8843129ece
Summary: Move arena, allocator, and memory tools under util to a separate memory/ directory. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5382 Differential Revision: D15564655 Pulled By: siying fbshipit-source-id: 9cd6b5d0d3d52b39606e19221fa154596e5852a5
212 lines
6.3 KiB
C++
212 lines
6.3 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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//
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#include "table/two_level_iterator.h"
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#include "db/pinned_iterators_manager.h"
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#include "memory/arena.h"
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#include "rocksdb/options.h"
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#include "rocksdb/table.h"
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#include "table/block_based/block.h"
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#include "table/format.h"
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namespace rocksdb {
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namespace {
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class TwoLevelIndexIterator : public InternalIteratorBase<BlockHandle> {
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public:
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explicit TwoLevelIndexIterator(
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TwoLevelIteratorState* state,
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InternalIteratorBase<BlockHandle>* first_level_iter);
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~TwoLevelIndexIterator() override {
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first_level_iter_.DeleteIter(false /* is_arena_mode */);
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second_level_iter_.DeleteIter(false /* is_arena_mode */);
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delete state_;
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}
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void Seek(const Slice& target) override;
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void SeekForPrev(const Slice& target) override;
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void SeekToFirst() override;
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void SeekToLast() override;
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void Next() override;
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void Prev() override;
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bool Valid() const override { return second_level_iter_.Valid(); }
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Slice key() const override {
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assert(Valid());
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return second_level_iter_.key();
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}
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BlockHandle value() const override {
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assert(Valid());
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return second_level_iter_.value();
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}
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Status status() const override {
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if (!first_level_iter_.status().ok()) {
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assert(second_level_iter_.iter() == nullptr);
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return first_level_iter_.status();
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} else if (second_level_iter_.iter() != nullptr &&
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!second_level_iter_.status().ok()) {
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return second_level_iter_.status();
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} else {
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return status_;
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}
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}
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void SetPinnedItersMgr(
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PinnedIteratorsManager* /*pinned_iters_mgr*/) override {}
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bool IsKeyPinned() const override { return false; }
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bool IsValuePinned() const override { return false; }
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private:
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void SaveError(const Status& s) {
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if (status_.ok() && !s.ok()) status_ = s;
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}
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void SkipEmptyDataBlocksForward();
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void SkipEmptyDataBlocksBackward();
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void SetSecondLevelIterator(InternalIteratorBase<BlockHandle>* iter);
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void InitDataBlock();
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TwoLevelIteratorState* state_;
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IteratorWrapperBase<BlockHandle> first_level_iter_;
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IteratorWrapperBase<BlockHandle> second_level_iter_; // May be nullptr
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Status status_;
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// If second_level_iter is non-nullptr, then "data_block_handle_" holds the
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// "index_value" passed to block_function_ to create the second_level_iter.
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BlockHandle data_block_handle_;
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};
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TwoLevelIndexIterator::TwoLevelIndexIterator(
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TwoLevelIteratorState* state,
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InternalIteratorBase<BlockHandle>* first_level_iter)
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: state_(state), first_level_iter_(first_level_iter) {}
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void TwoLevelIndexIterator::Seek(const Slice& target) {
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first_level_iter_.Seek(target);
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InitDataBlock();
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if (second_level_iter_.iter() != nullptr) {
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second_level_iter_.Seek(target);
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}
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SkipEmptyDataBlocksForward();
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}
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void TwoLevelIndexIterator::SeekForPrev(const Slice& target) {
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first_level_iter_.Seek(target);
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InitDataBlock();
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if (second_level_iter_.iter() != nullptr) {
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second_level_iter_.SeekForPrev(target);
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}
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if (!Valid()) {
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if (!first_level_iter_.Valid() && first_level_iter_.status().ok()) {
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first_level_iter_.SeekToLast();
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InitDataBlock();
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if (second_level_iter_.iter() != nullptr) {
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second_level_iter_.SeekForPrev(target);
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}
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}
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SkipEmptyDataBlocksBackward();
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}
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}
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void TwoLevelIndexIterator::SeekToFirst() {
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first_level_iter_.SeekToFirst();
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InitDataBlock();
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if (second_level_iter_.iter() != nullptr) {
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second_level_iter_.SeekToFirst();
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}
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SkipEmptyDataBlocksForward();
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}
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void TwoLevelIndexIterator::SeekToLast() {
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first_level_iter_.SeekToLast();
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InitDataBlock();
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if (second_level_iter_.iter() != nullptr) {
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second_level_iter_.SeekToLast();
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}
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SkipEmptyDataBlocksBackward();
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}
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void TwoLevelIndexIterator::Next() {
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assert(Valid());
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second_level_iter_.Next();
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SkipEmptyDataBlocksForward();
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}
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void TwoLevelIndexIterator::Prev() {
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assert(Valid());
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second_level_iter_.Prev();
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SkipEmptyDataBlocksBackward();
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}
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void TwoLevelIndexIterator::SkipEmptyDataBlocksForward() {
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while (second_level_iter_.iter() == nullptr ||
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(!second_level_iter_.Valid() && second_level_iter_.status().ok())) {
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// Move to next block
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if (!first_level_iter_.Valid()) {
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SetSecondLevelIterator(nullptr);
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return;
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}
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first_level_iter_.Next();
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InitDataBlock();
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if (second_level_iter_.iter() != nullptr) {
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second_level_iter_.SeekToFirst();
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}
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}
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}
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void TwoLevelIndexIterator::SkipEmptyDataBlocksBackward() {
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while (second_level_iter_.iter() == nullptr ||
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(!second_level_iter_.Valid() && second_level_iter_.status().ok())) {
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// Move to next block
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if (!first_level_iter_.Valid()) {
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SetSecondLevelIterator(nullptr);
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return;
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}
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first_level_iter_.Prev();
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InitDataBlock();
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if (second_level_iter_.iter() != nullptr) {
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second_level_iter_.SeekToLast();
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}
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}
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}
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void TwoLevelIndexIterator::SetSecondLevelIterator(
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InternalIteratorBase<BlockHandle>* iter) {
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InternalIteratorBase<BlockHandle>* old_iter = second_level_iter_.Set(iter);
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delete old_iter;
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}
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void TwoLevelIndexIterator::InitDataBlock() {
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if (!first_level_iter_.Valid()) {
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SetSecondLevelIterator(nullptr);
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} else {
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BlockHandle handle = first_level_iter_.value();
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if (second_level_iter_.iter() != nullptr &&
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!second_level_iter_.status().IsIncomplete() &&
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handle.offset() == data_block_handle_.offset()) {
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// second_level_iter is already constructed with this iterator, so
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// no need to change anything
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} else {
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InternalIteratorBase<BlockHandle>* iter =
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state_->NewSecondaryIterator(handle);
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data_block_handle_ = handle;
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SetSecondLevelIterator(iter);
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}
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}
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}
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} // namespace
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InternalIteratorBase<BlockHandle>* NewTwoLevelIterator(
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TwoLevelIteratorState* state,
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InternalIteratorBase<BlockHandle>* first_level_iter) {
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return new TwoLevelIndexIterator(state, first_level_iter);
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}
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} // namespace rocksdb
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