mirror of
https://github.com/facebook/rocksdb.git
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a4a4a2dabd
Summary: Previously, a `ReadOptions` object was stored in every `BlockBasedTableIterator` and every `LevelIterator`. This redundancy consumes extra memory, resulting in the `Arena` making more allocations, and iteration observing worse cache performance. This PR migrates callers of `NewInternalIterator()` and `MakeInputIterator()` to provide a `ReadOptions` object guaranteed to outlive the returned iterator. When the iterator's lifetime will be managed by the user, this lifetime guarantee is achieved by storing the `ReadOptions` value in `ArenaWrappedDBIter`. Then, sub-iterators of `NewInternalIterator()` and `MakeInputIterator()` can hold a reference-to-const `ReadOptions`. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7210 Test Plan: - `make check` under ASAN and valgrind - benchmark: on a DB with 2 L0 files and 3 L1+ levels, this PR reduced `Arena` allocation 4792 -> 4160 bytes. Reviewed By: anand1976 Differential Revision: D22861323 Pulled By: ajkr fbshipit-source-id: 54aebb3e89c872eeab0f5793b4b6e42878d093ce
82 lines
2.7 KiB
C++
82 lines
2.7 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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#ifndef ROCKSDB_LITE
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#include "rocksdb/utilities/debug.h"
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#include "db/db_impl/db_impl.h"
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namespace ROCKSDB_NAMESPACE {
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Status GetAllKeyVersions(DB* db, Slice begin_key, Slice end_key,
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size_t max_num_ikeys,
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std::vector<KeyVersion>* key_versions) {
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if (nullptr == db) {
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return Status::InvalidArgument("db cannot be null.");
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}
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return GetAllKeyVersions(db, db->DefaultColumnFamily(), begin_key, end_key,
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max_num_ikeys, key_versions);
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}
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Status GetAllKeyVersions(DB* db, ColumnFamilyHandle* cfh, Slice begin_key,
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Slice end_key, size_t max_num_ikeys,
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std::vector<KeyVersion>* key_versions) {
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if (nullptr == db) {
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return Status::InvalidArgument("db cannot be null.");
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}
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if (nullptr == cfh) {
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return Status::InvalidArgument("Column family handle cannot be null.");
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}
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if (nullptr == key_versions) {
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return Status::InvalidArgument("key_versions cannot be null.");
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}
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key_versions->clear();
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DBImpl* idb = static_cast<DBImpl*>(db->GetRootDB());
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auto icmp = InternalKeyComparator(idb->GetOptions(cfh).comparator);
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ReadOptions read_options;
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ReadRangeDelAggregator range_del_agg(&icmp,
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kMaxSequenceNumber /* upper_bound */);
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Arena arena;
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ScopedArenaIterator iter(idb->NewInternalIterator(
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read_options, &arena, &range_del_agg, kMaxSequenceNumber, cfh));
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if (!begin_key.empty()) {
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InternalKey ikey;
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ikey.SetMinPossibleForUserKey(begin_key);
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iter->Seek(ikey.Encode());
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} else {
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iter->SeekToFirst();
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}
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size_t num_keys = 0;
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for (; iter->Valid(); iter->Next()) {
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ParsedInternalKey ikey;
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if (!ParseInternalKey(iter->key(), &ikey)) {
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return Status::Corruption("Internal Key [" + iter->key().ToString() +
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"] parse error!");
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}
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if (!end_key.empty() &&
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icmp.user_comparator()->Compare(ikey.user_key, end_key) > 0) {
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break;
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}
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key_versions->emplace_back(ikey.user_key.ToString() /* _user_key */,
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iter->value().ToString() /* _value */,
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ikey.sequence /* _sequence */,
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static_cast<int>(ikey.type) /* _type */);
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if (++num_keys >= max_num_ikeys) {
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break;
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}
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}
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return Status::OK();
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}
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} // namespace ROCKSDB_NAMESPACE
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#endif // ROCKSDB_LITE
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