rocksdb/db/builder.cc
Peter Dillinger cb08a682d4 Fix/cleanup SeqnoToTimeMapping (#12253)
Summary:
The SeqnoToTimeMapping class (RocksDB internal) used by the preserve_internal_time_seconds / preclude_last_level_data_seconds options was essentially in a prototype state with some significant flaws that would risk biting us some day. This is a big, complicated change because both the implementation and the behavioral requirements of the class needed to be upgraded together. In short, this makes SeqnoToTimeMapping more internally responsible for maintaining good invariants, so that callers don't easily encounter dangerous scenarios.

* Some API functions were confusingly named and structured, so I fully refactored the APIs to use clear naming (e.g. `DecodeFrom` and `CopyFromSeqnoRange`), object states, function preconditions, etc.
  * Previously the object could informally be sorted / compacted or not, and there was limited checking or enforcement on these states. Now there's a well-defined "enforced" state that is consistently checked in debug mode for applicable operations. (I attempted to create a separate "builder" class for unenforced states, but IIRC found that more cumbersome for existing uses than it was worth.)
* Previously operations would coalesce data in a way that was better for `GetProximalTimeBeforeSeqno` than for `GetProximalSeqnoBeforeTime` which is odd because the latter is the only one used by DB code currently (what is the seqno cut-off for data definitely older than this given time?). This is now reversed to consistently favor `GetProximalSeqnoBeforeTime`, with that logic concentrated in one place: `SeqnoToTimeMapping::SeqnoTimePair::Merge()`. Unfortunately, a lot of unit test logic was specifically testing the old, suboptimal behavior.
* Previously, the natural behavior of SeqnoToTimeMapping was to THROW AWAY data needed to get reasonable answers to the important `GetProximalSeqnoBeforeTime` queries. This is because SeqnoToTimeMapping only had a FIFO policy for staying within the entry capacity (except in aggregate+sort+serialize mode). If the DB wasn't extremely careful to avoid gathering too many time mappings, it could lose track of where the seqno cutoff was for cold data (`GetProximalSeqnoBeforeTime()` returning 0) and preventing all further data migration to the cold tier--until time passes etc. for mappings to catch up with FIFO purging of them. (The problem is not so acute because SST files contain relevant snapshots of the mappings, but the problem would apply to long-lived memtables.)
  * Now the SeqnoToTimeMapping class has fully-integrated smarts for keeping a sufficiently complete history, within capacity limits, to give good answers to `GetProximalSeqnoBeforeTime` queries.
  * Fixes old `// FIXME: be smarter about how we erase to avoid data falling off the front prematurely.`
* Fix an apparent bug in how entries are selected for storing into SST files. Previously, it only selected entries within the seqno range of the file, but that would easily leave a gap at the beginning of the timeline for data in the file for the purposes of answering GetProximalXXX queries with reasonable accuracy. This could probably lead to the same problem discussed above in naively throwing away entries in FIFO order in the old SeqnoToTimeMapping. The updated testing of GetProximalSeqnoBeforeTime in BasicSeqnoToTimeMapping relies on the fixed behavior.
* Fix a potential compaction CPU efficiency/scaling issue in which each compaction output file would iterate over and sort all seqno-to-time mappings from all compaction input files. Now we distill the input file entries to a constant size before processing each compaction output file.

Intended follow-up (me or others):
* Expand some direct testing of SeqnoToTimeMapping APIs. Here I've focused on updating existing tests to make sense.
* There are likely more gaps in availability of needed SeqnoToTimeMapping data when the DB shuts down and is restarted, at least with WAL.
* The data tracked in the DB could be kept more accurate and limited if it used the oldest seqno of unflushed data. This might require some more API refactoring.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12253

Test Plan: unit tests updated

Reviewed By: jowlyzhang

Differential Revision: D52913733

Pulled By: pdillinger

fbshipit-source-id: 020737fcbbe6212f6701191a6ab86565054c9593
2024-01-19 21:50:38 -08:00

489 lines
20 KiB
C++

// 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/builder.h"
#include <algorithm>
#include <deque>
#include <vector>
#include "db/blob/blob_file_builder.h"
#include "db/compaction/compaction_iterator.h"
#include "db/dbformat.h"
#include "db/event_helpers.h"
#include "db/internal_stats.h"
#include "db/merge_helper.h"
#include "db/output_validator.h"
#include "db/range_del_aggregator.h"
#include "db/table_cache.h"
#include "db/version_edit.h"
#include "file/file_util.h"
#include "file/filename.h"
#include "file/read_write_util.h"
#include "file/writable_file_writer.h"
#include "monitoring/iostats_context_imp.h"
#include "monitoring/thread_status_util.h"
#include "options/options_helper.h"
#include "rocksdb/db.h"
#include "rocksdb/env.h"
#include "rocksdb/file_system.h"
#include "rocksdb/iterator.h"
#include "rocksdb/options.h"
#include "rocksdb/table.h"
#include "seqno_to_time_mapping.h"
#include "table/block_based/block_based_table_builder.h"
#include "table/format.h"
#include "table/internal_iterator.h"
#include "table/unique_id_impl.h"
#include "test_util/sync_point.h"
#include "util/stop_watch.h"
namespace ROCKSDB_NAMESPACE {
class TableFactory;
TableBuilder* NewTableBuilder(const TableBuilderOptions& tboptions,
WritableFileWriter* file) {
assert((tboptions.column_family_id ==
TablePropertiesCollectorFactory::Context::kUnknownColumnFamily) ==
tboptions.column_family_name.empty());
return tboptions.ioptions.table_factory->NewTableBuilder(tboptions, file);
}
Status BuildTable(
const std::string& dbname, VersionSet* versions,
const ImmutableDBOptions& db_options, const TableBuilderOptions& tboptions,
const FileOptions& file_options, TableCache* table_cache,
InternalIterator* iter,
std::vector<std::unique_ptr<FragmentedRangeTombstoneIterator>>
range_del_iters,
FileMetaData* meta, std::vector<BlobFileAddition>* blob_file_additions,
std::vector<SequenceNumber> snapshots,
SequenceNumber earliest_write_conflict_snapshot,
SequenceNumber job_snapshot, SnapshotChecker* snapshot_checker,
bool paranoid_file_checks, InternalStats* internal_stats,
IOStatus* io_status, const std::shared_ptr<IOTracer>& io_tracer,
BlobFileCreationReason blob_creation_reason,
const SeqnoToTimeMapping& seqno_to_time_mapping, EventLogger* event_logger,
int job_id, TableProperties* table_properties,
Env::WriteLifeTimeHint write_hint, const std::string* full_history_ts_low,
BlobFileCompletionCallback* blob_callback, Version* version,
uint64_t* num_input_entries, uint64_t* memtable_payload_bytes,
uint64_t* memtable_garbage_bytes) {
assert((tboptions.column_family_id ==
TablePropertiesCollectorFactory::Context::kUnknownColumnFamily) ==
tboptions.column_family_name.empty());
auto& mutable_cf_options = tboptions.moptions;
auto& ioptions = tboptions.ioptions;
// Reports the IOStats for flush for every following bytes.
const size_t kReportFlushIOStatsEvery = 1048576;
OutputValidator output_validator(
tboptions.internal_comparator,
/*enable_order_check=*/
mutable_cf_options.check_flush_compaction_key_order,
/*enable_hash=*/paranoid_file_checks);
Status s;
meta->fd.file_size = 0;
iter->SeekToFirst();
std::unique_ptr<CompactionRangeDelAggregator> range_del_agg(
new CompactionRangeDelAggregator(&tboptions.internal_comparator,
snapshots, full_history_ts_low));
uint64_t num_unfragmented_tombstones = 0;
uint64_t total_tombstone_payload_bytes = 0;
for (auto& range_del_iter : range_del_iters) {
num_unfragmented_tombstones +=
range_del_iter->num_unfragmented_tombstones();
total_tombstone_payload_bytes +=
range_del_iter->total_tombstone_payload_bytes();
range_del_agg->AddTombstones(std::move(range_del_iter));
}
std::string fname = TableFileName(ioptions.cf_paths, meta->fd.GetNumber(),
meta->fd.GetPathId());
std::vector<std::string> blob_file_paths;
std::string file_checksum = kUnknownFileChecksum;
std::string file_checksum_func_name = kUnknownFileChecksumFuncName;
EventHelpers::NotifyTableFileCreationStarted(ioptions.listeners, dbname,
tboptions.column_family_name,
fname, job_id, tboptions.reason);
Env* env = db_options.env;
assert(env);
FileSystem* fs = db_options.fs.get();
assert(fs);
TableProperties tp;
bool table_file_created = false;
if (iter->Valid() || !range_del_agg->IsEmpty()) {
std::unique_ptr<CompactionFilter> compaction_filter;
if (ioptions.compaction_filter_factory != nullptr &&
ioptions.compaction_filter_factory->ShouldFilterTableFileCreation(
tboptions.reason)) {
CompactionFilter::Context context;
context.is_full_compaction = false;
context.is_manual_compaction = false;
context.column_family_id = tboptions.column_family_id;
context.reason = tboptions.reason;
compaction_filter =
ioptions.compaction_filter_factory->CreateCompactionFilter(context);
if (compaction_filter != nullptr &&
!compaction_filter->IgnoreSnapshots()) {
s.PermitUncheckedError();
return Status::NotSupported(
"CompactionFilter::IgnoreSnapshots() = false is not supported "
"anymore.");
}
}
TableBuilder* builder;
std::unique_ptr<WritableFileWriter> file_writer;
{
std::unique_ptr<FSWritableFile> file;
#ifndef NDEBUG
bool use_direct_writes = file_options.use_direct_writes;
TEST_SYNC_POINT_CALLBACK("BuildTable:create_file", &use_direct_writes);
#endif // !NDEBUG
IOStatus io_s = NewWritableFile(fs, fname, &file, file_options);
assert(s.ok());
s = io_s;
if (io_status->ok()) {
*io_status = io_s;
}
if (!s.ok()) {
EventHelpers::LogAndNotifyTableFileCreationFinished(
event_logger, ioptions.listeners, dbname,
tboptions.column_family_name, fname, job_id, meta->fd,
kInvalidBlobFileNumber, tp, tboptions.reason, s, file_checksum,
file_checksum_func_name);
return s;
}
table_file_created = true;
FileTypeSet tmp_set = ioptions.checksum_handoff_file_types;
file->SetIOPriority(tboptions.write_options.rate_limiter_priority);
file->SetWriteLifeTimeHint(write_hint);
file_writer.reset(new WritableFileWriter(
std::move(file), fname, file_options, ioptions.clock, io_tracer,
ioptions.stats, Histograms::SST_WRITE_MICROS, ioptions.listeners,
ioptions.file_checksum_gen_factory.get(),
tmp_set.Contains(FileType::kTableFile), false));
builder = NewTableBuilder(tboptions, file_writer.get());
}
auto ucmp = tboptions.internal_comparator.user_comparator();
MergeHelper merge(
env, ucmp, ioptions.merge_operator.get(), compaction_filter.get(),
ioptions.logger, true /* internal key corruption is not ok */,
snapshots.empty() ? 0 : snapshots.back(), snapshot_checker);
std::unique_ptr<BlobFileBuilder> blob_file_builder(
(mutable_cf_options.enable_blob_files &&
tboptions.level_at_creation >=
mutable_cf_options.blob_file_starting_level &&
blob_file_additions)
? new BlobFileBuilder(
versions, fs, &ioptions, &mutable_cf_options, &file_options,
&(tboptions.write_options), tboptions.db_id,
tboptions.db_session_id, job_id, tboptions.column_family_id,
tboptions.column_family_name, write_hint, io_tracer,
blob_callback, blob_creation_reason, &blob_file_paths,
blob_file_additions)
: nullptr);
const std::atomic<bool> kManualCompactionCanceledFalse{false};
CompactionIterator c_iter(
iter, ucmp, &merge, kMaxSequenceNumber, &snapshots,
earliest_write_conflict_snapshot, job_snapshot, snapshot_checker, env,
ShouldReportDetailedTime(env, ioptions.stats),
true /* internal key corruption is not ok */, range_del_agg.get(),
blob_file_builder.get(), ioptions.allow_data_in_errors,
ioptions.enforce_single_del_contracts,
/*manual_compaction_canceled=*/kManualCompactionCanceledFalse,
true /* must_count_input_entries */,
/*compaction=*/nullptr, compaction_filter.get(),
/*shutting_down=*/nullptr, db_options.info_log, full_history_ts_low);
const size_t ts_sz = ucmp->timestamp_size();
const bool strip_timestamp =
ts_sz > 0 && !ioptions.persist_user_defined_timestamps;
std::string key_after_flush_buf;
c_iter.SeekToFirst();
for (; c_iter.Valid(); c_iter.Next()) {
const Slice& key = c_iter.key();
const Slice& value = c_iter.value();
const ParsedInternalKey& ikey = c_iter.ikey();
Slice key_after_flush = key;
// If user defined timestamps will be stripped from user key after flush,
// the in memory version of the key act logically the same as one with a
// minimum timestamp. We update the timestamp here so file boundary and
// output validator, block builder all see the effect of the stripping.
if (strip_timestamp) {
key_after_flush_buf.clear();
ReplaceInternalKeyWithMinTimestamp(&key_after_flush_buf, key, ts_sz);
key_after_flush = key_after_flush_buf;
}
// Generate a rolling 64-bit hash of the key and values
// Note :
// Here "key" integrates 'sequence_number'+'kType'+'user key'.
s = output_validator.Add(key_after_flush, value);
if (!s.ok()) {
break;
}
builder->Add(key_after_flush, value);
s = meta->UpdateBoundaries(key_after_flush, value, ikey.sequence,
ikey.type);
if (!s.ok()) {
break;
}
// TODO(noetzli): Update stats after flush, too.
// TODO(hx235): Replace `rate_limiter_priority` with `io_activity` for
// flush IO in repair when we have an `Env::IOActivity` enum for it
if ((tboptions.write_options.io_activity == Env::IOActivity::kFlush ||
tboptions.write_options.io_activity == Env::IOActivity::kDBOpen ||
tboptions.write_options.rate_limiter_priority == Env::IO_HIGH) &&
IOSTATS(bytes_written) >= kReportFlushIOStatsEvery) {
ThreadStatusUtil::SetThreadOperationProperty(
ThreadStatus::FLUSH_BYTES_WRITTEN, IOSTATS(bytes_written));
}
}
if (!s.ok()) {
c_iter.status().PermitUncheckedError();
} else if (!c_iter.status().ok()) {
s = c_iter.status();
}
if (s.ok()) {
auto range_del_it = range_del_agg->NewIterator();
Slice last_tombstone_start_user_key{};
for (range_del_it->SeekToFirst(); range_del_it->Valid();
range_del_it->Next()) {
auto tombstone = range_del_it->Tombstone();
auto kv = tombstone.Serialize();
// TODO(yuzhangyu): handle range deletion for UDT in memtables only.
builder->Add(kv.first.Encode(), kv.second);
InternalKey tombstone_end = tombstone.SerializeEndKey();
meta->UpdateBoundariesForRange(kv.first, tombstone_end, tombstone.seq_,
tboptions.internal_comparator);
if (version) {
if (last_tombstone_start_user_key.empty() ||
ucmp->CompareWithoutTimestamp(last_tombstone_start_user_key,
range_del_it->start_key()) < 0) {
SizeApproximationOptions approx_opts;
approx_opts.files_size_error_margin = 0.1;
meta->compensated_range_deletion_size += versions->ApproximateSize(
approx_opts, tboptions.read_options, version, kv.first.Encode(),
tombstone_end.Encode(), 0 /* start_level */, -1 /* end_level */,
TableReaderCaller::kFlush);
}
last_tombstone_start_user_key = range_del_it->start_key();
}
}
}
TEST_SYNC_POINT("BuildTable:BeforeFinishBuildTable");
const bool empty = builder->IsEmpty();
if (num_input_entries != nullptr) {
assert(c_iter.HasNumInputEntryScanned());
*num_input_entries =
c_iter.NumInputEntryScanned() + num_unfragmented_tombstones;
}
if (!s.ok() || empty) {
builder->Abandon();
} else {
SeqnoToTimeMapping relevant_mapping;
relevant_mapping.CopyFromSeqnoRange(seqno_to_time_mapping,
meta->fd.smallest_seqno,
meta->fd.largest_seqno);
relevant_mapping.SetCapacity(kMaxSeqnoTimePairsPerSST);
relevant_mapping.Enforce(tboptions.file_creation_time);
builder->SetSeqnoTimeTableProperties(
relevant_mapping,
ioptions.compaction_style == CompactionStyle::kCompactionStyleFIFO
? meta->file_creation_time
: meta->oldest_ancester_time);
s = builder->Finish();
}
if (io_status->ok()) {
*io_status = builder->io_status();
}
if (s.ok() && !empty) {
uint64_t file_size = builder->FileSize();
meta->fd.file_size = file_size;
meta->tail_size = builder->GetTailSize();
meta->marked_for_compaction = builder->NeedCompact();
meta->user_defined_timestamps_persisted =
ioptions.persist_user_defined_timestamps;
assert(meta->fd.GetFileSize() > 0);
tp = builder
->GetTableProperties(); // refresh now that builder is finished
if (memtable_payload_bytes != nullptr &&
memtable_garbage_bytes != nullptr) {
const CompactionIterationStats& ci_stats = c_iter.iter_stats();
uint64_t total_payload_bytes = ci_stats.total_input_raw_key_bytes +
ci_stats.total_input_raw_value_bytes +
total_tombstone_payload_bytes;
uint64_t total_payload_bytes_written =
(tp.raw_key_size + tp.raw_value_size);
// Prevent underflow, which may still happen at this point
// since we only support inserts, deletes, and deleteRanges.
if (total_payload_bytes_written <= total_payload_bytes) {
*memtable_payload_bytes = total_payload_bytes;
*memtable_garbage_bytes =
total_payload_bytes - total_payload_bytes_written;
} else {
*memtable_payload_bytes = 0;
*memtable_garbage_bytes = 0;
}
}
if (table_properties) {
*table_properties = tp;
}
}
delete builder;
// Finish and check for file errors
TEST_SYNC_POINT("BuildTable:BeforeSyncTable");
IOOptions opts;
*io_status =
WritableFileWriter::PrepareIOOptions(tboptions.write_options, opts);
if (s.ok() && io_status->ok() && !empty) {
StopWatch sw(ioptions.clock, ioptions.stats, TABLE_SYNC_MICROS);
*io_status = file_writer->Sync(opts, ioptions.use_fsync);
}
TEST_SYNC_POINT("BuildTable:BeforeCloseTableFile");
if (s.ok() && io_status->ok() && !empty) {
*io_status = file_writer->Close(opts);
}
if (s.ok() && io_status->ok() && !empty) {
// Add the checksum information to file metadata.
meta->file_checksum = file_writer->GetFileChecksum();
meta->file_checksum_func_name = file_writer->GetFileChecksumFuncName();
file_checksum = meta->file_checksum;
file_checksum_func_name = meta->file_checksum_func_name;
// Set unique_id only if db_id and db_session_id exist
if (!tboptions.db_id.empty() && !tboptions.db_session_id.empty()) {
if (!GetSstInternalUniqueId(tboptions.db_id, tboptions.db_session_id,
meta->fd.GetNumber(), &(meta->unique_id))
.ok()) {
// if failed to get unique id, just set it Null
meta->unique_id = kNullUniqueId64x2;
}
}
}
if (s.ok()) {
s = *io_status;
}
// TODO(yuzhangyu): handle the key copy in the blob when ts should be
// stripped.
if (blob_file_builder) {
if (s.ok()) {
s = blob_file_builder->Finish();
} else {
blob_file_builder->Abandon(s);
}
blob_file_builder.reset();
}
// TODO Also check the IO status when create the Iterator.
TEST_SYNC_POINT("BuildTable:BeforeOutputValidation");
if (s.ok() && !empty) {
// Verify that the table is usable
// We set for_compaction to false and don't OptimizeForCompactionTableRead
// here because this is a special case after we finish the table building.
// No matter whether use_direct_io_for_flush_and_compaction is true,
// the goal is to cache it here for further user reads.
std::unique_ptr<InternalIterator> it(table_cache->NewIterator(
tboptions.read_options, file_options, tboptions.internal_comparator,
*meta, nullptr /* range_del_agg */,
mutable_cf_options.prefix_extractor, nullptr,
(internal_stats == nullptr) ? nullptr
: internal_stats->GetFileReadHist(0),
TableReaderCaller::kFlush, /*arena=*/nullptr,
/*skip_filter=*/false, tboptions.level_at_creation,
MaxFileSizeForL0MetaPin(mutable_cf_options),
/*smallest_compaction_key=*/nullptr,
/*largest_compaction_key*/ nullptr,
/*allow_unprepared_value*/ false,
mutable_cf_options.block_protection_bytes_per_key));
s = it->status();
if (s.ok() && paranoid_file_checks) {
OutputValidator file_validator(tboptions.internal_comparator,
/*enable_order_check=*/true,
/*enable_hash=*/true);
for (it->SeekToFirst(); it->Valid(); it->Next()) {
// Generate a rolling 64-bit hash of the key and values
file_validator.Add(it->key(), it->value()).PermitUncheckedError();
}
s = it->status();
if (s.ok() && !output_validator.CompareValidator(file_validator)) {
s = Status::Corruption("Paranoid checksums do not match");
}
}
}
}
// Check for input iterator errors
if (!iter->status().ok()) {
s = iter->status();
}
if (!s.ok() || meta->fd.GetFileSize() == 0) {
TEST_SYNC_POINT("BuildTable:BeforeDeleteFile");
constexpr IODebugContext* dbg = nullptr;
if (table_file_created) {
IOOptions opts;
Status prepare =
WritableFileWriter::PrepareIOOptions(tboptions.write_options, opts);
if (prepare.ok()) {
Status ignored = fs->DeleteFile(fname, opts, dbg);
ignored.PermitUncheckedError();
}
}
assert(blob_file_additions || blob_file_paths.empty());
if (blob_file_additions) {
for (const std::string& blob_file_path : blob_file_paths) {
Status ignored = DeleteDBFile(&db_options, blob_file_path, dbname,
/*force_bg=*/false, /*force_fg=*/false);
ignored.PermitUncheckedError();
TEST_SYNC_POINT("BuildTable::AfterDeleteFile");
}
}
}
Status status_for_listener = s;
if (meta->fd.GetFileSize() == 0) {
fname = "(nil)";
if (s.ok()) {
status_for_listener = Status::Aborted("Empty SST file not kept");
}
}
// Output to event logger and fire events.
EventHelpers::LogAndNotifyTableFileCreationFinished(
event_logger, ioptions.listeners, dbname, tboptions.column_family_name,
fname, job_id, meta->fd, meta->oldest_blob_file_number, tp,
tboptions.reason, status_for_listener, file_checksum,
file_checksum_func_name);
return s;
}
} // namespace ROCKSDB_NAMESPACE