62f70f6d14
Summary: Our previous approach was to train one compression dictionary per compaction, using the first output SST to train a dictionary, and then applying it on subsequent SSTs in the same compaction. While this was great for minimizing CPU/memory/I/O overhead, it did not achieve good compression ratios in practice. In our most promising potential use case, moderate reductions in a dictionary's scope make a major difference on compression ratio. So, this PR changes compression dictionary to be scoped per-SST. It accepts the tradeoff during table building to use more memory and CPU. Important changes include: - The `BlockBasedTableBuilder` has a new state when dictionary compression is in-use: `kBuffered`. In that state it accumulates uncompressed data in-memory whenever `Add` is called. - After accumulating target file size bytes or calling `BlockBasedTableBuilder::Finish`, a `BlockBasedTableBuilder` moves to the `kUnbuffered` state. The transition (`EnterUnbuffered()`) involves sampling the buffered data, training a dictionary, and compressing/writing out all buffered data. In the `kUnbuffered` state, a `BlockBasedTableBuilder` behaves the same as before -- blocks are compressed/written out as soon as they fill up. - Samples are now whole uncompressed data blocks, except the final sample may be a partial data block so we don't breach the user's configured `max_dict_bytes` or `zstd_max_train_bytes`. The dictionary trainer is supposed to work better when we pass it real units of compression. Previously we were passing 64-byte KV samples which was not realistic. Pull Request resolved: https://github.com/facebook/rocksdb/pull/4952 Differential Revision: D13967980 Pulled By: ajkr fbshipit-source-id: 82bea6f7537e1529c7a1a4cdee84585f5949300f
244 lines
9.6 KiB
C++
244 lines
9.6 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 "db/builder.h"
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#include <algorithm>
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#include <deque>
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#include <vector>
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#include "db/compaction_iterator.h"
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#include "db/dbformat.h"
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#include "db/event_helpers.h"
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#include "db/internal_stats.h"
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#include "db/merge_helper.h"
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#include "db/range_del_aggregator.h"
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#include "db/table_cache.h"
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#include "db/version_edit.h"
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#include "monitoring/iostats_context_imp.h"
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#include "monitoring/thread_status_util.h"
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#include "rocksdb/db.h"
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#include "rocksdb/env.h"
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#include "rocksdb/iterator.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_table_builder.h"
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#include "table/format.h"
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#include "table/internal_iterator.h"
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#include "util/file_reader_writer.h"
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#include "util/filename.h"
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#include "util/stop_watch.h"
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#include "util/sync_point.h"
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namespace rocksdb {
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class TableFactory;
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TableBuilder* NewTableBuilder(
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const ImmutableCFOptions& ioptions, const MutableCFOptions& moptions,
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const InternalKeyComparator& internal_comparator,
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const std::vector<std::unique_ptr<IntTblPropCollectorFactory>>*
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int_tbl_prop_collector_factories,
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uint32_t column_family_id, const std::string& column_family_name,
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WritableFileWriter* file, const CompressionType compression_type,
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const CompressionOptions& compression_opts, int level,
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const bool skip_filters, const uint64_t creation_time,
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const uint64_t oldest_key_time, const bool is_bottommost_level,
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const uint64_t target_file_size) {
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assert((column_family_id ==
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TablePropertiesCollectorFactory::Context::kUnknownColumnFamily) ==
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column_family_name.empty());
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return ioptions.table_factory->NewTableBuilder(
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TableBuilderOptions(ioptions, moptions, internal_comparator,
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int_tbl_prop_collector_factories, compression_type,
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compression_opts, skip_filters, column_family_name,
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level, creation_time, oldest_key_time,
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is_bottommost_level, target_file_size),
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column_family_id, file);
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}
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Status BuildTable(
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const std::string& dbname, Env* env, const ImmutableCFOptions& ioptions,
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const MutableCFOptions& mutable_cf_options, const EnvOptions& env_options,
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TableCache* table_cache, InternalIterator* iter,
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std::vector<std::unique_ptr<FragmentedRangeTombstoneIterator>>
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range_del_iters,
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FileMetaData* meta, const InternalKeyComparator& internal_comparator,
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const std::vector<std::unique_ptr<IntTblPropCollectorFactory>>*
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int_tbl_prop_collector_factories,
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uint32_t column_family_id, const std::string& column_family_name,
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std::vector<SequenceNumber> snapshots,
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SequenceNumber earliest_write_conflict_snapshot,
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SnapshotChecker* snapshot_checker, const CompressionType compression,
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const CompressionOptions& compression_opts, bool paranoid_file_checks,
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InternalStats* internal_stats, TableFileCreationReason reason,
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EventLogger* event_logger, int job_id, const Env::IOPriority io_priority,
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TableProperties* table_properties, int level, const uint64_t creation_time,
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const uint64_t oldest_key_time, Env::WriteLifeTimeHint write_hint) {
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assert((column_family_id ==
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TablePropertiesCollectorFactory::Context::kUnknownColumnFamily) ==
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column_family_name.empty());
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// Reports the IOStats for flush for every following bytes.
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const size_t kReportFlushIOStatsEvery = 1048576;
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Status s;
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meta->fd.file_size = 0;
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iter->SeekToFirst();
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std::unique_ptr<CompactionRangeDelAggregator> range_del_agg(
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new CompactionRangeDelAggregator(&internal_comparator, snapshots));
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for (auto& range_del_iter : range_del_iters) {
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range_del_agg->AddTombstones(std::move(range_del_iter));
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}
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std::string fname = TableFileName(ioptions.cf_paths, meta->fd.GetNumber(),
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meta->fd.GetPathId());
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#ifndef ROCKSDB_LITE
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EventHelpers::NotifyTableFileCreationStarted(
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ioptions.listeners, dbname, column_family_name, fname, job_id, reason);
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#endif // !ROCKSDB_LITE
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TableProperties tp;
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if (iter->Valid() || !range_del_agg->IsEmpty()) {
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TableBuilder* builder;
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std::unique_ptr<WritableFileWriter> file_writer;
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{
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std::unique_ptr<WritableFile> file;
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#ifndef NDEBUG
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bool use_direct_writes = env_options.use_direct_writes;
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TEST_SYNC_POINT_CALLBACK("BuildTable:create_file", &use_direct_writes);
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#endif // !NDEBUG
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s = NewWritableFile(env, fname, &file, env_options);
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if (!s.ok()) {
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EventHelpers::LogAndNotifyTableFileCreationFinished(
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event_logger, ioptions.listeners, dbname, column_family_name, fname,
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job_id, meta->fd, tp, reason, s);
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return s;
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}
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file->SetIOPriority(io_priority);
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file->SetWriteLifeTimeHint(write_hint);
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file_writer.reset(
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new WritableFileWriter(std::move(file), fname, env_options, env,
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ioptions.statistics, ioptions.listeners));
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builder = NewTableBuilder(
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ioptions, mutable_cf_options, internal_comparator,
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int_tbl_prop_collector_factories, column_family_id,
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column_family_name, file_writer.get(), compression, compression_opts,
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level, false /* skip_filters */, creation_time, oldest_key_time);
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}
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MergeHelper merge(env, internal_comparator.user_comparator(),
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ioptions.merge_operator, nullptr, ioptions.info_log,
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true /* internal key corruption is not ok */,
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snapshots.empty() ? 0 : snapshots.back(),
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snapshot_checker);
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CompactionIterator c_iter(
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iter, internal_comparator.user_comparator(), &merge, kMaxSequenceNumber,
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&snapshots, earliest_write_conflict_snapshot, snapshot_checker, env,
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ShouldReportDetailedTime(env, ioptions.statistics),
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true /* internal key corruption is not ok */, range_del_agg.get());
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c_iter.SeekToFirst();
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for (; c_iter.Valid(); c_iter.Next()) {
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const Slice& key = c_iter.key();
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const Slice& value = c_iter.value();
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builder->Add(key, value);
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meta->UpdateBoundaries(key, c_iter.ikey().sequence);
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// TODO(noetzli): Update stats after flush, too.
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if (io_priority == Env::IO_HIGH &&
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IOSTATS(bytes_written) >= kReportFlushIOStatsEvery) {
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ThreadStatusUtil::SetThreadOperationProperty(
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ThreadStatus::FLUSH_BYTES_WRITTEN, IOSTATS(bytes_written));
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}
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}
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auto range_del_it = range_del_agg->NewIterator();
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for (range_del_it->SeekToFirst(); range_del_it->Valid();
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range_del_it->Next()) {
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auto tombstone = range_del_it->Tombstone();
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auto kv = tombstone.Serialize();
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builder->Add(kv.first.Encode(), kv.second);
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meta->UpdateBoundariesForRange(kv.first, tombstone.SerializeEndKey(),
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tombstone.seq_, internal_comparator);
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}
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// Finish and check for builder errors
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tp = builder->GetTableProperties();
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bool empty = builder->NumEntries() == 0 && tp.num_range_deletions == 0;
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s = c_iter.status();
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if (!s.ok() || empty) {
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builder->Abandon();
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} else {
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s = builder->Finish();
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}
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if (s.ok() && !empty) {
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uint64_t file_size = builder->FileSize();
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meta->fd.file_size = file_size;
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meta->marked_for_compaction = builder->NeedCompact();
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assert(meta->fd.GetFileSize() > 0);
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tp = builder->GetTableProperties(); // refresh now that builder is finished
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if (table_properties) {
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*table_properties = tp;
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}
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}
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delete builder;
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// Finish and check for file errors
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if (s.ok() && !empty) {
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StopWatch sw(env, ioptions.statistics, TABLE_SYNC_MICROS);
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s = file_writer->Sync(ioptions.use_fsync);
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}
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if (s.ok() && !empty) {
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s = file_writer->Close();
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}
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if (s.ok() && !empty) {
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// Verify that the table is usable
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// We set for_compaction to false and don't OptimizeForCompactionTableRead
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// here because this is a special case after we finish the table building
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// No matter whether use_direct_io_for_flush_and_compaction is true,
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// we will regrad this verification as user reads since the goal is
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// to cache it here for further user reads
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std::unique_ptr<InternalIterator> it(table_cache->NewIterator(
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ReadOptions(), env_options, internal_comparator, *meta,
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nullptr /* range_del_agg */,
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mutable_cf_options.prefix_extractor.get(), nullptr,
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(internal_stats == nullptr) ? nullptr
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: internal_stats->GetFileReadHist(0),
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false /* for_compaction */, nullptr /* arena */,
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false /* skip_filter */, level));
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s = it->status();
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if (s.ok() && paranoid_file_checks) {
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for (it->SeekToFirst(); it->Valid(); it->Next()) {
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}
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s = it->status();
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}
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}
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}
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// Check for input iterator errors
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if (!iter->status().ok()) {
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s = iter->status();
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}
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if (!s.ok() || meta->fd.GetFileSize() == 0) {
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env->DeleteFile(fname);
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}
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// Output to event logger and fire events.
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EventHelpers::LogAndNotifyTableFileCreationFinished(
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event_logger, ioptions.listeners, dbname, column_family_name, fname,
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job_id, meta->fd, tp, reason, s);
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return s;
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}
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} // namespace rocksdb
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