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30 Commits

Author SHA1 Message Date
Xingbo Wang
19b6f85266 Support async file open for SecondaryDB (#15294)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/15294

Why the change is required:
`open_files_async` reduces startup latency by moving SST validation and table-reader opening to background work, but `DB::OpenAsSecondary()` still performed that work synchronously.

Previous behavior:
A secondary using `open_files_async=true` replayed its MANIFEST through `ReactiveVersionSet`, synchronously verified and opened every current SST, and only then returned. The option therefore provided no startup benefit for secondary instances.

New behavior:
`DB::OpenAsSecondary()` can now return after installing its initial read view and start initial SST validation and table-reader pinning through the existing asynchronous opener. With `max_open_files=-1`, the opener processes all current SSTs in the background; a finite table cache can stop the eager pass at capacity and validate remaining files on demand. Later `TryCatchUpWithPrimary()` rounds remain synchronous. Async-open failures notify listeners and are latched according to the existing severity and `paranoid_checks` policy. If an error is not latched, a later read retries the file access and reports a persistent failure. A latched error requires fixing the underlying problem and reopening the secondary. Read-only instances do not start write-oriented recovery.

Implementation:
Initial reactive MANIFEST replay can defer SST verification and handler loading. The deferral is immutable constructor state on `ReactiveVersionSet`, is cleared before catch-up mode, and is restricted to normal secondary recovery. `VersionBuilder::GetAndClearIntermediateFiles()` now moves out and clears its own historical add-then-delete bookkeeping so callers cannot accidentally retain stale state. Secondary open schedules the background opener after publishing the read view. Its context pins the captured Versions and column families, including retained secondary handles whose column family was subsequently dropped by the primary. Existing table-reader opening performs SST size and unique-ID validation, avoiding a separate serial metadata pass. Closing the DB or canceling background work safely cancels a queued opener or waits for a running opener. Read-only async-open errors use an ErrorHandler path that notifies listeners without automatic recovery. Secondary async open explicitly rejects FIFO compaction.

Safety, compatibility, and limitations:
The default `open_files_async=false` path and existing primary async-open behavior are unchanged. WAL and blob recovery, as well as later secondary catch-up, remain synchronous. Follower DB and `OpenAndCompact()` do not use this deferral. There are no file-format, ABI, or public API signature changes. Secondary async open requires `skip_stats_update_on_db_open=true` and does not support FIFO compaction. Applications must keep files accessible by coordinating deletion with the primary or by using an Env/FileSystem that delays physical deletion until every instance releases a file. With asynchronous opening, `max_open_files=-1` cannot guarantee every SST is pinned before `OpenAsSecondary()` returns; the table-files-only `max_open_files=-1` workaround applies only when asynchronous opening is disabled. No completion API is added.

Validation covers initial deferral and pinning, synchronous catch-up, table-reader detection of physical-size mismatch, FIFO rejection, listener-adjusted errors and synchronous read retry, retained handles after primary column-family deletion, close and explicit cancellation with no HIGH-priority worker, stopping new table opens during shutdown, primary async open, follower isolation, and remote compaction. Linux Buck builds and focused tests passed. Cross-platform CI is pending, and `make check-sources` cannot run successfully in this Sapling checkout because its script requires Git.

Reviewed By: pdillinger

Differential Revision: D122417547

fbshipit-source-id: 91d408469c35c4ea21165c5e7db75068e65c2389
2026-10-02 12:21:46 -07:00
Xingbo Wang
e6a2ee0bd2 Fix subset checkpoints with incomplete MANIFEST tails (#15123)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/15123

Subset checkpoint post-processing appends column-family drop records to a copied MANIFEST. Recovery can tolerate an incomplete atomic group at the tail while retaining the reader high-water size, so appending at that size can produce a checkpoint that fails recovery.

Track the valid logical append boundary together with its MANIFEST file number, refresh it after recovery and successful writes, reset it across reactive MANIFEST switches, and trim only subset-checkpoint copies before appending drop records. Whole-DB checkpoints and the source MANIFEST remain unchanged.

Reviewed By: anand1976

Differential Revision: D116449394

fbshipit-source-id: a162dd6a2558f0f9ec40d878ee83956a89df698b
2026-08-22 12:17:33 -07:00
Peter Dillinger
e8554f1b11 Faster and safer MANIFEST recovery for remote compaction (OpenAndCompact) (#15133)
Summary:
Faster and safer MANIFEST recovery for remote compaction (OpenAndCompact)
`DB::OpenAndCompact` (remote/distributed compaction) opens the target DB as a
secondary and reconstructs the LSM state from the MANIFEST before running the
requested compaction. Previously, point-in-time recovery would stat/open the
SST (and blob) files referenced by the MANIFEST to classify them found/missing
and materialize candidate versions, and eagerly load their table handlers.
That is (a) a lot of unnecessary file operations and open latency, especially
on remote/distributed storage, and (b) fragile: when a file referenced by the
MANIFEST but not an input to the compaction was momentarily unavailable to the
worker -- e.g. an obsolete file the primary had already deleted -- recovery
could fail the job (surfacing as an incomplete "no valid result") or roll back
to an earlier version, even though the compaction only needs its own input
files, which the primary keeps referenced for the job's duration. This was seen
as a flaky failure of CompactionServiceTest.BasicCompactions on aarch64, and
reproduces on x86 under COERCE_CONTEXT_SWITCH.

Efficiency + reliability: recovery for the OpenAndCompact path now trusts the
MANIFEST. It reconstructs the current version from FileMetaData without
stat-ing/opening files to classify them and without eagerly opening
candidate-version table handlers, so it does far fewer file operations and
never fails or rolls back over a file the compaction does not need. The
compaction's input files are opened (and unique-id verified) on demand as it
reads them.

Correctness hardening: trusting the MANIFEST means the worker's own (possibly
eventually-consistent) view of CURRENT/MANIFEST drives the reconstructed LSM
shape, which feeds correctness-critical decisions (Compaction::IsBottommostLevel
/ KeyNotExistsBeyondOutputLevel). A worker that read a stale CURRENT (older
MANIFEST), a truncated MANIFEST, or a MANIFEST with a corrupt/torn tail could
reconstruct against an older LSM shape and silently drop keys that should be
kept. To prevent this, the primary records the MANIFEST position (file number
and size) it scheduled the compaction from and passes it in
CompactionServiceInput as a floor. After recovery the worker compares the size
of the maximal *valid* prefix it reconstructed -- which stops at any corrupt or
torn record and at a partial atomic group at EOF, so tolerated tail garbage
cannot inflate it -- against that floor, and refuses to compact against an older
view (an older file number, or the same file number whose valid prefix is
shorter), returning Status::Incomplete so the CompactionService can fall back to
a local compaction. Accept-equal-or-later is safe by monotonicity: while the
inputs stay locked (being_compacted), a later view can only have moved data
further down, never resurrecting a shadowed value, so only an older view is
unsafe.

Single kill switch: both behaviors are bundled behind one signal and one
option. Presence of the floor on the request (min_manifest_file_number != 0)
couples on both trust-manifest recovery and the floor check in the worker;
absence reverts the worker to the original point-in-time recovery with no floor
check. A single mutable DBOption, remote_compaction_manifest_floor (default
on), gates whether the primary populates the floor, so it is the one escape
hatch that disables the entire new recovery path on a running DB via
SetDBOptions if it ever misbehaves. The new CompactionServiceInput fields are
wire-compatible in both directions (0 = not provided), so an old worker or an
old primary simply behaves as if the switch were off.

Follow-up: recovery is not yet strictly "open only the compaction's inputs". A
limited number of non-input files are still opened by the bounded file-property
sampling in Version::PrepareAppend -> UpdateAccumulatedStats (tolerating any
that are missing), which today populates input FileMetaData::num_entries for
compaction input-record-count verification. A natural follow-up is to record
the needed per-file info (e.g. num_entries) in the MANIFEST so the worker can
skip these auxiliary opens entirely; alternatively, source input num_entries
from the worker's own read of its input table properties. Relatedly, the floor
comparand is the recovered "maximal valid prefix" size, which today equals the
MANIFEST file size but is defined to stay correct if a future MANIFEST format
writes trailing padding/footer past the last record.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/15133

Test Plan:
Added tests in compaction_service_test.cc:
- RemoteCompactionMissingLowerFileTrustsManifest: a non-input file referenced
  by the MANIFEST is unavailable during a remote compaction; the job completes
  with correct results (fails without trust-manifest recovery). The underlying
  race also reproduces under COERCE_CONTEXT_SWITCH.
- RemoteCompactionManifestFloorRejectsStaleView: inflate the floor so the
  worker's recovered MANIFEST is below it; assert the worker rejects, the job
  falls back to local, and a below-output deleted key stays deleted (no silent
  resurrection).
- RemoteCompactionManifestFloorSendsPosition: a non-zero floor is attached and
  the worker accepts its equal-or-later view.
- RemoteCompactionManifestFloorKillSwitchOff: with the option off, no floor is
  sent, the worker uses the original recovery, and a transiently-missing
  non-input file makes the job fail/roll back (the escape hatch reverts
  behavior).
- RemoteCompactionManifestFloorMutable: SetDBOptions flips the option; the
  floor stops being attached and the worker skips the check.
options_settable_test covers the new mutable DBOption.

Crash test: remote compaction is already exercised (db_crashtest randomly
enables remote_compaction_worker_threads, driving DB::OpenAndCompact), so with
remote_compaction_manifest_floor defaulting on, the new recovery path is
covered by the crash test by default -- no new crash-test plumbing is needed.
The kill switch is intentionally left un-randomized (always on): turning it off
re-enables the original, occasionally-broken recovery, which would only add
noisy failures for no benefit.

UPDATE: crash test is not well covered because of `"remote_compaction_failure_fall_back_to_local": 1` which is masking other existing failures. Addressing this is a high-priority follow-up item. (Not practical to fix in this diff.)

Reviewed By: jaykorean

Differential Revision: D116738823

Pulled By: pdillinger

fbshipit-source-id: c02e0a437d62fc526dbbfcf70edf43434dfc7c1f
2026-08-20 16:07:48 -07:00
Andrei Preda
b616b203b8 Drop flushed WAL data from the secondary's active memtable (#15066)
Summary:
Fix https://github.com/facebook/rocksdb/issues/15051: a secondary serves stale reads because entries replayed from a WAL the primary has since flushed are never evicted from the active memtable. During TryCatchUpWithPrimary(), seal the active memtable once the installed Version provably covers everything it holds, so the following RemoveOldMemTables() call drops it. Every memtable-dropping decision takes that same watermark, so a file set the secondary cannot read never turns the stale read into a vanished key.

## Why and How

A secondary replays the primary's WALs into its active memtable and stops replaying a WAL once the primary flushes it. Entries already replayed stayed behind, and since reads consult the memtable first, they shadowed the newer flushed values indefinitely. Iterators go stale too once bottommost compaction rewrites the flushed entry's sequence number to 0; until then Get() and an iterator disagree.

Seal the active memtable during catch-up, gated on the installed Version: each point-in-time Version now carries the column family's log number it reflects, exposed via the new
ReactiveVersionSet::GetInstalledVersionLogNumber(). Sealing requires cf_id_to_current_log_[cfd->GetID()] < that number, which guarantees the primary flushed everything the memtable holds (unflushed WAL data is kept) and that the flushed data is readable through the installed Version. The gate asks the Version directly because proxies fail: the log number alone advances even when no Version was installed, and "no missing files" misses atomic_flush groups parked by a sibling's missing file and corrupt-but-present files with
verify_sst_unique_id_in_manifest=false. In those cases the memtable holds the only readable copy, so dropping it would turn a stale read into a vanished key; the gate fails closed and keeps it.

Reconcile every initialized column family, not just cfds_changed: a round that failed after advancing the log number leaves a stale memtable that later rounds see no new MANIFEST record for. It can also leave a collectible immutable memtable, so the loop consults the new O(1) MemTableList::HasOldMemTablesToRemove() before skipping a column family. The predicate keeps the skip precise: reconciling any column family with a non-empty immutable list would be correct but wasteful, installing a fresh SuperVersion every catch-up call for memtables legitimately waiting on a primary flush and costing readers a mutex acquisition each time. With it, no extra super versions are installed in the steady state. That predicate and the RemoveOldMemTables() cutoff take the installed Version's log number as well, not cfd->GetLogNumber(): that advances as soon as the flush record is read, so an immutable memtable sealed on a WAL switch could otherwise be freed while the flushed file superseding it is unreadable. A sealed memtable is stamped with cf_id_to_current_log_[cfd->GetID()] + 1, the log number following its contents.

cf_id_to_current_log_ is keyed by column family id rather than ColumnFamilyData*, because ids are never reused while a dropped column family's pointer can be recycled, and it is recorded before WriteBatchInternal::InsertInto() rather than after: a batch stops at its first failure with earlier entries already inserted, so recording afterwards could leave the map naming an older WAL than the memtable holds. While the watermark lags and uncollectible memtables accumulate, the secondary warns, since it has no write path to enforce max_write_buffer_number.

The seal sequence, shared with RecoverLogFiles() and the follower's TryCatchUpWithLeader(), is extracted into
DBImplSecondary::SealActiveMemtable(). The follower is refactored onto it with no behaviour change: it keeps cfd->GetLogNumber() as its cutoff because that catch-up path never replays WALs, so its memtables hold nothing that only a not-yet-installed Version could make readable.

## Testing

New tests in db_secondary_test cover: the stale read via both Get() and an iterator, before and after bottommost compaction; unflushed WAL-only data surviving sealing, including two column families sharing a WAL; no data loss with a missing, atomic_flush-sibling-missing, or corrupt flushed file; an immutable memtable sealed on a WAL switch surviving an unreadable flushed file; a batch rejected partway through replay leaving the recorded WAL no older than the memtable's contents; and reconciliation after a failed round (injected via FaultInjectionTestFS at a sync point). Each mechanism was individually neutralized and confirmed to fail its test.

Verified with build_tools/rocksptest.sh over db_secondary_test, db_follower_test, memtable_list_test, version_set_test and version_edit_test (all pass, also under ASSERT_STATUS_CHECKED=1), plus db_basic_test, corruption_test, repair_test and db_flush_test; the secondary tests also ran 20x under COERCE_CONTEXT_SWITCH=1 with no flakes. make format-auto and make check-sources are clean.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/15066

Reviewed By: jaykorean, anand1976

Differential Revision: D115317523

Pulled By: xingbowang

fbshipit-source-id: a1d4615eb951d75e69ed242731336485c0dfa137
2026-08-17 13:47:30 -07:00
Peter Dillinger
1eb4a6e3e1 Rocksdb Secondary Cache Test failed: assertion failed - corruption: corrupted atomic group The file (#15000)
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/15000

Reviewed By: xingbowang

Differential Revision: D113225538

Pulled By: pdillinger

fbshipit-source-id: fea9a671e9291ed030c5396264734195b2fb78bf
2026-07-24 08:30:27 -07:00
Anand Ananthabhotla
c734b7cc60 Add reuse_manifest_on_open DBOption (#14704)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/14704

Add an immutable DBOption `reuse_manifest_on_open` (default false). When enabled, `DB::Open` can keep using the recovered MANIFEST for the first post-open metadata update instead of rebuilding a fresh MANIFEST, which can reduce warm-open latency for DBs whose MANIFEST is expensive to regenerate.

Reuse is still best-effort. If RocksDB cannot safely resume appending to the recovered MANIFEST, it falls back to the existing fresh-MANIFEST path. The option is also disabled under `best_efforts_recovery`.

This diff also teaches the reopened MANIFEST writer to adopt the existing file size before appending, documents the small-`max_manifest_file_size` caveat for the reused path, and keeps the full warm-reopen composition working with `optimize_manifest_for_recovery`.

Reviewed By: hx235, pdillinger

Differential Revision: D103568447

fbshipit-source-id: f4f5c35ea3ef0b80a0d52d94be40c6bd11505999
2026-05-07 13:10:59 -07:00
Josh Kang
f25fb41da6 Add option to validate sst files in the background on DB open (#14322)
Summary:
Add `open_files_async` option for faster DB startup. When enabled, SST file opening and validation is deferred to a background thread after `DB::Open` returns, reducing startup latency for databases with many SST files. WAL recovery remains synchronous.

To support this, `FindTable` is extended with a pinning mechanism that stores the cache handle directly on `FileMetaData` via a new `PinnedTableReader` class, and sets the table reader atomically so subsequent reads skip cache lookups. `FileDescriptor::table_reader` is replaced with `PinnedTableReader pinned_reader` which wraps a `std::atomic<TableReader*>` with acquire/release ordering to safely handle concurrent access between the background opener and read threads.

Should validations fail, the background opener sets a `kAsyncFileOpen` background error. Future read requests will look up the table reader again via the cache, and if any validations fail there it will get propagated to the user (existing behavior when `max_open_files > 0`).

This feature is most useful when `max_open_files=-1`, because otherwise file opening is already capped at 16 files and DB open should be fast.

## Restrictions
- This feature also is incompatible with fifo compaction because fifo compaction requires reading table properties under DB mutex. When table reader is unpinned, this may cause a DB hang.
- This feature is also incompatible with `skip_stats_update_on_db_open=false` because it will result in even longer DB open

## Key changes

- New `open_files_async` DB option with C, Java, and `db_bench` bindings
- `BGWorkAsyncFileOpen` background worker that opens all SST files post-`DB::Open`, with shutdown awareness via `shutting_down_` flag
- New `PinnedTableReader` class in `version_edit.h` — thread-safe wrapper holding `std::atomic<TableReader*>` and `Cache::Handle*` with proper acquire/release ordering. Replaces the old `FileDescriptor::table_reader` raw pointer and `FileMetaData::table_reader_handle`
- Extract `LoadTableHandlersHelper` into `db/version_util.cc` — shared between `VersionBuilder::LoadTableHandlers` (for version edits during recovery) and `BGWorkAsyncFileOpen` (for base storage post-open)
- `FindTable` extended with `pin_table_handle` and `out_table_reader` params — when pinning is enabled, the table reader is stored on `FileMetaData` so Get/MultiGet/Iterator skip redundant cache lookups. `FindTable` now performs the pinned-reader fast-path check internally instead of requiring callers to check `fd.table_reader` beforehand
  - Note: pinning is explicit (not default) because some callers create temporary `FileMetaData`s that would need to properly clean up table handles
- `CompactedDBImpl` updated to use `FindTable` + pinning instead of raw `fd.table_reader` access for Get/MultiGet
- New `kAsyncFileOpen` background error reason in `listener.h` and `error_handler.cc`
- Add a check in ~DBImpl to ensure async file open task has not been forgotten to be scheduled in (future) subclasses of DBImpl. Certain subclasses that never use it will need to explicitly mark it.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/14322

Test Plan:
- `OpenFilesAsyncTest` parameterized over `num_flushes` (1, 20), `ReadType` (Get, MultiGet, Iterator), `max_open_files` (-1, 10), and `read_only` (true, false)
  - **ConcurrentFileAccess**: concurrent reads and compactions race with async opener
  - **AfterRead**: reads happen before async opener, verifying lazy open and that the opener sees already-pinned readers
  - **BeforeRead**: async opener completes first, verifying reads use pre-loaded table readers
  - **Shutdown**: DB closes before async opener starts, verifying clean cancellation with 0 file opens
  - **Error**: corrupted SST files, verifying `kAsyncFileOpen` background error is set and reads return corruption
  - **DropColumnFamily**: CF dropped before async opener runs, verifying the opener gracefully skips dropped CFs
- Added to crash test

### Benchmark

To simulate a high-latency remote filesystem, I set up a virtual filesystem with dm-delay using 10ms reads, 0 ms writes.

```
# Generate a DB with many L0 files

TEST_TMPDIR=/data/users/jkangs/dm-delay-test/mnt ./db_bench -benchmarks=fillseq -disable_auto_compactions=true -write_buffer_size=1000 -num=1000000
```

```
./db_bench -use_existing_db=true -db=/data/users/jkangs/dm-delay-test/mnt/dbbench -benchmarks=readrandom -reads=1 -report_open_timing=true -open_files_async=true -use_direct_reads -file_opening_threads=1 -skip_stats_update_on_db_open

OpenDb:     25.1419 milliseconds
```

```
./db_bench -use_existing_db=true -db=/data/users/jkangs/dm-delay-test/mnt/dbbench -benchmarks=readrandom -reads=1 -report_open_timing=true -open_files_async=false -use_direct_reads -file_opening_threads=1 -skip_stats_update_on_db_open

OpenDb:     23109.4 milliseconds
```

### No read regressions

On main branch
```
./db_bench -use_existing_db=true -db=/dev/shm/dbbench -benchmarks=readrandom -seed=1 -threads=8 -duration=30

readrandom   :       4.827 micros/op 1657100 ops/sec 30.005 seconds 49720992 operations;  183.3 MB/s (6198999 of 6198999 found)
```

On this branch
```
./db_bench -use_existing_db=true -db=/dev/shm/dbbench -benchmarks=readrandom -seed=1 -threads=8 -duration=30

readrandom   :       4.863 micros/op 1644808 ops/sec 30.007 seconds 49354992 operations;  182.0 MB/s (6099999 of 6099999 found)

./db_bench -use_existing_db=true -db=/dev/shm/dbbench -benchmarks=readrandom -seed=1 -threads=8 -duration=30 -open_files_async=true

readrandom   :       4.803 micros/op 1665392 ops/sec 30.004 seconds 49968992 operations;  184.2 MB/s (6222999 of 6222999 found)
```

Reviewed By: pdillinger, xingbowang

Differential Revision: D93538033

Pulled By: joshkang97

fbshipit-source-id: 32ac70c112cd733b7c1e1c1e2e7ce6422318a5ae
2026-03-02 16:18:14 -08:00
Maciej Szeszko
799079cac5 Handle drop column family version edit in file checksum retriever (#13832)
Summary:
... by ensuring that files in dropped column family are not returned to the caller upon successful, offline MANIFEST iteration.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/13832

Test Plan: `DBTest2, GetFileChecksumsFromCurrentManifest_CRC32`

Reviewed By: pdillinger

Differential Revision: D79607298

Pulled By: mszeszko-meta

fbshipit-source-id: e7948e086ba6e6fb953a3959fdcc81300613d73e
2025-08-05 10:48:49 -07:00
Peter Dillinger
b9c7481fc2 Fix some secondary/read-only DB logic (#13441)
Summary:
Primarily, fix an issue from https://github.com/facebook/rocksdb/issues/13316 with opening secondary DB with preserve/preclude option (crash test disable in https://github.com/facebook/rocksdb/issues/13439). The issue comes down to mixed-up interpretations of "read_only" which should now be resolved. I've introduced the stronger notion of "unchanging" which means the VersionSet never sees any changes to the LSM tree, and the weaker notion of "read_only" which means LSM tree changes are not written through this VersionSet/etc. but can pick up externally written changes. In particular, ManifestTailer should use read_only=true (along with unchanging=false) for proper handling of preserve/preclude options.

A new assertion in VersionSet::CreateColumnFamily to help ensure sane usage of the two boolean flags is incompatible with the known wart of allowing CreateColumnFamily on a read-only DB. So to keep that assertion, I have fixed that issue by disallowing it. And this in turn required downstream clean-up in ldb, where I cleaned up some call sites as well.

Also, rename SanitizeOptions for ColumnFamilyOptions to SanitizeCfOptions, for ease of search etc.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/13441

Test Plan:
* Added preserve option to a test in db_secondary_test, which reproduced the failure seen in the crash test.
* Revert https://github.com/facebook/rocksdb/issues/13439 to re-enable crash test functionality
* Update some tests to deal with disallowing CF creation on read-only DB
* Add some testing around read-only DBs and CreateColumnFamily(ies)
* Resurrect a nearby test for read-only DB to be sure it doesn't write to the DB dir. New EnforcedReadOnlyReopen should probably be used in more places but didn't want to attempt a big migration here and now. (Suggested follow-up.)

Reviewed By: jowlyzhang

Differential Revision: D70808033

Pulled By: pdillinger

fbshipit-source-id: 486b4e9f9c9045150a0ebb9cb302753d03932a3f
2025-03-07 14:56:45 -08:00
Yu Zhang
945f60b157 Add some documentation for version edit handlers (#12948)
Summary:
As titled. No functional change.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12948

Reviewed By: hx235

Differential Revision: D61551254

Pulled By: jowlyzhang

fbshipit-source-id: ccf53d78bd2f18f174d7e61972e5de467c96ce76
2024-08-21 10:09:10 -07:00
Yu Zhang
295326b6ee Best efforts recovery recover seqno prefix (#12938)
Summary:
This PR make best efforts recovery more permissive by allowing it to recover incomplete Version that presents a valid point in time view from the user's perspective. Currently, a Version is only valid and saved if all files consisting that Version can be found. With this change, if only a suffix of L0 files (and their associated blob files) are missing,  a valid Version is also available to be saved and recover to. Note that we don't do this if the column family was atomically flushed. Because atomic flush also need a consistent view across the column families, we cannot guarantee that if we are recovering to incomplete version.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12938

Test Plan: Existing tests and added unit tests.

Reviewed By: anand1976

Differential Revision: D61414381

Pulled By: jowlyzhang

fbshipit-source-id: f9b73deb34d35ad696ab42315928b656d586262a
2024-08-16 17:18:54 -07:00
Yu Zhang
d458331ee9 Move file tracking in VersionEditHandlerPointInTime to VersionBuilder (#12928)
Summary:
`VersionEditHandlerPointInTime` is tracking found files, missing files, intermediate files in order to decide to build a `Version` on negative edge trigger (transition from valid to invalid) without applying  the current `VersionEdit`.  However, applying `VersionEdit` and check completeness of a `Version` are specialization of `VersionBuilder`.  More importantly, when we augment best efforts recovery to recover not just complete point in time Version but also a prefix of seqno for a point in time Version, such checks need to be duplicated in `VersionEditHandlerPointInTime` and `VersionBuilder`.

To avoid this, this refactor move all the file tracking functionality in `VersionEditHandlerPointInTime` into `VersionBuilder`.  To continue to let `VersionEditHandlerPIT` do the edge trigger check and  build a `Version` before applying the current `VersionEdit`, a suite of APIs to supporting creating a save point and its associated functions are added in `VersionBuilder` to achieve this.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12928

Test Plan: Existing tests

Reviewed By: anand1976

Differential Revision: D61171320

Pulled By: jowlyzhang

fbshipit-source-id: 604f66f8b1e3a3e13da59d8ba357c74e8a366dbc
2024-08-12 21:09:37 -07:00
HypenZou
8765a0f546 Fix version edit dump in json (#12703)
Summary:
**Context/Summary:**
the flag --json of manifest_dump in ldb tool has no effect
The bug may  be introduced by pr https://github.com/facebook/rocksdb/pull/8378

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12703

Reviewed By: cbi42

Differential Revision: D57848094

Pulled By: ajkr

fbshipit-source-id: 3d1ce65528bf4ce9c53593a7208406ab90e8994b
2024-05-28 16:44:25 -07:00
anand76
0ed93552f4 Implement obsolete file deletion (GC) in follower (#12657)
Summary:
This PR implements deletion of obsolete files in a follower RocksDB instance. The follower tails the leader's MANIFEST and creates links to newly added SST files. These links need to be deleted once those files become obsolete in order to reclaim space. There are three cases to be considered -
1. New files added and links created, but the Version could not be installed due to some missing files. Those links need to be preserved so a subsequent catch up attempt can succeed. We insert the next file number in the `VersionSet` to `pending_outputs_` to prevent their deletion.
2. Files deleted from the previous successfully installed `Version`. These are deleted as usual in `PurgeObsoleteFiles`.
3. New files added by a `VersionEdit` and deleted by a subsequent `VersionEdit`, both processed in the same catchup attempt. Links will be created for the new files when verifying a candidate `Version`. Those need to be deleted explicitly as they're never added to `VersionStorageInfo`, and thus not deleted by `PurgeObsoleteFiles`.

Test plan -
New unit tests in `db_follower_test`.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12657

Reviewed By: jowlyzhang

Differential Revision: D57462697

Pulled By: anand1976

fbshipit-source-id: 898f15570638dd4930f839ffd31c560f9cb73916
2024-05-17 19:13:33 -07:00
Andrew Kryczka
27a2473668 Best-effort recovery support for atomic flush (#12406)
Summary:
This PR updates `VersionEditHandlerPointInTime` to recover all or none of the updates in an AtomicGroup. This makes best-effort recovery properly handle atomic flushes during recovery, so the features are now allowed to both be enabled at once.

The new logic requires that AtomicGroups do not contain column family additions or removals. AtomicGroups are currently written for atomic flush, which does not include such edits.

Column family additions or removals are recovered independently of AtomicGroups. The new logic needs to be aware of removal, though, so that a dropped CF does not prevent completion of an AtomicGroup recovery.

The new logic treats each AtomicGroup as if it contains updates for all existing column families, even though it is possible to create AtomicGroups that only affect a subset of column families. This simplifies the logic at the expense of recovering less data in certain edge case scenarios.

The usage of `MaybeCreateVersion()` is pretty tricky. The goal is to create a barrier at the start of an AtomicGroup such that all valid states up to that point will be applied to `versions_`. Here is a summary.

- `MaybeCreateVersion(..., false)` creates a `Version` on a negative edge trigger (transition from valid to invalid). It was  previously called when applying each update. Now, it is only called when applying non-AtomicGroup updates.
- `MaybeCreateVersion(..., true)` creates a `Version` on a positive level trigger (valid state). It was previously called only at the end of iteration. Now, it is additionally called before processing an AtomicGroup.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12406

Reviewed By: jaykorean, cbi42

Differential Revision: D54494904

Pulled By: ajkr

fbshipit-source-id: 0114a9fe1d04b471d086dcab5978ea8a3a56ad52
2024-03-06 14:40:40 -08:00
Yu Zhang
4b013dcbed Remove VersionEdit's friends pattern (#12024)
Summary:
Almost each of VersionEdit private member has its own getter and setter. Current code access them with a combination of directly accessing private members and via getter and setters. There is no obvious benefits to have this pattern except potential performance gains. I tried this simple benchmark for removing the friends pattern completely, and there is no obvious regression. So I think it would good to remove VersionEdit's friends completely.

```TEST_TMPDIR=/dev/shm/rocksdb1 ./db_bench -benchmarks=fillseq -memtablerep=vector -allow_concurrent_memtable_write=false -num_column_families=10 -num=50000000```

With change:
fillseq      :       2.994 micros/op 333980 ops/sec 149.710 seconds 50000000 operations;   36.9 MB/s
fillseq      :       3.033 micros/op 329656 ops/sec 151.673 seconds 50000000 operations;   36.5 MB/s
fillseq      :       2.991 micros/op 334369 ops/sec 149.535 seconds 50000000 operations;   37.0 MB/s
Without change:
fillseq      :       3.015 micros/op 331715 ops/sec 150.732 seconds 50000000 operations;   36.7 MB/s
fillseq      :       3.044 micros/op 328553 ops/sec 152.182 seconds 50000000 operations;   36.3 MB/s
fillseq      :       3.091 micros/op 323520 ops/sec 154.550 seconds 50000000 operations;   35.8 MB/s

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12024

Reviewed By: pdillinger

Differential Revision: D50806066

Pulled By: jowlyzhang

fbshipit-source-id: 35d287ce638a38c30f243f85992e615b4c90eb27
2023-11-01 12:04:11 -07:00
Yu Zhang
c24ef26ca7 Support switching on / off UDT together with in-Memtable-only feature (#11623)
Summary:
Add support to allow enabling / disabling user-defined timestamps feature for an existing column family in combination with the in-Memtable only feature.

To do this, this PR includes:
1) Log the `persist_user_defined_timestamps` option per column family in Manifest to facilitate detecting an attempt to enable / disable UDT. This entry is enforced to be logged in the same VersionEdit as the user comparator name entry.

2) User-defined timestamps related options are validated when re-opening a column family, including user comparator name and the `persist_user_defined_timestamps` flag. These type of settings and settings change are considered valid:
     a) no user comparator change and no effective `persist_user_defined_timestamp` flag change.
     b) switch user comparator to enable UDT provided the immediately effective `persist_user_defined_timestamps` flag
         is false.
     c) switch user comparator to disable UDT provided that the before-change `persist_user_defined_timestamps` is
         already false.
3) when an attempt to enable UDT is detected, we mark all its existing SST files as "having no UDT" by marking its `FileMetaData.user_defined_timestamps_persisted` flag to false and handle their file boundaries `FileMetaData.smallest`, `FileMetaData.largest` by padding a min timestamp.

4) while enabling / disabling UDT feature, timestamp size inconsistency in existing WAL logs are handled to make it compatible with the running user comparator.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11623

Test Plan:
```
make all check
./db_with_timestamp_basic_test --gtest-filter="*EnableDisableUDT*"
./db_wal_test --gtest_filter="*EnableDisableUDT*"
```

Reviewed By: ltamasi

Differential Revision: D47636862

Pulled By: jowlyzhang

fbshipit-source-id: dcd19f67292da3c3cc9584c09ad00331c9ab9322
2023-07-26 20:16:32 -07:00
Yu Zhang
f74526341d Handle file boundaries when timestamps should not be persisted (#11578)
Summary:
Handle file boundaries `FileMetaData.smallest`, `FileMetaData.largest` for when `persist_user_defined_timestamps` is false:
    1) on the manifest write path, the original user-defined timestamps in file boundaries are stripped. This stripping is done during `VersionEdit::Encode` to limit the effect of the stripping to only the persisted version of the file boundaries.
    2) on the manifest read path during DB open, a a min timestamp is padded to the file boundaries. Ideally, this padding should happen during `VersionEdit::Decode` so that all in memory file boundaries have a compatible user key format as the running user comparator. However, because the user-defined timestamp size information is not available at that time. This change is added to `VersionEditHandler::OnNonCfOperation`.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11578

Test Plan:
```
make all check
./version_edit_test --gtest_filter="*EncodeDecodeNewFile4HandleFileBoundary*".
./db_with_timestamp_basic_test --gtest_filter="*HandleFileBoundariesTest*"
```

Reviewed By: pdillinger

Differential Revision: D47309399

Pulled By: jowlyzhang

fbshipit-source-id: 21b4d54d2089a62826b31d779094a39cb2bbbd51
2023-07-10 11:03:25 -07:00
Hui Xiao
151242ce46 Group rocksdb.sst.read.micros stat by IOActivity flush and compaction (#11288)
Summary:
**Context:**
The existing stat rocksdb.sst.read.micros does not reflect each of compaction and flush cases but aggregate them, which is not so helpful for us to understand IO read behavior of each of them.

**Summary**
- Update `StopWatch` and `RandomAccessFileReader` to record `rocksdb.sst.read.micros` and `rocksdb.file.{flush/compaction}.read.micros`
   - Fixed the default histogram in `RandomAccessFileReader`
- New field `ReadOptions/IOOptions::io_activity`; Pass `ReadOptions` through paths under db open, flush and compaction to where we can prepare `IOOptions` and pass it to `RandomAccessFileReader`
- Use `thread_status_util` for assertion in `DbStressFSWrapper` for continuous testing on we are passing correct `io_activity` under db open, flush and compaction

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11288

Test Plan:
- **Stress test**
- **Db bench 1: rocksdb.sst.read.micros COUNT ≈ sum of rocksdb.file.read.flush.micros's and rocksdb.file.read.compaction.micros's.**  (without blob)
     - May not be exactly the same due to `HistogramStat::Add` only guarantees atomic not accuracy across threads.
```
./db_bench -db=/dev/shm/testdb/ -statistics=true -benchmarks="fillseq" -key_size=32 -value_size=512 -num=50000 -write_buffer_size=655 -target_file_size_base=655 -disable_auto_compactions=false -compression_type=none -bloom_bits=3 (-use_plain_table=1 -prefix_size=10)
```
```
// BlockBasedTable
rocksdb.sst.read.micros P50 : 2.009374 P95 : 4.968548 P99 : 8.110362 P100 : 43.000000 COUNT : 40456 SUM : 114805
rocksdb.file.read.flush.micros P50 : 1.871841 P95 : 3.872407 P99 : 5.540541 P100 : 43.000000 COUNT : 2250 SUM : 6116
rocksdb.file.read.compaction.micros P50 : 2.023109 P95 : 5.029149 P99 : 8.196910 P100 : 26.000000 COUNT : 38206 SUM : 108689

// PlainTable
Does not apply
```
- **Db bench 2: performance**

**Read**

SETUP: db with 900 files
```
./db_bench -db=/dev/shm/testdb/ -benchmarks="fillseq" -key_size=32 -value_size=512 -num=50000 -write_buffer_size=655  -disable_auto_compactions=true -target_file_size_base=655 -compression_type=none
```run till convergence
```
./db_bench -seed=1678564177044286 -use_existing_db=true -db=/dev/shm/testdb -benchmarks=readrandom[-X60] -statistics=true -num=1000000 -disable_auto_compactions=true -compression_type=none -bloom_bits=3
```
Pre-change
`readrandom [AVG 60 runs] : 21568 (± 248) ops/sec`
Post-change (no regression, -0.3%)
`readrandom [AVG 60 runs] : 21486 (± 236) ops/sec`

**Compaction/Flush**run till convergence
```
./db_bench -db=/dev/shm/testdb2/ -seed=1678564177044286 -benchmarks="fillseq[-X60]" -key_size=32 -value_size=512 -num=50000 -write_buffer_size=655  -disable_auto_compactions=false -target_file_size_base=655 -compression_type=none

rocksdb.sst.read.micros  COUNT : 33820
rocksdb.sst.read.flush.micros COUNT : 1800
rocksdb.sst.read.compaction.micros COUNT : 32020
```
Pre-change
`fillseq [AVG 46 runs] : 1391 (± 214) ops/sec;    0.7 (± 0.1) MB/sec`

Post-change (no regression, ~-0.4%)
`fillseq [AVG 46 runs] : 1385 (± 216) ops/sec;    0.7 (± 0.1) MB/sec`

Reviewed By: ajkr

Differential Revision: D44007011

Pulled By: hx235

fbshipit-source-id: a54c89e4846dfc9a135389edf3f3eedfea257132
2023-04-21 09:07:18 -07:00
Hui Xiao
98d5db5c2e Sort L0 files by newly introduced epoch_num (#10922)
Summary:
**Context:**
Sorting L0 files by `largest_seqno` has at least two inconvenience:
-  File ingestion and compaction involving ingested files can create files of overlapping seqno range with the existing files. `force_consistency_check=true` will catch such overlap seqno range even those harmless overlap.
    - For example, consider the following sequence of events ("key@n" indicates key at seqno "n")
       - insert k1@1 to memtable m1
       - ingest file s1 with k2@2, ingest file s2 with k3@3
        - insert k4@4 to m1
       - compact files s1, s2 and  result in new file s3 of seqno range [2, 3]
       - flush m1 and result in new file s4 of seqno range [1, 4]. And `force_consistency_check=true` will think s4 and s3 has file reordering corruption that might cause retuning an old value of k1
    - However such caught corruption is a false positive since s1, s2 will not have overlapped keys with k1 or whatever inserted into m1 before ingest file s1 by the requirement of file ingestion (otherwise the m1 will be flushed first before any of the file ingestion completes). Therefore there in fact isn't any file reordering corruption.
- Single delete can decrease a file's largest seqno and ordering by `largest_seqno` can introduce a wrong ordering hence file reordering corruption
    - For example, consider the following sequence of events ("key@n" indicates key at seqno "n", Credit to ajkr  for this example)
        - an existing SST s1 contains only k1@1
        - insert k1@2 to memtable m1
        - ingest file s2 with k3@3, ingest file s3 with k4@4
        - insert single delete k5@5 in m1
        - flush m1 and result in new file s4 of seqno range [2, 5]
        - compact s1, s2, s3 and result in new file s5 of seqno range [1, 4]
        - compact s4 and result in new file s6 of seqno range [2] due to single delete
    - By the last step, we have file ordering by largest seqno (">" means "newer") : s5 > s6 while s6 contains a newer version of the k1's value (i.e, k1@2) than s5, which is a real reordering corruption. While this can be caught by `force_consistency_check=true`, there isn't a good way to prevent this from happening if ordering by `largest_seqno`

Therefore, we are redesigning the sorting criteria of L0 files and avoid above inconvenience. Credit to ajkr , we now introduce `epoch_num` which describes the order of a file being flushed or ingested/imported (compaction output file will has the minimum `epoch_num` among input files'). This will avoid the above inconvenience in the following ways:
- In the first case above, there will no longer be overlap seqno range check in `force_consistency_check=true` but `epoch_number`  ordering check. This will result in file ordering s1 <  s2 <  s4 (pre-compaction) and s3 < s4 (post-compaction) which won't trigger false positive corruption. See test class `DBCompactionTestL0FilesMisorderCorruption*` for more.
- In the second case above, this will result in file ordering s1 < s2 < s3 < s4 (pre-compacting s1, s2, s3), s5 < s4 (post-compacting s1, s2, s3), s5 < s6 (post-compacting s4), which are correct file ordering without causing any corruption.

**Summary:**
- Introduce `epoch_number` stored per `ColumnFamilyData` and sort CF's L0 files by their assigned `epoch_number` instead of `largest_seqno`.
  - `epoch_number` is increased and assigned upon `VersionEdit::AddFile()` for flush (or similarly for WriteLevel0TableForRecovery) and file ingestion (except for allow_behind_true, which will always get assigned as the `kReservedEpochNumberForFileIngestedBehind`)
  - Compaction output file  is assigned with the minimum `epoch_number` among input files'
      - Refit level: reuse refitted file's epoch_number
  -  Other paths needing `epoch_number` treatment:
     - Import column families: reuse file's epoch_number if exists. If not, assign one based on `NewestFirstBySeqNo`
     - Repair: reuse file's epoch_number if exists. If not, assign one based on `NewestFirstBySeqNo`.
  -  Assigning new epoch_number to a file and adding this file to LSM tree should be atomic. This is guaranteed by us assigning epoch_number right upon `VersionEdit::AddFile()` where this version edit will be apply to LSM tree shape right after by holding the db mutex (e.g, flush, file ingestion, import column family) or  by there is only 1 ongoing edit per CF (e.g, WriteLevel0TableForRecovery, Repair).
  - Assigning the minimum input epoch number to compaction output file won't misorder L0 files (even through later `Refit(target_level=0)`). It's due to for every key "k" in the input range, a legit compaction will cover a continuous epoch number range of that key. As long as we assign the key "k" the minimum input epoch number, it won't become newer or older than the versions of this key that aren't included in this compaction hence no misorder.
- Persist `epoch_number` of each file in manifest and recover `epoch_number` on db recovery
   - Backward compatibility with old db without `epoch_number` support is guaranteed by assigning `epoch_number` to recovered files by `NewestFirstBySeqno` order. See `VersionStorageInfo::RecoverEpochNumbers()` for more
   - Forward compatibility with manifest is guaranteed by flexibility of `NewFileCustomTag`
- Replace `force_consistent_check` on L0 with `epoch_number` and remove false positive check like case 1 with `largest_seqno` above
   - Due to backward compatibility issue, we might encounter files with missing epoch number at the beginning of db recovery. We will still use old L0 sorting mechanism (`NewestFirstBySeqno`) to check/sort them till we infer their epoch number. See usages of `EpochNumberRequirement`.
- Remove fix https://github.com/facebook/rocksdb/pull/5958#issue-511150930 and their outdated tests to file reordering corruption because such fix can be replaced by this PR.
- Misc:
   - update existing tests with `epoch_number` so make check will pass
   - update https://github.com/facebook/rocksdb/pull/5958#issue-511150930 tests to verify corruption is fixed using `epoch_number` and cover universal/fifo compaction/CompactRange/CompactFile cases
   - assert db_mutex is held for a few places before calling ColumnFamilyData::NewEpochNumber()

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10922

Test Plan:
- `make check`
- New unit tests under `db/db_compaction_test.cc`, `db/db_test2.cc`, `db/version_builder_test.cc`, `db/repair_test.cc`
- Updated tests (i.e, `DBCompactionTestL0FilesMisorderCorruption*`) under https://github.com/facebook/rocksdb/pull/5958#issue-511150930
- [Ongoing] Compatibility test: manually run 36a5686ec0 (with file ingestion off for running the `.orig` binary to prevent this bug affecting upgrade/downgrade formality checking) for 1 hour on `simple black/white box`, `cf_consistency/txn/enable_ts with whitebox + test_best_efforts_recovery with blackbox`
- [Ongoing] normal db stress test
- [Ongoing] db stress test with aggressive value https://github.com/facebook/rocksdb/pull/10761

Reviewed By: ajkr

Differential Revision: D41063187

Pulled By: hx235

fbshipit-source-id: 826cb23455de7beaabe2d16c57682a82733a32a9
2022-12-13 13:29:37 -08:00
Yanqin Jin
3d0d6b8140 Make best-efforts recovery verify SST unique ID before Version construction (#10962)
Summary:
The check for SST unique IDs added to best-efforts recovery (`Options::best_efforts_recovery` is true).

With best_efforts_recovery being true, RocksDB will recover to the latest point in
MANIFEST such that all valid SST files included up to this point pass unique ID checks as well.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10962

Test Plan: make check

Reviewed By: pdillinger

Differential Revision: D41378241

Pulled By: riversand963

fbshipit-source-id: a036064e2c17dec13d080a24ef2a9f85d607b16c
2022-11-22 22:53:31 -08:00
Baptiste Lemaire
d61a449364 Fixed manifest_dump issues when printing keys and values containing null characters (#8378)
Summary:
Changed fprintf function to fputc in ApplyVersionEdit, and replaced null characters with whitespaces.
Added unit test in ldb_test.py - verifies that manifest_dump --verbose output is correct when keys and values containing null characters are inserted.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8378

Reviewed By: pdillinger

Differential Revision: D29034584

Pulled By: bjlemaire

fbshipit-source-id: 50833687a8a5f726e247c38457eadc3e6dbab862
2021-06-10 12:55:20 -07:00
Yanqin Jin
314352761f Ignore comparator name mismatch in ldb manifest dump (#8216)
Summary:
RocksDB allows user-specified custom comparators which may not be known to `ldb`,
a built-in tool for checking/mutating the database. Therefore, column family comparator
names mismatch encountered during manifest dump should not prevent the dumping from
proceeding.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8216

Test Plan:
```
make check
```

Also manually do the following
```
KEEP_DB=1 ./db_with_timestamp_basic_test
./ldb --db=<db> manifest_dump --verbose
```
The ldb should succeed and print something like:
```
...
--------------- Column family "default"  (ID 0) --------------
log number: 6
comparator: <TestComparator>, but the comparator object is not available.
...
```

Reviewed By: ltamasi

Differential Revision: D27927581

Pulled By: riversand963

fbshipit-source-id: f610b2c842187d17f575362070209ee6b74ec6d4
2021-04-21 20:43:10 -07:00
Yanqin Jin
b0e20194ea Handle blob files when options.best_efforts_recovery is true (#8180)
Summary:
If `options.best_efforts_recovery == true`, RocksDB currently tolerates missing table files and recovers to the latest version without missing table files (not considering WAL). It is necessary to handle blob files as well to make the feature more complete.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8180

Test Plan: make check

Reviewed By: ltamasi

Differential Revision: D27840556

Pulled By: riversand963

fbshipit-source-id: 041685d0dc2e7779ac4f0374c07a8a327704aa5e
2021-04-19 11:56:14 -07:00
Yanqin Jin
64517d184a Make secondary instance use ManifestTailer (#7998)
Summary:
This PR

- adds a class `ManifestTailer` that inherits from `VersionEditHandlerPointInTime`. `ManifestTailer::Iterate()` can be called multiple times to tail the primary instance's MANIFEST and apply the changes to the secondary,
- updates the implementation of `ReactiveVersionSet::ReadAndApply` to use this class,
- removes unused code in version_set.cc,
- updates existing tests, e.g. removing deleted sync points from unit tests,
- adds a new test to address the bug in https://github.com/facebook/rocksdb/issues/7815.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7998

Test Plan:
make check
Existing and newly-added tests in version_set_test.cc and db_secondary_test.cc

Reviewed By: jay-zhuang

Differential Revision: D26926641

Pulled By: riversand963

fbshipit-source-id: 8d4dd15db0ba863c213f743e33b5a207e948c980
2021-03-10 10:59:44 -08:00
Yanqin Jin
8b6b6aeb1a Refactor with VersionEditHandler (#6581)
Summary:
Added a few classes in the same class hierarchy to remove code duplication and
refactor the logic of reading and processing MANIFEST files.

New classes are as follows.
```
class VersionEditHandlerBase;
class ListColumnFamiliesHandler : VersionEditHandlerBase;
class FileChecksumRetriever : VersionEditHandlerBase;
class DumpManifestHandler : VersionEditHandler;
```
Classes that already existed before this PR are as follows.
```
class VersionEditHandler : VersionEditHandlerBase;
```

With these classes, refactored functions: `VersionSet::Recover()`,
`VersionSet::ListColumnFamilies()`, `VersionSet::DumpManifest()`,
`GetFileChecksumFromManifest()`.

Test Plan (devserver):
```
make check
COMPILE_WITH_ASAN=1 make check
```
These refactored code, especially recovery-related logic, will be tested intensively by
all existing unit tests and stress tests. For example, run
```
make crash_test
```
Verified 3 successful runs on devserver.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/6581

Reviewed By: ajkr

Differential Revision: D20616217

Pulled By: riversand963

fbshipit-source-id: 048c7743aa4be2623ccd0cc3e61c0027e604e78b
2020-11-11 08:00:14 -08:00
Cheng Chang
1b224324b5 Track WAL in MANIFEST: persist WALs to and recover WALs from MANIFEST (#7256)
Summary:
This PR makes it able to `LogAndApply` `VersionEdit`s related to WALs, and also be able to `Recover` from MANIFEST with WAL related `VersionEdit`s.

The `VersionEdit`s related to WAL are treated similarly as those related to column family operations, they are not applied to versions, but can be in a commit group. Mixing WAL related `VersionEdit`s with other types of edits will make logic in `ProcessManifestWrite` more complicated, so `VersionEdit`s related to WAL can either be WAL additions or deletions, like column family add and drop.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7256

Test Plan: a set of unit tests are added in `version_set_test.cc`

Reviewed By: riversand963

Differential Revision: D23123238

Pulled By: cheng-chang

fbshipit-source-id: 246be2ed4744fd03fa2738aba408aaa611d0379c
2020-10-23 22:49:51 -07:00
Akanksha Mahajan
b175eceb09 Store FSWritableFilePtr object in WritableFileWriter (#7193)
Summary:
Replace FSWritableFile pointer with FSWritableFilePtr
    object in WritableFileWriter.
    This new object wraps FSWritableFile pointer.

    Objective: If tracing is enabled, FSWritableFile Ptr returns
    FSWritableFileTracingWrapper pointer that includes all necessary
    information in IORecord and calls underlying FileSystem and invokes
    IOTracer to dump that record in a binary file. If tracing is disabled
    then, underlying FileSystem pointer is returned directly.
    FSWritableFilePtr wrapper class is added to bypass the
    FSWritableFileWrapper when
    tracing is disabled.

    Test Plan: make check -j64

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7193

Reviewed By: anand1976

Differential Revision: D23355915

Pulled By: akankshamahajan15

fbshipit-source-id: e62a27a13c1fd77e36a6dbafc7006d969bed25cf
2020-09-08 10:56:08 -07:00
Yanqin Jin
569b87e8c7 Fail recovery when MANIFEST record checksum mismatch (#6996)
Summary:
https://github.com/facebook/rocksdb/issues/5411 refactored `VersionSet::Recover` but introduced a bug, explained as follows.
Before, once a checksum mismatch happens, `reporter` will set `s` to be non-ok. Therefore, Recover will stop processing the MANIFEST any further.
```
// Correct
// Inside Recover
LogReporter reporter;
reporter.status = &s;
log::Reader reader(..., reporter);
while (reader.ReadRecord() && s.ok()) {
...
}
```
The bug is that, the local variable `s` in `ReadAndRecover` won't be updated by `reporter` while reading the MANIFEST. It is possible that the reader sees a checksum mismatch in a record, but `ReadRecord` retries internally read and finds the next valid record. The mismatched record will be ignored and no error is reported.
```
// Incorrect
// Inside Recover
LogReporter reporter;
reporter.status = &s;
log::Reader reader(..., reporter);
s = ReadAndRecover(reader, ...);

// Inside ReadAndRecover
  Status s;  // Shadows the s in Recover.
  while (reader.ReadRecord() && s.ok()) {
   ...
  }
```
`LogReporter` can use a separate `log_read_status` to track the errors while reading the MANIFEST. RocksDB can process more MANIFEST entries only if `log_read_status.ok()`.
Test plan (devserver):
make check
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6996

Reviewed By: ajkr

Differential Revision: D22105746

Pulled By: riversand963

fbshipit-source-id: b22f717a423457a41ca152a242abbb64cf91fc38
2020-06-18 10:09:12 -07:00
Yanqin Jin
fb09ef05dc Attempt to recover from db with missing table files (#6334)
Summary:
There are situations when RocksDB tries to recover, but the db is in an inconsistent state due to SST files referenced in the MANIFEST being missing. In this case, previous RocksDB will just fail the recovery and return a non-ok status.
This PR enables another possibility. During recovery, RocksDB checks possible MANIFEST files, and try to recover to the most recent state without missing table file. `VersionSet::Recover()` applies version edits incrementally and "materializes" a version only when this version does not reference any missing table file. After processing the entire MANIFEST, the version created last will be the latest version.
`DBImpl::Recover()` calls `VersionSet::Recover()`. Afterwards, WAL replay will *not* be performed.
To use this capability, set `options.best_efforts_recovery = true` when opening the db. Best-efforts recovery is currently incompatible with atomic flush.

Test plan (on devserver):
```
$make check
$COMPILE_WITH_ASAN=1 make all && make check
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6334

Reviewed By: anand1976

Differential Revision: D19778960

Pulled By: riversand963

fbshipit-source-id: c27ea80f29bc952e7d3311ecf5ee9c54393b40a8
2020-03-20 19:30:48 -07:00