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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 18:24:20 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 18:24:20 +0000 |
commit | 483eb2f56657e8e7f419ab1a4fab8dce9ade8609 (patch) | |
tree | e5d88d25d870d5dedacb6bbdbe2a966086a0a5cf /src/rocksdb/db/dbformat.h | |
parent | Initial commit. (diff) | |
download | ceph-upstream.tar.xz ceph-upstream.zip |
Adding upstream version 14.2.21.upstream/14.2.21upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | src/rocksdb/db/dbformat.h | 689 |
1 files changed, 689 insertions, 0 deletions
diff --git a/src/rocksdb/db/dbformat.h b/src/rocksdb/db/dbformat.h new file mode 100644 index 00000000..7a5ddc1a --- /dev/null +++ b/src/rocksdb/db/dbformat.h @@ -0,0 +1,689 @@ +// 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 <string> +#include <utility> +#include "monitoring/perf_context_imp.h" +#include "rocksdb/comparator.h" +#include "rocksdb/db.h" +#include "rocksdb/filter_policy.h" +#include "rocksdb/slice.h" +#include "rocksdb/slice_transform.h" +#include "rocksdb/table.h" +#include "rocksdb/types.h" +#include "util/coding.h" +#include "util/logging.h" +#include "util/user_comparator_wrapper.h" + +namespace rocksdb { + +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. + kMaxValue = 0x7F // Not used for storing records. +}; + +// Defined in dbformat.cc +extern const ValueType kValueTypeForSeek; +extern const ValueType kValueTypeForSeekForPrev; + +// 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 || t == kTypeSingleDeletion || t == kTypeBlobIndex; +} + +// Checks whether a type is from user operation +// kTypeRangeDeletion is in meta block so this API is separated from above +inline bool IsExtendedValueType(ValueType t) { + return IsValueType(t) || t == kTypeRangeDeletion; +} + +// 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 = port::kMaxUint64; + +struct ParsedInternalKey { + Slice user_key; + SequenceNumber sequence; + ValueType type; + + ParsedInternalKey() + : sequence(kMaxSequenceNumber) // Make code analyzer happy + {} // Intentionally left uninitialized (for speed) + ParsedInternalKey(const Slice& u, const SequenceNumber& seq, ValueType t) + : user_key(u), sequence(seq), type(t) {} + std::string DebugString(bool hex = false) const; + + void clear() { + user_key.clear(); + sequence = 0; + type = kTypeDeletion; + } +}; + +// Return the length of the encoding of "key". +inline size_t InternalKeyEncodingLength(const ParsedInternalKey& key) { + return key.user_key.size() + 8; +} + +// Pack a sequence number and a ValueType into a uint64_t +extern uint64_t PackSequenceAndType(uint64_t seq, ValueType t); + +// Given the result of PackSequenceAndType, store the sequence number in *seq +// and the ValueType in *t. +extern void UnPackSequenceAndType(uint64_t packed, uint64_t* seq, ValueType* t); + +EntryType GetEntryType(ValueType value_type); + +// Append the serialization of "key" to *result. +extern void AppendInternalKey(std::string* result, + const ParsedInternalKey& key); +// 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. +extern void AppendInternalKeyFooter(std::string* result, SequenceNumber s, + ValueType t); + +// 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. +extern bool ParseInternalKey(const Slice& internal_key, + ParsedInternalKey* result); + +// Returns the user key portion of an internal key. +inline Slice ExtractUserKey(const Slice& internal_key) { + assert(internal_key.size() >= 8); + return Slice(internal_key.data(), internal_key.size() - 8); +} + +inline uint64_t ExtractInternalKeyFooter(const Slice& internal_key) { + assert(internal_key.size() >= 8); + const size_t n = internal_key.size(); + return DecodeFixed64(internal_key.data() + n - 8); +} + +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 Comparator { + private: + UserComparatorWrapper user_comparator_; + std::string name_; + + public: + explicit InternalKeyComparator(const Comparator* c) + : user_comparator_(c), + name_("rocksdb.InternalKeyComparator:" + + std::string(user_comparator_.Name())) {} + virtual ~InternalKeyComparator() {} + + virtual const char* Name() const override; + virtual int Compare(const Slice& a, const Slice& b) const override; + // Same as Compare except that it excludes the value type from comparison + virtual int CompareKeySeq(const Slice& a, const Slice& b) const; + virtual void FindShortestSeparator(std::string* start, + const Slice& limit) const override; + virtual void FindShortSuccessor(std::string* key) const override; + + 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; + virtual const Comparator* GetRootComparator() const override { + return user_comparator_.GetRootComparator(); + } +}; + +// Modules in this directory should keep internal keys wrapped inside +// the following class instead of plain strings so that we do not +// incorrectly use string comparisons instead of an InternalKeyComparator. +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)); + } + + // 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); + } + + 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() { return rep_.size(); } + + void Set(const Slice& _user_key, SequenceNumber s, ValueType t) { + SetFrom(ParsedInternalKey(_user_key, s, t)); + } + + void SetFrom(const ParsedInternalKey& p) { + rep_.clear(); + AppendInternalKey(&rep_, p); + } + + 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 = false) const; +}; + +inline int InternalKeyComparator::Compare(const InternalKey& a, + const InternalKey& b) const { + return Compare(a.Encode(), b.Encode()); +} + +inline bool ParseInternalKey(const Slice& internal_key, + ParsedInternalKey* result) { + const size_t n = internal_key.size(); + if (n < 8) return false; + uint64_t num = DecodeFixed64(internal_key.data() + n - 8); + 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 - 8); + return IsExtendedValueType(result->type); +} + +// 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 >= 8); + 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 - 8], 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 >= 8); + uint64_t num = DecodeFixed64(internal_key.data() + n - 8); + return num >> 8; +} + +// A helper class useful for DBImpl::Get() +class LookupKey { + public: + // Initialize *this for looking up user_key at a snapshot with + // the specified sequence number. + LookupKey(const Slice& _user_key, SequenceNumber sequence); + + ~LookupKey(); + + // Return a key suitable for lookup in a MemTable. + Slice memtable_key() const { + return Slice(start_, static_cast<size_t>(end_ - start_)); + } + + // Return an internal key (suitable for passing to an internal iterator) + Slice internal_key() const { + return Slice(kstart_, static_cast<size_t>(end_ - kstart_)); + } + + // Return the user key + Slice user_key() const { + return Slice(kstart_, static_cast<size_t>(end_ - kstart_ - 8)); + } + + private: + // We construct a char array of the form: + // klength varint32 <-- start_ + // userkey char[klength] <-- kstart_ + // tag uint64 + // <-- end_ + // The array is a suitable MemTable key. + // The suffix starting with "userkey" can be used as an InternalKey. + const char* start_; + const char* kstart_; + const char* end_; + char space_[200]; // Avoid allocation for short keys + + // No copying allowed + LookupKey(const LookupKey&); + void operator=(const LookupKey&); +}; + +inline LookupKey::~LookupKey() { + if (start_ != space_) delete[] start_; +} + +class IterKey { + public: + IterKey() + : buf_(space_), + key_(buf_), + key_size_(0), + buf_size_(sizeof(space_)), + is_user_key_(true) {} + + ~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 + Slice GetKey() const { return Slice(key_, key_size_); } + + Slice GetInternalKey() const { + assert(!IsUserKey()); + return Slice(key_, key_size_); + } + + Slice GetUserKey() const { + if (IsUserKey()) { + return Slice(key_, key_size_); + } else { + assert(key_size_ >= 8); + return Slice(key_, key_size_ - 8); + } + } + + 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; + } + + Slice SetKey(const Slice& key, bool copy = true) { + // is_user_key_ expected to be set already via SetIsUserKey + return SetKeyImpl(key, copy); + } + + 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 >= 8); + SetInternalKey(key); + ikey->user_key = Slice(key_, key_n - 8); + 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) { + assert(!IsKeyPinned()); + assert(key_size_ >= 8); + uint64_t newval = (seq << 8) | t; + EncodeFixed64(&buf_[key_size_ - 8], newval); + } + + bool IsKeyPinned() const { return (key_ != buf_); } + + void SetInternalKey(const Slice& key_prefix, const Slice& user_key, + SequenceNumber s, + ValueType value_type = kValueTypeForSeek) { + size_t psize = key_prefix.size(); + size_t usize = user_key.size(); + EnlargeBufferIfNeeded(psize + usize + sizeof(uint64_t)); + if (psize > 0) { + memcpy(buf_, key_prefix.data(), psize); + } + memcpy(buf_ + psize, user_key.data(), usize); + EncodeFixed64(buf_ + usize + psize, PackSequenceAndType(s, value_type)); + + key_ = buf_; + key_size_ = psize + usize + sizeof(uint64_t); + is_user_key_ = false; + } + + void SetInternalKey(const Slice& user_key, SequenceNumber s, + ValueType value_type = kValueTypeForSeek) { + SetInternalKey(Slice(), user_key, s, value_type); + } + + 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_[32]; // 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); + + // No copying allowed + IterKey(const IterKey&) = delete; + void operator=(const IterKey&) = delete; +}; + +class InternalKeySliceTransform : public SliceTransform { + public: + explicit InternalKeySliceTransform(const SliceTransform* transform) + : transform_(transform) {} + + virtual const char* Name() const override { return transform_->Name(); } + + virtual Slice Transform(const Slice& src) const override { + auto user_key = ExtractUserKey(src); + return transform_->Transform(user_key); + } + + virtual bool InDomain(const Slice& src) const override { + auto user_key = ExtractUserKey(src); + return transform_->InDomain(user_key); + } + + virtual 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. +extern 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. +extern Status ReadRecordFromWriteBatch(Slice* input, char* tag, + uint32_t* column_family, Slice* key, + Slice* value, Slice* blob, Slice* xid); + +// When user call DeleteRange() to delete a range of keys, +// we will store a serialized RangeTombstone in MemTable and SST. +// the struct here is a 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_; + RangeTombstone() = default; + RangeTombstone(Slice sk, Slice ek, SequenceNumber sn) + : start_key_(sk), end_key_(ek), seq_(sn) {} + + 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); + Slice value = end_key_; + return std::make_pair(std::move(key), std::move(value)); + } + + // 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 { + 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() - 8); + const uint64_t bnum = DecodeFixed64(bkey.data() + bkey.size() - 8); + 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() - 8) >> 8; + const uint64_t bnum = DecodeFixed64(bkey.data() + bkey.size() - 8) >> 8; + if (anum > bnum) { + r = -1; + } else if (anum < bnum) { + r = +1; + } + } + return r; +} + +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 |