno + type>
void ReplaceInternalKeyWithMinTimestamp(std::string* result, const Slice& key,
size_t ts_sz);
// Attempt to parse an internal key from "internal_key". On success,
// stores the parsed data in "*result", and returns true.
//
// On error, returns false, leaves "*result" in an undefined state.
Status ParseInternalKey(const Slice& internal_key, ParsedInternalKey* result,
bool log_err_key);
// Returns the user key portion of an internal key.
//
// input [internal key]: <user_key | seqno + type>
// output: <user_key>
inline Slice ExtractUserKey(const Slice& internal_key) {
assert(internal_key.size() >= kNumInternalBytes);
return Slice(internal_key.data(), internal_key.size() - kNumInternalBytes);
}
// input [internal key]: <user_provided_key | ts | seqno + type>
// output : <user_provided_key>
inline Slice ExtractUserKeyAndStripTimestamp(const Slice& internal_key,
size_t ts_sz) {
Slice ret = internal_key;
ret.remove_suffix(kNumInternalBytes + ts_sz);
return ret;
}
// input [user key]: <user_provided_key | ts>
// output: <user_provided_key>
inline Slice StripTimestampFromUserKey(const Slice& user_key, size_t ts_sz) {
Slice ret = user_key;
ret.remove_suffix(ts_sz);
return ret;
}
// input [user key]: <user_provided_key | ts>
// output: <ts>
inline Slice ExtractTimestampFromUserKey(const Slice& user_key, size_t ts_sz) {
assert(user_key.size() >= ts_sz);
return Slice(user_key.data() + user_key.size() - ts_sz, ts_sz);
}
// input [internal key]: <user_provided_key | ts | seqno + type>
// output: <ts>
inline Slice ExtractTimestampFromKey(const Slice& internal_key, size_t ts_sz) {
const size_t key_size = internal_key.size();
assert(key_size >= kNumInternalBytes + ts_sz);
return Slice(internal_key.data() + key_size - ts_sz - kNumInternalBytes,
ts_sz);
}
// input [internal key]: <user_provided_key | ts | seqno + type>
// output: <seqno + type>
inline uint64_t ExtractInternalKeyFooter(const Slice& internal_key) {
assert(internal_key.size() >= kNumInternalBytes);
const size_t n = internal_key.size();
return DecodeFixed64(internal_key.data() + n - kNumInternalBytes);
}
// input [internal key]: <user_provided_key | ts | seqno + type>
// output: <type>
inline ValueType ExtractValueType(const Slice& internal_key) {
uint64_t num = ExtractInternalKeyFooter(internal_key);
unsigned char c = num & 0xff;
return static_cast<ValueType>(c);
}
// A comparator for internal keys that uses a specified comparator for
// the user key portion and breaks ties by decreasing sequence number.
class InternalKeyComparator
#ifdef NDEBUG
final
#endif
: public CompareInterface {
private:
UserComparatorWrapper user_comparator_;
public:
// `InternalKeyComparator`s constructed with the default constructor are not
// usable and will segfault on any attempt to use them for comparisons.
InternalKeyComparator() = default;
// @param named If true, assign a name to this comparator based on the
// underlying comparator's name. This involves an allocation and copy in
// this constructor to precompute the result of `Name()`. To avoid this
// overhead, set `named` to false. In that case, `Name()` will return a
// generic name that is non-specific to the underlying comparator.
explicit InternalKeyComparator(const Comparator* c) : user_comparator_(c) {}
virtual ~InternalKeyComparator() {}
int Compare(const Slice& a, const Slice& b) const override;
bool Equal(const Slice& a, const Slice& b) const {
// TODO Use user_comparator_.Equal(). Perhaps compare seqno before
// comparing the user key too.
return Compare(a, b) == 0;
}
// Same as Compare except that it excludes the value type from comparison
int CompareKeySeq(const Slice& a, const Slice& b) const;
int CompareKeySeq(const ParsedInternalKey& a, const Slice& b) const;
const Comparator* user_comparator() const {
return user_comparator_.user_comparator();
}
int Compare(const InternalKey& a, const InternalKey& b) const;
int Compare(const ParsedInternalKey& a, const ParsedInternalKey& b) const;
int Compare(const Slice& a, const ParsedInternalKey& b) const;
int Compare(const ParsedInternalKey& a, const Slice& b) const;
// In this `Compare()` overload, the sequence numbers provided in
// `a_global_seqno` and `b_global_seqno` override the sequence numbers in `a`
// and `b`, respectively. To disable sequence number override(s), provide the
// value `kDisableGlobalSequenceNumber`.
int Compare(const Slice& a, SequenceNumber a_global_seqno, const Slice& b,
SequenceNumber b_global_seqno) const;
};
// The class represent the internal key in encoded form.
class InternalKey {
private:
std::string rep_;
public:
InternalKey() {} // Leave rep_ as empty to indicate it is invalid
InternalKey(const Slice& _user_key, SequenceNumber s, ValueType t) {
AppendInternalKey(&rep_, ParsedInternalKey(_user_key, s, t));
}
InternalKey(const Slice& _user_key, SequenceNumber s, ValueType t, Slice ts) {
AppendInternalKeyWithDifferentTimestamp(
&rep_, ParsedInternalKey(_user_key, s, t), ts);
}
// sets the internal key to be bigger or equal to all internal keys with this
// user key
void SetMaxPossibleForUserKey(const Slice& _user_key) {
AppendInternalKey(
&rep_, ParsedInternalKey(_user_key, 0, static_cast<ValueType>(0)));
}
// sets the internal key to be smaller or equal to all internal keys with this
// user key
void SetMinPossibleForUserKey(const Slice& _user_key) {
AppendInternalKey(&rep_, ParsedInternalKey(_user_key, kMaxSequenceNumber,
kValueTypeForSeek));
}
bool Valid() const {
ParsedInternalKey parsed;
return (ParseInternalKey(Slice(rep_), &parsed, false /* log_err_key */)
.ok()); // TODO
}
void DecodeFrom(const Slice& s) { rep_.assign(s.data(), s.size()); }
Slice Encode() const {
assert(!rep_.empty());
return rep_;
}
Slice user_key() const { return ExtractUserKey(rep_); }
size_t size() const { return rep_.size(); }
void Set(const Slice& _user_key, SequenceNumber s, ValueType t) {
SetFrom(ParsedInternalKey(_user_key, s, t));
}
void Set(const Slice& _user_key_with_ts, SequenceNumber s, ValueType t,
const Slice& ts) {
ParsedInternalKey pik(_user_key_with_ts, s, t);
// Should not call pik.SetTimestamp() directly as it overwrites the buffer
// containing _user_key.
SetFrom(pik, ts);
}
void SetFrom(const ParsedInternalKey& p) {
rep_.clear();
AppendInternalKey(&rep_, p);
}
void SetFrom(const ParsedInternalKey& p, const Slice& ts) {
rep_.clear();
AppendInternalKeyWithDifferentTimestamp(&rep_, p, ts);
}
void Clear() { rep_.clear(); }
// The underlying representation.
// Intended only to be used together with ConvertFromUserKey().
std::string* rep() { return &rep_; }
// Assuming that *rep() contains a user key, this method makes internal key
// out of it in-place. This saves a memcpy compared to Set()/SetFrom().
void ConvertFromUserKey(SequenceNumber s, ValueType t) {
AppendInternalKeyFooter(&rep_, s, t);
}
std::string DebugString(bool hex, const Comparator* ucmp = nullptr) const;
};
inline int InternalKeyComparator::Compare(const InternalKey& a,
const InternalKey& b) const {
return Compare(a.Encode(), b.Encode());
}
inline Status ParseInternalKey(const Slice& internal_key,
ParsedInternalKey* result, bool log_err_key) {
const size_t n = internal_key.size();
if (n < kNumInternalBytes) {
return Status::Corruption("Corrupted Key: Internal Key too small. Size=" +
std::to_string(n) + ". ");
}
uint64_t num = DecodeFixed64(internal_key.data() + n - kNumInternalBytes);
unsigned char c = num & 0xff;
result->sequence = num >> 8;
result->type = static_cast<ValueType>(c);
assert(result->type <= ValueType::kMaxValue);
result->user_key = Slice(internal_key.data(), n - kNumInternalBytes);
if (IsExtendedValueType(result->type)) {
return Status::OK();
} else {
return Status::Corruption("Corrupted Key",
result->DebugString(log_err_key, true));
}
}
// Update the sequence number in the internal key.
// Guarantees not to invalidate ikey.data().
inline void UpdateInternalKey(std::string* ikey, uint64_t seq, ValueType t) {
size_t ikey_sz = ikey->size();
assert(ikey_sz >= kNumInternalBytes);
uint64_t newval = (seq << 8) | t;
// Note: Since C++11, strings are guaranteed to be stored contiguously and
// string::operator[]() is guaranteed not to change ikey.data().
EncodeFixed64(&(*ikey)[ikey_sz - kNumInternalBytes], newval);
}
// Get the sequence number from the internal key
inline uint64_t GetInternalKeySeqno(const Slice& internal_key) {
const size_t n = internal_key.size();
assert(n >= kNumInternalBytes);
uint64_t num = DecodeFixed64(internal_key.data() + n - kNumInternalBytes);
return num >> 8;
}
// The class to store keys in an efficient way. It allows:
// 1. Users can either copy the key into it, or have it point to an unowned
// address.
// 2. For copied key, a short inline buffer is kept to reduce memory
// allocation for smaller keys.
// 3. It tracks user key or internal key, and allow conversion between them.
class IterKey {
public:
IterKey()
: buf_(space_),
key_(buf_),
key_size_(0),
buf_size_(sizeof(space_)),
is_user_key_(true) {}
// No copying allowed
IterKey(const IterKey&) = delete;
void operator=(const IterKey&) = delete;
~IterKey() { ResetBuffer(); }
// The bool will be picked up by the next calls to SetKey
void SetIsUserKey(bool is_user_key) { is_user_key_ = is_user_key; }
// Returns the key in whichever format that was provided to KeyIter
// If user-defined timestamp is enabled, then timestamp is included in the
// return result.
Slice GetKey() const { return Slice(key_, key_size_); }
Slice GetInternalKey() const {
assert(!IsUserKey());
return Slice(key_, key_size_);
}
// If user-defined timestamp is enabled, then timestamp is included in the
// return result of GetUserKey();
Slice GetUserKey() const {
if (IsUserKey()) {
return Slice(key_, key_size_);
} else {
assert(key_size_ >= kNumInternalBytes);
return Slice(key_, key_size_ - kNumInternalBytes);
}
}
size_t Size() const { return key_size_; }
void Clear() { key_size_ = 0; }
// Append "non_shared_data" to its back, from "shared_len"
// This function is used in Block::Iter::ParseNextKey
// shared_len: bytes in [0, shard_len-1] would be remained
// non_shared_data: data to be append, its length must be >= non_shared_len
void TrimAppend(const size_t shared_len, const char* non_shared_data,
const size_t non_shared_len) {
assert(shared_len <= key_size_);
size_t total_size = shared_len + non_shared_len;
if (IsKeyPinned() /* key is not in buf_ */) {
// Copy the key from external memory to buf_ (copy shared_len bytes)
EnlargeBufferIfNeeded(total_size);
memcpy(buf_, key_, shared_len);
} else if (total_size > buf_size_) {
// Need to allocate space, delete previous space
char* p = new char[total_size];
memcpy(p, key_, shared_len);
if (buf_ != space_) {
delete[] buf_;
}
buf_ = p;
buf_size_ = total_size;
}
memcpy(buf_ + shared_len, non_shared_data, non_shared_len);
key_ = buf_;
key_size_ = total_size;
}
// A version of `TrimAppend` assuming the last bytes of length `ts_sz` in the
// user key part of `key_` is not counted towards shared bytes. And the
// decoded key needed a min timestamp of length `ts_sz` pad to the user key.
void TrimAppendWithTimestamp(const size_t shared_len,
const char* non_shared_data,
const size_t non_shared_len,
const size_t ts_sz) {
std::string kTsMin(ts_sz, static_cast<unsigned char>(0));
std::string key_with_ts;
std::vector<Slice> key_parts_with_ts;
if (IsUserKey()) {
key_parts_with_ts = {Slice(key_, shared_len),
Slice(non_shared_data, non_shared_len),
Slice(kTsMin)};
} else {
assert(shared_len + non_shared_len >= kNumInternalBytes);
// Invaraint: shared_user_key_len + shared_internal_bytes_len = shared_len
// In naming below `*_len` variables, keyword `user_key` refers to the
// user key part of the existing key in `key_` as apposed to the new key.
// Similary, `internal_bytes` refers to the footer part of the existing
// key. These bytes potentially will move between user key part and the
// footer part in the new key.
const size_t user_key_len = key_size_ - kNumInternalBytes;
const size_t sharable_user_key_len = user_key_len - ts_sz;
const size_t shared_user_key_len =
std::min(shared_len, sharable_user_key_len);
const size_t shared_internal_bytes_len = shared_len - shared_user_key_len;
// One Slice among the three Slices will get split into two Slices, plus
// a timestamp slice.
key_parts_with_ts.reserve(5);
bool ts_added = false;
// Add slice parts and find the right location to add the min timestamp.
MaybeAddKeyPartsWithTimestamp(
key_, shared_user_key_len,
shared_internal_bytes_len + non_shared_len < kNumInternalBytes,
shared_len + non_shared_len - kNumInternalBytes, kTsMin,
key_parts_with_ts, &ts_added);
MaybeAddKeyPartsWithTimestamp(
key_ + user_key_len, shared_internal_bytes_len,
non_shared_len < kNumInternalBytes,
shared_internal_bytes_len + non_shared_len - kNumInternalBytes,
kTsMin, key_parts_with_ts, &ts_added);
MaybeAddKeyPartsWithTimestamp(non_shared_data, non_shared_len,
non_shared_len >= kNumInternalBytes,
non_shared_len - kNumInternalBytes, kTsMin,
key_parts_with_ts, &ts_added);
assert(ts_added);
}
Slice new_key(SliceParts(&key_parts_with_ts.front(),
static_cast<int>(key_parts_with_ts.size())),
&key_with_ts);
SetKey(new_key);
}
Slice SetKey(const Slice& key, bool copy = true) {
// is_user_key_ expected to be set already via SetIsUserKey
return SetKeyImpl(key, copy);
}
// If user-defined timestamp is enabled, then `key` includes timestamp.
// TODO(yanqin) this is also used to set prefix, which do not include
// timestamp. Should be handled.
Slice SetUserKey(const Slice& key, bool copy = true) {
is_user_key_ = true;
return SetKeyImpl(key, copy);
}
Slice SetInternalKey(const Slice& key, bool copy = true) {
is_user_key_ = false;
return SetKeyImpl(key, copy);
}
// Copies the content of key, updates the reference to the user key in ikey
// and returns a Slice referencing the new copy.
Slice SetInternalKey(const Slice& key, ParsedInternalKey* ikey) {
size_t key_n = key.size();
assert(key_n >= kNumInternalBytes);
SetInternalKey(key);
ikey->user_key = Slice(key_, key_n - kNumInternalBytes);
return Slice(key_, key_n);
}
// Copy the key into IterKey own buf_
void OwnKey() {
assert(IsKeyPinned() == true);
Reserve(key_size_);
memcpy(buf_, key_, key_size_);
key_ = buf_;
}
// Update the sequence number in the internal key. Guarantees not to
// invalidate slices to the key (and the user key).
void UpdateInternalKey(uint64_t seq, ValueType t, const Slice* ts = nullptr) {
assert(!IsKeyPinned());
assert(key_size_ >= kNumInternalBytes);
if (ts) {
assert(key_size_ >= kNumInternalBytes + ts->size());
memcpy(&buf_[key_size_ - kNumInternalBytes - ts->size()], ts->data(),
ts->size());
}
uint64_t newval = (seq << 8) | t;
EncodeFixed64(&buf_[key_size_ - kNumInternalBytes], newval);
}
bool IsKeyPinned() const { return (key_ != buf_); }
// If `ts` is provided, user_key should not contain timestamp,
// and `ts` is appended after user_key.
// TODO: more efficient storage for timestamp.
void SetInternalKey(const Slice& key_prefix, const Slice& user_key,
SequenceNumber s,
ValueType value_type = kValueTypeForSeek,
const Slice* ts = nullptr) {
size_t psize = key_prefix.size();
size_t usize = user_key.size();
size_t ts_sz = (ts != nullptr ? ts->size() : 0);
EnlargeBufferIfNeeded(psize + usize + sizeof(uint64_t) + ts_sz);
if (psize > 0) {
memcpy(buf_, key_prefix.data(), psize);
}
memcpy(buf_ + psize, user_key.data(), usize);
if (ts) {
memcpy(buf_ + psize + usize, ts->data(), ts_sz);
}
EncodeFixed64(buf_ + usize + psize + ts_sz,
PackSequenceAndType(s, value_type));
key_ = buf_;
key_size_ = psize + usize + sizeof(uint64_t) + ts_sz;
is_user_key_ = false;
}
void SetInternalKey(const Slice& user_key, SequenceNumber s,
ValueType value_type = kValueTypeForSeek,
const Slice* ts = nullptr) {
SetInternalKey(Slice(), user_key, s, value_type, ts);
}
void Reserve(size_t size) {
EnlargeBufferIfNeeded(size);
key_size_ = size;
}
void SetInternalKey(const ParsedInternalKey& parsed_key) {
SetInternalKey(Slice(), parsed_key);
}
void SetInternalKey(const Slice& key_prefix,
const ParsedInternalKey& parsed_key_suffix) {
SetInternalKey(key_prefix, parsed_key_suffix.user_key,
parsed_key_suffix.sequence, parsed_key_suffix.type);
}
void EncodeLengthPrefixedKey(const Slice& key) {
auto size = key.size();
EnlargeBufferIfNeeded(size + static_cast<size_t>(VarintLength(size)));
char* ptr = EncodeVarint32(buf_, static_cast<uint32_t>(size));
memcpy(ptr, key.data(), size);
key_ = buf_;
is_user_key_ = true;
}
bool IsUserKey() const { return is_user_key_; }
private:
char* buf_;
const char* key_;
size_t key_size_;
size_t buf_size_;
char space_[39]; // Avoid allocation for short keys
bool is_user_key_;
Slice SetKeyImpl(const Slice& key, bool copy) {
size_t size = key.size();
if (copy) {
// Copy key to buf_
EnlargeBufferIfNeeded(size);
memcpy(buf_, key.data(), size);
key_ = buf_;
} else {
// Update key_ to point to external memory
key_ = key.data();
}
key_size_ = size;
return Slice(key_, key_size_);
}
void ResetBuffer() {
if (buf_ != space_) {
delete[] buf_;
buf_ = space_;
}
buf_size_ = sizeof(space_);
key_size_ = 0;
}
// Enlarge the buffer size if needed based on key_size.
// By default, static allocated buffer is used. Once there is a key
// larger than the static allocated buffer, another buffer is dynamically
// allocated, until a larger key buffer is requested. In that case, we
// reallocate buffer and delete the old one.
void EnlargeBufferIfNeeded(size_t key_size) {
// If size is smaller than buffer size, continue using current buffer,
// or the static allocated one, as default
if (key_size > buf_size_) {
EnlargeBuffer(key_size);
}
}
void EnlargeBuffer(size_t key_size);
void MaybeAddKeyPartsWithTimestamp(const char* slice_data,
const size_t slice_sz, bool add_timestamp,
const size_t left_sz,
const std::string& min_timestamp,
std::vector<Slice>& key_parts,
bool* ts_added) {
if (add_timestamp && !*ts_added) {
assert(slice_sz >= left_sz);
key_parts.emplace_back(slice_data, left_sz);
key_parts.emplace_back(min_timestamp);
key_parts.emplace_back(slice_data + left_sz, slice_sz - left_sz);
*ts_added = true;
} else {
key_parts.emplace_back(slice_data, slice_sz);
}
}
};
// Convert from a SliceTransform of user keys, to a SliceTransform of
// internal keys.
class InternalKeySliceTransform : public SliceTransform {
public:
explicit InternalKeySliceTransform(const SliceTransform* transform)
: transform_(transform) {}
const char* Name() const override { return transform_->Name(); }
Slice Transform(const Slice& src) const override {
auto user_key = ExtractUserKey(src);
return transform_->Transform(user_key);
}
bool InDomain(const Slice& src) const override {
auto user_key = ExtractUserKey(src);
return transform_->InDomain(user_key);
}
bool InRange(const Slice& dst) const override {
auto user_key = ExtractUserKey(dst);
return transform_->InRange(user_key);
}
const SliceTransform* user_prefix_extractor() const { return transform_; }
private:
// Like comparator, InternalKeySliceTransform will not take care of the
// deletion of transform_
const SliceTransform* const transform_;
};
// Read the key of a record from a write batch.
// if this record represent the default column family then cf_record
// must be passed as false, otherwise it must be passed as true.
bool ReadKeyFromWriteBatchEntry(Slice* input, Slice* key, bool cf_record);
// Read record from a write batch piece from input.
// tag, column_family, key, value and blob are return values. Callers own the
// slice they point to.
// Tag is defined as ValueType.
// input will be advanced to after the record.
// If user-defined timestamp is enabled for a column family, then the `key`
// resulting from this call will include timestamp.
Status ReadRecordFromWriteBatch(Slice* input, char* tag,
uint32_t* column_family, Slice* key,
Slice* value, Slice* blob, Slice* xid,
uint64_t* write_unix_time);
// When user call DeleteRange() to delete a range of keys,
// we will store a serialized RangeTombstone in MemTable and SST.
// the struct here is an easy-understood form
// start/end_key_ is the start/end user key of the range to be deleted
struct RangeTombstone {
Slice start_key_;
Slice end_key_;
SequenceNumber seq_;
// TODO: we should optimize the storage here when user-defined timestamp
// is NOT enabled: they currently take up (16 + 32 + 32) bytes per tombstone.
Slice ts_;
std::string pinned_start_key_;
std::string pinned_end_key_;
RangeTombstone() = default;
RangeTombstone(Slice sk, Slice ek, SequenceNumber sn)
: start_key_(sk), end_key_(ek), seq_(sn) {}
// User-defined timestamp is enabled, `sk` and `ek` should be user key
// with timestamp, `ts` will replace the timestamps in `sk` and
// `ek`.
// When `logical_strip_timestamp` is true, the timestamps in `sk` and `ek`
// will be replaced with min timestamp.
RangeTombstone(Slice sk, Slice ek, SequenceNumber sn, Slice ts,
bool logical_strip_timestamp)
: seq_(sn) {
const size_t ts_sz = ts.size();
assert(ts_sz > 0);
pinned_start_key_.reserve(sk.size());
pinned_end_key_.reserve(ek.size());
if (logical_strip_timestamp) {
AppendUserKeyWithMinTimestamp(&pinned_start_key_, sk, ts_sz);
AppendUserKeyWithMinTimestamp(&pinned_end_key_, ek, ts_sz);
} else {
AppendUserKeyWithDifferentTimestamp(&pinned_start_key_, sk, ts);
AppendUserKeyWithDifferentTimestamp(&pinned_end_key_, ek, ts);
}
start_key_ = pinned_start_key_;
end_key_ = pinned_end_key_;
ts_ = Slice(pinned_start_key_.data() + sk.size() - ts_sz, ts_sz);
}
RangeTombstone(ParsedInternalKey parsed_key, Slice value) {
start_key_ = parsed_key.user_key;
seq_ = parsed_key.sequence;
end_key_ = value;
}
// be careful to use Serialize(), allocates new memory
std::pair<InternalKey, Slice> Serialize() const {
auto key = InternalKey(start_key_, seq_, kTypeRangeDeletion);
return std::make_pair(std::move(key), end_key_);
}
// be careful to use SerializeKey(), allocates new memory
InternalKey SerializeKey() const {
return InternalKey(start_key_, seq_, kTypeRangeDeletion);
}
// The tombstone end-key is exclusive, so we generate an internal-key here
// which has a similar property. Using kMaxSequenceNumber guarantees that
// the returned internal-key will compare less than any other internal-key
// with the same user-key. This in turn guarantees that the serialized
// end-key for a tombstone such as [a-b] will compare less than the key "b".
//
// be careful to use SerializeEndKey(), allocates new memory
InternalKey SerializeEndKey() const {
if (!ts_.empty()) {
static constexpr char kTsMax[] = "\xff\xff\xff\xff\xff\xff\xff\xff\xff";
if (ts_.size() <= strlen(kTsMax)) {
return InternalKey(end_key_, kMaxSequenceNumber, kTypeRangeDeletion,
Slice(kTsMax, ts_.size()));
} else {
return InternalKey(end_key_, kMaxSequenceNumber, kTypeRangeDeletion,
std::string(ts_.size(), '\xff'));
}
}
return InternalKey(end_key_, kMaxSequenceNumber, kTypeRangeDeletion);
}
};
inline int InternalKeyComparator::Compare(const Slice& akey,
const Slice& bkey) const {
// Order by:
// increasing user key (according to user-supplied comparator)
// decreasing sequence number
// decreasing type (though sequence# should be enough to disambiguate)
int r = user_comparator_.Compare(ExtractUserKey(akey), ExtractUserKey(bkey));
if (r == 0) {
const uint64_t anum =
DecodeFixed64(akey.data() + akey.size() - kNumInternalBytes);
const uint64_t bnum =
DecodeFixed64(bkey.data() + bkey.size() - kNumInternalBytes);
if (anum > bnum) {
r = -1;
} else if (anum < bnum) {
r = +1;
}
}
return r;
}
inline int InternalKeyComparator::CompareKeySeq(const Slice& akey,
const Slice& bkey) const {
// Order by:
// increasing user key (according to user-supplied comparator)
// decreasing sequence number
int r = user_comparator_.Compare(ExtractUserKey(akey), ExtractUserKey(bkey));
if (r == 0) {
// Shift the number to exclude the last byte which contains the value type
const uint64_t anum =
DecodeFixed64(akey.data() + akey.size() - kNumInternalBytes) >> 8;
const uint64_t bnum =
DecodeFixed64(bkey.data() + bkey.size() - kNumInternalBytes) >> 8;
if (anum > bnum) {
r = -1;
} else if (anum < bnum) {
r = +1;
}
}
return r;
}
inline int InternalKeyComparator::CompareKeySeq(const ParsedInternalKey& a,
const Slice& b) const {
// Order by:
// increasing user key (according to user-supplied comparator)
// decreasing sequence number
int r = user_comparator_.Compare(a.user_key, ExtractUserKey(b));
if (r == 0) {
// Shift the number to exclude the last byte which contains the value type
const uint64_t anum = a.sequence;
const uint64_t bnum =
DecodeFixed64(b.data() + b.size() - kNumInternalBytes) >> 8;
if (anum > bnum) {
r = -1;
} else if (anum < bnum) {
r = +1;
}
}
return r;
}
inline int InternalKeyComparator::Compare(const Slice& a,
SequenceNumber a_global_seqno,
const Slice& b,
SequenceNumber b_global_seqno) const {
int r = user_comparator_.Compare(ExtractUserKey(a), ExtractUserKey(b));
if (r == 0) {
uint64_t a_footer, b_footer;
if (a_global_seqno == kDisableGlobalSequenceNumber) {
a_footer = ExtractInternalKeyFooter(a);
} else {
a_footer = PackSequenceAndType(a_global_seqno, ExtractValueType(a));
}
if (b_global_seqno == kDisableGlobalSequenceNumber) {
b_footer = ExtractInternalKeyFooter(b);
} else {
b_footer = PackSequenceAndType(b_global_seqno, ExtractValueType(b));
}
if (a_footer > b_footer) {
r = -1;
} else if (a_footer < b_footer) {
r = +1;
}
}
return r;
}
// Wrap InternalKeyComparator as a comparator class for ParsedInternalKey.
struct ParsedInternalKeyComparator {
explicit ParsedInternalKeyComparator(const InternalKeyComparator* c)
: cmp(c) {}
bool operator()(const ParsedInternalKey& a,
const ParsedInternalKey& b) const {
return cmp->Compare(a, b) < 0;
}
const InternalKeyComparator* cmp;
};
} // namespace ROCKSDB_NAMESPACE
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