1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
|
// 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.
#include "db/arena_wrapped_db_iter.h"
#include "memory/arena.h"
#include "rocksdb/env.h"
#include "rocksdb/iterator.h"
#include "rocksdb/options.h"
#include "table/internal_iterator.h"
#include "table/iterator_wrapper.h"
#include "util/user_comparator_wrapper.h"
namespace ROCKSDB_NAMESPACE {
Status ArenaWrappedDBIter::GetProperty(std::string prop_name,
std::string* prop) {
if (prop_name == "rocksdb.iterator.super-version-number") {
// First try to pass the value returned from inner iterator.
if (!db_iter_->GetProperty(prop_name, prop).ok()) {
*prop = std::to_string(sv_number_);
}
return Status::OK();
}
return db_iter_->GetProperty(prop_name, prop);
}
void ArenaWrappedDBIter::Init(
Env* env, const ReadOptions& read_options, const ImmutableOptions& ioptions,
const MutableCFOptions& mutable_cf_options, const Version* version,
const SequenceNumber& sequence, uint64_t max_sequential_skip_in_iteration,
uint64_t version_number, ReadCallback* read_callback, DBImpl* db_impl,
ColumnFamilyData* cfd, bool expose_blob_index, bool allow_refresh) {
auto mem = arena_.AllocateAligned(sizeof(DBIter));
db_iter_ =
new (mem) DBIter(env, read_options, ioptions, mutable_cf_options,
ioptions.user_comparator, /* iter */ nullptr, version,
sequence, true, max_sequential_skip_in_iteration,
read_callback, db_impl, cfd, expose_blob_index);
sv_number_ = version_number;
read_options_ = read_options;
allow_refresh_ = allow_refresh;
memtable_range_tombstone_iter_ = nullptr;
}
Status ArenaWrappedDBIter::Refresh() {
if (cfd_ == nullptr || db_impl_ == nullptr || !allow_refresh_) {
return Status::NotSupported("Creating renew iterator is not allowed.");
}
assert(db_iter_ != nullptr);
// TODO(yiwu): For last_seq_same_as_publish_seq_==false, this is not the
// correct behavior. Will be corrected automatically when we take a snapshot
// here for the case of WritePreparedTxnDB.
uint64_t cur_sv_number = cfd_->GetSuperVersionNumber();
TEST_SYNC_POINT("ArenaWrappedDBIter::Refresh:1");
TEST_SYNC_POINT("ArenaWrappedDBIter::Refresh:2");
auto reinit_internal_iter = [&]() {
Env* env = db_iter_->env();
db_iter_->~DBIter();
arena_.~Arena();
new (&arena_) Arena();
SuperVersion* sv = cfd_->GetReferencedSuperVersion(db_impl_);
SequenceNumber latest_seq = db_impl_->GetLatestSequenceNumber();
if (read_callback_) {
read_callback_->Refresh(latest_seq);
}
Init(env, read_options_, *(cfd_->ioptions()), sv->mutable_cf_options,
sv->current, latest_seq,
sv->mutable_cf_options.max_sequential_skip_in_iterations,
cur_sv_number, read_callback_, db_impl_, cfd_, expose_blob_index_,
allow_refresh_);
InternalIterator* internal_iter = db_impl_->NewInternalIterator(
read_options_, cfd_, sv, &arena_, latest_seq,
/* allow_unprepared_value */ true, /* db_iter */ this);
SetIterUnderDBIter(internal_iter);
};
while (true) {
if (sv_number_ != cur_sv_number) {
reinit_internal_iter();
break;
} else {
SequenceNumber latest_seq = db_impl_->GetLatestSequenceNumber();
// Refresh range-tombstones in MemTable
if (!read_options_.ignore_range_deletions) {
SuperVersion* sv = cfd_->GetThreadLocalSuperVersion(db_impl_);
TEST_SYNC_POINT_CALLBACK("ArenaWrappedDBIter::Refresh:SV", nullptr);
auto t = sv->mem->NewRangeTombstoneIterator(
read_options_, latest_seq, false /* immutable_memtable */);
if (!t || t->empty()) {
// If memtable_range_tombstone_iter_ points to a non-empty tombstone
// iterator, then it means sv->mem is not the memtable that
// memtable_range_tombstone_iter_ points to, so SV must have changed
// after the sv_number_ != cur_sv_number check above. We will fall
// back to re-init the InternalIterator, and the tombstone iterator
// will be freed during db_iter destruction there.
if (memtable_range_tombstone_iter_) {
assert(!*memtable_range_tombstone_iter_ ||
sv_number_ != cfd_->GetSuperVersionNumber());
}
delete t;
} else { // current mutable memtable has range tombstones
if (!memtable_range_tombstone_iter_) {
delete t;
db_impl_->ReturnAndCleanupSuperVersion(cfd_, sv);
// The memtable under DBIter did not have range tombstone before
// refresh.
reinit_internal_iter();
break;
} else {
delete *memtable_range_tombstone_iter_;
*memtable_range_tombstone_iter_ = new TruncatedRangeDelIterator(
std::unique_ptr<FragmentedRangeTombstoneIterator>(t),
&cfd_->internal_comparator(), nullptr, nullptr);
}
}
db_impl_->ReturnAndCleanupSuperVersion(cfd_, sv);
}
// Refresh latest sequence number
db_iter_->set_sequence(latest_seq);
db_iter_->set_valid(false);
// Check again if the latest super version number is changed
uint64_t latest_sv_number = cfd_->GetSuperVersionNumber();
if (latest_sv_number != cur_sv_number) {
// If the super version number is changed after refreshing,
// fallback to Re-Init the InternalIterator
cur_sv_number = latest_sv_number;
continue;
}
break;
}
}
return Status::OK();
}
ArenaWrappedDBIter* NewArenaWrappedDbIterator(
Env* env, const ReadOptions& read_options, const ImmutableOptions& ioptions,
const MutableCFOptions& mutable_cf_options, const Version* version,
const SequenceNumber& sequence, uint64_t max_sequential_skip_in_iterations,
uint64_t version_number, ReadCallback* read_callback, DBImpl* db_impl,
ColumnFamilyData* cfd, bool expose_blob_index, bool allow_refresh) {
ArenaWrappedDBIter* iter = new ArenaWrappedDBIter();
iter->Init(env, read_options, ioptions, mutable_cf_options, version, sequence,
max_sequential_skip_in_iterations, version_number, read_callback,
db_impl, cfd, expose_blob_index, allow_refresh);
if (db_impl != nullptr && cfd != nullptr && allow_refresh) {
iter->StoreRefreshInfo(db_impl, cfd, read_callback, expose_blob_index);
}
return iter;
}
} // namespace ROCKSDB_NAMESPACE
|
