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241 Commits

Author SHA1 Message Date
Yoshinori Matsunobu
d6a7847d37 Add a DB option to log long-held global mutexes and release sites (#15436)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/15436

## Why
Long-held global mutexes can stall foreground and background work. Existing mutex statistics measure acquisition waits, not continuous ownership. This adds opt-in logging to identify the mutex, owning thread, operation and release site.

## Enable for an investigation
Provide an INFO logger and shared `Statistics` object when opening the DB, then:
- Set the shared statistics level to `StatsLevel::kAll`.
- Set `mutex_hold_log_threshold_us` through `DB::SetDBOptions`; `100000` means 100 ms.
- Restore threshold 0 and the previous statistics level afterward.

The threshold defaults to **0 (disabled)**. `kAll` alone does not enable these hold probes; threshold 0 leaves existing statistics timers unchanged.

## Output
Illustrative records, not production observations:
```
SLOW_GLOBAL_MUTEX mutex=DBImpl::mutex_ mutex_addr=0x12340000 owner_thread_id=12345 thread_operation=Compaction hold_us=200000 threshold_us=100000 observed_end_us=1792205400000000 buffer_dropped_records=0 unlock=db_impl_compaction_flush.cc:4660 BackgroundCallCompaction()
SLOW_GLOBAL_MUTEX mutex=DBImpl::wal_write_mutex_ mutex_addr=0x12340100 owner_thread_id=12346 thread_operation= hold_us=35000 threshold_us=25000 observed_end_us=1792205401000000 buffer_dropped_records=0 scope_exit=db_impl_write.cc:2250 PreprocessWrite()
```
The first proves a completed 200 ms DB-mutex ownership interval on a thread tagged `Compaction`. The second uses a 25 ms threshold; an empty operation tag means none was available. Neither record reports acquisition wait or proves the cause of a stall.

Release attribution uses compiler-embedded strings available in optimized, stripped builds, with a GCC/Clang fallback where standard source locations are unavailable. Direct unlock and condition wait identify their call sites; scope exit and temporary unlock identify guard declarations, not closing braces. No stack unwinding or symbol lookup.

## Scope and safety
- Track six selected mutexes: DB, WAL, point-lock wait graph, two prepare-log bookkeeping mutexes and transaction name map. This is not comprehensive synchronization tracing.
- Acquisition waits and condition-variable release gaps are excluded from hold duration. Configuration is pre-first-use; repeated setup retains the first valid context.
- Sample at most once per mutex per second, with eight deferred records per thread. `buffer_dropped_records` counts capacity overflow only; rate limiting, pause and emission contention can omit samples.
- Emit after covered outer lock scopes release. Emission is nonblocking best-effort; shutdown drains/pauses emission and stops diagnostics before the owned logger closes. Closing from that logger's own callback is unsupported.
- No data-file format change. The mutable option is persisted in OPTIONS and wired into bench/stress tools. Typed C binding is deferred; string DB-option APIs are available.

Disabled bookkeeping still has a cost. Release A/B measurements found about 3 ns added per selected mutex pair at level 1, and about 70 ns for hold timing over `kAll`/0. Get and reused-iterator Seek showed no resolved small probe effect; fresh iterator+Seek at 16 threads showed +8.7% CPU/query and -9.4% QPS. No logs were emitted in those benchmarks; logging cost and broader workload qualification remain open.

Reviewed By: xingbowang

Differential Revision: D125790955

fbshipit-source-id: 1096163f3bd25ffee585dc6ec8ebfd7f1759851a
2026-10-22 09:50:20 -07:00
Peter Dillinger
539532377d Remove Solaris support (#15449)
Summary:
Solaris support was contributed by outside users starting with d78c6b28c (2016), and no project CI has ever run on Solaris. The last Solaris-motivated change was c76688745 (https://github.com/facebook/rocksdb/issues/4012, June 2018). Four months later, d6ec28870 (https://github.com/facebook/rocksdb/issues/4226, 5.18) gave PerfContext a user-declared destructor while the Solaris-only definition was still `__thread PerfContext perf_context_`, which GCC rejects, so the Solaris build has not compiled since. fd00f39f9 (https://github.com/facebook/rocksdb/issues/8117, 2021) then renamed that definition to `perf_context` while keeping
`#define perf_context (*get_perf_context())` in perf_context_imp.h, so the definition expands to `thread_local PerfContext (*get_perf_context());`, an error still present today. The Solaris-only paths are dead and untestable, yet still attract new carve-outs.

Because Solaris support is apparently unused and complicating things, this change removes all OS_SOLARIS / SunOS handling from the build (Make, CMake, build_detect_platform, INSTALL.md), the portability layer and Env (endianness, gethrtime, directio, stack trace), the perf_context macro and destructor carve-out, Solaris-only test workarounds and exclusions, and RocksJava's Environment.isSolaris() and Solaris JNI library naming.

Not Solaris-specific and kept: SPARC unaligned-access handling in util/coding.h, sparc64 in Makefile machine lists (Linux/OpenBSD), and sparcv9 in RocksJava Environment.is64Bit(). Third-party sources are untouched.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/15449

Test Plan: On non-Solaris platforms every removed condition was either an OS_SOLARIS-only branch or a `!defined(OS_SOLARIS)` term that was always true, so the code compiled is unchanged and the CI matrix covers it. The Solaris breakage was confirmed by syntax-checking monitoring/perf_context.cc with -DOS_SOLARIS (GCC 11, stub sys/isa_defs.h) at each commit touching the perf_context files from c31979205 through fd00f39f9: clean before d6ec28870, failing at every commit from d6ec28870 on.

Reviewed By: archang19

Differential Revision: D126714985

Pulled By: pdillinger

fbshipit-source-id: 40d22fcd5a462375c9d2c93f52407df651286ef7
2026-10-22 08:25:11 -07:00
Andrew Chang
ee305ac1c3 Avoid a TLS init call on every perf counter update (#15428)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/15428

RocksDB counts per-operation statistics (blocks read, bytes read, mutex waits,
timings) in `perf_context`. It is a `thread_local` variable: each thread has its
own copy, so threads never contend on it. This per-thread copy is "thread-local
storage" (TLS).

**Problem**: `PerfContext` has a non-trivial destructor. For such a variable, C++
must make sure the calling thread's copy is constructed before each use from
another source file, so the compiler emits a call to a small "TLS init"
function. That call goes through the PLT (procedure linkage table, the jump
table used to call functions that may live in another shared library). Every
`PERF_COUNTER_ADD` therefore paid a real function call before incrementing a
counter, and these macros run in hot loops such as key comparisons during block
iteration. `perf_level`, the on/off switch, has a smaller cost: it is
`extern thread_local` without `constinit`, so each read also tests whether it
has been initialized.

**Fix**:
- The perf macros read a `constinit thread_local PerfContext*` that each
  thread sets on first use. After that, a counter update is a pointer load,
  a null check and the increment.
- `perf_level` is declared and defined `constinit`, so reading it is a plain
  thread-local load.
- No public API change. `perf_context`, `get_perf_context()` and macro
  behavior are unchanged, and so is thread-exit behavior.

**Results**:
- Microbenchmark (`PERF_COUNTER_ADD` in a loop): 2.10 -> 0.84 ns per update
  with counting enabled; unchanged at 0.42 ns with counting disabled.
- Calls to the TLS init functions drop from 40 and 96 to 0 in block.cc.o
  and memtable.cc.o.
- In CPU profiles of large production RocksDB deployments, these accessors
  cost roughly 0.3-0.6% of total CPU. This change removes most of the
  `perf_context` part.

Reviewed By: xingbowang

Differential Revision: D125982209

fbshipit-source-id: f38b4fffda09611d28322e7534b135fb35631389
2026-10-21 11:47:50 -07:00
Josh Kang
4b983da055 Spell out special member functions (rule of five) (#15387)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/15387

## Summary

RocksDB's `.clang-tidy` enables `cppcoreguidelines-special-member-functions`,
`cppcoreguidelines-virtual-class-destructor` and the noexcept-move checks,
and clang warns `-Wdeprecated-copy-with-user-provided-dtor`. A full scan
reports 476 findings. In most of them, a class declares a destructor (or
copy operations) but leaves the rest of copy/move implicit. That has two
costs. Readers can't tell whether a class may be copied or moved. And
resource-owning classes keep an implicit copy that would double-free if
anyone ever used it. This diff resolves 453 of the 476.

Approach, picked per class from least to most invasive:
1. An empty user-provided destructor becomes `= default`. This covers most
   interface classes, such as `virtual ~X() {}` -> `= default`. If the
   class is still copied, that would only rename the deprecated-copy
   warning, so the destructor is removed instead when nothing needs it
   (`Customizable`, `TableFactory` and `InternalKeyComparator` inherit a
   virtual one; `IteratorWrapperBase` isn't polymorphic), and
   `MemTableRep::KeyComparator` gets defaulted copy and move.
2. Classes whose copy is already deleted get explicitly deleted move
   operations too. Move was already unavailable, so this only documents
   it.
3. Resource-owning classes that are never copied get deleted copy and move
   operations. Examples: the C API wrapper structs, which run a
   `destructor_` callback (edited in `tools/c_api_gen/c_base.cc` and
   regenerated into `db/c.cc`); `ShardedCache`, which frees its shards;
   iterator wrappers; and RAII handles.
4. Value types that are copied or moved get the missing operations as
   `= default`, which keeps their current behavior.
5. Exception specifications of existing functions are unchanged, except
   for `WriteBatch`'s move assignment (below): no other `noexcept` is
   added or removed. Only the move operations this diff
   newly declares (`Comparator`, `FileSampledStats` and the thread-local
   `Entry`) are `noexcept`; they copy only scalars or atomics.

`WriteBatch`'s copy and move assignment destroyed `*this` and
placement-new'ed a new `WriteBatch` over it. That is undefined behavior
when `*this` is a subclass, and if the copy constructor threw, `*this`
was left destroyed and was later destroyed again. Move assignment now
assigns member-wise and ends in the same state as the move constructor,
which leaves `has_key_with_ts_`, the timestamp-size tracking and the
other fields it doesn't copy at their defaults. `rep_` is swapped through
a temporary, because a plain string move-assignment can keep the old
buffer (e.g. a large batch reset with `batch = WriteBatch()` would keep
its memory). Nothing in it can throw, so it is now `noexcept`. Copy
assignment copies into a temporary and moves it in, so a throwing copy
leaves `*this` unchanged.

Bugs this exposed and fixed:
- `RestoreAfterCopyOrCreateWorkItem` (backup engine): the hand-written
  move constructor and assignment moved only some fields, so `from_file`
  and `to_file` were empty after `push_back(std::move(...))`. A restore
  that hit a checksum mismatch then reported "While restoring  -> : ..."
  without file names. It now uses the compiler-generated moves, which
  are still `noexcept`.
- `ExternalSstFileIngestionJob` lived in a `std::vector`, and its
  destructor frees raw-owned pointers, so the implicit copy used on
  vector reallocation would double-free. Its file batches also point into
  its own inline file storage, so neither a copy nor a move is safe after
  `Prepare()`. Copy and move are now deleted, and `DBImpl` holds jobs
  through `std::unique_ptr`.

Compatibility: no public class loses an operation users can call. Public
interfaces mostly only get `virtual ~X() = default;`.
`WriteBatch`'s move assignment becomes `noexcept`, which is not part of
the mangled name, so the ABI doesn't change.
`SubcompactionJobInfo` and `CompactionJobInfo` intentionally stay C++20
aggregates, so users' aggregate and designated initializers keep
compiling. `Configurable`, `CompareInterface`, `WriteBatchBase`,
`ObjectLibrary::Entry` and `MemTableRep::KeyComparator` declare defaulted
copy and move, and `Customizable` no longer declares a destructor. As a
result, `Configurable` and `Customizable` subclasses that declare no
destructor or copy operations of their own now move their
registered-options list instead of copying it. In-tree, these are the
mutable-options adapters, the table factories, the memory allocators and
test classes; all are held through smart pointers or used in place, and
`Clone()` copies, so none is moved by value.

Not changed (23): `IODebugContext` (custom deep copy plus a
`std::shared_mutex`), `DBWithColumnFamilies` in db_bench (stored in a
`std::vector` with non-movable members), `Snapshot`'s protected virtual
destructor (intended), `ManagedSnapshot`, the `SubcompactionJobInfo` and
`CompactionJobInfo` aggregates, and the 16 noexcept-move-constructor and
noexcept-swap findings on existing functions, including `autovector`'s
move assignment (adding `noexcept` would change their exception
specifications). Copying `ManagedSnapshot` already double-releases the
snapshot. Fixing that needs a real move implementation and is a behavior
change, so it is left for a separate diff.

Reviewed By: rban1

Differential Revision: D123186309

fbshipit-source-id: 6f8e57e233e12199a007407130bb9a1f6d52e8d1
2026-10-12 16:00:09 -07:00
Josh Kang
da82001d81 Mark overriding methods and destructors override (#15366)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/15366

## Summary

RocksDB's `.clang-tidy` enables `modernize-use-override`, and clang
reports `-Winconsistent-missing-destructor-override` when a class marks
its other overrides `override` but not its destructor. A full scan finds
190 `modernize-use-override`, 100
`inconsistent-missing-destructor-override` and 2 `suggest-override`
findings in existing code. Each one comes back whenever a nearby line is
edited. They also leave classes where it isn't obvious which methods are
overrides and which introduce new virtuals.

This diff marks every overriding member function and destructor
`override` and drops the redundant `virtual` on them. It also changes
`final override` to plain `final`, following the check's default. Methods
that introduce a new virtual keep `virtual`. Most edits are clang-tidy's
own fix-its, applied mechanically and then clang-formatted.

Compatibility: no signatures change. In public headers the only effect is
`override` on existing overrides (mostly destructors, plus
`Cache::Name()` and `Cache::GetPrintableOptions()`, whose base
declarations are unconditional), so user code that subclasses these types
is unaffected. Every touched class now marks all of its overrides
consistently. This matters because a partially-marked class would make
clang emit `-Winconsistent-missing-override` in user builds.

Reviewed By: rban1

Differential Revision: D123186308

fbshipit-source-id: 1f489ea32d938e3ec0faf9abc4f7ff49e042d37a
2026-10-09 14:39:14 -07:00
Josh Kang
928527b869 Fix bugs and false positives from clang-analyzer/bugprone (#15325)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/15325

## Summary

RocksDB's `.clang-tidy` enables the `clang-analyzer-*` and `bugprone-*`
checks. A full scan of the repo still reports 78 findings from these
checks in existing code. Each time a nearby line is edited, they come
back as noise, and a few of them are real defects. This diff resolves 73
of the 78; upstream has since fixed one more, and the four left are
listed under "Intentionally not changed". Some fixes repair real bugs.
The rest make the code's intent explicit to the analyzer without
changing behavior.

Real bugs fixed:
- `port/mmap.cc`: `MemMapping::operator=(MemMapping&&)` ran the
  destructor on `*this`, `memcpy`'d over a non-trivially-copyable object,
  then placement-new'd the source. That is undefined behavior, and `*this`
  can be the base subobject of a `TypedMemMapping`. It now moves the
  members one by one, and the previous mapping is released through a
  local `MemMapping`.
- `port/mmap.h`: `TypedMemMapping::operator=(MemMapping&&)` had no
  `return *this;`, so calling it was undefined behavior.
- `cache/typed_cache.h`: `if constexpr (sizeof(TCreateContext) > 0)` is
  always true, so the branch meant for empty create contexts (for example
  `BlobContentsCreator`) could never run. The check is now
  `!std::is_empty_v<TCreateContext>`. Existing instantiations still call
  the same `Create` function.
- `cassandra_row_merge_test.cc`: the test reused a vector after
  `std::move`-ing it into `RowValue::Merge(std::vector<RowValue>&&)`. That
  only worked because `Merge` happens not to consume its input. The test
  now rebuilds the input.

Behavior-preserving changes:
- Virtual calls in constructors and destructors are now explicitly
  qualified (for example `DBImpl::CloseImpl()` in `~DBImpl`). During
  construction and destruction, dispatch already resolved to these
  functions.
- Stale `/*name=*/` argument comments now match the parameter names.
- `unique_ptr::release()` after a successful cache `Insert` (where the
  cache takes ownership) uses `[[maybe_unused]] T* released = x.release();`,
  the pattern already used in `table_cache.cc`.
- Removed `class Mutex;` and `class StaticMeta;` forward declarations
  that sat in the wrong namespace.
- Added default member initializers for the
  `TablePropertiesCollectorFactory::Context` fields that its default
  constructor left uninitialized.
- Smaller cleanups: a redundant `cond ? 3 : 3` in a test,
  `sizeof(std::string)` in a memory estimate, and an explicit
  `Cleanable` base move via `up_cast`. Tests that intentionally use
  moved-from objects now carry `NOLINT(bugprone-use-after-move)`,
  matching the existing convention.

Intentionally not changed: enum casts in tests that check invalid-value
handling; three `clang-analyzer-core.NullDereference` reports the
analyzer can't prove safe (the C API timestamp out-parameters in
`db/c.cc`, which are only written when the caller asked for a
timestamp, and the waiter-list walk in `util/async_file_reader.cc`);
bit-flag enums in public headers (`FileOpenContract`,
`OptionTypeFlags`), where OR-combined values are valid; ownership
transfers the analyzer can't see across translation units
(`partitioned_index_reader.cc`, `fs_posix.cc`); and the intentional
two-separator check in `file/filename.cc`.

Reviewed By: rban1

Differential Revision: D123186307

fbshipit-source-id: 623e871286b1c73263b1309cb194692194199e0f
2026-10-08 17:19:47 -07:00
Ranjan Banerjee
0561153b73 Add configurable largest-memtable flush policies to WriteBufferManager (#15047)
Summary:
Motivation

A WriteBufferManager can be shared by many RocksDB instances and column families. Under the existing policy, the DB whose writer first observes memory pressure flushes its own oldest mutable memtable. That DB might own only a small fraction of the reclaimable memory, so workloads with many DBs or CFs can generate many small flushes while the largest memory consumer remains untouched. Scanning every registered DB while holding process-wide or DB mutexes would improve selection accuracy but would serialize unrelated write paths and is not viable for deployments with thousands of DBs.

Previous behavior

kFlushOldest was the only behavior: the write-group leader that noticed WBM pressure synchronously selected the oldest eligible mutable memtable in its own DB. The WBM had no per-DB view of reclaimable memory and could not direct reclamation to another DB sharing the same budget.

New behavior

This change adds configurable WriteBufferFlushPolicy modes:

- kFlushOldest preserves the existing behavior and remains the default.
- kFlushLargest selects the largest eligible flushable column family in the writing DB.
- kFlushLargestAcrossDBs selects the DB advertising the most reclaimable memory across all DBs sharing the WBM, then flushes its largest eligible CF. Atomic-flush DBs advertise and flush the aggregate eligible memory across their CFs.

High-level implementation

Each writable DB registers a lightweight FlushInitiator with the shared WBM. Per-DB accounting publishes two approximate values using atomics: total mutable memory and the largest flushable CF contribution, including eligible immutable memtables waiting for flush. Allocator reporting is batched, so the allocation hot path avoids registry scans and DB mutexes.

A dedicated WBM coordinator thread maintains an approximate ranked snapshot of registered DBs. Refreshes are driven by accounting changes, threshold crossings, and periodic pressure checks. Ranking and O(number of DBs) work happen on that coordinator thread; writers only update counters and signal the coordinator. Registration lifetime is protected independently so DB close can safely drain an in-flight handoff.

Threading and flush handoff

The coordinator reserves and pins one ranked candidate at a time, without holding a registry lock while invoking the DB. The target DB uses TryLock on its DB mutex and rejects the handoff if it is closing, paused, stopped, stalled, already handling a WBM job, or no longer has flushable memory. Rejected candidates do not block consideration of the next DB.

An accepted handoff queues one LOW-priority WBM job. The LOW worker joins the target DB write thread and revalidates eligibility before switching the memtable. The resulting ordinary flush is then scheduled through RocksDB's existing flush machinery on the HIGH-priority flush pool. Keeping the write-thread join off the requesting writer avoids making one DB's write path wait on another DB's mutex or write queue.

Only one manager-wide remote handoff is active at a time. Completion or cancellation clears the handoff and requests a rerank. If memory reaches the hard limit while remote coordination is delayed, a rate-limited local fallback lets a writer seal a local memtable to preserve forward progress. Write stalls, shutdown, WaitForCompact, policy changes, and DB deregistration explicitly drain or reject outstanding handoffs.

Compatibility

The legacy constructor and kFlushOldest behavior remain unchanged unless a new policy is explicitly selected. There are no on-disk format changes.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/15047

Reviewed By: xingbowang

Differential Revision: D112396106

fbshipit-source-id: 3049adc7034dd4e00d74d7d86e1d19004292d299
2026-10-06 16:26:51 -07:00
Peter Dillinger
8e1569b351 Lazy wide-column byte-range (partial) blob reads (#15067)
Summary:
Builds on the lazy wide-column read API (DB::GetEntityLazy / DB::MultiGetEntityLazy) to serve true byte-range reads: resolving a sub-range of an uncompressed blob column now reads only the requested bytes from storage instead of fetching and slicing the whole column. This covers blobs in separate blob files and embedded (same-file) blobs in the SST, so a caller that knows a large value's layout can pull just the parts it needs.

A partial read skips whole-record checksum verification (a strict sub-range cannot cover the checksum) and does not populate the blob cache (the cache entry holds the whole record). A compressed column, a whole-column read, a cache hit, or a read with LazyColumnReadRequest::force_verify still resolves (and verifies) the whole column; force_verify forces verification even when ReadOptions::verify_checksums is off.

Mechanics: new range primitives mirror the whole-value read paths -- BlobFileReader::GetBlobRange, BlobSource::GetBlobRange, Version::GetBlobRange, and VersionBlobFetcherBase::FetchBlobRange for separate-file blobs; ReadSimpleGen2BlobRange, BlobSource::GetSimpleGen2BlobRange, and SameFileBlobReader::GetSameFileBlobRange (implemented by BlockBasedTable) for embedded blobs. ReadPathBlobResolver::ResolveColumnRange owns the partial-vs-whole decision and routes same-file references through the current SST's reader; the whole-column path also gained
VersionBlobFetcherBase::FetchBlobForceVerify to honor force_verify.

Observability: deferred resolve reads are attributed to a new Env::IOActivity::kLazyResolve (distinct from the kGetEntity / kMultiGetEntity of the initial entity read), and lazy resolution's storage reads are counted by new statistics rocksdb.blobdb.lazy.read.count / .read.bytes (all lazy reads) and rocksdb.blobdb.lazy.partial.read.count / .partial.bytes.saved (the byte-range subset and the bytes it avoided). The whole-column read sites gate recording on kLazyResolve so non-lazy reads are excluded.

Also fixes a latent bug in LazyWideColumnsBatch::MultiResolve where an empty/default-constructed batch (null rep_) would accept a foreign standalone column (null owning_batch_rep_) through a nullptr == nullptr comparison instead of returning InvalidArgument.

Follow-ups (in a local plan): unifying the blob-read API surface -- folding the whole/range method twins and the verify-policy flags (verify_checksums x force_verify) into one internal BlobReadRequest primitive (a range descriptor plus a 3-valued verify policy), which retires FetchBlobForceVerify and the whole/range method pairs; this is deferred for feature velocity and is not public-API affecting (the public force_verify bool stays). Marked in code with TODO(lazy-blob-resolution-cleanup) in db/blob/blob_fetcher.h and db/wide/read_path_blob_resolver.cc. Also cross-key coalescing (Phase 3) and async execution (Phase 4).

Pull Request resolved: https://github.com/facebook/rocksdb/pull/15067

Test Plan:
Extended db/wide/db_lazy_entity_test.cc: separate-file and embedded partial reads return the exact sub-span and read only the requested bytes; a partial read does not fill the blob cache and a cache hit slices with no I/O; a compressed column resolves whole and slices; force_verify does a full verified read and is detected via a tampered record even with verify_checksums off; the lazy statistics distinguish whole vs partial reads and are not touched by non-lazy reads; deferred reads carry kLazyResolve (verified with a FileSystem wrapper); and a regression test for the empty-batch ownership check. Added an IOActivityToString case in env/env_test.cc and registered the new tickers in the statistics name map.

Crash test: extended the db_stress lazy-vs-eager differential (db_stress_tool/db_stress_test_base.cc) to fuzz per-column byte ranges. Each resolved column now randomly picks a whole-column read or a partial (offset, length) sub-range -- occasionally with an offset past the end or a length beyond the remainder to exercise clamping -- for both GetEntityLazy and MultiGetEntityLazy; when an eager reference is available the resolved bytes are compared against the same clamped sub-range of it. No new flags (reuses --lazy_entity_read_one_in); force_verify fuzzing remains a follow-up.

Reviewed By: xingbowang

Differential Revision: D115130388

Pulled By: pdillinger

fbshipit-source-id: 454368dea8fae069d9de649c2c51611469d3c809
2026-08-07 12:08:03 -07:00
Josh Kang
c64f682946 Fix IoUringBackend crash in ReadIOExecutor worker threads (#15020)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/15020

Each read executor worker creates its own `IoUringBackend`, and Folly's I/O thread pool creates its worker threads and EventBases lazily. A successful calling-thread probe or `DB::Open()` therefore does not validate every worker. A later read can start a new worker; previously, an `IoUringBackend` initialization exception on that worker could escape startup and terminate the process. The previous 512-submit setup also allowed Folly's capacity retry to reduce the completion queue to 512 while retaining a 1024-entry submission queue, which the kernel rejects with `EINVAL`.

Use a 256-submit limit so the 512-entry retry remains valid. Configure the shared read executor during `DB::Open()` through `DBOptions::read_io_executor_threads`, defaulting to one thread. The backend factory catches per-worker io_uring initialization failures and uses Folly's default backend. Each worker's thread-local availability marker starts false and is set true only after `IoUringBackend` construction succeeds. When construction fails, the marker remains false and `SubmitReadAsync()` performs the read synchronously. The executor's maximum thread capacity can be raised or lowered; `db_stress` requests eight threads for async DB APIs.

To expose this degradation, `FSRandomAccessFile::SubmitReadAsync()` now reports whether the asynchronous path was used. `RandomAccessFileReader` increments the `FILE_SUBMIT_ASYNC_READ_FALLBACK` ticker for every submission that falls back to synchronous I/O, making the fallback visible through the DB's `Statistics`.

Reviewed By: xingbowang

Differential Revision: D114031018

fbshipit-source-id: 1b7f6c1cea693e5dd743ea1ada0fca1cf757b3f9
2026-07-30 11:18:08 -07:00
Josh Kang
7247edbf0a Add opt-in stats for async RocksDB reads (#15017)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/15017

## Summary

RocksDB async `GetAsync` and `MultiGetAsync` callbacks now default to a completion-only path. Callbacks can override `EnableStats()` when they need request-specific `PerfContext` or `IOStatsContext`; otherwise RocksDB avoids creating a coroutine stats context and returns null stats pointers. Callbacks must not initiate another async read from `OnComplete()`.

RocksDB stats normally use thread-local storage, which does not compose with interleaved coroutine reads. A stats-enabled request captures only the caller's configuration: perf level, per-level perf enablement, and whether io stats are disabled. It then starts with empty request contexts. `onSet()` loads that request's contexts into TLS, while `onUnset()` saves the accumulated contexts back into request data. On resume, the same contexts are loaded again. This isolates request counters without preserving or restoring pre-existing executor TLS state. The synchronous fallback similarly resets TLS before executing a stats-enabled read.

`PerfContext` and `IOStatsContext` gain `Merge()` support for caller-side aggregation. `PerfContext` move construction and assignment now transfer ownership of per-level state rather than deep-copying it, avoiding allocations during coroutine context handoffs. A fbcode-wide audit found no caller that reads a moved-from `PerfContext`.

`db_bench` opts in only for coroutine jobs that print per-job perf context and merges every completed request's callback stats into the job aggregate.

## Example: Two Async Gets on One Thread

Both callbacks enable stats. Each request starts with empty counters and carries its contexts across suspensions.

```text
Shared executor thread
|
|  onSet(A): load A's empty contexts into TLS
|  A records 3 reads
|  onUnset(A): save TLS contexts back into A
|
|  onSet(B): load B's empty contexts into TLS
|  B records 4 reads
|  onUnset(B): save TLS contexts back into B
|
|  onSet(A): load A's contexts containing 3 reads
|  A records 2 more reads
|  callback A receives block_read_count = 5
|
|  onSet(B): load B's contexts containing 4 reads
|  callback B receives block_read_count = 4
```

Isolation comes from replacing TLS with the active request's saved contexts on every `onSet()`.

### Timers

Existing wall-clock timers remain in coroutine frames, so timers spanning `co_await` include suspended time and measure end-to-end latency.

Request-level `get_cpu_nanos` is suspension-aware: it starts in `onSet()` and stops in `onUnset()` or `Finalize()`, charging only time while the request is active.

Nested CPU timers remain disabled because normal RAII CPU timers would also charge executor work performed while their coroutine is suspended. `MultiGetAsync` fanout additionally requires per-child timer state to avoid double counting.

## Benchmarks

Benchmarked to confirm no performance regressions when perf is disabled, and also to see the overhead of enabling perf.

```bash
db_bench --benchmarks=<readrandomcoroutine|multireadrandomcoroutine> --db=<db_path> --coro_jobs_per_thread=10 --use_existing_db=true --num=2000000 --value_size=1024 --compression_type=none --threads=8 --batch_size=16 --multiread_batched=true --use_direct_reads=true --cache_size=1428076626 --reads=320000 --perf_level=<1|3> --seed=<seed>
```

| Workload | Before change | Perf level 1 | Before -> 1 | Perf level 3 | 1 -> 3 |
| -------- | ------------- | ------------ | ----------- | ------------ | ------ |
| Async Get | 475.6K ops/s | 476.7K ops/s | +0.2% | 470.5K ops/s | -1.3% |
| Async MultiGet | 567.3K ops/s | 567.4K ops/s | +0.0% | 552.2K ops/s | -2.7% |

Reviewed By: xingbowang

Differential Revision: D112634874

fbshipit-source-id: 94e240aeb1496fa12dac995b5aa5a9c3543cc5fc
2026-07-28 09:32:26 -07:00
Ranjan Banerjee
f5c0c3e274 Record CheckpointEngine copy bytes under checkpoint tickers (#14997)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/14997

`CheckpointEngine`'s shared `CopyEngine` recorded copied bytes under the
`BACKUP_READ_BYTES` / `BACKUP_WRITE_BYTES` tickers (the `CopyEngineOptions`
defaults), conflating checkpoint I/O with backup I/O in statistics. This adds
dedicated `CHECKPOINT_READ_BYTES` / `CHECKPOINT_WRITE_BYTES` tickers and points
`CheckpointEngineImpl`'s `CopyEngineOptions` at them, so checkpoint copies report
under their own metric names. `BackupEngine` is unchanged (still uses the
backup-ticker defaults).

Addresses review feedback that the shared `CopyEngine` should not hardcode
backup metric names for non-backup callers.

The new tickers are intentionally not mirrored in the Java bindings
(`TickerType.java` / `portal.h`): the signed-`jbyte` id space there is exhausted,
so they remain C++-only, documented inline in `statistics.h`.

Reviewed By: xingbowang

Differential Revision: D113469742

fbshipit-source-id: 2a6a7ef04c939a1240f1c48c7bcaba8b2e7a1c10
2026-07-28 09:23:58 -07:00
Xingbo Wang
03c3c090fb Measure IODispatcher async read latency (#15001)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/15001

Add IODispatcher-specific histograms for async read observed completion latency, `FileSystem::Poll` wait time, and submit-to-consumer-poll prefetch lead time. Record submit timestamps on async read state, report completion latency from the callback, and report poll wait/prefetch lead when the block consumer polls the handle.

Keep Java histogram byte mappings stable by assigning the new histogram IDs after the existing range. Add a controlled async filesystem test that verifies one deferred async read records all three histograms.

Address Infer feedback by iterating `async_state->block_indices` directly when removing async IO map entries. Keep `PollAndProcessAsyncIO()` holding an owning `shared_ptr<AsyncIOState>` while erasing those entries so the coalesced request state cannot be destroyed mid-loop.

Format `util/io_dispatcher_imp.cc` and `util/io_dispatcher_test.cc` with clang-format 21.1.2 to fix the format signal.

Reviewed By: pdillinger, anand1976

Differential Revision: D113549401

fbshipit-source-id: dafc272c9252e1baccf404f681d33f76890ce0b2
2026-07-24 13:51:09 -07:00
Jay Huh
dcb5c2bf53 Restore MultiScan prefetch stats dropped in the IODispatcher refactor (#14991)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/14991

D91705195 ("Replace Prefetch Logic in BlockBasedTableIterator with IODispatcher") moved MultiScan block prefetching out of BlockBasedTableIterator and into the IODispatcher. The IO-level RecordTick/RecordInHistogram calls lived in the deleted prefetch code, and the IODispatcher was not given equivalent instrumentation, so these tickers were still defined but never populated (they published as absent):

- MULTISCAN_BLOCKS_PREFETCHED
- MULTISCAN_BLOCKS_FROM_CACHE
- MULTISCAN_PREFETCH_BYTES
- MULTISCAN_IO_REQUESTS
- MULTISCAN_IO_COALESCED_NONADJACENT
- MULTISCAN_BLOCKS_PER_PREPARE (histogram)

The PREPARE_*, SEEK_ERRORS, and PREFETCH_BLOCKS_WASTED tickers were unaffected (recorded on the prepare/teardown path, which was not replaced).

Fix:
- ReadSet now exposes generic, caller-agnostic prefetch counters (GetNumBlocksPrefetched, GetNumIORequests, GetPrefetchBytes, GetNumCoalescedNonadjacent), incremented once per block in DispatchPrefetch -- the single choke point for both immediate and memory-deferred dispatch. Counting at dispatch time (not completion) keeps async and deferred prefetches accounted for without double counting the async->sync fallback.
- PrepareIORequests now outputs prefetch_bytes (sum of request len) and num_coalesced_nonadjacent (within-threshold gap count) while building coalesced requests, per review feedback to avoid the extra pass over read_reqs/coalesced_block_indices at former line 836. DispatchPrefetch now gets stats directly from PrepareIORequests.
- The MULTISCAN_* ticker names stay at the caller: MultiScanIndexIterator's destructor records the aggregate counters at end-of-scan (alongside the existing PREFETCH_BLOCKS_WASTED), so async/deferred reads that complete during iteration are included. MULTISCAN_BLOCKS_PER_PREPARE is recorded in BlockBasedTableIterator::Prepare. This keeps the IODispatcher a generic mechanism rather than leaking a caller's metric names into it.
- Also plumb the same metrics into PerfContext for per-operation visibility.

Reviewed By: xingbowang

Differential Revision: D113356436

fbshipit-source-id: 660e9755d6b1b9aecccd112df94eb6838061b298
2026-07-23 14:09:07 -07:00
Andrew Chang
0745290ca6 Add OpenAndCompact DB open latency histogram (#14986)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/14986

Why: We want to measure the DB open time during offloaded compactions.

What: Add a histogram for the DB open time in `DB::OpenAndCompact()`.

Reviewed By: anand1976

Differential Revision: D113136652

fbshipit-source-id: f8b2d74bcda3506f7b9ac80fa3e50a172deafc5e
2026-07-22 15:57:50 -07:00
Xingbo Wang
de7b8e8f7d Add RocksDB flush reason and atomic flush request metrics (#14898)
Summary:
This PR adds flush observability for debugging write stalls and flush bottlenecks.

  Changes include:

  - Add flush reason tickers for physical flush jobs:
      - rocksdb.flush.reason.write_buffer_full
      - rocksdb.flush.reason.write_buffer_manager
      - rocksdb.flush.reason.memtable_max_range_deletions

  - Add flush memtable size histograms:
      - rocksdb.flush.memtable.memory.bytes
      - rocksdb.flush.memtable.total.data.size.bytes
      - rocksdb.flush.write_buffer_full.memtable.memory.bytes
      - rocksdb.flush.write_buffer_manager.memtable.memory.bytes

  - Add FlushReason::kMemtableMaxRangeDeletions and propagate it from memtables when memtable_max_range_deletions triggers a flush.
  - Preserve atomic flush as a single request-level reason. For atomic flush, the reason is derived only from CFs that scheduled the flush, not every CF selected into the atomic flush cut.
  - Add atomic flush request-level counters:
      - rocksdb.atomic_flush.request.reason.write_buffer_full
      - rocksdb.atomic_flush.request.reason.write_buffer_manager
      - rocksdb.atomic_flush.request.reason.memtable_max_range_deletions
      - rocksdb.atomic_flush.request.reason.other

  - Keep existing per-CF flush job reason counters unchanged. Under atomic flush, rocksdb.flush.reason.* still counts physical CF flush jobs, while rocksdb.atomic_flush.request.reason.* counts one logical atomic flush request.
  - Wire the new flush reason, ticker, and histogram types through Java and JNI bindings.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/14898

Test Plan: CI

Reviewed By: anand1976

Differential Revision: D110214337

Pulled By: xingbowang

fbshipit-source-id: 4a445c4175d2e09ff5edbe66fde81fa00bb9e8da
2026-07-01 10:34:16 -07:00
Xingbo Wang
75c1ffd4e3 Add RocksDB rate limiter I/O usage metrics (#14884)
Summary:
Add rate limiter statistics that make it easier to diagnose whether RocksDB background IO is being throttled by the GenericRateLimiter.

New ticker counters:
- rocksdb.rate.limiter.bytes.read/write: bytes granted by the limiter, split by operation type.
- rocksdb.rate.limiter.requests.read/write: requests granted by the limiter, split by operation type.
- rocksdb.rate.limiter.delayed.requests.read/write: requests that actually had to wait for a future refill because available tokens were exhausted.
- rocksdb.rate.limiter.total.wait.micros.read/write: cumulative wait time for delayed requests.

New histograms:
- rocksdb.rate.limiter.wait.micros.read/write: per-request wait latency for delayed requests, enabling percentile debugging.

GenericRateLimiter now overrides the OpType-aware Request() path so these stats preserve the configured limiter mode. The legacy three-argument Request() path is treated as write IO for compatibility. Existing NUMBER_RATE_LIMITER_DRAINS is left intact, but the new delayed request counters are the clearer signal for out-of-token throttling because one delayed request can observe multiple drain intervals.

Also update the Java ticker and histogram mappings so Java consumers can access the new statistics.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/14884

Test Plan:
- make format-auto
- make -j16 rate_limiter_test statistics_test
- ./rate_limiter_test
- ./statistics_test
- make check-sources

Reviewed By: anand1976

Differential Revision: D109694030

Pulled By: xingbowang

fbshipit-source-id: e92756788ba629f25655958c7beb91099184cda4
2026-06-29 16:22:57 -07:00
Josh Kang
1ede57e5b0 Add file ingestion histograms (#14836)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/14836

Adds a public `Statistics` histogram, `INGEST_EXTERNAL_FILE_TIME` (`"rocksdb.ingest.external.file.micros"`), recording the end-to-end latency in microseconds of each `IngestExternalFile(s)` call. Ingestion timing was previously only available through per-thread `perf_context` counters, which require setting a `PerfLevel` and are not aggregated, so there was no process-wide latency distribution (p50/p99/max) for dashboards.

It is recorded with an RAII `StopWatch` at the top of `DBImpl::IngestExternalFiles` -- one sample per call (not per column family), covering all return paths. It is null-safe and self-gating on the stats level, so there is no cost when statistics are off, and ingestion is not a hot path. Java bindings are kept in sync per the `statistics.h` requirement; the C API needs no change.

Reviewed By: xingbowang

Differential Revision: D107721260

fbshipit-source-id: 0705f9e0f7392329a7bcbdbd9f3afd34594d20bb
2026-06-08 18:13:38 -07:00
Michael Huang
9270dc8149 Add blob_cache_read_byte perf context counter (#14792)
Summary:
Added blob_cache_read_byte in the rocksdb::PerContextBase to expose the blob cache read bytes when blob cache is enabled.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/14792

Reviewed By: xingbowang

Differential Revision: D106528572

Pulled By: mikechuangmeta

fbshipit-source-id: 555b2f01785bb819e62ed834ee45f0436dfb2875
2026-05-28 17:46:45 -07:00
Xingbo Wang
21723bbbef Add async WAL precreation
Summary:
- Add experimental immutable `DBOptions::async_wal_precreate` to reserve and open one future WAL on a background HIGH-priority task, with sanitization that disables the optimization when WAL recycling is configured.
- Split WAL creation into open/preallocate and start phases so `SwitchMemtable()` can consume a prepared WAL after writing normal WAL metadata, wait for in-flight precreation, fall back to synchronous creation, and delete an unstarted prepared WAL on start failure.
- Keep WAL numbering, close, recovery, and read-only open safe for empty future WAL files left by async precreation; `error_if_wal_file_exists=true` now rejects non-empty WALs while tolerating empty WALs.
- Add public option plumbing for the C API, options parsing/stringification, random option testing, `db_bench`, `db_stress`, and crash-test configuration.
- Add WAL precreate statistics counters plus Java `TickerType`/JNI mappings, and update C++, C, and Java read-only-open documentation for the empty-WAL behavior.
- Add focused WAL/option/C/Java tests for async precreate ready/wait/failure/recovery paths, read-only WAL detection, option sanitization, and API plumbing, plus write-flow docs and unreleased history entries for the new feature and behavior change.

PR https://github.com/facebook/rocksdb/pull/14738

Reviewed By: pdillinger

Differential Revision: D105020559

fbshipit-source-id: 5059b424702e021abb8de65ceeb6d3b975280ffc
2026-05-15 10:59:47 -07:00
Danny Chen
2e7cf42cda Add MANIFEST_VALIDATION_FAILURE_COUNT statistic (#14657)
Summary:
CONTEXT: The manifest validation on close feature (verify_manifest_content_on_close) detects corruption but does not increment any statistics counter, making it harder to monitor in production.

WHAT: Add a new ticker MANIFEST_VALIDATION_FAILURE_COUNT that is incremented each time content validation detects manifest corruption during DB::Close(). The counter fires per corruption detection, so it can increment up to 2 times per close (once on initial check, once after rewrite attempt). Updated all existing manifest validation tests to verify the counter value.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/14657

Test Plan:
- All 7 manifest validation tests pass with new stat assertions
- 5x repeat with COERCE_CONTEXT_SWITCH=1 shows no flakiness
- Full version_set_test suite (212 tests) passes

Reviewed By: anand1976

Differential Revision: D102404260

Pulled By: dannyhchen

fbshipit-source-id: 21a0aa1ad8de12a935caf5642e41ccf2a47b46d9
2026-04-24 15:22:15 -07:00
Anand Ananthabhotla
1cc216a45b Fast file open: retrieve, persist, and pass file open metadata (#14596)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/14596

When DBOptions::fast_sst_open is enabled, RocksDB retrieves opaque file system
metadata for SST files after flush, compaction, and external file ingestion via
FSRandomAccessFile::GetFileOpenMetadata(). This metadata is persisted in the
MANIFEST using a new forward-compatible NewFileCustomTag (kFileOpenMetadata = 17),
and passed back to the file system via FileOptions::file_metadata on subsequent
file opens. This accelerates DB open time on remote storage systems by allowing
the file system to skip expensive metadata RPCs.

The feature is gated by DBOptions::fast_sst_open (default false). Everything
works seamlessly regardless of the option setting, file metadata support, or
presence/absence of the metadata in the MANIFEST. The MANIFEST change is backward
compatible - older RocksDB versions safely ignore the new tag.

Reviewed By: xingbowang

Differential Revision: D100220973

fbshipit-source-id: f52de9dd853a50653b3297ab4a37a868fe41cc04
2026-04-14 19:07:29 -07:00
Josh Kang
3f51c0a185 Convert sequential single deletes into range tombstones (#14448)
Summary:
Add a read-path optimization that converts contiguous point tombstones into range tombstones during forward/reverse iteration. When a configurable threshold of consecutive point deletions (kTypeDeletion, kTypeDeletionWithTimestamp, kTypeSingleDeletion — with no live keys between them) is detected, a range tombstone covering `[first_tombstone_key, next_live_key)` is inserted into the active mutable memtable. This benefits future iterators by enabling efficient skipping via range tombstone fragmentation.

If there is a memtable switch during the read iteration, then the range deletion entry is discarded.

The inserted range tombstones are logically redundant (they don't delete anything that isn't already deleted by point tombstones), skip WAL (they're a derived optimization regenerated by future reads on crash), and use the max tombstone sequence number so they don't interfere with newer writes.

## Key changes
- **New option `min_tombstones_for_range_conversion`** (`AdvancedColumnFamilyOptions`): Threshold of contiguous point tombstones before converting to a range tombstone. Default 0 (disabled). Dynamically changeable via `SetOptions()`.
- **`DBIter` tracking logic** (`db/db_iter.cc`): Tracks contiguous tombstones during `FindNextUserEntryInternal()` (forward) and `PrevInternal()` (reverse). When a live key terminates a run that meets the threshold, `MaybeInsertRangeTombstone()` inserts `[first_tombstone, live_key)` into the active memtable.
- **`FindValueForCurrentKey` `found_visible` output** (`db/db_iter.cc`): Distinguishes "key deleted at this snapshot" from "no visible entries" so reverse tracking doesn't treat post-snapshot keys as tombstones.
- **`IterKey::Swap()`** (`db/dbformat.h`): Efficiently tracks reverse tombstone run end keys without extra allocations.
- **`MemTable::AddLogicallyRedundantRangeTombstone()`** (`db/memtable.cc`): Concurrent-safe range tombstone insertion into the active memtable. Range tombstone skiplist always uses concurrent inserts.
- **`ConstructFragmentedRangeTombstones` race fix** (`db/db_impl/db_impl_write.cc`): Moved after `MarkImmutable()` to prevent lost entries.
- **`MarkImmutable` ordering fix** (`db/memtable_list.cc`): Called before `current_->Add()` to close a race window.
- **Prefix filter awareness** (`db/db_iter.cc`): Tombstone tracking scoped to the seek prefix when prefix filtering is active. See dedicated section below.
- **Transaction awareness** (`db/db_iter.cc`): Tombstones with `seq > snapshot` excluded from tracking. `min_uncommitted` guard uses `insert_seq` (which may be bumped to `earliest_seq`) instead of `range_tomb_max_seq_`. See dedicated section below.
- **Duplicate range check**: Skips insertion if the memtable already covers `[start, end)`.
- **New statistics**: `READ_PATH_RANGE_TOMBSTONES_INSERTED` and `READ_PATH_RANGE_TOMBSTONES_DISCARDED`.
- **Memtable MultiGet batch lookup** (`memtable/inlineskiplist.h`, `db/memtable.cc`): `InlineSkipList::MultiGet()` with cached search path ("finger") for sorted key lookups.
- **New option `memtable_batch_lookup_optimization`** (`AdvancedColumnFamilyOptions`): Enables batch lookup for memtable MultiGet. Default false. Immutable.

## Deciding Range Tombstone Seqno
- The range tombstone is inserted with `insert_seq = max(range_tomb_max_seq_, earliest_seq)` where `range_tomb_max_seq_` is the maximum sequence number across all point tombstones in the contiguous run, and `earliest_seq` is the memtable's earliest sequence number. This preserves the memtable's `earliest_seqno_` invariant.
- If the iterator's snapshot sequence (`sequence_`) predates the memtable's `earliest_seq`, insertion is skipped entirely to avoid unintentionally covering entries between `sequence_` and `earliest_seq`.

## ConstructFragmentedRangeTombstones Race Fix
- `MarkImmutable()` and `ConstructFragmentedRangeTombstones()` are now called before `mutex_.Lock()` in `SwitchMemtable`, keeping this work outside the DB mutex. `MarkImmutable()` blocks concurrent `AddLogicallyRedundantRangeTombstone()` calls via `immutable_mutex_`, ensuring no range tombstones are inserted after the fragmented list is built. `MarkImmutable()` is idempotent, so `MemTableList::Add()` calling it again inside the mutex is harmless.

## Prefix Filter Safety
- When prefix filtering is active, the BBTI bloom filter may reject SST files outside the seek prefix, but the memtable (no bloom filter) returns keys across prefix boundaries. Tombstone tracking is scoped to the seek prefix so that converted range tombstones cannot cover live keys hidden in filtered files.
- `total_order_seek=true` disables prefix filtering — all files are visible, so tombstones safely span prefix boundaries.

- **Behavior change**: Seeking to an out-of-domain key with `total_order_seek=false` now treats it as total-order (prefix_ not set). When `prefix_same_as_start=true`, iterating past an out-of-domain key cleanly invalidates the iterator instead of calling `Transform()` on it (which was UB in release builds with `FixedPrefixTransform`). This is a requirement because an incorrect iterator scan could lead to a range tombstone covering a live key.

## Transaction Support
- Tombstones written by the transaction's own uncommitted writes (sequence > snapshot) are now excluded from contiguous tombstone tracking entirely at the tracking site in `FindNextUserEntryInternal()` and `PrevInternal()`. Previously, tracking relied on a `min_uncommitted` check at insertion time, but this was insufficient — a transaction's own Delete with `seq > snapshot` could extend a run of committed tombstones, and the resulting range tombstone would cover data visible to other snapshots.
- The fix skips any tombstone with `ikey_.sequence > sequence_` during tracking. If a transaction-owned tombstone appears mid-run, it flushes the accumulated committed run first, then resets tracking. This ensures only tombstones visible to the current snapshot are ever converted.
- Both WritePrepared and WriteUnprepared transactions are supported with dedicated test coverage:
  - **WritePrepared**: When tombstones are committed before `Prepare()`, their seqnos are below `min_uncommitted` and insertion proceeds safely. When `Prepare()` happens first, tombstone seqnos exceed `min_uncommitted` and insertion is blocked.
  - **WriteUnprepared**: Multiple unprepared batches with different seqno ranges are handled correctly. Own transaction Deletes that extend a committed tombstone run block insertion of the entire run. After rollback, data correctness is verified.

## UDT support
- When user-defined timestamps (UDT) are enabled, keys include an 8-byte timestamp suffix. The comparator, Put/Delete APIs, and ReadOptions all require timestamps.
- Forward exhaustion with UDT: `iterate_upper_bound_` is a plain user key without a timestamp suffix. It is padded with min timestamp via `AppendKeyWithMinTimestamp()` so it sorts after all entries with this user key, preserving the exclusive bound semantics.
- Reverse exhaustion with UDT: The end key comes from either the previous live key (which already has a proper timestamp suffix) or the seek target set by `SetSavedKeyToSeekForPrevTarget()` (which appends a timestamp via `SetInternalKey(..., timestamp_ub_)` and `UpdateInternalKey(..., ts)`). In both cases, the end key is already properly timestamped, so no additional padding is needed unlike forward exhaustion.
- Contiguous tombstone detection works correctly with UDT because the underlying `kTypeDeletionWithTimestamp` entries are tracked the same way as `kTypeDeletion`.

## Concurrent Iterators
- Should concurrent iterators happen to read the range at the same time, both will produce the same range and seqno entry. Only one will be accepted by the skip list and the others will be rejected. Future iterators will read the range and not even attempt to insert the range.
- There is nothing preventing similar ranges from being inserted however. Two iterators can produce overlapping ranges, but this protection would be complicated to implement and there is no evidence that it is a likely scenario yet.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/14448

Test Plan:
- **Unit tests** (`db/db_iterator_test.cc`): `ReadPathRangeTombstoneTest` parameterized by forward/reverse with cases for basic insertion, non-contiguous (below threshold), memtable switch, exhausted iterator with/without bounds, direction change, mixed Delete/SingleDelete, single-delete-only runs, snapshot predating memtable, block cache tier incomplete, skip when covered by existing range, UDT basic scan, UDT exhaustion, prefix filter cross-prefix scan (`PrefixFilterCrossPrefixScanCoversLiveKey` with default/total_order_seek/prefix_same_as_start variants), stale ikey from forward-then-reverse scan (`StaleIkeyFromForwardThenReverse`), and reseek stale ikey (`ReseekStaleIkey`).
- **Concurrency test** (`db/db_test2.cc`): `DBTestConcurrentRangeTombstoneConversions` parameterized by `(allow_concurrent_memtable_write, min_tombstones_for_range_conversion)` with mixed writers, deleters, range deleters, and concurrent forward/reverse readers.
- **Transaction tests** (`utilities/transactions/write_prepared_transaction_test.cc`, `write_unprepared_transaction_test.cc`): Tests for WritePrepared (insertion allowed when tombstones committed before prepare, blocked when after; seqno bump shadowing prepared writes `RangeTombstoneSeqnoBumpShadowsPreparedWrite`) and WriteUnprepared (multiple batches, extended visibility with CalcMaxVisibleSeq, own deletions with rollback).
- **IterKey::Swap tests** (`db/dbformat_test.cc`): `IterKeySwapTest` parameterized over `(key_len, copy, use_secondary)` × 2 covering all inline/heap/pinned/secondary combinations.
- **InlineSkipList MultiGet tests** (`memtable/inlineskiplist_test.cc`): Basic, exact matches, empty, single key, randomized validation against `std::set::lower_bound`, duplicate keys with callback walk, and concurrent MultiGet with read-after-write consistency.
- **Memtable MultiGet tests** (`db/db_basic_test.cc`): Batch lookup, overwrite, flush, merge, disabled by default, paranoid checks, and snapshot tests.
- **Stress test coverage**: `min_tombstones_for_range_conversion` and `memtable_batch_lookup_optimization` options added to `db_crashtest.py` and `db_stress` flags.
- `make check` passes all tests.

### Benchmark results

Tombstones scattered randomly in clusters via `seek_nexts_to_delete` for realistic workloads.

**DB Setup A (scattered deletes, 100 per seek)**:
```
# Step 1: Create and compact
./db_bench --benchmarks=fillseq,compact --seed=1 --compression_type=none --num=1000000 --db=<DB>
# Step 2: Scatter tombstones (5000 seeks × 100 deletes ≈ 500k tombstones)
./db_bench --benchmarks=seekrandom,flush --seed=1 --compression_type=none --num=2000 \
  --seek_nexts=0 --seek_nexts_to_delete=100 --use_existing_db=1 --threads=1 --db=<DB>
```

**DB Setup A2 (scattered deletes, 8 per seek)**:
```
# Step 1: Create and compact
./db_bench --benchmarks=fillseq,compact --seed=1 --compression_type=none --num=1000000 --db=<DB>
# Step 2: Scatter tombstones (5000 seeks × 8 deletes ≈ 40k tombstones)
./db_bench --benchmarks=seekrandom,flush --seed=1 --compression_type=none --num=2000 \
  --seek_nexts=0 --seek_nexts_to_delete=8 --use_existing_db=1 --threads=1 --db=<DB>
```

**DB Setup B (no deletes)**:
```
./db_bench --benchmarks=fillseq,compact --seed=1 --compression_type=none --num=1000000 \
  [--key_size=100] --db=<DB>
```

**Read workload** (same for all):
```
./db_bench --benchmarks=seekrandom --seek_nexts=100 --threads=8 \
  --reverse_iterator={true,false} --seed=1 --use_existing_db=1 \
  --compression_type=none --num=1000000 --duration=10 \
  --disable_auto_compactions \
  [--key_size=100] [--min_tombstones_for_range_conversion=X] --db=<DB_COPY>
```

Each workload averaged over 3 runs.

**Table 1: seekrandom forward, scattered deletes (2000 seeks × 100 deletes/seek)**

| Variant | avg ops/s | % vs main |
|---------|-----------|-----------|
| main | 2,895 | - |
| threshold=0 | 2,869 | -0.9% |
| threshold=8 | 287,334 | +9,824% |

**Table 2: seekrandom reverse, scattered deletes (2000 seeks × 100 deletes/seek)**

| Variant | avg ops/s | % vs main |
|---------|-----------|-----------|
| main | 544 | - |
| threshold=0 | 548 | +0.7% |
| threshold=8 | 206,491 | +37,860% |

**Table 3: seekrandom forward, scattered deletes (2000 seeks × 8 deletes/seek)**

| Variant | avg ops/s | % vs main |
|---------|-----------|-----------|
| main | 194,049 | - |
| threshold=0 | 195,703 | +0.9% |
| threshold=8 | 310,740 | +60.1% |

**Table 4: seekrandom reverse, scattered deletes (2000 seeks × 8 deletes/seek)**

| Variant | avg ops/s | % vs main |
|---------|-----------|-----------|
| main | 63,854 | - |
| threshold=0 | 69,266 | +8.5% |
| threshold=8 | 218,101 | +241.6% |

**Table 5: seekrandom forward, no deletes (regression check)**

| Variant | key=16B avg ops/s | % vs main | key=100B avg ops/s | % vs main |
|---------|-------------------|-----------|---------------------|-----------|
| main | 330,901 | - | 236,048 | - |
| threshold=0 | 328,398 | -0.8% | 238,055 | +0.9% |
| threshold=8 | 332,539 | +0.5% | 233,776 | -1.0% |

**Table 6: seekrandom reverse, no deletes (regression check)**

| Variant | key=16B avg ops/s | % vs main | key=100B avg ops/s | % vs main |
|---------|-------------------|-----------|---------------------|-----------|
| main | 261,445 | - | 192,177 | - |
| threshold=0 | 265,020 | +1.4% | 191,616 | -0.3% |
| threshold=8 | 250,881 | -4.0% | 189,239 | -1.5% |

Reviewed By: xingbowang

Differential Revision: D96203950

Pulled By: joshkang97

fbshipit-source-id: 06ba66ebde3c355f04671d1e681f1b1586e8751d
2026-04-03 22:47:51 -07:00
Jialiang Tan
65e77282ce Add block_decompress_count to PerfContext (#14557)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/14557

RocksDB's PerfContext tracks block_decompress_time but has no counter for the
number of block decompressions. The global Statistics ticker
NUMBER_BLOCK_DECOMPRESSED exists but is not accessible through PerfContext,
which is the thread-local, per-operation metric system used by benchmarks.

Add block_decompress_count as a new PerfContext counter (gated at
kEnableCount level) incremented in DecompressBlockData alongside the existing
NUMBER_BLOCK_DECOMPRESSED ticker. This enables benchmarks and applications to
observe how many blocks required decompression per operation, complementing
the existing block_read_count.

Reviewed By: anand1976

Differential Revision: D99233514

fbshipit-source-id: 40a68c1d9321f560cebdb7c30a544a0c62ae64f0
2026-04-03 16:48:09 -07:00
Yoshinori Matsunobu
b23fc77aca Add per-block-type block read byte perf counters (#14473)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/14473

Add separate PerfContext byte counters for data, index, filter, compression-dictionary, and metadata block reads while preserving block_read_byte as the aggregate. Wire the new counters through the block fetch and multi-read data block paths, expose them via the C perfcontext API, and extend table tests to verify byte attribution and that the classified counters sum back to block_read_byte.

Reviewed By: xingbowang

Differential Revision: D97333746

fbshipit-source-id: 3411844d7fa9c76c9ff28af477b3a72a5d6e5d9b
2026-03-19 14:54:24 -07:00
Josh Kang
42eff8b632 Add new heauristic 'num_collapsible_entry_reads_sampled' (#14434)
Summary:
Add per-file sampling of "collapsible" entry reads (single deletions, merges, and kNotFound results) that may later be used to help inform read-triggered compactions. This is a better metric than `num_reads_sampled` as it is more targeted towards reads that could be avoided via compaction.

The existing behavior of `num_reads_sampled` is that reads only gets sampled on iterator creation for a file. It is problematic because next/prev() calls are not sampled, nor are additional seeks().

This PR moves sampling to per-seek/next granularity within `LevelIterator` and adds a new `num_collapsible_entry_reads_sampled` counter that tracks how often a file serves entries that could be eliminated by compaction.

 Note only L1+ files have iterator seeks/nexts/prevs sampled. Introducing this at L0 would require wrapping table reader iterators, introducing a performance cost.

## Key changes

- **New counter `num_collapsible_entry_reads_sampled`** in `FileSampledStats` tracks sampled reads that encounter deletions, single deletions, merges, or kNotFound results in both Get and Iterator paths.
- **Moved sampling from file-open to per-operation** in `LevelIterator`: sampling now happens in `SampleRead()` called from `Seek()`, `SeekForPrev()`, `SeekToFirst()`, `SeekToLast()`, `Next()`, `NextAndGetResult()`, and `Prev()`. The `should_sample` parameter was removed from `LevelIterator`'s constructor.
- **Differentiated sampling rate for Next() vs Seek()**: `should_sample_file_read_next()` uses a 64x lower sampling rate (`kFileReadSampleRate * 64`) since Next() is cheaper than Seek() and called more frequently.
- **Collapsible tracking in Get path**: `Version::Get()` now increments the collapsible counter when `GetContext::State()` is `kNotFound`, `kMerge`, or `kDeleted`.
- **Collapsible tracking in MultiGet path**: `MultiGetFromSST` also increments the collapsible counter for the same states.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/14434

Test Plan:
- Added new DB tests for both num_reads_sampled and num_collapsible_entry_reads_sampled

### Benchmark results (readrandom, readseq)

Setup: 1M keys, 16-byte keys, 100-byte values, no compression, fillrandom+compact

| Benchmark  | Params             | ops/s (main) | ops/s (feature) | % change |
|------------|--------------------|-------------|--------------------------|----------|
| readrandom | seed=1, threads=1  | 387,194     | 389,449                  | +0.6%    |
| readseq    | seed=1, threads=1  | 5,598,371   | 5,572,975                | -0.5%    |

No meaningful performance regression observed — differences are within run-to-run noise.

Reviewed By: xingbowang

Differential Revision: D95613793

Pulled By: joshkang97

fbshipit-source-id: 9dd09c9b7527b148424bde5686f4157c7a9e1214
2026-03-09 16:42:41 -07:00
Josh Kang
3ad23b2d94 Support automated interpolation search (#14383)
Summary:
Add automatic per-block interpolation search selection (`kAuto` mode) for index blocks. During SST construction, each index block's key distribution is analyzed using the coefficient of variation (CV) of gaps between restart-point keys. Blocks with uniformly distributed keys are flagged via a new bit in the data block footer, and at read time, `kAuto` resolves to interpolation search for uniform blocks and binary search otherwise.

## Key changes

- **New `BlockSearchType::kAuto` enum value**: Resolves per-block at read time to either `kInterpolation` or `kBinary` based on the block's uniformity flag. Falls back to `kBinary` on older versions that don't recognize it.
- **Write-path uniformity analysis**: `BlockBuilder::ScanForUniformity()` uses Welford's online algorithm to incrementally compute the CV of key gaps at restart points. The result is stored in a new bit (bit 30) of the data block footer's packed restart count.
- **New table option `uniform_cv_threshold`** (default: -1 `disabled`): Controls how strict the uniformity check is. Set to negative to disable. Exposed in C++, Java (JNI), and `db_bench`.
- **Code reorganization**: Block entry decode helpers (`DecodeEntry`, `DecodeKey`, `DecodeKeyV4`, `ReadBe64FromKey`) moved from `block.cc` to a new shared header `block_util.h` so they can be reused by `BlockBuilder` on the write path.
- **New histogram `BLOCK_KEY_DISTRIBUTION_CV`**: Records the CV (scaled by 10000) of each index block's key distribution for observability.
- **Java bindings**: `IndexSearchType.kAuto`, `uniformCvThreshold` getter/setter, JNI portal constructor signature updated, and `HistogramType.BLOCK_KEY_DISTRIBUTION_CV` added.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/14383

Test Plan:
- `IndexBlockTest.IndexValueEncodingTest` parameterized to include `kAuto` search type alongside `kBinary` and `kInterpolation`, verifying correct seek/iteration behavior across all combinations of key distributions, restart intervals, and key lengths.
- Uniformity detection validated: blocks with uniform key distribution correctly set `is_uniform = true`, blocks with clustered/non-uniform keys set `is_uniform = false`.
- Stress test coverage
- Updated check_format_compatible to also include a "uniform" dataset. By default using uniform_cv_threshold=-1 does not result in an incompatibility issues. When manually changing the threshold (e.g. `uniform_cv_threshold=1000`), I see `bad block contents`, which is expected

## Benchmark

readrandom with `fillrandom,compact -seed=1 --statistics`:

| Benchmark | Branch | Params | avg ops/s | % change vs main | CV P50 |
|-----------|--------|--------|-----------|------------------|--------|
| readrandom | main | `binary_search, shortening=1` | 335,791 | baseline | N/A |
| readrandom | feature | `binary_search, shortening=1` (default) | 335,749 | -0.0% | 1,500 |
| readrandom | feature | `auto_search, shortening=1` (kAuto) | 366,832 | **+9.2%** | 1,500 |
| readrandom | feature | `interpolation_search, shortening=1` | 366,598 | **+9.2%** | 1,500 |
| readrandom | feature | `auto_search, shortening=2` (kAuto) | 344,631 | **+2.6%** | 1,030,000 |
| readrandom | feature | `interpolation_search, shortening=2` | 201,178 | **-40.1%** | 1,030,000 |

As seen with shortening=2, a non-uniform distribution produces a high CV, which does not use interpolation search.

## Write benchmark

There is a write overhead which scans each restart entry for a block upon Finish. In practice this is very low because currently it is only applied to index blocks.

See cpu profile (https://fburl.com/strobelight/io5hwj9h) here of `-benchmarks=fillseq,compact -compression_type=none -disable_wal=1`. Only 0.08% attributed to `ScanForUniformity`.

Reviewed By: pdillinger

Differential Revision: D94738890

Pulled By: joshkang97

fbshipit-source-id: 9661ac593c5fef89d49f3a8a027f1338a0c96766
2026-03-06 10:13:51 -08:00
Peter Dillinger
871f79d6ef Reformat source files (#14331)
Summary:
probably something changed, maybe https://github.com/facebook/rocksdb/issues/14311

Full command:
```
git ls-files '*.cc' '*.h' | grep -v '^third-party/' | grep -v 'range_tree' | xargs clang-format -i
```

Pull Request resolved: https://github.com/facebook/rocksdb/pull/14331

Test Plan: CI

Reviewed By: mszeszko-meta

Differential Revision: D93246992

Pulled By: pdillinger

fbshipit-source-id: 6bc5b97978fef8aee52823dadb6daa4bea57343d
2026-02-13 11:56:22 -08:00
Ryan Hancock
8f9cb1a708 Introduce Memory restrictions for IO Dispatcher. (#14300)
Summary:
Introduction of memory limiter for IO Dispatch.

Currently, the user has no way of enacting policy with IO dispatcher. One important policy is the ability to restrict the amount of memory a multiscan or set of multiscans is allowed to pin. This PR introduces the max_prefetch_memory_bytes in the IODispatcherOptions, allowing for users to specify bounds on block cache memory usage.

There seems to be a minor performance increase however, I have found the scans to be a bit noisy. Each benchmark is run with a stride size of 30000 keys. This was done to ensure we maintain parity with trunk.
```
Configuration: 10 concurrent scans, 1024B values, 5242880 byte SST files
Scan sizes: 1024 keys = 1MiB, 2048 keys = 2MiB, 4096 keys = 4MiB per scan

| Keys/Scan | Mode  | Main (ops/sec)   | Main (us/op)     | limiter              (ops/sec) | limiter            (us/op) | Delta ops/sec |
|-----------|-------|------------------|------------------|----------------------|--------------------|---------------|
| 1024      | sync  |   151.6 +/- 8.0   | 6591.14 +/- 343.30 |    170.6 +/- 4.0      | 5855.32 +/- 136.19   | +12.00%       |
| 1024      | async |   156.4 +/- 24.7  | 6589.64 +/- 1345.73 |    173.8 +/- 2.7      | 5744.51 +/- 91.35   | +11.00%       |
| 2048      | sync  |    77.8 +/- 1.6   | 12785.64 +/- 286.49 |     87.6 +/- 3.4      | 11354.01 +/- 441.71   | +12.00%       |
| 2048      | async |    85.6 +/- 4.7   | 11658.11 +/- 618.49 |     91.4 +/- 1.2      | 10873.63 +/- 143.49   | +6.00%        |
| 4096      | sync  |    43.2 +/- 1.5   | 22932.27 +/- 730.66 |     43.8 +/- 0.7      | 22563.90 +/- 320.93   | +1.00%        |
| 4096      | async |    45.4 +/- 0.8   | 21875.64 +/- 357.04 |     46.2 +/- 0.7      | 21416.95 +/- 311.89   | +1.00%        |

```

Pull Request resolved: https://github.com/facebook/rocksdb/pull/14300

Reviewed By: anand1976

Differential Revision: D92316556

Pulled By: krhancoc

fbshipit-source-id: dc0b7958a33b8ef5fa5af82b1c6d960041837fc1
2026-02-06 11:29:30 -08:00
Xingbo Wang
656b734a5f Support abort background compaction jobs. (#14227)
Summary:
This adds a new public API to allow applications to abort all running compactions and prevent new ones from starting. Unlike DisableManualCompaction() which only pauses manual compactions and waits for them to finish naturally, AbortAllCompactions() actively signals running compactions (both automatic and manual) to terminate early and waits for them to complete before returning.

The abort signal is checked periodically during compaction (every 100 keys), so ongoing compactions abort quickly. Any output files from aborted compactions are automatically cleaned up to prevent partial results from being installed.

This is useful for scenarios where applications need to quickly stop all compaction activity, such as during graceful shutdown or when performing maintenance operations.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/14227

Test Plan:
- Unit tests in db_compaction_abort_test.cc cover various abort scenarios including: abort before/during compaction, abort with multiple subcompactions, nested abort/resume calls, abort with CompactFiles API, abort across multiple column families, and timing guarantees
- Updated compaction_job_test.cc to include the new parameter

Reviewed By: anand1976

Differential Revision: D91480994

Pulled By: xingbowang

fbshipit-source-id: 36837971d8a540cd34d3ec28a78bc94b582625b0
2026-01-30 05:53:04 -08:00
Maciej Szeszko
6b5ccbbec6 Remove inline values support (#14270)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/14270

Legacy BlobDB's inline values feature (storing small values directly in the LSM tree via `min_blob_size` threshold) is unused in production - all
deployments use `min_blob_size = 0`. This removes the functionality entirely.

Changes:
- Remove `min_blob_size` from `BlobDBOptions`
- Remove `IsInlined()` check from compaction filter (dead code path)
- Remove inline-related statistics (`BLOB_DB_WRITE_INLINED*`)
- Remove `InlineSmallValues` test
- Update stale comments referencing inlined data

Reviewed By: xingbowang

Differential Revision: D91088985

fbshipit-source-id: ec67848ece1a7dc071ca8e8a17faebb435394733
2026-01-28 16:08:10 -08:00
Anand Ananthabhotla
b89d290c20 Add MultiScan statistics (#14248)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/14248

### Overview

This diff introduces the addition of multi-scan statistics to RocksDB, enhancing the database's ability to monitor and analyze performance during multi-scan operations.

### Key Changes

#### Implemented Multi-Scan Statistics

The following statistics were implemented to provide deeper insights into multi-scan operations:

- **MULTISCAN_PREPARE_MICROS**: Measures the time (in microseconds) spent preparing for multi-scan operations.
- **MULTISCAN_BLOCKS_PER_PREPARE**: Tracks the number of blocks processed per multi-scan prepare operation.
- **Wasted Prefetch Blocks Count**: Counts the number of prefetched blocks that were not used (i.e., wasted) if the iterator is abandoned before accessing them.
- **MULTISCAN_TOTAL_BLOCKS_SCANNED**: Tracks the total number of blocks scanned during all multi-scan operations.
- **MULTISCAN_TOTAL_KEYS_SCANNED**: Measures the total number of keys scanned across all multi-scan operations.
- **MULTISCAN_TOTAL_MICROS**: Captures the total time (in microseconds) spent in multi-scan operations.
- **MULTISCAN_PREFETCHED_BLOCKS**: Counts the number of blocks that were prefetched during multi-scan operations.
- **MULTISCAN_USED_PREFETCH_BLOCKS**: Tracks the number of prefetched blocks that were actually used during multi-scan operations.

### Impact

This diff provides more fine-grained statistics for multi-scan operations, allowing developers and users to better understand and optimize the performance of their RocksDB instances.

Reviewed By: krhancoc

Differential Revision: D91053297

fbshipit-source-id: 7158741b9f026c0b5ce8ba1264dbd137e7fe985d
2026-01-21 23:23:38 -08:00
Ryan Hancock
b9951ded37 Introducing Prepare all iterators for LevelIterator (#14100)
Summary:
This diff introduces the async prepare of all iterators within a MultiScan. The current state has each iterator be prepared as its needed, and with this diff, we prepare all iterators during the prepare phase of the Level Iterator, this will allow more time for each IO to be dispatched and serviced, increasing the odds that a block is ready as the scan seeks to it.

Benchmark is prefilled using
```
KEYSIZE=64
VALUESIZE=512
NUMKEYS=5000000
SCAN_SIZE=100
DISTANCE=25000
NUM_SCANS=15
THREADS=1

./db_bench --db=$DB \
    --benchmarks="fillseq" \
    --write_buffer_size=5242880 \
    --max_write_buffer_number=4 \
    --target_file_size_base=5242880 \
    --disable_wal=1 --key_size=$KEYSIZE \
    --value_size=$VALUESIZE --num=$NUMKEYS --threads=32

}
```

And benchmark ran is
```
run() {
echo 1 | sudo tee /proc/sys/vm/drop_caches
./db_bench --db=$DB --use_existing_db=1 \
    --benchmarks=multiscan \
    --disable_auto_compactions=1 --seek_nexts=$SCAN_SIZE \
    --multiscan-use-async-io=1 \
    --multiscan-size=$NUM_SCANS --multiscan-stride=$DISTANCE \
    --key_size=$KEYSIZE --value_size=$VALUESIZE \
    --num=$NUMKEYS --threads=$THREADS --duration=60 --statistics
}
```

The benchmark uses large stride sides to ensure that two scans would touch separate files. We reduce the size of the block cache to increase likelyhood of reads (and simulate larger data sets)

**Branch:**

```
Integrated BlobDB: blob cache disabled
RocksDB:    version 10.8.0
Date:       Tue Nov 11 13:26:29 2025
CPU:        166 * AMD EPYC-Milan Processor
CPUCache:   512 KB
Keys:       64 bytes each (+ 0 bytes user-defined timestamp)
Values:     512 bytes each (256 bytes after compression)
Entries:    5000000
Prefix:    0 bytes
Keys per prefix:    0
RawSize:    2746.6 MB (estimated)
FileSize:   1525.9 MB (estimated)
Write rate: 0 bytes/second
Read rate: 0 ops/second
Compression: Snappy
Compression sampling rate: 0
Memtablerep: SkipListFactory
Perf Level: 1
------------------------------------------------
multiscan_stride = 25000
multiscan_size = 15
seek_nexts = 100
DB path: [/data/rocksdb/mydb]
multiscan    :     837.941 micros/op 1193 ops/sec 60.001 seconds 71605 operations; (multscans:71605)
```

**Baseline:**

```
Set seed to 1762898809121995 because --seed was 0
Initializing RocksDB Options from the specified file
Initializing RocksDB Options from command-line flags
Integrated BlobDB: blob cache disabled
RocksDB:    version 10.9.0
Date:       Tue Nov 11 14:06:49 2025
CPU:        166 * AMD EPYC-Milan Processor
CPUCache:   512 KB
Keys:       64 bytes each (+ 0 bytes user-defined timestamp)
Values:     512 bytes each (256 bytes after compression)
Entries:    5000000
Prefix:    0 bytes
Keys per prefix:    0
RawSize:    2746.6 MB (estimated)
FileSize:   1525.9 MB (estimated)
Write rate: 0 bytes/second
Read rate: 0 ops/second
Compression: Snappy
Compression sampling rate: 0
Memtablerep: SkipListFactory
Perf Level: 1
------------------------------------------------
multiscan_stride = 25000
multiscan_size = 15
seek_nexts = 100
DB path: [/data/rocksdb/mydb]
multiscan    :    1129.916 micros/op 885 ops/sec 60.001 seconds 53102 operations; (multscans:53102)
```
Repeated for confirmation.

This introduces a ~20% improvement in latency and op/s.

Note: Benchmarks are single threaded as, when increasing thread count, we start seeing large amounts of overhead being induced by block cache contention, finally resulting in both baseline and branch becoming equal.

Further on network attached storage with high latency, the level iterator, preparing all iterators so a 20% improvement even at high thread counts.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/14100

Reviewed By: anand1976

Differential Revision: D86913584

Pulled By: krhancoc

fbshipit-source-id: da9d0c890e25e392a33389ce6b80f9bfb84d3f85
2025-11-18 15:57:03 -08:00
Peter Dillinger
befa6b8050 Fix and check for potential ODR violations (#14096)
Summary:
... caused by public headers depending on build parameters (macro definitions). This change also adds a check under 'make check-headers' (already in CI) looking for potential future violations.

I've audited the uses of '#if' in public headers and either
* Eliminated them
* Systematically excluded them because they are intentional or similar (details in comments in check-public-header.sh
* Manually excluded them as being ODR-SAFE

In the case of ROCKSDB_USING_THREAD_STATUS, there was no good reason for this to appear in public headers so I've replaced it with a static bool ThreadStatus::kEnabled. I considered getting rid of the ability to disable this code but some relatively recent PRs have been submitted for fixing that case. I've added a release note and updated one of the CI jobs to use this build configuration. (I didn't want to combine with some jobs like no_compression and status_checked because the interaction might limit what is checked.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/14096

Test Plan: manual 'make check-headers' + manual cmake as in new CI config + CI

Reviewed By: jaykorean

Differential Revision: D86241864

Pulled By: pdillinger

fbshipit-source-id: d16addc9e3480706b174a006720a4def0740bf2e
2025-11-04 19:47:42 -08:00
Hui Xiao
8edb99f904 Statistics for successfully resumed compaction output bytes (#14054)
Summary:
Context/Summary: as titled

Pull Request resolved: https://github.com/facebook/rocksdb/pull/14054

Test Plan: new UT, manually checking

Reviewed By: jaykorean

Differential Revision: D84828431

Pulled By: hx235

fbshipit-source-id: 56e1a9159f7597a10d6c549657d8b22788aa0599
2025-10-17 11:38:20 -07:00
Peter Dillinger
1c8a012727 Add kCool Temperature (#14000)
Summary:
also requested by internal user, like kIce in https://github.com/facebook/rocksdb/issues/13927

Pull Request resolved: https://github.com/facebook/rocksdb/pull/14000

Test Plan: unit tests updated

Reviewed By: archang19

Differential Revision: D83200479

Pulled By: pdillinger

fbshipit-source-id: 31f2842d87bcad40227aeee9687ff5772393689c
2025-09-25 11:27:00 -07:00
Peter Dillinger
67af5bdc38 Add Temperature::kIce (#13927)
Summary:
... and associated statistics, etc. Someone needs it, so here it is.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/13927

Test Plan: Updated / extended / added some unit tests

Reviewed By: cbi42

Differential Revision: D81981469

Pulled By: pdillinger

fbshipit-source-id: 52558c08741890b781310906acbc18d9eb479363
2025-09-10 10:29:49 -07:00
anand76
0044a76d36 Make failure to load UDI when opening an SST a soft failure (#13921)
Summary:
If user_defined_index_factory in BlockBasedTableOptions is configured and we try to open an SST file without the corresponding UDI (either during DB open or file ingestion), ignore a failure to load the UDI by default. If fail_if_no_udi_on_open in BlockBasedTableOptions is true, then treat it as a fatal error.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/13921

Test Plan: Update unit tests

Reviewed By: xingbowang

Differential Revision: D81826054

Pulled By: anand1976

fbshipit-source-id: f4fe0b13ccb02b9448622af487680131e349c52b
2025-09-05 19:06:28 -07:00
Changyu Bi
b42bf48310 Add stats for WBWI ingestion and transaction size (#13611)
Summary:
Add stats to monitor the large transaction optimization. A stat is added for how many times wbwi ingestion is used. A histogram is added to track transaction size. We could also just track write batch size for all writes but I don't want to add the overhead to all writes yet.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/13611

Test Plan:
ran `python3 ./tools/db_crashtest.py --txn blackbox  --txn_write_policy=0 --commit_bypass_memtable_one_in=50 --test_batches_snapshots=0 --stats_dump_period_sec=2 --dump_malloc_stats=0 --statistics=1` and manually check LOG files
```
rocksdb.number.wbwi.ingest COUNT : 57
...
rocksdb.num.op.per.transaction P50 : 1.000000 P95 : 1.000000 P99 : 1.000000 P100 : 1.000000 COUNT : 2265 SUM : 2265
```

Reviewed By: jowlyzhang

Differential Revision: D74829087

Pulled By: cbi42

fbshipit-source-id: 5a9c3ab2d4cb6071cedfc47201ce2cf65a77d3c6
2025-05-16 11:51:58 -07:00
Michael C Huang
13d865f6f1 Add trivial copy support when FIFO compaction reason is kChangeTemperature (#13562)
Summary:
Prior to this PR, for FIFO kChangeTemperature compaction was done by iterating and reading thru the input sst and generate the output sst. This was wasteful since for FIFO we could apply the "trivial" move by copying the input sst to the out sst without need decompress/compress and reading thru the input sst content at all. This PR added "allow_trivial_copy_when_change_temperature" to the CompactionOptionsFIFO.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/13562

Reviewed By: cbi42

Differential Revision: D73295404

Pulled By: mikechuangmeta

fbshipit-source-id: 02241c7389797730ecd4a3b636837cb5f912b424
2025-05-08 15:51:37 -07:00
Hui Xiao
29c6610617 Add compaction explicit prefetch stats (#13520)
Summary:
**Context/Summary:**
This PR adds new stats to measure compaction readahead size for rocksdb managed prefetching (not FS prefetching). It can be used to verify compaction read-ahead is doing what's configured. This PR also excludes compaction readahead stats from user scan readahead stats measured in existing stats so there is a cleaner separating between these two.

Bonus: this PR also included some typo fixing about "io activities"

Pull Request resolved: https://github.com/facebook/rocksdb/pull/13520

Test Plan: Modified existing test to verify stats

Reviewed By: archang19

Differential Revision: D72892850

Pulled By: hx235

fbshipit-source-id: 1a73182061baa044c9c9193a2b0fd967ffe75c4a
2025-04-14 12:08:38 -07:00
Peter Dillinger
2a0ee4ddd8 Refactor wal related naming and more (#13490)
Summary:
* Clarify in API comments which `log_` options in DBOptions relate to WALs, info log, and/or manifest files.
* Rename a bunch of "log" things to "wal" for clarity, especially in DBImpl. (More to go, especially some more challenging cases like `DBImpl::logs_`, but a step in the right direction IMHO)
* Simplify DBImpl ctor by moving constant initializers to field definitions.
* Use RelaxedAtomic for (renamed) `wals_total_size_`

Pull Request resolved: https://github.com/facebook/rocksdb/pull/13490

Test Plan: existing tests

Reviewed By: cbi42

Differential Revision: D71939382

Pulled By: pdillinger

fbshipit-source-id: 852f4737eca83e6ad653010cc197ad1b6e6bae13
2025-04-11 10:08:29 -07:00
Hui Xiao
2e175124d8 Rename Env::IOActivity::kReadManifest (#13471)
Summary:
Context/Summary: as mentioned in the [comment](https://github.com/facebook/rocksdb/pull/13178?fbclid=IwZXh0bgNhZW0CMTAAAR1nvz-1Ifh6Pm8PwFZbGHAxhLtwfi4W_XaSe-BqnBx3ICJOq-9DTdqFvs0_aem_ITO_0B6cca0kTViRmsAA8g#issuecomment-2702510373) , we want to rename this public name to align with the naming convention.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/13471

Test Plan:
- Compilation
- Manually check for no internal usage of this name. Hopefully it's good for OSS as well as this field is relatively new and the whole IOActivity is marked "EXPERIMENTAL"

Reviewed By: mszeszko-meta

Differential Revision: D71485300

Pulled By: hx235

fbshipit-source-id: 318c8b6c2a4d874f2f831e3ca690aa2fb8974c0f
2025-03-19 12:08:06 -07:00
Yu Zhang
c8bc2b63fc Add time measuring metrics for file ingestion in PerfContext (#13219)
Summary:
As titled. And also added some documentation for an approach to name perf context metrics that can help identify the starting `PerfLevel` that enables collecting it.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/13219

Test Plan: Unit test

Reviewed By: hx235

Differential Revision: D67362022

Pulled By: jowlyzhang

fbshipit-source-id: 7ed1bb475b5497961612d4e331600609da42074b
2024-12-19 16:53:42 -08:00
Peter Dillinger
c72e79a262 Standardize on clang-format version 18 (#13233)
Summary:
... which is the default for CentOS 9 and Ubuntu 24, the latter of which is now available in GitHub Actions. Relevant CI job updated.

Re-formatted all cc|c|h files except in third-party/, using

```
clang-format -i `git ls-files | grep -E '[.](cc|c|h)$' | grep -v third-party/`
```

Pull Request resolved: https://github.com/facebook/rocksdb/pull/13233

Test Plan: CI

Reviewed By: jaykorean, archang19

Differential Revision: D67461638

Pulled By: pdillinger

fbshipit-source-id: 0c9ac21a3f5eea6f5ade68bb6af7b6ba16c8b301
2024-12-19 10:58:40 -08:00
Maciej Szeszko
be7703b27d Offline file checksum manifest retriever (#13178)
Summary:
This change introduces a new, lightweight _experimental_ API that reconstructs the [file # -> file checksum -> file checksum function] 1-1-1 mapping directly from the `MANIFEST` file considered `CURRENT` in scope of specific DB instance at the time. The goal is to provide a cheap alternative to `DB::GetLiveFilesMetaData` that doesn't require opening the database, reconstructing version sets and/or accessing files that are _potentially_ in disaggregated storage.

### Housekeeping:

1. Moved the `GetCurrentManifestPath` out of `version_set` to a new `manifest_ops` file(s) dedicated to manifest related operations.
2. Introduced new `Env::IOActivity::kReadManifest` to better reflect the IO intent in offline file checksum retrieving function.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/13178

Test Plan:
Added a unit test comparing the outcome of newly introduced API against the established `GetLiveFilesMetaData`:

```hcl
./db_test2 --gtest_filter="*GetFileChecksumsFromCurrentManifest_CRC32*"
```

Reviewed By: pdillinger

Differential Revision: D66711910

Pulled By: mszeszko-meta

fbshipit-source-id: 57091c550a14ac2e832bf7eea136dab5450e71bc
2024-12-06 13:29:52 -08:00
anand76
c21fe1a47f Add ticker stats for read corruption retries (#12923)
Summary:
Add a couple of ticker stats for corruption retry count and successful retries. This PR also eliminates an extra read attempt when there's a checksum mismatch in a block read from the prefetch buffer.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12923

Test Plan: Update existing tests

Reviewed By: jowlyzhang

Differential Revision: D61024687

Pulled By: anand1976

fbshipit-source-id: 3a08403580ab244000e0d480b7ee0f5a03d76b06
2024-08-12 15:32:07 -07:00
anand76
98d8a85624 New PerfContext counters for block cache bytes read (#12459)
Summary:
Add PerfContext counters for measuring the cumulative size of blocks found in the block cache.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12459

Reviewed By: ajkr

Differential Revision: D55170694

Pulled By: anand1976

fbshipit-source-id: 8cbba76eece116cefce7f00e2fc9d74757661d25
2024-03-21 10:46:46 -07:00
anand76
4868c10b44 Retry block reads on checksum mismatch (#12427)
Summary:
On file systems that support storage level data checksum and reconstruction, retry SST block reads for point lookups, scans, and flush and compaction if there's a checksum mismatch on the initial read. A file system can indicate its support by setting the `FSSupportedOps::kVerifyAndReconstructRead` bit in `SupportedOps`.

Tests:
Add new unit tests

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12427

Reviewed By: ajkr

Differential Revision: D55025941

Pulled By: anand1976

fbshipit-source-id: dbd990cb75e03f756c8a66d42956f645c0b6d55e
2024-03-18 16:16:05 -07:00
jsteemann
3fff57fa6a fix linking without thread status support (#12400)
Summary:
When compiling with `-DNROCKSDB_THREAD_STATUS`, some functions in ThreadStatusUtil are declared but their definition is missing. Their definitions are only compiled when not defining `NROCKSDB_THREAD_STATUS`. This causes problems on linking, when the linker cannot find the definitions of

- ThreadStatusUtil::GetThreadOperation
- ThreadStatusUtil::SetEnableTracking

This PR fixes it by adding stubs for these functions in case `NROCKSDB_THREAD_STATUS` is defined.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12400

Reviewed By: ajkr

Differential Revision: D54510769

Pulled By: cbi42

fbshipit-source-id: e79e9257492d3dba59615e9e306df7e79838d73b
2024-03-04 17:39:03 -08:00
jsteemann
965364972d fix compile warning (#12399)
Summary:
Fix compile warning
```
monitoring/thread_status_util.cc: In static member function ‘static void rocksdb::ThreadStatusUtil::NewColumnFamilyInfo(const rocksdb::DB*, const rocksdb::ColumnFamilyData*, const std::string&, const rocksdb::Env*)’: monitoring/thread_status_util.cc:193:55: warning: unused parameter ‘env’ [-Wunused-parameter]
  193 |                                            const Env* env) {}
      |                                            ~~~~~~~~~~~^~~
```

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12399

Reviewed By: jaykorean

Differential Revision: D54424333

Pulled By: cbi42

fbshipit-source-id: 3dcb89f85d3a63b1b0d0d6a8b277f49ce03b6d1a
2024-03-01 11:25:16 -08:00