Commit graph

362 commits

Author SHA1 Message Date
Changyu Bi 5620efc794 Remove deprecated option ignore_max_compaction_bytes_for_input (#12323)
Summary:
The option is introduced in https://github.com/facebook/rocksdb/issues/10835 to allow disabling the new compaction behavior if it's not safe. The option is enabled by default and there has not been a need to disable it. So it should be safe to remove now.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12323

Reviewed By: ajkr

Differential Revision: D53330336

Pulled By: cbi42

fbshipit-source-id: 36eef4664ac96b3a7ed627c48bd6610b0a7eafc5
2024-02-02 17:09:42 -08:00
Changyu Bi ace1721b28 Remove deprecated option level_compaction_dynamic_file_size (#12325)
Summary:
The option is introduced in https://github.com/facebook/rocksdb/issues/10655 to allow reverting to old behavior. The option is enabled by default and there has not been a need to disable it. Remove it for 9.0 release. Also fixed and improved a few unit tests that depended on setting this option to false.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12325

Test Plan: existing tests.

Reviewed By: hx235

Differential Revision: D53369430

Pulled By: cbi42

fbshipit-source-id: 0ec2440ca8d88db7f7211c581542c7581bd4d3de
2024-02-02 15:37:40 -08:00
Peter Dillinger 1d6dbfb8b7 Rename IntTblPropCollector -> InternalTblPropColl (#12320)
Summary:
I've always found this name difficult to read, because it sounds like it's for collecting int(eger)
table properties.

I'm fixing this now to set up for a change that I have stubbed out in the public API (table_properties.h):
a new adapter function `TablePropertiesCollector::AsInternal()` that allows RocksDB-provided
TablePropertiesCollectors (such as CompactOnDeletionCollector) to implement the easier-to-upgrade
internal interface while still (superficially) implementing the public interface. In addition to added flexibility,
this should be a performance improvement as the adapter class UserKeyTablePropertiesCollector can be
avoided for such cases where a RocksDB-provided collector is used (AsInternal() returns non-nullptr).

table_properties.h is the only file with changes that aren't simple find-replace renaming.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12320

Test Plan: existing tests, CI

Reviewed By: ajkr

Differential Revision: D53336945

Pulled By: pdillinger

fbshipit-source-id: 02535bcb30bbfb00e29e8478af62e5dad50a63b8
2024-02-02 14:14:43 -08:00
Andrew Kryczka f9d45358ca Removed check_flush_compaction_key_order (#12311)
Summary:
`check_flush_compaction_key_order` option was introduced for the key order checking online validation. It gave users the ability to disable the validation without downgrade in case the validation caused inefficiencies or false positives. Over time this validation has shown to be cheap and correct, so the option to disable it can now be removed.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12311

Reviewed By: cbi42

Differential Revision: D53233379

Pulled By: ajkr

fbshipit-source-id: 1384361104021d6e3e580dce2ec123f9f99ce637
2024-01-31 16:30:26 -08:00
Peter Dillinger 76c834e441 Remove 'virtual' when implied by 'override' (#12319)
Summary:
... to follow modern C++ style / idioms.

Used this hack:
```
for FILE in `cat my_list_of_files`; do perl -pi -e 'BEGIN{undef $/;} s/ virtual( [^;{]* override)/$1/smg' $FILE; done
```

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12319

Test Plan: existing tests, CI

Reviewed By: jaykorean

Differential Revision: D53275303

Pulled By: pdillinger

fbshipit-source-id: bc0881af270aa8ef4d0ae4f44c5a6614b6407377
2024-01-31 13:14:42 -08:00
Yu Zhang 071a146fa0 Add support for range deletion when user timestamps are not persisted (#12254)
Summary:
For the user defined timestamps in memtable only feature, some special handling for range deletion blocks are needed since both the key (start_key) and the value (end_key) of a range tombstone can contain user-defined timestamps. Handling for the key is taken care of in the same way as the other data blocks in the block based table. This PR adds the special handling needed for the value (end_key) part. This includes:

1) On the write path, when L0 SST files are first created from flush, user-defined timestamps are removed from an end key of a range tombstone. There are places where it's logically removed (replaced with a min timestamp) because there is still logic with the running comparator that expects a user key that contains timestamp. And in the block based builder, it is eventually physically removed before persisted in a block.

2) On the read path, when range deletion block is being read, we artificially pad a min timestamp to the end key of a range tombstone in `BlockBasedTableReader`.

3) For file boundary `FileMetaData.largest`, we artificially pad a max timestamp to it if it contains a range deletion sentinel. Anytime when range deletion end_key is used to update file boundaries, it's using max timestamp instead of the range tombstone's actual timestamp to mark it as an exclusive end. d69628e6ce/db/dbformat.h (L923-L935)
This max timestamp is removed when in memory `FileMetaData.largest` is persisted into Manifest, we pad it back when it's read from Manifest while handling related `VersionEdit` in `VersionEditHandler`.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12254

Test Plan: Added unit test and enabled this feature combination's stress test.

Reviewed By: cbi42

Differential Revision: D52965527

Pulled By: jowlyzhang

fbshipit-source-id: e8315f8a2c5268e2ae0f7aec8012c266b86df985
2024-01-29 11:37:34 -08:00
Peter Dillinger 4e60663b31 Remove unnecessary, confusing 'extern' (#12300)
Summary:
In C++, `extern` is redundant in a number of cases:
* "Global" function declarations and definitions
* "Global" variable definitions when already declared `extern`

For consistency and simplicity, I've removed these in code that *we own*. In a couple of cases, I removed obsolete declarations, and for MagicNumber constants, I have consolidated the declarations into a header file (format.h)
as standard best practice would prescribe.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12300

Test Plan: no functional changes, CI

Reviewed By: ajkr

Differential Revision: D53148629

Pulled By: pdillinger

fbshipit-source-id: fb8d927959892e03af09b0c0d542b0a3b38fd886
2024-01-29 10:38:08 -08:00
Changyu Bi 2233a2f4c0 Enhance corruption status message for record mismatch in compaction (#12297)
Summary:
... to include the actual numbers of processed and expected records, and the file number for input files. The purpose is to be able to find the offending files even when the relevant LOG file is gone.

Another change is to check the record count even when `compaction_verify_record_count` is false, and log a warning message without setting corruption status if there is a mismatch. This is consistent with how we check the record count for flush.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12297

Test Plan:
print the status message in `DBCompactionTest.VerifyRecordCount`
```
before
Corruption: Compaction number of input keys does not match number of keys processed.
after
Compaction number of input keys does not match number of keys processed. Expected 20 but processed 10. Compaction summary: Base version 4 Base level 0, inputs: [11(2156B) 9(2156B)]
```

Reviewed By: ajkr

Differential Revision: D53110130

Pulled By: cbi42

fbshipit-source-id: 6325cbfb8f71f25ce37f23f8277ebe9264863c3b
2024-01-26 09:12:07 -08:00
Hui Xiao 96fb7de3bc Rate-limit un-ratelimited flush/compaction code paths (#12290)
Summary:
**Context/Summary:**

We recently found out some code paths in flush and compaction aren't rate-limited when they should.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12290

Test Plan: existing UT**

Reviewed By: anand1976

Differential Revision: D53066103

Pulled By: hx235

fbshipit-source-id: 9dc4cab5f841230d18e5504dc480ac523e9d3950
2024-01-25 12:00:15 -08:00
Changyu Bi 4b684e96b7 Allow more intra-L0 compaction when L0 is small (#12214)
Summary:
introduce a new option `intra_l0_compaction_size` to allow more intra-L0 compaction when total L0 size is under a threshold. This option applies only to leveled compaction. It is enabled by default and set to `max_bytes_for_level_base / max_bytes_for_level_multiplier` only for atomic_flush users. When atomic_flush=true, it is more likely that some CF's total L0 size is small when it's eligible for compaction. This option aims to reduce write amplification in this case.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12214

Test Plan:
- new unit test
- benchmark:
```
TEST_TMPDIR=/dev/shm ./db_bench --benchmarks=fillrandom --write_buffer_size=51200 --max_bytes_for_level_base=5242880 --level0_file_num_compaction_trigger=4 --statistics=1

main:
fillrandom   :     234.499 micros/op 4264 ops/sec 234.499 seconds 1000000 operations;    0.5 MB/s
rocksdb.compact.read.bytes COUNT : 1490756235
rocksdb.compact.write.bytes COUNT : 1469056734
rocksdb.flush.write.bytes COUNT : 71099011

branch:
fillrandom   :     128.494 micros/op 7782 ops/sec 128.494 seconds 1000000 operations;    0.9 MB/s
rocksdb.compact.read.bytes COUNT : 807474156
rocksdb.compact.write.bytes COUNT : 781977610
rocksdb.flush.write.bytes COUNT : 71098785
```

Reviewed By: ajkr

Differential Revision: D52637771

Pulled By: cbi42

fbshipit-source-id: 4f2c7925d0c3a718635c948ea0d4981ed9fabec3
2024-01-22 10:23:57 -08:00
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
Hui Xiao 06e593376c Group SST write in flush, compaction and db open with new stats (#11910)
Summary:
## Context/Summary
Similar to https://github.com/facebook/rocksdb/pull/11288, https://github.com/facebook/rocksdb/pull/11444, categorizing SST/blob file write according to different io activities allows more insight into the activity.

For that, this PR does the following:
- Tag different write IOs by passing down and converting WriteOptions to IOOptions
- Add new SST_WRITE_MICROS histogram in WritableFileWriter::Append() and breakdown FILE_WRITE_{FLUSH|COMPACTION|DB_OPEN}_MICROS

Some related code refactory to make implementation cleaner:
- Blob stats
   - Replace high-level write measurement with low-level WritableFileWriter::Append() measurement for BLOB_DB_BLOB_FILE_WRITE_MICROS. This is to make FILE_WRITE_{FLUSH|COMPACTION|DB_OPEN}_MICROS  include blob file. As a consequence, this introduces some behavioral changes on it, see HISTORY and db bench test plan below for more info.
   - Fix bugs where BLOB_DB_BLOB_FILE_SYNCED/BLOB_DB_BLOB_FILE_BYTES_WRITTEN include file failed to sync and bytes failed to write.
- Refactor WriteOptions constructor for easier construction with io_activity and rate_limiter_priority
- Refactor DBImpl::~DBImpl()/BlobDBImpl::Close() to bypass thread op verification
- Build table
   - TableBuilderOptions now includes Read/WriteOpitons so BuildTable() do not need to take these two variables
   - Replace the io_priority passed into BuildTable() with TableBuilderOptions::WriteOpitons::rate_limiter_priority. Similar for BlobFileBuilder.
This parameter is used for dynamically changing file io priority for flush, see  https://github.com/facebook/rocksdb/pull/9988?fbclid=IwAR1DtKel6c-bRJAdesGo0jsbztRtciByNlvokbxkV6h_L-AE9MACzqRTT5s for more
   - Update ThreadStatus::FLUSH_BYTES_WRITTEN to use io_activity to track flush IO in flush job and db open instead of io_priority

## Test
### db bench

Flush
```
./db_bench --statistics=1 --benchmarks=fillseq --num=100000 --write_buffer_size=100

rocksdb.sst.write.micros P50 : 1.830863 P95 : 4.094720 P99 : 6.578947 P100 : 26.000000 COUNT : 7875 SUM : 20377
rocksdb.file.write.flush.micros P50 : 1.830863 P95 : 4.094720 P99 : 6.578947 P100 : 26.000000 COUNT : 7875 SUM : 20377
rocksdb.file.write.compaction.micros P50 : 0.000000 P95 : 0.000000 P99 : 0.000000 P100 : 0.000000 COUNT : 0 SUM : 0
rocksdb.file.write.db.open.micros P50 : 0.000000 P95 : 0.000000 P99 : 0.000000 P100 : 0.000000 COUNT : 0 SUM : 0
```

compaction, db oopen
```
Setup: ./db_bench --statistics=1 --benchmarks=fillseq --num=10000 --disable_auto_compactions=1 -write_buffer_size=100 --db=../db_bench

Run:./db_bench --statistics=1 --benchmarks=compact  --db=../db_bench --use_existing_db=1

rocksdb.sst.write.micros P50 : 2.675325 P95 : 9.578788 P99 : 18.780000 P100 : 314.000000 COUNT : 638 SUM : 3279
rocksdb.file.write.flush.micros P50 : 0.000000 P95 : 0.000000 P99 : 0.000000 P100 : 0.000000 COUNT : 0 SUM : 0
rocksdb.file.write.compaction.micros P50 : 2.757353 P95 : 9.610687 P99 : 19.316667 P100 : 314.000000 COUNT : 615 SUM : 3213
rocksdb.file.write.db.open.micros P50 : 2.055556 P95 : 3.925000 P99 : 9.000000 P100 : 9.000000 COUNT : 23 SUM : 66
```

blob stats - just to make sure they aren't broken by this PR
```
Integrated Blob DB

Setup: ./db_bench --enable_blob_files=1 --statistics=1 --benchmarks=fillseq --num=10000 --disable_auto_compactions=1 -write_buffer_size=100 --db=../db_bench

Run:./db_bench --enable_blob_files=1 --statistics=1 --benchmarks=compact  --db=../db_bench --use_existing_db=1

pre-PR:
rocksdb.blobdb.blob.file.write.micros P50 : 7.298246 P95 : 9.771930 P99 : 9.991813 P100 : 16.000000 COUNT : 235 SUM : 1600
rocksdb.blobdb.blob.file.synced COUNT : 1
rocksdb.blobdb.blob.file.bytes.written COUNT : 34842

post-PR:
rocksdb.blobdb.blob.file.write.micros P50 : 2.000000 P95 : 2.829360 P99 : 2.993779 P100 : 9.000000 COUNT : 707 SUM : 1614
- COUNT is higher and values are smaller as it includes header and footer write
- COUNT is 3X higher due to each Append() count as one post-PR, while in pre-PR, 3 Append()s counts as one. See https://github.com/facebook/rocksdb/pull/11910/files#diff-32b811c0a1c000768cfb2532052b44dc0b3bf82253f3eab078e15ff201a0dabfL157-L164

rocksdb.blobdb.blob.file.synced COUNT : 1 (stay the same)
rocksdb.blobdb.blob.file.bytes.written COUNT : 34842 (stay the same)
```

```
Stacked Blob DB

Run: ./db_bench --use_blob_db=1 --statistics=1 --benchmarks=fillseq --num=10000 --disable_auto_compactions=1 -write_buffer_size=100 --db=../db_bench

pre-PR:
rocksdb.blobdb.blob.file.write.micros P50 : 12.808042 P95 : 19.674497 P99 : 28.539683 P100 : 51.000000 COUNT : 10000 SUM : 140876
rocksdb.blobdb.blob.file.synced COUNT : 8
rocksdb.blobdb.blob.file.bytes.written COUNT : 1043445

post-PR:
rocksdb.blobdb.blob.file.write.micros P50 : 1.657370 P95 : 2.952175 P99 : 3.877519 P100 : 24.000000 COUNT : 30001 SUM : 67924
- COUNT is higher and values are smaller as it includes header and footer write
- COUNT is 3X higher due to each Append() count as one post-PR, while in pre-PR, 3 Append()s counts as one. See https://github.com/facebook/rocksdb/pull/11910/files#diff-32b811c0a1c000768cfb2532052b44dc0b3bf82253f3eab078e15ff201a0dabfL157-L164

rocksdb.blobdb.blob.file.synced COUNT : 8 (stay the same)
rocksdb.blobdb.blob.file.bytes.written COUNT : 1043445 (stay the same)
```

###  Rehearsal CI stress test
Trigger 3 full runs of all our CI stress tests

###  Performance

Flush
```
TEST_TMPDIR=/dev/shm ./db_basic_bench_pre_pr --benchmark_filter=ManualFlush/key_num:524288/per_key_size:256 --benchmark_repetitions=1000
-- default: 1 thread is used to run benchmark; enable_statistics = true

Pre-pr: avg 507515519.3 ns
497686074,499444327,500862543,501389862,502994471,503744435,504142123,504224056,505724198,506610393,506837742,506955122,507695561,507929036,508307733,508312691,508999120,509963561,510142147,510698091,510743096,510769317,510957074,511053311,511371367,511409911,511432960,511642385,511691964,511730908,

Post-pr: avg 511971266.5 ns, regressed 0.88%
502744835,506502498,507735420,507929724,508313335,509548582,509994942,510107257,510715603,511046955,511352639,511458478,512117521,512317380,512766303,512972652,513059586,513804934,513808980,514059409,514187369,514389494,514447762,514616464,514622882,514641763,514666265,514716377,514990179,515502408,
```

Compaction
```
TEST_TMPDIR=/dev/shm ./db_basic_bench_{pre|post}_pr --benchmark_filter=ManualCompaction/comp_style:0/max_data:134217728/per_key_size:256/enable_statistics:1  --benchmark_repetitions=1000
-- default: 1 thread is used to run benchmark

Pre-pr: avg 495346098.30 ns
492118301,493203526,494201411,494336607,495269217,495404950,496402598,497012157,497358370,498153846

Post-pr: avg 504528077.20, regressed 1.85%. "ManualCompaction" include flush so the isolated regression for compaction should be around 1.85-0.88 = 0.97%
502465338,502485945,502541789,502909283,503438601,504143885,506113087,506629423,507160414,507393007
```

Put with WAL (in case passing WriteOptions slows down this path even without collecting SST write stats)
```
TEST_TMPDIR=/dev/shm ./db_basic_bench_pre_pr --benchmark_filter=DBPut/comp_style:0/max_data:107374182400/per_key_size:256/enable_statistics:1/wal:1  --benchmark_repetitions=1000
-- default: 1 thread is used to run benchmark

Pre-pr: avg 3848.10 ns
3814,3838,3839,3848,3854,3854,3854,3860,3860,3860

Post-pr: avg 3874.20 ns, regressed 0.68%
3863,3867,3871,3874,3875,3877,3877,3877,3880,3881
```

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11910

Reviewed By: ajkr

Differential Revision: D49788060

Pulled By: hx235

fbshipit-source-id: 79e73699cda5be3b66461687e5147c2484fc5eff
2023-12-29 15:29:23 -08:00
anand76 a036525809 Lightweight verification of MANIFEST file after close on shutdown (#12174)
Summary:
Do a size verification on the MANIFEST file during DB shutdown, after closing the file. If the verification fails, write a new MANIFEST file. In the future, we can do a more thorough verification if we want to.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12174

Test Plan: Unit test, and some manual verification

Reviewed By: ajkr

Differential Revision: D52451184

Pulled By: anand1976

fbshipit-source-id: fc3bc170e22f6c9a9c482ee5ff592abab889df83
2023-12-28 18:25:29 -08:00
hulk b7ecbe309d Trigger compaction to the next level if the data age exceeds periodic_compaction_seconds (#12175)
Summary:
Currently, the data are always compacted to the same level if exceed periodic_compaction_seconds which may confuse users, so we change it to allow trigger compaction to the next level here. It's a behavior change to users, and may affect users
who have disabled their ttl or ttl > periodic_compaction_seconds.

Relate issue: https://github.com/facebook/rocksdb/issues/12165

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12175

Reviewed By: ajkr

Differential Revision: D52446722

Pulled By: cbi42

fbshipit-source-id: ccd3d2c6434ed77055735a03408d4a62d119342f
2023-12-28 12:50:08 -08:00
Changyu Bi 3d81f175b4 Prioritize marked file in level compaction (#12187)
Summary:
When ranking file by compaction priority in a level, prioritize files marked for compaction over files that are not marked. This only applies to default CompactPri kMinOverlappingRatio for now.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12187

Test Plan: * New unit tests

Reviewed By: ajkr

Differential Revision: D52437194

Pulled By: cbi42

fbshipit-source-id: 65ea9ce5bb421e598d539a55c8219b70844b82b3
2023-12-28 10:28:37 -08:00
Changyu Bi fb5c8c7ea3 Do not compare op_type in WithinPenultimateLevelOutputRange() (#12081)
Summary:
`WithinPenultimateLevelOutputRange()` is updated in https://github.com/facebook/rocksdb/issues/12063 to check internal key range. However, op_type of a key can change during compaction, e.g. MERGE -> PUT, which makes a key larger and becomes out of penultimate output range. This has caused stress test failures with error message "Unsafe to store Seq later than snapshot in the last level if per_key_placement is enabled". So update `WithinPenultimateLevelOutputRange()` to only check user key and sequence number.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12081

Test Plan:
* This repro can produce the corruption within a few runs. Ran it a few times after the fix and did not see Corruption failure.
```
python3 ./tools/db_crashtest.py whitebox --test_tiered_storage --random_kill_odd=888887 --use_merge=1 --writepercent=100 --readpercent=0 --prefixpercent=0 --delpercent=0 --delrangepercent=0 --iterpercent=0 --write_buffer_size=419430 --column_families=1 --read_fault_one_in=0 --write_fault_one_in=0
```

Reviewed By: ajkr

Differential Revision: D51481202

Pulled By: cbi42

fbshipit-source-id: cad6b65099733e03071b496e752bbdb09cf4db82
2023-11-20 17:07:28 -08:00
Changyu Bi 4e58cc6437 Check internal key range when compacting from last level to penultimate level (#12063)
Summary:
The test failure in https://github.com/facebook/rocksdb/issues/11909 shows that we may compact keys outside of internal key range of penultimate level input files from last level to penultimate level, which can potentially cause overlapping files in the penultimate level. This PR updates the  `Compaction::WithinPenultimateLevelOutputRange()` to check internal key range instead of user key.

Other fixes:
* skip range del sentinels when deciding output level for tiered compaction

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12063

Test Plan:
- existing unit tests
- apply the fix to https://github.com/facebook/rocksdb/issues/11905 and run `./tiered_compaction_test --gtest_filter="*RangeDelsCauseFileEndpointsToOverlap*"`

Reviewed By: ajkr

Differential Revision: D51288985

Pulled By: cbi42

fbshipit-source-id: 70085db5f5c3b15300bcbc39057d57b83fd9902a
2023-11-17 10:50:40 -08:00
Changyu Bi e7896f03ad Enable unit test PrecludeLastLevelTest.RangeDelsCauseFileEndpointsToOverlap (#12064)
Summary:
Fixes https://github.com/facebook/rocksdb/issues/11909. The test passes after the change in https://github.com/facebook/rocksdb/issues/11917 to start mock clock from a non-zero time.

The reason for test failing is a bit complicated:
- The Put here e4ad4a0ef1/db/compaction/tiered_compaction_test.cc (L2045) happens before mock clock advances beyond 0.
- This causes oldest_key_time_ to be 0 for memtable.
- oldest_ancester_time of the first L0 file becomes 0
- L0 -> L5/6 compaction output files sets `oldest_ancestoer_time` to the current time due to these lines: 509947ce2c/db/compaction/compaction_job.cc (L1898C34-L1904).
- This causes some small sequence number to be mapped to current time: 509947ce2c/db/compaction/compaction_job.cc (L301)
- Keys in L6 is being moved up to L5 due to the unexpected seqno_to_time mapping
- When compacting keys from last level to the penultimate level, we only check keys to be within user key range of penultimate level input files. If we compact the following file 3 with file 1 and output keys to L5, we can get the reported inconsistency bug.
```
L5: file 1 [K5@20, K10@kMaxSeqno], file 2 [K10@30, K14@34)
L6: file 3 [K6@5, K10@20]
```

https://github.com/facebook/rocksdb/issues/12063 will add fixes to check internal key range when compacting keys from last level up to the penultimate level.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12064

Test Plan: the unit test passes

Reviewed By: ajkr

Differential Revision: D51281149

Pulled By: cbi42

fbshipit-source-id: 00b7f026c453454d9f3af5b2de441383a96f0c62
2023-11-13 15:26:52 -08:00
Yu Zhang 509947ce2c Quarantine files in a limbo state after a manifest error (#12030)
Summary:
Part of the procedures to handle manifest IO error is to disable file deletion in case some files in limbo state get deleted prematurely. This is not ideal because: 1) not all the VersionEdits whose commit encounter such an error contain updates for files, disabling file deletion sometimes are not necessary. 2) `EnableFileDeletion` has a force mode that could make other threads accidentally disrupt this procedure in recovery.  3) Disabling file deletion as a whole is also not as efficient as more precisely tracking impacted files from being prematurely deleted.  This PR replaces this mechanism with tracking such files and quarantine them from being deleted in `ErrorHandler`.

These are the types of files being actively tracked in quarantine in this PR:
1) new table files and blob files from a background job
2) old manifest file whose immediately following new manifest file's CURRENT file creation gets into unclear state. Current handling is not sufficient to make sure the old manifest file is kept in case it's needed.

Note that WAL logs are not part of the quarantine because `min_log_number_to_keep` is a safe mechanism and it's only updated after successful manifest commits so it can prevent this premature deletion issue from happening.

We track these files' file numbers because they share the same file number space.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12030

Test Plan: Modified existing unit tests

Reviewed By: ajkr

Differential Revision: D51036774

Pulled By: jowlyzhang

fbshipit-source-id: 84ef26271fbbc888ef70da5c40fe843bd7038716
2023-11-11 08:11:11 -08:00
Jay Huh 2dab137182 Mark more files for periodic compaction during offpeak (#12031)
Summary:
- The struct previously named `OffpeakTimeInfo` has been renamed to `OffpeakTimeOption` to indicate that it's a user-configurable option. Additionally, a new struct, `OffpeakTimeInfo`, has been introduced, which includes two fields: `is_now_offpeak` and `seconds_till_next_offpeak_start`. This change prevents the need to parse the `daily_offpeak_time_utc` string twice.
- It's worth noting that we may consider adding more fields to the `OffpeakTimeInfo` struct, such as `elapsed_seconds` and `total_seconds`, as needed for further optimization.
- Within `VersionStorageInfo::ComputeFilesMarkedForPeriodicCompaction()`, we've adjusted the `allowed_time_limit` to include files that are expected to expire by the next offpeak start.
- We might explore further optimizations, such as evenly distributing files to mark during offpeak hours, if the initial approach results in marking too many files simultaneously during the first scoring in offpeak hours. The primary objective of this PR is to prevent periodic compactions during non-offpeak hours when offpeak hours are configured. We'll start with this straightforward solution and assess whether it suffices for now.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12031

Test Plan:
Unit Tests added
- `DBCompactionTest::LevelPeriodicCompactionOffpeak` for Leveled
- `DBTestUniversalCompaction2::PeriodicCompaction` for Universal

Reviewed By: cbi42

Differential Revision: D50900292

Pulled By: jaykorean

fbshipit-source-id: 267e7d3332d45a5d9881796786c8650fa0a3b43d
2023-11-06 11:43:59 -08:00
Jay Huh e230e4d248 Make OffpeakTimeInfo available in VersionSet (#12018)
Summary:
As mentioned in  https://github.com/facebook/rocksdb/issues/11893, we are going to use the offpeak time information to pre-process TTL-based compactions. To do so, we need to access `daily_offpeak_time_utc` in `VersionStorageInfo::ComputeCompactionScore()` where we pick the files to compact. This PR is to make the offpeak time information available at the time of compaction-scoring. We are not changing any compaction scoring logic just yet. Will follow up in a separate PR.

There were two ways to achieve what we want.
1.  Make `MutableDBOptions` available in `ColumnFamilyData` and `ComputeCompactionScore()` take `MutableDBOptions` along with `ImmutableOptions` and `MutableCFOptions`.
2. Make `daily_offpeak_time_utc` and `IsNowOffpeak()` available in `VersionStorageInfo`.

We chose the latter as it involves smaller changes.

This change includes the following
- Introduction of `OffpeakTimeInfo` and `IsNowOffpeak()` has been moved from `MutableDBOptions`
- `OffpeakTimeInfo` added to `VersionSet` and it can be set during construction and by `ChangeOffpeakTimeInfo()`
- During `SetDBOptions()`, if offpeak time info needs to change, it calls `MaybeScheduleFlushOrCompaction()` to re-compute compaction scores and process compactions as needed

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12018

Test Plan:
- `DBOptionsTest::OffpeakTimes` changed to include checks for `MaybeScheduleFlushOrCompaction()` calls and `VersionSet`'s OffpeakTimeInfo value change during `SetDBOptions()`.
- `VersionSetTest::OffpeakTimeInfoTest` added to test `ChangeOffpeakTimeInfo()`. `IsNowOffpeak()` tests moved from `DBOptionsTest::OffpeakTimes`

Reviewed By: pdillinger

Differential Revision: D50723881

Pulled By: jaykorean

fbshipit-source-id: 3cff0291936f3729c0e9c7750834b9378fb435f6
2023-10-27 15:56:48 -07:00
Hui Xiao 0836a2b26d New tickers on deletion compactions grouped by reasons (#11957)
Summary:
Context/Summary: as titled

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11957

Test Plan: piggyback on existing tests; fixed a failed test due to adding new stats

Reviewed By: ajkr, cbi42

Differential Revision: D50294310

Pulled By: hx235

fbshipit-source-id: d99b97ebac41efc1bdeaf9ca7a1debd2927d54cd
2023-10-18 18:00:07 -07:00
Peter Dillinger 1d5bddbc58 Bootstrap, pre-populate seqno_to_time_mapping (#11922)
Summary:
This change has two primary goals (follow-up to https://github.com/facebook/rocksdb/issues/11917, https://github.com/facebook/rocksdb/issues/11920):
* Ensure the DB seqno_to_time_mapping has entries that allow us to put a good time lower bound on any writes that happen after setting up preserve/preclude options (either in a new DB, new CF, SetOptions, etc.) and haven't yet aged out of that time window. This allows us to remove a bunch of work-arounds in tests.
* For new DBs using preserve/preclude options, automatically reserve some sequence numbers and pre-map them to cover the time span back to the preserve/preclude cut-off time. In the future, this will allow us to import data from another DB by key, value, and write time by assigning an appropriate seqno in this DB for that write time.

Note that the pre-population (historical mappings) does not happen if the original options at DB Open time do not have preserve/preclude, so it is recommended to create initial column families at that time with create_missing_column_families, to take advantage of this (future) feature. (Adding these historical mappings after DB Open would risk non-monotonic seqno_to_time_mapping, which is dubious if not dangerous.)

Recommended follow-up:
* Solve existing race conditions (not memory safety) where parallel operations like CreateColumnFamily or SetDBOptions could leave the wrong setting in effect.
* Make SeqnoToTimeMapping more gracefully handle a possible case in which too many mappings are added for the time range of concern. It seems like there could be cases where data is massively excluded from the cold tier because of entries falling off the front of the mapping list (causing GetProximalSeqnoBeforeTime() to return 0). (More investigation needed.)

No release note for the minor bug fix because this is still an experimental feature with limited usage.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11922

Test Plan: tests added / updated

Reviewed By: jowlyzhang

Differential Revision: D49956563

Pulled By: pdillinger

fbshipit-source-id: 92beb918c3a298fae9ca8e509717b1067caa1519
2023-10-06 08:21:21 -07:00
Hui Xiao 8e949116f7 Fix comments about creation_time/oldest_ancester_time/oldest_key_time (#11921)
Summary:
Code reference for the comments change:

40b618f234/table/block_based/block_based_table_builder.cc?fbclid=IwAR0JlfnG8wysclFP5wv0fSngFbi_j32BUCKbFayeGdr10tzDhyyk5QqpclA#L2093

40b618f234/db/flush_job.cc?fbclid=IwAR1ri6eTX3wyD_2fAEBRzFSwZItcbmDS8LaB11k1letDMQmB2L8nF6TfXDs#L945-L949

40b618f234/db/compaction/compaction_job.cc (L1882-L1904)

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11921

Reviewed By: cbi42

Differential Revision: D49921304

Pulled By: hx235

fbshipit-source-id: 2ae17e43c0fd52044404d7b63fea254d2d1f3595
2023-10-04 14:42:35 -07:00
Peter Dillinger 7bebd3036d Update tiered storage tests (ahead of next change) (#11917)
Summary:
After https://github.com/facebook/rocksdb/issues/11905, I am preparing a DBImpl change to ensure all sufficiently recent sequence numbers since Open are covered by SeqnoToTimeMapping. **Intended follow-up**

However, there are a number of test changes I want to make prior to that to make it clear that I am not regressing the tests and production behavior at the same time.

* Start mock time in the tests well beyond epoch (time 0) so that we aren't normally reaching into pre-history for current time minus the preserve/preclude duration.
* Majorly clean up BasicSeqnoToTimeMapping to avoid confusing hard-coded bounds on GetProximalTimeBeforeSeqno() results.
  * There is an unresolved/unexplained issue marked with FIXME that should be investigated when GetProximalTimeBeforeSeqno() is put into production.
* MultiCFs test was strangely generating 5 L0 files, four of which would be compacted into an L1, and then letting TTL compaction compact 1@L0+1@L1. Changing the starting time of the tests seemed to mess up the TTL compaction. But I suspect the TTL compaction was unintentional, so I've cut it down to just 4 L0 files, which compacts predictably.
* Unrelated: allow ROCKSDB_NO_STACK=1 to skip printing a stack trace on assertion failures.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11917

Test Plan: no changes to production code

Reviewed By: jowlyzhang

Differential Revision: D49841436

Pulled By: pdillinger

fbshipit-source-id: 753348ace9c548e82bcb77fcc8b2ffb7a6beeb0a
2023-10-02 16:19:05 -07:00
Peter Dillinger 02443dd93f Refactor, clean up, fixes, and more testing for SeqnoToTimeMapping (#11905)
Summary:
This change is before a planned DBImpl change to ensure all sufficiently recent sequence numbers since Open are covered by SeqnoToTimeMapping (bug fix with existing test work-arounds). **Intended follow-up**

However, I found enough issues with SeqnoToTimeMapping to warrant this PR first, including very small fixes in DB implementation related to API contract of SeqnoToTimeMapping.

Functional fixes / changes:
* This fixes some mishandling of boundary cases. For example, if the user decides to stop writing to DB, the last written sequence number would perpetually have its write time updated to "now" and would always be ineligible for migration to cold tier. Part of the problem is that the SeqnoToTimeMapping would return a seqno known to have been written before (immediately or otherwise) the requested time, but compaction_job.cc would include that seqno in the preserve/exclude set. That is fixed (in part) by adding one in compaction_job.cc
* That problem was worse because a whole range of seqnos could be updated perpetually with new times in SeqnoToTimeMapping::Append (if no writes to DB). That logic was apparently optimized for GetOldestApproximateTime (now GetProximalTimeBeforeSeqno), which is not used in production, to the detriment of GetOldestSequenceNum (now GetProximalSeqnoBeforeTime), which is used in production. (Perhaps plans changed during development?) This is fixed in Append to optimize for accuracy of GetProximalSeqnoBeforeTime. (Unit tests added and updated.)
* Related: SeqnoToTimeMapping did not have a clear contract about the relationships between seqnos and times, just the idea of a rough correspondence. Now the class description makes it clear that the write time of each recorded seqno comes before or at the associated time, to support getting best results for GetProximalSeqnoBeforeTime. And this makes it easier to make clear the contract of each API function.
  * Update `DBImpl::RecordSeqnoToTimeMapping()` to follow this ordering in gathering samples.

Some part of these changes has required an expanded test work-around for the problem (see intended follow-up above) that the DB does not immediately ensure recent seqnos are covered by its mapping. These work-arounds will be removed with that planned work.

An apparent compaction bug is revealed in
PrecludeLastLevelTest::RangeDelsCauseFileEndpointsToOverlap, so that test is disabled. Filed GitHub issue #11909

Cosmetic / code safety things (not exhaustive):
* Fix some confusing names.
  * `seqno_time_mapping` was used inconsistently in places. Now just `seqno_to_time_mapping` to correspond to class name.
  * Rename confusing `GetOldestSequenceNum` -> `GetProximalSeqnoBeforeTime` and `GetOldestApproximateTime` -> `GetProximalTimeBeforeSeqno`. Part of the motivation is that our times and seqnos here have the same underlying type, so we want to be clear about which is expected where to avoid mixing.
  * Rename `kUnknownSeqnoTime` to `kUnknownTimeBeforeAll` because the value is a bad choice for unknown if we ever add ProximalAfterBlah functions.
  * Arithmetic on SeqnoTimePair doesn't make sense except for delta encoding, so use better names / APIs with that in mind.
  * (OMG) Don't allow direct comparison between SeqnoTimePair and SequenceNumber. (There is no checking that it isn't compared against time by accident.)
  * A field name essentially matching the containing class name is a confusing pattern (`seqno_time_mapping_`).
  * Wrap calls to confusing (but useful) upper_bound and lower_bound functions to have clearer names and more code reuse.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11905

Test Plan: GetOldestSequenceNum (now GetProximalSeqnoBeforeTime) and TruncateOldEntries were lacking unit tests, despite both being used in production (experimental feature). Added those and expanded others.

Reviewed By: jowlyzhang

Differential Revision: D49755592

Pulled By: pdillinger

fbshipit-source-id: f72a3baac74d24b963c77e538bba89a7fc8dce51
2023-09-29 11:21:59 -07:00
Hui Xiao 089070cb36 Expose more info about input files in CompactionFilter::Context (#11857)
Summary:
**Context:**
As requested, lowest level as well as a map from input file to its table properties among all input files used in table creation  (if any) are exposed in `CompactionFilter::Context`.

**Summary:**
This PR contains two commits:
(1) [Refactory](0012777f0e) to make resonating/using what is in `Compaction:: table_properties_` easier
- Separate `Compaction:: table_properties_` into `Compaction:: input_table_properties_` and `Compaction:: output_table_properties_`
- Separate the "set input table properties" logic into `Compaction:: SetInputTableProperties()`) from `Compaction:: GetInputTableProperties`
- Call `Compaction:: SetInputTableProperties()` as soon as possible, which is right after `Compaction::SetInputVersion()`. Bundle these two functions into one `Compaction::FinalizeInputInfo()` to minimize missing one or the other

(2) [Expose more info about input files:](6093e7dfba) `CompactionFilter::Context::input_start_level/input_table_properties`

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11857

Test Plan:
- Modify existing UT `
TEST_F(DBTestCompactionFilter, CompactionFilterContextManual)` to cover new logics

Reviewed By: ajkr

Differential Revision: D49402540

Pulled By: hx235

fbshipit-source-id: 469fff50fa0e5964ffa5ea8db0743f61438ea392
2023-09-20 13:34:39 -07:00
Changyu Bi cc254efea6 Release compaction files in manifest write callback (#11764)
Summary:
Fixes https://github.com/facebook/rocksdb/issues/10257 (also see [here](https://github.com/facebook/rocksdb/pull/10355#issuecomment-1684308556)) by releasing compaction files earlier when writing to manifest in LogAndApply().  This is done by passing in a [callback](ba59751430/db/version_set.h (L1199)) to LogAndApply(). The new Version is created in the same critical section where compaction files are released. When compaction picker is picking compaction based on the new version, these compaction files will already be released.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11764

Test Plan:
* Existing unit tests
* A repro unit test to validate that compaction files are released: `./db_compaction_test --gtest_filter=DBCompactionTest.ReleaseCompactionDuringManifestWrite`
* `python3 ./tools/db_crashtest.py --simple whitebox` with some assertions to check compaction files are released

Reviewed By: ajkr

Differential Revision: D48742152

Pulled By: cbi42

fbshipit-source-id: 7560fd0e723a63fe692234015d2b96850f8b5d77
2023-09-18 13:11:53 -07:00
Hui Xiao ef3e289b2d Conditionally exclude some L0 input files in size amp compaction (#11749)
Summary:
**Context/Summary:**
A size amp compaction can select and prevent a large number of L0 files from being selected by other compaction. If such compaction is running long or being queued behind, these L0 files will exist for long. With a few more flushes, we can run into write stop triggered by # L0 files. We've seen this happen on a host with many DBs sharing same thread pool, each of these DBs submits a size amp compaction with (110-180)+ files to the pool upon reopen and with a few more flushes, they hit the 200 L0 write stop condition.

The idea is to exclude some L0 input files in size amp compaction that are harmless to size amp reduction but improve the situation described above.

The exclusion algorithm is in `MightExcludeNewL0sToReduceWriteStop()` with two elements:

1.  #L0 to exclude + (level0_stop_writes_trigger - num_l0_input_pre_exclusion) should be in the range of [min_merge_width, max_merge_width].
    -  This is to ensure we are excluding enough L0 input files but not too many to be qualified to picked for another compaction along with the incoming future L0 files before write stop.
2. Based on (1), further constrain #L0 to exclude based on the post-exclusion compaction score. The goal is to ensure our exclusion will not disqualify the size amp compaction from being a size amp compaction after exclusion.

**Tets plan:** New unit test

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11749

Reviewed By: ajkr

Differential Revision: D48850631

Pulled By: hx235

fbshipit-source-id: 2c321036e164087c36319dd5645cbbf6b6152092
2023-09-12 15:53:15 -07:00
Changyu Bi 9d71682d1b Add statistics COMPACTION_CPU_TOTAL_TIME for total compaction time (#11741)
Summary:
Existing compaction statistics are `COMPACTION_TIME` and `COMPACTION_CPU_TIME` which are histogram and are logged at the end of a compaction. The new statistics `COMPACTION_CPU_TOTAL_TIME` is for cumulative total compaction time which is updated regularly during a compaction. This allows user to more closely track compaction cpu usage.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11741

Test Plan: * new unit test `DBTestWithParam.CompactionTotalTimeTest`

Reviewed By: ajkr

Differential Revision: D48608094

Pulled By: cbi42

fbshipit-source-id: b597109f3e4bf2237fb5a216b6fd036e5363b4c0
2023-09-12 15:48:36 -07:00
Levi Tamasi 1e63fc9925 Add a helper method WideColumnsHelper::SortColumns (#11823)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/11823

Similarly to https://github.com/facebook/rocksdb/pull/11813, the patch is a small refactoring that eliminates some copy-paste around sorting the columns of entities by column name.

Reviewed By: jaykorean

Differential Revision: D49195504

fbshipit-source-id: d48c9f290e3203f838cc5949856c469ecf730008
2023-09-12 12:36:07 -07:00
Hui Xiao 4b123f3a54 Change file size related variables type to uint64_t in PickCompactionToReduceSizeAmp() (#11814)
Summary:
**Context/Summary:**
size_t is not most likely not needed as SortedRun::size/compensated_file_size is uint64_t. This is a pre-requisite to addressing https://github.com/facebook/rocksdb/pull/11749/files#r1321828933.  Other places already uses uint64_t e.g, https://github.com/facebook/rocksdb/blob/8.6.fb/db/compaction/compaction_picker_universal.cc#L349-L353

**Test**
CI

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11814

Reviewed By: ajkr

Differential Revision: D49169155

Pulled By: hx235

fbshipit-source-id: 2b3ad70e6f18aa360e94ed8907c8534ad2797e62
2023-09-12 10:00:57 -07:00
Hui Xiao f833ca3878 Pick files from the last sorted run in size amp compaction picker (#11740)
Summary:
**Context/Summary:**
Same intention as https://github.com/facebook/rocksdb/pull/2693 - basically we now pick from the last sorted run and expand forward till we can't

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11740

Test Plan:
Existing UT
Stress test

Reviewed By: ajkr

Differential Revision: D48586475

Pulled By: hx235

fbshipit-source-id: 3eb3c3ee1d5f7e0b0d6d649baaeb8c6990fee398
2023-08-23 11:27:48 -07:00
Changyu Bi d1ff401472 Delay bottommost level single file compactions (#11701)
Summary:
For leveled compaction, RocksDB has a special kind of compaction with reason "kBottommmostFiles" that compacts bottommost level files to clear data held by snapshots (more detail in https://github.com/facebook/rocksdb/issues/3009). Such compactions can happen soon after a relevant snapshot is released. For some use cases, a bottommost file may contain only a small amount of keys that can be cleared, so compacting such a file has a high write amp. In addition, these bottommost files may be compacted in compactions with reason other than "kBottommmostFiles" if we wait for some time (so that enough data is ingested to trigger such a compaction). This PR introduces an option `bottommost_file_compaction_delay` to specify the delay of these bottommost level single file compactions.

* The main change is in `VersionStorageInfo::ComputeBottommostFilesMarkedForCompaction()` where we only add a file to `bottommost_files_marked_for_compaction_` if it oldest_snapshot is larger than its non-zero largest_seqno **and** the file is old enough. Note that if a file is not old enough but its largest_seqno is less than oldest_snapshot, we exclude it from the calculation of `bottommost_files_mark_threshold_`. This makes the change simpler, but such a file's eligibility for compaction will only be checked the next time `ComputeBottommostFilesMarkedForCompaction()` is called. This happens when a new Version is created (compaction, flush, SetOptions()...), a new enough snapshot is released (`VersionStorageInfo::UpdateOldestSnapshot()`) or when a compaction is picked and compaction score has to be re-calculated.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11701

Test Plan:
* Add two unit tests to test when bottommost_file_compaction_delay > 0.
* Ran crash test with the new option.

Reviewed By: jaykorean, ajkr

Differential Revision: D48331564

Pulled By: cbi42

fbshipit-source-id: c584f3dc5f6354fce3ed65f4c6366dc450b15ba8
2023-08-16 17:45:44 -07:00
Changyu Bi eca48bc166 Avoid shifting component too large error in FileTtlBooster (#11673)
Summary:
When `num_levels` > 65, we may be shifting more than 63 bits in FileTtlBooster. This can give errors like: `runtime error: shift exponent 98 is too large for 64-bit type 'uint64_t' (aka 'unsigned long')`. This PR makes a quick fix for this issue by taking a min in the shifting component. This issue should be rare since it requires a user using a large `num_levels`. I'll follow up with a more complex fix if needed.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11673

Test Plan: * Add a unit test that produce the above error before this PR. Need to compile it with ubsan: `COMPILE_WITH_UBSAN=1 OPT="-fsanitize-blacklist=.circleci/ubsan_suppression_list.txt" ROCKSDB_DISABLE_ALIGNED_NEW=1 USE_CLANG=1 make V=1 -j32 compaction_picker_test`

Reviewed By: hx235

Differential Revision: D48074386

Pulled By: cbi42

fbshipit-source-id: 25e59df7e93f20e0793cffb941de70ac815d9392
2023-08-04 14:29:50 -07:00
Changyu Bi 6a0f637633 Compare the number of input keys and processed keys for compactions (#11571)
Summary:
... to improve data integrity validation during compaction.

A new option `compaction_verify_record_count` is introduced for this verification and is enabled by default. One exception when the verification is not done is when a compaction filter returns kRemoveAndSkipUntil which can cause CompactionIterator to seek until some key and hence not able to keep track of the number of keys processed.

For expected number of input keys, we sum over the number of total keys - number of range tombstones across compaction input files (`CompactionJob::UpdateCompactionStats()`). Table properties are consulted if `FileMetaData` is not initialized for some input file. Since table properties for all input files were also constructed during `DBImpl::NotifyOnCompactionBegin()`, `Compaction::GetTableProperties()` is introduced to reduce duplicated code.

For actual number of keys processed, each subcompaction will record its number of keys processed to `sub_compact->compaction_job_stats.num_input_records` and aggregated when all subcompactions finish (`CompactionJob::AggregateCompactionStats()`). In the case when some subcompaction encountered kRemoveAndSkipUntil from compaction filter and does not have accurate count, it propagates this information through `sub_compact->compaction_job_stats.has_num_input_records`.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11571

Test Plan:
* Add a new unit test `DBCompactionTest.VerifyRecordCount` for the corruption case.
* All other unit tests for non-corrupted case.
* Ran crash test for a few hours: `python3 ./tools/db_crashtest.py whitebox --simple`

Reviewed By: ajkr

Differential Revision: D47131965

Pulled By: cbi42

fbshipit-source-id: cc8e94565dd526c4347e9d3843ecf32f6727af92
2023-07-28 09:47:31 -07:00
leipeng bc0db33483 Optimize about sstableKeyCompare (#11610)
Summary:
We observed `CompactionOutputs::UpdateGrandparentBoundaryInfo` consumes much time for `InternalKey::DecodeFrom` and `InternalKey::~InternalKey` in flame graph.

This PR omit the InternalKey object in `CompactionOutputs::UpdateGrandparentBoundaryInfo` .

![image](https://github.com/facebook/rocksdb/assets/1574991/661eaeec-2f46-46c6-a6a8-9738d6c191de)

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11610

Reviewed By: ajkr

Differential Revision: D47426971

Pulled By: cbi42

fbshipit-source-id: f0d3a8186d778294515c0685032f5b395c4d6a62
2023-07-13 22:26:55 -07:00
weedge 1a7c741977 fix: std::optional value() build error on older macOS SDK (#11574)
Summary:
`PORTABLE=1 USE_SSE=1 USE_PCLMUL=1 WITH_JEMALLOC_FLAG=1 JEMALLOC=1 make static_lib`  on MacOS

clang --version:

Apple clang version 12.0.0 (clang-1200.0.32.29)
Target: x86_64-apple-darwin22.4.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin

compile err like this:

util/udt_util.cc:39:39: error: 'value' is unavailable: introduced in macOS 10.14
  if (running_ts_sz != recorded_ts_sz.value()) {
                                      ^
/Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/optional:944:33: note: 'value' has been explicitly marked
      unavailable here
    constexpr value_type const& value() const&
                                ^
util/udt_util.cc:217:62: error: 'value' is unavailable: introduced in macOS 10.14
      *new_key = StripTimestampFromUserKey(key, record_ts_sz.value());
                                                             ^
/Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/optional:953:27: note: 'value' has been explicitly marked
      unavailable here
    constexpr value_type& value() &
                          ^
2 errors generated.
make: *** [util/udt_util.o] Error 1

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11574

Reviewed By: ajkr

Differential Revision: D47269519

Pulled By: cbi42

fbshipit-source-id: da49d90cdf00a0af519f91c0cf7d257401eb395f
2023-07-10 14:21:34 -07:00
Yu Zhang 7521478b43 Record the persist_user_defined_timestamps flag in manifest (#11515)
Summary:
Start to record the value of the flag `AdvancedColumnFamilyOptions.persist_user_defined_timestamps` in the Manifest and table properties for a SST file when it is created. And use the recorded flag when creating a table reader for the SST file. This flag's default value is true, it is only explicitly recorded if it's false.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11515

Test Plan:
```
make all check
./version_edit_test
```

Reviewed By: ltamasi

Differential Revision: D46920386

Pulled By: jowlyzhang

fbshipit-source-id: 075c20363d3d2cc1368422ecc805617ed135cc26
2023-06-21 21:49:01 -07:00
Changyu Bi bc04ec85db Make option level_compaction_dynamic_level_bytes true by default (#11525)
Summary:
after https://github.com/facebook/rocksdb/issues/11321 and https://github.com/facebook/rocksdb/issues/11340 (both included in RocksDB v8.2), migration from `level_compaction_dynamic_level_bytes=false` to `level_compaction_dynamic_level_bytes=true` is automatic by RocksDB and requires no manual compaction from user. Making the option true by default as it has several advantages: 1. better space amplification guarantee (a more stable LSM shape). 2. compaction is more adaptive to write traffic. 3. automatic draining of unneeded levels. Wiki is updated with more detail: https://github.com/facebook/rocksdb/wiki/Leveled-Compaction#option-level_compaction_dynamic_level_bytes-and-levels-target-size.

The PR mostly contains fixes for unit tests as they assumed `level_compaction_dynamic_level_bytes=false`. Most notable change is commit f742be330c and b1928e42b3 which override the default option in DBTestBase to still set `level_compaction_dynamic_level_bytes=false` by default. This helps to reduce the change needed for unit tests. I think this default option override in unit tests is okay since the behavior of `level_compaction_dynamic_level_bytes=true` is tested by explicitly setting this option. Also, `level_compaction_dynamic_level_bytes=false` may be more desired in unit tests as it makes it easier to create a desired LSM shape.

Comment for option `level_compaction_dynamic_level_bytes` is updated to reflect this change and change made in https://github.com/facebook/rocksdb/issues/10057.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11525

Test Plan: `make -j32 J=32 check` several times to try to catch flaky tests due to this option change.

Reviewed By: ajkr

Differential Revision: D46654256

Pulled By: cbi42

fbshipit-source-id: 6b5827dae124f6f1fdc8cca2ac6f6fcd878830e1
2023-06-15 21:12:39 -07:00
Changyu Bi 15e8a843d9 Do not include last level in compaction when allow_ingest_behind=true (#11489)
Summary:
when a DB is configured with `allow_ingest_behind = true`, the last level should be reserved for ingested files and these files should not be included in any compaction. Currently, a major compaction can compact these files to smaller levels. This can cause future files to be rejected for ingest behind (see `ExternalSstFileIngestionJob::CheckLevelForIngestedBehindFile()`). This PR fixes the issue such that files in the last level is not included in any compaction.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11489

Test Plan: * Updated unit test `ExternalSSTFileTest.IngestBehind` to test that last level is not included in manual and auto-compaction.

Reviewed By: ajkr

Differential Revision: D46455711

Pulled By: cbi42

fbshipit-source-id: 5e2142c2a709ef932ad797897795021c06c4ac8c
2023-06-14 11:28:56 -07:00
Changyu Bi 2e8cc98ab2 Fix subcompaction bug to allow running two subcompactions (#11501)
Summary:
as reported in https://github.com/facebook/rocksdb/issues/11476, RocksDB currently does not execute compactions in two subcompactions even when they qualify. This PR fixes this issue.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11501

Test Plan:
* Add a new unit test.
* Run crash test with max_subcompactions=2: `python3 tools/db_crashtest.py blackbox --simple  --subcompactions=2 --target_file_size_base=1048576 --compaction_style=0`
  * saw logs showing compactions being executed as 2 subcompactions
```
2023/06/01-17:28:44.028470 3147486 (Original Log Time 2023/06/01-17:28:44.025972) EVENT_LOG_v1 {"time_micros": 1685665724025939, "job": 6, "event": "compaction_finished", "compaction_time_micros": 34539, "compaction_time_cpu_micros": 26404, "output_level": 6, "num_output_files": 2, "total_output_size": 1109796, "num_input_records": 13188, "num_output_records": 13021, "num_subcompactions": 2, "output_compression": "NoCompression", "num_single_delete_mismatches": 0, "num_single_delete_fallthrough": 0, "lsm_state": [0, 0, 0, 0, 0, 0, 13]}
```

Reviewed By: ajkr

Differential Revision: D46411497

Pulled By: cbi42

fbshipit-source-id: 3ebfc02e19f78f782e114a9546dc3d481d496258
2023-06-06 13:36:02 -07:00
Changyu Bi 4aa52d89cf Drop range tombstone during non-bottommost compaction (#11459)
Summary:
Similar to point tombstones, we can drop a range tombstone during compaction when we know its range does not exist in any higher level. This PR adds this optimization. Some existing test in db_range_del_test is fixed to work under this optimization.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11459

Test Plan:
* Add unit test `DBRangeDelTest, NonBottommostCompactionDropRangetombstone`.
* Ran crash test that issues range deletion for a few hours: `python3 tools/db_crashtest.py blackbox --simple --write_buffer_size=1048576 --delrangepercent=10 --writepercent=31 --readpercent=40`

Reviewed By: ajkr

Differential Revision: D46007904

Pulled By: cbi42

fbshipit-source-id: 3f37205b6778b7d55ed106369ca41b0632a6d0fd
2023-06-05 10:26:40 -07:00
Changyu Bi e95cc1217d CompactRange() always compacts to bottommost level for leveled compaction (#11468)
Summary:
currently for leveled compaction, the max output level of a call to `CompactRange()` is pre-computed before compacting each level. This max output level is the max level whose key range overlaps with the manual compaction key range. However, during manual compaction, files in the max output level may be compacted down further by some background compaction. When this background compaction is a trivial move, there is a race condition and the manual compaction may not be able to compact all keys in the specified key range. This PR updates `CompactRange()` to always compact to the bottommost level to make this race condition more unlikely (it can still happen, see more in comment here: 796f58f42a/db/db_impl/db_impl_compaction_flush.cc (L1180C29-L1184)).

This PR also changes the behavior of CompactRange() when `bottommost_level_compaction=kIfHaveCompactionFilter` (the default option). The old behavior is that, if a compaction filter is provided, CompactRange() always does an intra-level compaction at the final output level for all files in the manual compaction key range. The only exception when `first_overlapped_level = 0` and `max_overlapped_level = 0`. It’s awkward to maintain the same behavior after this PR since we do not compute max_overlapped_level anymore. So the new behavior is similar to kForceOptimized: always does intra-level compaction at the bottommost level, but not including new files generated during this manual compaction.

Several unit tests are updated to work with this new manual compaction behavior.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11468

Test Plan: Add new unit tests `DBCompactionTest.ManualCompactionCompactAllKeysInRange*`

Reviewed By: ajkr

Differential Revision: D46079619

Pulled By: cbi42

fbshipit-source-id: 19d844ba4ec8dc1a0b8af5d2f36ff15820c6e76f
2023-06-01 15:27:29 -07:00
Soli de1dd4ca19 Tweak on IsTrivialMove() (#11467)
Summary:
`output_level_` and `number_levels_` are not changing in iteration of `inputs_` files.

Moving the check out of `for` loop could slightly improve performance.

It is easier to review when ignore whitespace changes.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11467

Reviewed By: cbi42

Differential Revision: D46155962

Pulled By: ajkr

fbshipit-source-id: 45ec80b13152b3bed7305e6f707cb9b187d5f315
2023-05-26 16:40:50 -07:00
Jay Huh 81aeb15988 Add WaitForCompact with WaitForCompactOptions to public API (#11436)
Summary:
Context:

This is the first PR for WaitForCompact() Implementation with WaitForCompactOptions. In this PR, we are introducing `Status WaitForCompact(const WaitForCompactOptions& wait_for_compact_options)` in the public API. This currently utilizes the existing internal `WaitForCompact()` implementation (with default abort_on_pause = false). `abort_on_pause` has been moved to `WaitForCompactOptions&`. In the later PRs, we will introduce the following two options in `WaitForCompactOptions`

1. `bool flush = false` by default - If true, flush before waiting for compactions to finish. Must be set to true to ensure no immediate compactions (except perhaps periodic compactions) after closing and re-opening the DB.
2. `bool close_db = false` by default - If true, will also close the DB upon compactions finishing.

1. struct `WaitForCompactOptions` added to options.h and `abort_on_pause` in the internal API moved to the option struct.
2. `Status WaitForCompact(const WaitForCompactOptions& wait_for_compact_options)` introduced in `db.h`
3. Changed the internal WaitForCompact() to `WaitForCompact(const WaitForCompactOptions& wait_for_compact_options)` and checks for the `abort_on_pause` inside the option.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11436

Test Plan:
Following tests added
- `DBCompactionTest::WaitForCompactWaitsOnCompactionToFinish`
- `DBCompactionTest::WaitForCompactAbortOnPauseAborted`
- `DBCompactionTest::WaitForCompactContinueAfterPauseNotAborted`
- `DBCompactionTest::WaitForCompactShutdownWhileWaiting`
- `TransactionTest::WaitForCompactAbortOnPause`

NOTE: `TransactionTest::WaitForCompactAbortOnPause` was added to use `StackableDB` to ensure the wrapper function is in place.

Reviewed By: pdillinger

Differential Revision: D45799659

Pulled By: jaykorean

fbshipit-source-id: b5b58f95957f2ab47d1221dee32a61d6cdc4685b
2023-05-25 17:25:51 -07:00
Jay Huh 586d78b31e Remove wait_unscheduled from waitForCompact internal API (#11443)
Summary:
Context:

In pull request https://github.com/facebook/rocksdb/issues/11436, we are introducing a new public API `waitForCompact(const WaitForCompactOptions& wait_for_compact_options)`. This API invokes the internal implementation `waitForCompact(bool wait_unscheduled=false)`. The unscheduled parameter indicates the compactions that are not yet scheduled but are required to process items in the queue.

In certain cases, we are unable to wait for compactions, such as during a shutdown or when background jobs are paused. It is important to return the appropriate status in these scenarios. For all other cases, we should wait for all compaction and flush jobs, including the unscheduled ones. The primary purpose of this new API is to wait until the system has resolved its compaction debt. Currently, the usage of `wait_unscheduled` is limited to test code.

This pull request eliminates the usage of wait_unscheduled. The internal `waitForCompact()` API now waits for unscheduled compactions unless the db is undergoing a shutdown. In the event of a shutdown, the API returns `Status::ShutdownInProgress()`.

Additionally, a new parameter, `abort_on_pause`, has been introduced with a default value of `false`. This parameter addresses the possibility of waiting indefinitely for unscheduled jobs if `PauseBackgroundWork()` was called before `waitForCompact()` is invoked. By setting `abort_on_pause` to `true`, the API will immediately return `Status::Aborted`.

Furthermore, all tests that previously called `waitForCompact(true)` have been fixed.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11443

Test Plan:
Existing tests that involve a shutdown in progress:

- DBCompactionTest::CompactRangeShutdownWhileDelayed
- DBTestWithParam::PreShutdownMultipleCompaction
- DBTestWithParam::PreShutdownCompactionMiddle

Reviewed By: pdillinger

Differential Revision: D45923426

Pulled By: jaykorean

fbshipit-source-id: 7dc93fe6a6841a7d9d2d72866fa647090dba8eae
2023-05-17 18:13:50 -07:00
Peter Dillinger 206fdea3d9 Change internal headers with duplicate names (#11408)
Summary:
In IDE navigation I find it annoying that there are two statistics.h files (etc.) and often land on the wrong one. Here I migrate several headers to use the blah.h <- blah_impl.h <- blah.cc idiom. Although clang-format wants "blah.h" to be the top include for "blah.cc", I think overall this is an improvement.

No public API changes.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11408

Test Plan: existing tests

Reviewed By: ltamasi

Differential Revision: D45456696

Pulled By: pdillinger

fbshipit-source-id: 809d931253f3272c908cf5facf7e1d32fc507373
2023-05-17 11:27:09 -07:00
Changyu Bi 8827cd0618 Support compacting files to different temperatures in FIFO compaction (#11428)
Summary:
- Add a new option `CompactionOptionsFIFO::file_temperature_age_thresholds` that allows user to specify age thresholds for compacting files to different temperatures. File temperature can be used to store files in different storage media. The new options allows specifying multiple temperature-age pairs. The option uses struct for a temperature-age pair to use the existing parsing functionality to make the option dynamically settable.
- Deprecate the old option `age_for_warm` that was added for a similar purpose.
- Compaction score calculation logic is updated to check if a file needs to be compacted to change its temperature.
- Some refactoring is done in `FIFOCompactionPicker::PickTemperatureChangeCompaction`.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11428

Test Plan: adapted unit tests that were for `age_for_warm` to this new option.

Reviewed By: ajkr

Differential Revision: D45611412

Pulled By: cbi42

fbshipit-source-id: 2dc384841f61cc04abb9681e31aa2de0f0b06106
2023-05-11 16:40:59 -07:00
Hui Xiao 8f763bdeab Record and use the tail size to prefetch table tail (#11406)
Summary:
**Context:**
We prefetch the tail part of a SST file (i.e, the blocks after data blocks till the end of the file) during each SST file open in hope to prefetch all the stuff at once ahead of time for later read e.g, footer, meta index, filter/index etc. The existing approach to estimate the tail size to prefetch is through `TailPrefetchStats` heuristics introduced in https://github.com/facebook/rocksdb/pull/4156, which has caused small reads in unlucky case (e.g,  small read into the tail buffer during table open in thread 1 under the same BlockBasedTableFactory object can make thread 2's tail prefetching use a small size that it shouldn't) and is hard to debug.  Therefore we decide to record the exact tail size and use it directly  to prefetch tail of the SST instead of relying heuristics.

**Summary:**
- Obtain and record in manifest the tail size in `BlockBasedTableBuilder::Finish()`
   - For backward compatibility, we fall back to TailPrefetchStats and last to simple heuristics that the tail size is a linear portion of the file size - see PR conversation for more.
- Make`tail_start_offset` part of the table properties and deduct tail size to record in manifest for external files (e.g, file ingestion, import CF) and db repair (with no access to manifest).

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11406

Test Plan:
1. New UT
2. db bench
Note: db bench on /tmp/ where direct read is supported is too slow to finish and the default pinning setting in db bench is not helpful to profile # sst read of Get. Therefore I hacked the following to obtain the following comparison.
```
 diff --git a/table/block_based/block_based_table_reader.cc b/table/block_based/block_based_table_reader.cc
index bd5669f0f..791484c1f 100644
 --- a/table/block_based/block_based_table_reader.cc
+++ b/table/block_based/block_based_table_reader.cc
@@ -838,7 +838,7 @@ Status BlockBasedTable::PrefetchTail(
                            &tail_prefetch_size);

   // Try file system prefetch
-  if (!file->use_direct_io() && !force_direct_prefetch) {
+  if (false && !file->use_direct_io() && !force_direct_prefetch) {
     if (!file->Prefetch(prefetch_off, prefetch_len, ro.rate_limiter_priority)
              .IsNotSupported()) {
       prefetch_buffer->reset(new FilePrefetchBuffer(
 diff --git a/tools/db_bench_tool.cc b/tools/db_bench_tool.cc
index ea40f5fa0..39a0ac385 100644
 --- a/tools/db_bench_tool.cc
+++ b/tools/db_bench_tool.cc
@@ -4191,6 +4191,8 @@ class Benchmark {
           std::shared_ptr<TableFactory>(NewCuckooTableFactory(table_options));
     } else {
       BlockBasedTableOptions block_based_options;
+      block_based_options.metadata_cache_options.partition_pinning =
+      PinningTier::kAll;
       block_based_options.checksum =
           static_cast<ChecksumType>(FLAGS_checksum_type);
       if (FLAGS_use_hash_search) {
```
Create DB
```
./db_bench --bloom_bits=3 --use_existing_db=1 --seed=1682546046158958 --partition_index_and_filters=1 --statistics=1 -db=/dev/shm/testdb/ -benchmarks=readrandom -key_size=3200 -value_size=512 -num=1000000 -write_buffer_size=6550000 -disable_auto_compactions=false -target_file_size_base=6550000 -compression_type=none
```
ReadRandom
```
./db_bench --bloom_bits=3 --use_existing_db=1 --seed=1682546046158958 --partition_index_and_filters=1 --statistics=1 -db=/dev/shm/testdb/ -benchmarks=readrandom -key_size=3200 -value_size=512 -num=1000000 -write_buffer_size=6550000 -disable_auto_compactions=false -target_file_size_base=6550000 -compression_type=none
```
(a) Existing (Use TailPrefetchStats for tail size + use seperate prefetch buffer in PartitionedFilter/IndexReader::CacheDependencies())
```
rocksdb.table.open.prefetch.tail.hit COUNT : 3395
rocksdb.sst.read.micros P50 : 5.655570 P95 : 9.931396 P99 : 14.845454 P100 : 585.000000 COUNT : 999905 SUM : 6590614
```

(b) This PR (Record tail size + use the same tail buffer in PartitionedFilter/IndexReader::CacheDependencies())
```
rocksdb.table.open.prefetch.tail.hit COUNT : 14257
rocksdb.sst.read.micros P50 : 5.173347 P95 : 9.015017 P99 : 12.912610 P100 : 228.000000 COUNT : 998547 SUM : 5976540
```

As we can see, we increase the prefetch tail hit count and decrease SST read count with this PR

3. Test backward compatibility by stepping through reading with post-PR code on a db generated pre-PR.

Reviewed By: pdillinger

Differential Revision: D45413346

Pulled By: hx235

fbshipit-source-id: 7d5e36a60a72477218f79905168d688452a4c064
2023-05-08 13:14:28 -07:00