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rocksdb/db/builder.cc

207 lines
7.2 KiB

// 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/builder.h"
#include "db/filename.h"
#include "db/dbformat.h"
#include "db/merge_helper.h"
#include "db/table_cache.h"
#include "db/version_edit.h"
#include "rocksdb/db.h"
#include "rocksdb/env.h"
#include "rocksdb/iterator.h"
#include "util/stop_watch.h"
namespace leveldb {
Status BuildTable(const std::string& dbname,
Env* env,
const Options& options,
const EnvOptions& soptions,
TableCache* table_cache,
Iterator* iter,
FileMetaData* meta,
const Comparator* user_comparator,
const SequenceNumber newest_snapshot,
const SequenceNumber earliest_seqno_in_memtable) {
Status s;
meta->file_size = 0;
meta->smallest_seqno = meta->largest_seqno = 0;
iter->SeekToFirst();
// If the sequence number of the smallest entry in the memtable is
// smaller than the most recent snapshot, then we do not trigger
// removal of duplicate/deleted keys as part of this builder.
bool purge = options.purge_redundant_kvs_while_flush;
if (earliest_seqno_in_memtable <= newest_snapshot) {
purge = false;
}
std::string fname = TableFileName(dbname, meta->number);
if (iter->Valid()) {
unique_ptr<WritableFile> file;
s = env->NewWritableFile(fname, &file, soptions);
if (!s.ok()) {
return s;
}
TableBuilder* builder = new TableBuilder(options, file.get(), 0);
// the first key is the smallest key
Slice key = iter->key();
meta->smallest.DecodeFrom(key);
meta->smallest_seqno = GetInternalKeySeqno(key);
meta->largest_seqno = meta->smallest_seqno;
MergeHelper merge(user_comparator, options.merge_operator.get(),
options.info_log.get(),
true /* internal key corruption is not ok */);
if (purge) {
// Ugly walkaround to avoid compiler error for release build
bool ok __attribute__((unused)) = true;
// Will write to builder if current key != prev key
ParsedInternalKey prev_ikey;
std::string prev_key;
bool is_first_key = true; // Also write if this is the very first key
while (iter->Valid()) {
bool iterator_at_next = false;
// Get current key
ParsedInternalKey this_ikey;
Slice key = iter->key();
Slice value = iter->value();
// In-memory key corruption is not ok;
// TODO: find a clean way to treat in memory key corruption
ok = ParseInternalKey(key, &this_ikey);
assert(ok);
assert(this_ikey.sequence >= earliest_seqno_in_memtable);
// If the key is the same as the previous key (and it is not the
// first key), then we skip it, since it is an older version.
// Otherwise we output the key and mark it as the "new" previous key.
if (!is_first_key && !user_comparator->Compare(prev_ikey.user_key,
this_ikey.user_key)) {
// seqno within the same key are in decreasing order
assert(this_ikey.sequence < prev_ikey.sequence);
} else {
is_first_key = false;
if (this_ikey.type == kTypeMerge) {
// Handle merge-type keys using the MergeHelper
merge.MergeUntil(iter, 0 /* don't worry about snapshot */);
iterator_at_next = true;
if (merge.IsSuccess()) {
// Merge completed correctly.
// Add the resulting merge key/value and continue to next
builder->Add(merge.key(), merge.value());
prev_key.assign(merge.key().data(), merge.key().size());
ok = ParseInternalKey(Slice(prev_key), &prev_ikey);
assert(ok);
} else {
// Merge did not find a Put/Delete.
// Can not compact these merges into a kValueType.
// Write them out one-by-one. (Proceed back() to front())
const std::deque<std::string>& keys = merge.keys();
const std::deque<std::string>& values = merge.values();
assert(keys.size() == values.size() && keys.size() >= 1);
std::deque<std::string>::const_reverse_iterator key_iter;
std::deque<std::string>::const_reverse_iterator value_iter;
for (key_iter=keys.rbegin(), value_iter = values.rbegin();
key_iter != keys.rend() && value_iter != values.rend();
++key_iter, ++value_iter) {
builder->Add(Slice(*key_iter), Slice(*value_iter));
}
// Sanity check. Both iterators should end at the same time
assert(key_iter == keys.rend() && value_iter == values.rend());
prev_key.assign(keys.front());
ok = ParseInternalKey(Slice(prev_key), &prev_ikey);
assert(ok);
}
} else {
// Handle Put/Delete-type keys by simply writing them
builder->Add(key, value);
prev_key.assign(key.data(), key.size());
ok = ParseInternalKey(Slice(prev_key), &prev_ikey);
assert(ok);
}
}
if (!iterator_at_next) iter->Next();
}
// The last key is the largest key
meta->largest.DecodeFrom(Slice(prev_key));
SequenceNumber seqno = GetInternalKeySeqno(Slice(prev_key));
meta->smallest_seqno = std::min(meta->smallest_seqno, seqno);
meta->largest_seqno = std::max(meta->largest_seqno, seqno);
} else {
for (; iter->Valid(); iter->Next()) {
Slice key = iter->key();
meta->largest.DecodeFrom(key);
builder->Add(key, iter->value());
SequenceNumber seqno = GetInternalKeySeqno(key);
meta->smallest_seqno = std::min(meta->smallest_seqno, seqno);
meta->largest_seqno = std::max(meta->largest_seqno, seqno);
}
}
// Finish and check for builder errors
if (s.ok()) {
s = builder->Finish();
if (s.ok()) {
meta->file_size = builder->FileSize();
assert(meta->file_size > 0);
}
} else {
builder->Abandon();
}
delete builder;
// Finish and check for file errors
if (s.ok() && !options.disableDataSync) {
if (options.use_fsync) {
StopWatch sw(env, options.statistics, TABLE_SYNC_MICROS);
s = file->Fsync();
} else {
StopWatch sw(env, options.statistics, TABLE_SYNC_MICROS);
s = file->Sync();
}
}
if (s.ok()) {
s = file->Close();
}
if (s.ok()) {
// Verify that the table is usable
Iterator* it = table_cache->NewIterator(ReadOptions(),
soptions,
meta->number,
meta->file_size);
s = it->status();
delete it;
}
}
// Check for input iterator errors
if (!iter->status().ok()) {
s = iter->status();
}
if (s.ok() && meta->file_size > 0) {
// Keep it
} else {
env->DeleteFile(fname);
}
return s;
}
} // namespace leveldb