Conflicts: db/db_impl.cc db/db_impl.h db/db_impl_readonly.h db/db_test.cc include/rocksdb/db.h include/utilities/stackable_db.hmain
Igor Canadi
11 years ago
commit
28d1a0c6f5
@ -1,10 +1,11 @@ |
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{ |
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"project_id" : "leveldb", |
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"project_id" : "rocksdb", |
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"conduit_uri" : "https://reviews.facebook.net/", |
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"copyright_holder" : "", |
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"copyright_holder" : "Facebook", |
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"load" : [ |
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"linters/src/" |
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"linters" |
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], |
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"lint.engine" : "FacebookFbcodeLintEngine", |
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"lint.engine.single.linter" : "FbcodeCppLinter" |
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"lint.engine.single.linter" : "FbcodeCppLinter", |
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"lint.cpplint.prefix" : "linters" |
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} |
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|
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@ -0,0 +1,173 @@ |
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// Copyright (c) 2013, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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#include "db/tailing_iter.h" |
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#include <string> |
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#include <utility> |
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#include "db/db_impl.h" |
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namespace rocksdb { |
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TailingIterator::TailingIterator(DBImpl* db, const ReadOptions& options, |
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const Comparator* comparator) |
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: db_(db), options_(options), comparator_(comparator), |
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version_number_(0), current_(nullptr), |
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status_(Status::InvalidArgument("Seek() not called on this iterator")) {} |
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bool TailingIterator::Valid() const { |
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return current_ != nullptr; |
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} |
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void TailingIterator::SeekToFirst() { |
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if (!IsCurrentVersion()) { |
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CreateIterators(); |
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} |
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mutable_->SeekToFirst(); |
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immutable_->SeekToFirst(); |
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UpdateCurrent(); |
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} |
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void TailingIterator::Seek(const Slice& target) { |
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if (!IsCurrentVersion()) { |
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CreateIterators(); |
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} |
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mutable_->Seek(target); |
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// We maintain the interval (prev_key_, immutable_->key()] such that there
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// are no records with keys within that range in immutable_ other than
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// immutable_->key(). Since immutable_ can't change in this version, we don't
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// need to do a seek if 'target' belongs to that interval (i.e. immutable_ is
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// already at the correct position)!
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//
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// If options.prefix_seek is used and immutable_ is not valid, seek if target
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// has a different prefix than prev_key.
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//
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// prev_key_ is updated by Next(). SeekImmutable() sets prev_key_ to
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// 'target' -- in this case, prev_key_ is included in the interval, so
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// prev_inclusive_ has to be set.
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if (!is_prev_set_ || |
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comparator_->Compare(prev_key_, target) >= !is_prev_inclusive_ || |
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(immutable_->Valid() && |
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comparator_->Compare(target, immutable_->key()) > 0) || |
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(options_.prefix_seek && !IsSamePrefix(target))) { |
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SeekImmutable(target); |
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} |
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UpdateCurrent(); |
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} |
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void TailingIterator::Next() { |
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assert(Valid()); |
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if (!IsCurrentVersion()) { |
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// save the current key, create new iterators and then seek
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std::string current_key = key().ToString(); |
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Slice key_slice(current_key.data(), current_key.size()); |
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CreateIterators(); |
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Seek(key_slice); |
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if (!Valid() || key().compare(key_slice) != 0) { |
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// record with current_key no longer exists
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return; |
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} |
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} else if (current_ == immutable_.get()) { |
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// immutable iterator is advanced -- update prev_key_
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prev_key_ = key().ToString(); |
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is_prev_inclusive_ = false; |
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is_prev_set_ = true; |
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} |
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current_->Next(); |
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UpdateCurrent(); |
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} |
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Slice TailingIterator::key() const { |
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assert(Valid()); |
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return current_->key(); |
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} |
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Slice TailingIterator::value() const { |
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assert(Valid()); |
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return current_->value(); |
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} |
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Status TailingIterator::status() const { |
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if (!status_.ok()) { |
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return status_; |
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} else if (!mutable_->status().ok()) { |
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return mutable_->status(); |
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} else { |
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return immutable_->status(); |
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} |
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} |
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void TailingIterator::Prev() { |
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status_ = Status::NotSupported("This iterator doesn't support Prev()"); |
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} |
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void TailingIterator::SeekToLast() { |
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status_ = Status::NotSupported("This iterator doesn't support SeekToLast()"); |
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} |
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void TailingIterator::CreateIterators() { |
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std::pair<Iterator*, Iterator*> iters = |
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db_->GetTailingIteratorPair(options_, &version_number_); |
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assert(iters.first && iters.second); |
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mutable_.reset(iters.first); |
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immutable_.reset(iters.second); |
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current_ = nullptr; |
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is_prev_set_ = false; |
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} |
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void TailingIterator::UpdateCurrent() { |
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current_ = nullptr; |
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if (mutable_->Valid()) { |
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current_ = mutable_.get(); |
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} |
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if (immutable_->Valid() && |
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(current_ == nullptr || |
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comparator_->Compare(immutable_->key(), current_->key()) < 0)) { |
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current_ = immutable_.get(); |
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} |
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if (!status_.ok()) { |
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// reset status that was set by Prev() or SeekToLast()
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status_ = Status::OK(); |
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} |
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} |
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bool TailingIterator::IsCurrentVersion() const { |
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return mutable_ != nullptr && immutable_ != nullptr && |
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version_number_ == db_->CurrentVersionNumber(); |
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} |
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bool TailingIterator::IsSamePrefix(const Slice& target) const { |
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const SliceTransform* extractor = db_->options_.prefix_extractor; |
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assert(extractor); |
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assert(is_prev_set_); |
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return extractor->Transform(target) |
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.compare(extractor->Transform(prev_key_)) == 0; |
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} |
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void TailingIterator::SeekImmutable(const Slice& target) { |
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prev_key_ = target.ToString(); |
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is_prev_inclusive_ = true; |
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is_prev_set_ = true; |
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immutable_->Seek(target); |
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} |
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} // namespace rocksdb
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@ -0,0 +1,88 @@ |
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// Copyright (c) 2013, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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#pragma once |
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#include <string> |
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#include "rocksdb/db.h" |
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#include "rocksdb/iterator.h" |
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#include "rocksdb/options.h" |
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namespace rocksdb { |
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class DBImpl; |
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/**
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* TailingIterator is a special type of iterator that doesn't use an (implicit) |
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* snapshot. In other words, it can be used to read data that was added to the |
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* db after the iterator had been created. |
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* |
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* TailingIterator is optimized for sequential reading. It doesn't support |
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* Prev() and SeekToLast() operations. |
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*/ |
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class TailingIterator : public Iterator { |
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public: |
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TailingIterator(DBImpl* db, const ReadOptions& options, |
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const Comparator* comparator); |
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virtual ~TailingIterator() {} |
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virtual bool Valid() const override; |
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virtual void SeekToFirst() override; |
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virtual void SeekToLast() override; |
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virtual void Seek(const Slice& target) override; |
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virtual void Next() override; |
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virtual void Prev() override; |
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virtual Slice key() const override; |
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virtual Slice value() const override; |
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virtual Status status() const override; |
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private: |
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DBImpl* const db_; |
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const ReadOptions options_; |
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const Comparator* const comparator_; |
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uint64_t version_number_; |
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// TailingIterator merges the contents of the two iterators below (one using
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// mutable memtable contents only, other over SSTs and immutable memtables).
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// See DBIter::GetTailingIteratorPair().
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std::unique_ptr<Iterator> mutable_; |
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std::unique_ptr<Iterator> immutable_; |
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// points to either mutable_ or immutable_
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Iterator* current_; |
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// key that precedes immutable iterator's current key
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std::string prev_key_; |
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// unless prev_set is true, prev_key/prev_head is not valid and shouldn't be
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// used; reset by createIterators()
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bool is_prev_set_; |
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// prev_key_ was set by SeekImmutable(), which means that the interval of
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// keys covered by immutable_ is [prev_key_, current], i.e. it includes the
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// left endpoint
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bool is_prev_inclusive_; |
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// internal iterator status
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Status status_; |
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// check if this iterator's version matches DB's version
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bool IsCurrentVersion() const; |
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// check if SeekImmutable() is needed due to target having a different prefix
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// than prev_key_ (used when options.prefix_seek is set)
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bool IsSamePrefix(const Slice& target) const; |
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// creates mutable_ and immutable_ iterators and updates version_number_
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void CreateIterators(); |
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// set current_ to be one of the iterators with the smallest key
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void UpdateCurrent(); |
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// seek on immutable_ and update prev_key
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void SeekImmutable(const Slice& target); |
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}; |
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} // namespace rocksdb
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File diff suppressed because it is too large
Load Diff
@ -1 +0,0 @@ |
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