mirror of
https://github.com/facebook/rocksdb.git
synced 2026-07-07 14:47:40 +08:00
Josh Kang
36d4b2e075
External file ingestion (`DB::IngestExternalFile[s]`) re-opens every SST file and scans it -- footer, properties, index, filter, and the first/last data blocks -- to recompute the boundary keys, sequence-number bounds, and table properties before committing. For cold, I/O-bound files this scan dominates ingest latency, even when the file is moved/linked rather than copied.
This change lets a caller skip that work when it already has the file's metadata. `SstFileWriter::Finish()` now populates the full `ExternalSstFileInfo` (its `smallest_internal_key`, `largest_internal_key`, and `table_properties`), and a new `IngestExternalFileArg::file_infos` field carries one `ExternalSstFileInfo` per file into `IngestExternalFiles()`. When set, ingestion reuses that metadata instead of re-opening and scanning each file. The file is still copied/linked, and the checksum is still verified when `verify_checksums_before_ingest` is set (the fast path opens the file only for that). Range tombstones and user-defined-timestamp files (including the "UDT in Memtables only" format, whose boundary keys carry no timestamp) are handled.
Internally, ingestion-job metadata acquisition was split into `GetIngestedFileInfoFromFileInfo` (reuse caller metadata) and `GetIngestedFileInfoFromFile` (open + scan).
## Benchmark results
`db_bench` `ingestexternalfile` benchmark, release build, on SSD (btrfs). Files are linked (`move_files`) so the measurement isolates the ingest path rather than file-copy throughput.
| Config | Ingest latency / call (P50) |
| --- | --- |
| Baseline (open + scan each file) | 28,111 us |
| `--ingest_external_file_use_file_info=true` | 18,444 us |
~34% lower median ingest latency by skipping the per-file open + scan (a warm/page-cache number; the gain is larger for cold files).
Command:
```
make clean && DEBUG_LEVEL=0 make -j$(nproc) db_bench
B=/data/$USER/ingest_bench
for fi in false true; do
rm -rf $B
./db_bench --benchmarks=ingestexternalfile --num=1000000 --value_size=100 \
--compression_type=none --ingest_external_file_batch_size=10 \
--ingest_external_file_num_batches=10 --disable_auto_compactions=1 \
--statistics --db=$B --ingest_external_file_use_file_info=$fi 2>&1 \
| grep rocksdb.ingest.external.file.micros
done
```
Differential Revision: [D107721261](https://our.internmc.facebook.com/intern/diff/D107721261/)
**NOTE FOR REVIEWERS**: This PR has internal Meta-specific changes or comments, please review them on [Phabricator](https://our.internmc.facebook.com/intern/diff/D107721261/)!
ghstack-source-id: 390599675
Pull-Request: https://github.com/facebook/rocksdb/pull/14835
34 lines
1.2 KiB
C++
34 lines
1.2 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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#pragma once
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#include <cstdint>
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#include <string>
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#include "rocksdb/table_properties.h"
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namespace ROCKSDB_NAMESPACE {
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// Definition of the type that is opaque to public API users (declared only as a
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// forward declaration in rocksdb/options.h and rocksdb/sst_file_writer.h).
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// Produced by SstFileWriter::Finish and consumed by ExternalSstFileIngestionJob
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// so ingestion can skip re-opening and scanning the file to recompute its
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// metadata.
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struct PreparedFileInfo {
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uint64_t file_size = 0;
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// Encoded internal keys (user key + 8-byte footer), with the user-defined
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// timestamp stripped when timestamps are not persisted.
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std::string smallest_internal_key;
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std::string largest_internal_key;
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// Range-deletion boundary user keys (timestamp-stripped when applicable);
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// empty when the file has no range deletions.
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std::string smallest_range_del_key;
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std::string largest_range_del_key;
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TableProperties table_properties;
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};
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} // namespace ROCKSDB_NAMESPACE
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