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115 Commits

Author SHA1 Message Date
cm-sally-mate
94c7f76da0 Keep read-path tombstone conversion from deleting ingested files an older iterator cannot see (#15461)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/15461

**What:** With `min_tombstones_for_range_conversion` set, an iterator whose view predates an ingestion can delete the ingested keys for good.

**Why it matters:** Silent, permanent data loss. `Get` returns the ingested key right after ingestion. After one scan from the older iterator, `Get` returns NotFound, also after flush and reopen. Every MyRocks bulk load with the option set takes this path: MyRocks ingests with `allow_global_seqno=false` and `snapshot_consistency=false` (seqno 0).

**Root cause:**
- The older iterator does not see the ingested file. It sees the deleted keys on both sides of the file as one run, and inserts a range tombstone at its read sequence number. The tombstone covers the ingested keys.
- `ingest_seqno_barrier_` (D102044512) refuses a conversion only when the iterator's sequence number is below the ingested seqno. That misses two cases:
  1. The file gets no new seqno: no overlap (seqno 0), `ingest_behind`, or `allow_db_generated_files`. Ingestion does not move the barrier at all (`assigned > 0`).
  2. `NewIterator()` references the SuperVersion before it reads the sequence number. If an ingestion and a write happen in between, the iterator reads at a sequence number above the ingested file, with a SuperVersion that does not have it. This also loses files ingested with a new seqno.
- Ingestions that flush the memtable are safe: the older iterator's memtable becomes immutable.

**Fix:** Barrier on the Version, not only on the sequence number.
- After `LogAndApply()`, ingestion records the new Version number on the active memtable (`ingest_version_barrier_`), while it still holds the per-CF `ingest_sst_lock`.
- `DBIter` passes the number of the Version it reads. `AddLogicallyRedundantRangeTombstone()` refuses the conversion if that number is below the barrier.
- Version numbers only go up, and every later Version of the column family has the ingested files. So the check is true exactly when the iterator cannot see an ingestion into this memtable. Iterators created after the ingestion convert as before.
- The seqno barrier stays: it still covers old explicit snapshots that read a newer Version.

**Related:** D126796014 (`Disable tombstone conversion for kMemtableTier iterators`) fixes a different trigger of the same feature.

Reviewed By: joshkang97, archang19

Differential Revision: D126875720

fbshipit-source-id: 5767b866c6174d791f9ddae78311816300ac49f3
2026-10-22 15:31:52 -07:00
Josh Kang
014e1c43c1 Apply readability fixes (isolate decls, braces) (#15394)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/15394

## Summary

RocksDB's `.clang-tidy` enables several readability checks that existing
code still violates: `readability-isolate-declaration` (476 findings),
`readability-braces-around-statements` (49),
`readability-redundant-string-init` (25), `modernize-use-using` (10),
`misc-definitions-in-headers` (3) and `readability-duplicate-include`
(1). They keep getting flagged whenever nearby lines change. This diff
fixes 553 of the 564; upstream has since fixed the other 11.

What changed:
- Multi-variable declarations such as `std::string a, b;` are split into
  one declaration per variable. Pointer and reference declarators are kept
  per variable.
- Braces are added around single-statement `if`/`else`/`for`/`while`
  bodies, and empty spin loops get an empty `{}` body.
- `std::string s = ""` / `member("")` initializers are removed.
- Remaining `typedef`s in the touched C++ files become `using`. C headers
  and `extern "C"` code are untouched.
- `inline` is added to non-template function definitions in test headers.
- A duplicate `#include "util/udt_util.h"` in `db_impl.cc` is removed.

These are clang-tidy's own fix-its, applied mechanically and then
clang-formatted on the changed lines. Three kinds of broken fix-it output
were repaired by hand. Removing a `member("")` initializer left a dangling
comma in constructor initializer lists (`ExternalSstFileInfo`,
`ColumnFamilyMetaData` and others). The function-type typedefs in
`block_test.cc` came out malformed. Empty `while (cond);` spin loops got a
`{;` body. Splitting declarations also exposed two vectors in
`db_etc2_test.cc` to `performance-inefficient-vector-operation`, so a
`reserve()` was added for each.

The lint bot reports every finding in a file a diff touches. This diff
splits declarations in `options/configurable_test.cc`, so it also fixes
that file's 14 older `cert-err58-cpp` and
`cppcoreguidelines-avoid-non-const-global-variables` findings, which come
from seven mutable file-level maps. Six are now `const` and built where
they are used (function-local statics, or locals in their only user).
The unused `imm_struct_option_info` is deleted.

Compatibility: no behavior change. In public headers, the only edits are
removed redundant `""` initializers, split declarations and added braces.

Reviewed By: rban1

Differential Revision: D123186310

fbshipit-source-id: f9c8e88b00e997db0196f8725c7c8d880cf798da
2026-10-13 14:06:55 -07:00
Omkar Gawde
7510773057 Fix ClipColumnFamily key lifetime and atomic-flush wait alignment (#15273)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/15273

**What**: `ClipColumnFamily` keeps boundary keys valid across unlocked writes, and atomic-flush waits pair every column family with the correct memtable bound.
**How**: `DBImpl::ClipColumnFamily` copies boundary keys from the current `Version` while holding the DB mutex, with a sync point that lets the regression test replace that version before deletion. `DBImpl::AtomicFlushMemTables` and `DBImpl::RetryFlushesForErrorRecovery` construct wait bounds in `cfds` order and supply no-bound fallbacks when a column family is absent from the flush-request map. Both wait sites gain a debug invariant asserting each id matches the map entry for the cfd at the same index.
**Why**: Background version replacement could leave `ClipColumnFamily` reading freed metadata, while unordered or missing atomic-flush map entries could cause early completion or out-of-bounds access for idle or duplicate column families.

Reviewed By: xingbowang

Differential Revision: D121840843

fbshipit-source-id: 8e49b5c953a1aa29a0244fc0aae2ca3ab84be74f
2026-09-28 14:31:40 -07:00
Josh Kang
03b8d1afa0 Prevent normal flushes from starving error recovery (#15132)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/15132

This fixes a liveness bug in background-error recovery. Retryable soft errors allow foreground writes to continue, but recovery must wait for every scheduled background flush worker to exit before it can submit the recovery flush.

While recovery was active, normal flush requests could still enter `flush_queue_`. Atomic flush requests bypass per-column-family deduplication, so writes could accumulate a backlog of normal requests.

For each request, the background worker:

  1. Pops and drops the normal request because BG work is stopped
  2. Sleeps for the one-second background-error backoff
  3. Decrements `bg_flush_scheduled_`: 1 -> 0
  4. Calls `MaybeScheduleFlushOrCompaction()`
  5. Schedules the next queued request: 0 -> 1
  6. Only then signals the recovery thread

The rescheduling happens under the DB mutex before recovery is signaled:

  Queued requests: R1, R2, R3, ...

  Flush worker                      Recovery thread
  ------------                      ---------------
  drop R1
  sleep 1 second                    waiting for scheduled == 0
  scheduled: 1 -> 0
  schedule R2: 0 -> 1
  signal -------------------------> wake, observe scheduled == 1
                                    wait again

  drop R2
  sleep 1 second
  scheduled: 1 -> 0
  schedule R3: 0 -> 1
  signal -------------------------> wake, observe scheduled == 1
                                    wait again

The dropped request is not requeued. Instead, the worker exit path guarantees that the next queued request is scheduled while `unscheduled_flushes_ > 0`.

A finite backlog therefore delays recovery by roughly one second per request. If writes keep producing requests as quickly as workers discard them, the queue may never drain and recovery is starved indefinitely. Recovery can complete after writes become quiescent, so this is a liveness failure rather than a lock deadlock or data-corruption bug.

There is also a queue-accounting edge. Scheduling consumes `unscheduled_flushes_`, but a worker does not own its `FlushRequest` until it pops `flush_queue_`. A worker can exit on the background error before popping, leaving:

  flush_queue_.size()  > 0
  unscheduled_flushes_ == 0

Clearing only unscheduled requests therefore misses scheduled-but-unclaimed requests.

The fix:

- Reject new non-recovery requests while background work is stopped.
- Allow error-recovery flush reasons to bypass that guard.
- Clear the entire flush queue before recovery waits for scheduled workers.
- Retain the worker-side reason check for requests queued before the error.
- Rebuild recovery flushes and schedule a catch-up flush for writes made during recovery.

Reviewed By: pdillinger

Differential Revision: D116708546

fbshipit-source-id: 6e29fd3653ef72d047c64ca89d311a7bee51ab84
2026-08-20 10:54:15 -07:00
Peter Dillinger
021374c62c Start format_version=8 development toward new features (#15104)
Summary:
format_version background: SST files are shared across RocksDB versions. format_version is a critical tool in ensuring prior (and later) versioned readers do not misinterpret a file created by some version. Opt-in features can sometimes rely on previously-rejected corners of the schema space, but not always.

This change: lands much of the format_version=8 (fv8) format surface as an internal-only draft -- readable and testable but not user-writable -- so upcoming features can build on a stable base. fv8 is NOT published: kLatestBbtFormatVersion stays 7, and reading or writing fv8 is gated behind the existing TEST-only TEST_AllowUnsupportedFormatVersion() hook. Publishing fv8 (raising the ceiling) is deferred to a later change.

The pieces of fv8 added here, and what each unlocks:

- Index value-delta escape. Existing behavior: index blocks (format_version >= 4) store each block handle as a delta against the previous entry's handle, and signal "this value is a full handle instead" by reusing the key sentinel `shared == 0`. Because the two are coupled, an index entry whose handle is not contiguous with the previous one must be forced to a restart, costing a full key as well as a full value. fv8 decouples them with an in-value escape codepoint: varint 0 means "a full BlockHandle follows," and genuine size deltas are remapped to zigzag(delta)+1 so that 0 stays free. A non-contiguous entry can then remain an ordinary key-delta-encoded, on-cadence entry. The escape applies to every index-shaped block, which includes the top-level index of index partitions and the index of filter partitions, not just the index over data blocks. Unlocks: the upcoming optimize_key_common_prefix index feature (removes its need to special-case super_block_alignment) and value-delta encoding for embedded-blob SSTs (previously disabled outright because interleaved blob records break handle contiguity). Guarded strictly on fv8; format_version <= 7 encoding and decoding are byte-for-byte unchanged. Note that restart points must not delta-encode, so they still have full values without a sentinel.

- Data block footer bit 30 is reserved as an "extended metadata present" escape. Decode rejects a set bit as unsupported/corrupt at all versions. Unlocks: adding block-level metadata in the future through the one shared footer decoder, without another format_version bump or plumbing format_version into every block parser. (Older reader versions relied on this bit being zero for some integrity/consistency checking; format_version bump now makes it safe to use.)

- Footer metaindex gap. For fv8, the top 16 bits of the footer's 4-byte metaindex-size field record the gap (in bytes) between the end of the metaindex block and the start of the footer; the low 16 bits hold the metaindex block size. Unlocks: a space very near the end of the file to save full file checksum state, for a "files carry their own checksums" feature that doesn't require SST parsing to extract the checksum states (to run them to completion on the trivial file tail).

- Reserved "user_key_common_prefix" table property. The reader returns NotSupported when it is present and non-empty. Unlocks: a future whole-file optimization that stores the common prefix of all user keys once instead of in every restart key; until implemented, fv8 readers refuse such a file rather than mis-read it.
  - Because of the problem of inferring such a prefix at the start of constructing an SST file, we expect it will rely on SstPartitioner. Here we've added SstPartitioner::ShouldPartitionByPrefix() (not yet used) that will enable this optimization, and avoid the overhead of a virtual callback to SstPartitioner on every key written to an SST file.

Supporting cleanups: the Footer's "unset" format_version sentinel is named (kInvalidFormatVersion) and the FormatVersionUses*() predicates assert against it, as each is a `version >= N` test that an unpopulated Footer would silently satisfy. Index block reader entry points (Block::NewIndexIterator() and friends) drop their defaulted trailing arguments so each caller states which codec it expects, and BlockBuilder::Add() takes delta_value by const reference rather than a pointer whose null case no caller used.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/15104

Test Plan:
New unit tests, all exercising fv8 through TEST_AllowUnsupportedFormatVersion():

- block_test: value-delta escape codec round-trip (delta 0, negative, large, and the escape; asserts format_version <= 7 bytes match the legacy encoding and a legacy 0x00 still decodes as delta 0), and rejection of footer bit 30 at all versions.

- db_flush_test: fv7-vs-fv8 read equivalence for super_block_alignment, including the separate_key_value_in_data_block intersection, confirming padding events (hence escape entries) occur and fv8 index values are delta encoded.

- sst_file_reader_test: fv7-vs-fv8 read equivalence for embedded-blob SSTs, confirming fv8 (unlike fv7) delta-encodes their index values and actually emits escape entries (counted through a sync point).

- block_based_table_reader_test: a builder+reader test that injects a footer metaindex gap via a sync point (verifies the gap bytes are written and the reader locates the metaindex via the recorded gap, and that too large a gap surfaces as a builder error), and that a non-empty reserved user_key_common_prefix property makes the reader return NotSupported.

- table_test: two-level index with partitioned filters and index_block_restart_interval > 1, the configuration in which both top-level indexes delta-encode their values; verifies scan and point lookup round trips at each tested format_version including fv8.

- (Not strictly fv8) Basic SstPartitionerFixedPrefix tests in slice_test (ShouldPartition, ShouldPartitionByPrefix, their mutual consistency, and CanDoTrivialMove), which had no non-DB coverage before.

fv8 is also added to the table_test harness (GenerateArgList) and the shared footer version set (test::kFooterFormatVersionsToTest), so the existing table-level and DB-level property/checksum suites now also run at fv8. And added to crash test (minor revisions to db_stress).

## Performance details
Release db_bench (PORTABLE=0, -march=native) A/B/C on the read/write fast path,
comparing (a) parent, (b) this commit @ fv7, (c) this commit @ fv8. All DBs on
tmpfs, 20M keys, block_size=2048, compression=none. Note index_block_restart_
interval=16 (not the default 1) is required to actually exercise the fv7<->fv8
index value-delta codec -- with restart interval 1 every index entry is a full-
handle restart and the changed path never runs (confirmed delta-value=1 via
sst_dump). Reads single-thread + core-pinned, warm cache, interleaved/rotated
rounds, paired deltas.

Reads (readrandom + seekrandom, non-partitioned single ~1.9MB index block and
partitioned index+filters): fv7->fv8 in the *same* binary is within noise on all
four workloads (largest -1.0%, CIs cross zero). before->after (fv7 path) is also
within noise; perf shows a deterministic +0.4-0.6% instructions/op from the added
branches (the format_version>=8 value_delta_escape guard + refactored data-block
footer decode), which is below the throughput noise floor.

Writes (fillseq + compact total CPU): fv7->fv8 null. compact (which rewrites all
index blocks) is null before->after. fillseq showed +3.5% CPU before->after, but
perf attributes it entirely to cycles/IPC with *identical* instructions/op
(+0.01-0.04%) -- a code-layout effect on the untouched memtable-insert loop, not
this change.

Sanity: any single throughput/CPU delta <~1% is within the build-to-build noise
floor, measured directly by comparing two byte-identical binaries (swings up to
~0.9% reads; the pre-native/PORTABLE=1 build showed a spurious -1.85% that
vanished under -march=native).

Net: no measurable regression from fv8 draft; fv7 encoding/decoding byte-for-byte
unchanged, only the noted sub-1% instruction bump on the shared read path.

Reviewed By: xingbowang

Differential Revision: D116105558

Pulled By: pdillinger

fbshipit-source-id: ead776cdd396d497d47872c0956ea8c651c0d13f
2026-08-17 12:08:59 -07:00
Peter Dillinger
bb77d17072 Make Flush() optionally wait for OnFlushCompleted (FlushOptions::listener_wait) (#14992)
Summary:
DB::Flush() with wait=true only waits until the flush result is committed (memtables removed from the immutable list). The EventListener::OnFlushCompleted callbacks run afterward, on the background flush thread, with the DB mutex released, and the waiter is only woken by a shared condition variable that many unrelated events also signal. As a result a Flush(wait=true) caller can return before -- or in the middle of -- its OnFlushCompleted callbacks. This surfaced as a flaky failure in the c_test table_filter_listener_metadata case, which asserts listener_state.flush_count == 3 immediately after Flush() returns (https://github.com/facebook/rocksdb/actions/runs/29976431449). It is also long-standing behavior that other tests have worked around with TEST_WaitForBackgroundWork().

This adds an opt-in FlushOptions::listener_wait (default false). When set together with wait=true, Flush() does not return until the OnFlushCompleted callbacks for the flushed memtables have finished. Default behavior is unchanged.

Implementation: MemTableList gains a per-column-family num_pending_flush_notifications_ counter (guarded by the DB mutex). The background flush thread reserves a pending notification at flush-commit time -- before the mutex is released to run the callbacks -- and releases it after they return, in both the single-CF (FlushMemTableToOutputFile) and atomic (AtomicFlushMemTablesToOutputFiles) paths. WaitForFlushMemTables treats a CF as finished only when its normal predicate holds and the counter is zero. Because the memtables are removed and the counter incremented under one continuous mutex hold (and, for atomic flush, all CFs are reserved before the per-CF notify loop starts releasing the mutex), a listener_wait waiter can never observe the flush as finished before the callbacks complete.

The counter is per-CF rather than per-flush, so a listener_wait waiter can wait somewhat longer than strictly necessary: under rapid flushing it may block until an unrelated, later flush's OnFlushCompleted on the same CF also drains (e.g. a waiter satisfied by GetEarliestMemTableID() advancing still waits for the whole CF's pending notifications). This can only over-wait, never return early, and is tolerated in favor of implementation simplicity; a per-memtable-id watermark could tighten it if it ever matters.

To keep the counter balanced against future edits, the release uses an RAII Defer (runs on every exit path) and ~MemTableList asserts the counter has drained to zero; SubPendingFlushNotifications asserts against underflow. A reservation is taken only when a callback will actually fire (committed flush info non-empty, not a mempurge, CF not dropped, listeners registered).

Also adds the C API rocksdb_flushoptions_set/get_listener_wait (regenerated via tools/c_api_gen) and a DBImpl::TEST_FlushMemTableWithListenerWait() helper.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/14992

Test Plan:
New db_flush_test cases ListenerWaitWaitsForOnFlushCompleted and ListenerWaitAtomicFlushWaitsForAllOnFlushCompleted use a listener that blocks inside OnFlushCompleted plus spurious bg_cv_ wakeups to deterministically verify that Flush(wait=true, listener_wait=true) does not return until the callback (all CFs, for atomic flush) has finished; the atomic case guards the per-CF mutex-release gap in the notify loop.

Converted existing racy/worked-around cases to the new option: c_test table_filter_listener_metadata, listener_test OnSingleDBFlushTest and MultiDBMultiListeners, and db_flush_test FireOnFlushCompletedAfterCommittedResult (the last previously relied on TEST_WaitForBackgroundWork()). The auto-generated C API roundtrip test covers the new flushoptions field.

db_stress StressTest::TestFlush now sets listener_wait on a hard-coded 1 in 4 of its manual flushes (both the atomic and non-atomic branches), so the crash test exercises the new path with the DbStressListener registered.

Reviewed By: jaykorean

Differential Revision: D113425407

Pulled By: pdillinger

fbshipit-source-id: 6fd0f5bc93fabaccd8010c2fead1d93c4c44ccfb
2026-07-24 09:36:04 -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
4707775ae9 Fix GetContext status propagation and blob-backed wide-column merge operands (#14640)
Summary:
- propagate lower-level read and merge failures through `GetContext` via `read_status`, so `Get` and `GetEntity` preserve the original error instead of synthesizing `Corruption` when blob-backed reads or merge resolution fail
- teach `GetMergeOperands` to resolve blob-backed default columns from wide-column entities, covering both the direct base-value path and the merge-plus-base path
- add regression coverage for blob-read IO errors during `Get`/`GetEntity` merge resolution and for `GetMergeOperands` on blob-backed wide-column entities
- fix the `DBFlushTest.MemPurgeCorrectLogNumberAndSSTFileCreation` test race by waiting for flush callbacks and cleaning up sync points

## Testing

- `make db_blob_basic_test -j14`
- `/usr/bin/perl -e 'alarm shift; exec ARGV' 60 ./db_blob_basic_test --gtest_filter='DBBlobBasicTest/DBBlobBasicIOErrorTest.GetBlob_IOError/*:DBBlobBasicTest/DBBlobBasicIOErrorTest.GetEntityMergeWithBlobBaseIOError/*'`

## Task
T265824017, T265415808

Pull Request resolved: https://github.com/facebook/rocksdb/pull/14640

Reviewed By: anand1976

Differential Revision: D101690700

Pulled By: xingbowang

fbshipit-source-id: 2b6fc357b37a01efa72a2d54dcff55be8992f42a
2026-05-12 15:29:27 -07:00
Peter Dillinger
795f3bd61f Fix check-sources.sh non-ASCII check and remove non-ASCII from sources (#14729)
Summary:
The non-ASCII character check in check-sources.sh used git grep -P (Perl regex), which requires git compiled with PCRE support. On systems without it, the command fails with exit code 128, which is != 1 (no match), so the check always reported a violation -- effectively dead.

Even in CI where git has PCRE2 support, the check was silently broken: git grep -P uses PCRE2 in UTF mode by default, which interprets [\x80-\xFF] as a Unicode codepoint range (U+0080 to U+00FF). Characters like em-dash (U+2014), arrows (U+2192), and math symbols (U+2248, etc.) fall outside that range and were not detected. Only Latin-1 Supplement characters (U+0080-U+00FF) would have been caught.

Replace with LC_ALL=C git grep using bash $'[\x80-\xff]' literal byte range, which works with basic regex in the C locale, and replace all non-ASCII characters in non-excluded source files:
- em-dash to --
- arrow to ->
- math symbols to ASCII equivalents (~=, <=, >=)
- box-drawing characters to ASCII art

Also exclude .github/ from the check, as scripts there can use non-ascii without disrupting RocksDB builds on non-UTF-8 systems.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/14729

Test Plan: manual / CI (make check-sources passes clean)

Reviewed By: hx235

Differential Revision: D104692574

Pulled By: pdillinger

fbshipit-source-id: 1d884c21056dcd83558b825a04b867f1c08e3f45
2026-05-11 17:02:22 -07:00
Josh Kang
03e5a0b9a8 Fix range tombstone conversion + ingest sst and re-enable crash tests (#14654)
Summary:
Fixes a correctness bug in read-path range-tombstone synthesis when it races with `IngestExternalFile`. The synthesis path could insert a tombstone into the active memtable at a snapshot's sequence number, while ingestion installed an L0 SST at `LastSequence + 1` — a higher seqno than the synthesized tombstone. This breaks the main assumption of range tombstone reads that all lower levels have lower seqno.

The fix introduces a per-CF `port::RWMutex` (`ColumnFamilyData::ingest_sst_lock_`) plus a per-memtable `ingest_seqno_barrier_`. Ingestion takes the read lock and range tombstone synthesis **tries** to take a write lock.

If iterator lock is successful, then we have a new updated barrier seqno that we can validate the iterator seqno against. An added benefit is we no longer need to gate against empty memtable. This was originally added as an easy fix to prevent memtables from being inserted into while ingestion was happening.

## The bug, by example

`ReadPathRangeTombstoneTest.NewerPointInOlderFileStillVisible` (`db/db_iterator_test.cc:6929`):

1. L0 file `b@1, c@2, d@3`, then L0 file `Delete(b)4, Delete(c)5`.
2. Active memtable: `Put(z)6`. Snapshot taken at seq 6.
3. `IngestExternalFile({c → "vc_live"})` → installed at L0 with seq 7.
4. Iterator at snap 6 walks the deletion run and synthesizes `[b, d) @ seq 6` into the active memtable via `MemTable::AddLogicallyRedundantRangeTombstone`.
5. `Get("c")` at the latest snapshot: memtable returns covering tombstone (seq 6), `Version::Get` short-circuits, **never reads `c@7`** — returns `NotFound` instead of `"vc_live"`.

The invariant `Version::Get` relies on (memtable seqs ≥ any L0 seq for the same key) is broken because synthesis writes at the *snapshot's* seq while ingestion writes at `LastSequence + 1`.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/14654

Test Plan:
- Updated regression test
- Re-enable crashtests and manually run

| Flavor | Jobs |
|---|---:|
| `fbcode_blackbox_crash_test` | 200 |
| `fbcode_whitebox_crash_test` | 30 |
| `fbcode_asan_blackbox_crash_test` | 30 |
| `fbcode_tsan_blackbox_crash_test` | 30 |
| `fbcode_crash_test_with_atomic_flush` | 30 |
| `fbcode_crash_test_with_wc_txn` | 30 |
| `fbcode_crash_test_with_ts` | 30 |
| **Total** | **380** |

Reviewed By: xingbowang

Differential Revision: D102044512

Pulled By: joshkang97

fbshipit-source-id: 0c69187595edc5a5fa80be24bffdba710a92e56e
2026-04-23 18:59:14 -07:00
Peter Dillinger
92cedd58af Fix table cache leak when flush install fails (#14577)
Summary:
When BuildTable succeeds during flush, it caches the output SST file in the table cache for subsequent user reads (builder.cc:460). If the flush then fails to install — e.g., LogAndApply MANIFEST I/O error, CF dropped, or shutdown — the cache entry was never evicted. BuildTable only cleans up its own failures (builder.cc:511), not failures in the install path.

The FindObsoleteFiles full-scan backstop would normally catch this by finding the orphan file on disk and evicting the cache entry. However, under crash test metadata read fault injection
(open_metadata_read_fault_one_in), GetChildren fails and the orphan is never found, causing the TEST_VerifyNoObsoleteFilesCached assertion to fire during Close().

This is the same class of bug previously fixed in the compaction path by https://github.com/facebook/rocksdb/issues/14469 (Run failure) and https://github.com/facebook/rocksdb/issues/14549 (Install failure), but in the flush path which had no analogous cleanup.

Fix: call TableCache::ReleaseObsolete in FlushJob::Run() when the flush fails after BuildTable succeeded (meta_.fd.GetFileSize() > 0).

Pull Request resolved: https://github.com/facebook/rocksdb/pull/14577

Test Plan:
New unit test DBFlushTest.LeakedTableCacheEntryOnFlushInstallFailure:
- Injects failure after BuildTable via sync point, deactivates filesystem to prevent backstop cleanup
- Without fix: assertion fires ("Leaked table cache entry")
- With fix: passes
```
COMPILE_WITH_ASAN=1 make -j db_flush_test
./db_flush_test --gtest_filter="DBFlushTest.LeakedTableCacheEntry*"
[  PASSED  ] 1 test.
```

Existing compaction leak tests still pass:
```
COMPILE_WITH_ASAN=1 make -j db_compaction_test
./db_compaction_test --gtest_filter="*LeakedTableCacheEntry*"
[  PASSED  ] 2 tests.
```

Reviewed By: xingbowang

Differential Revision: D99692601

Pulled By: pdillinger

fbshipit-source-id: ff5aa1ad165b3abec915844f97f6af9e59d85774
2026-04-06 15:21:58 -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
Maciej Szeszko
071b5eff7a Fix MemPurge memtable ID ordering assertion (#14424)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/14424

## Context

`MemPurge` releases db_mutex_ to do its merge work and re-acquires it before adding the output memtable to the immutable list. During this window, concurrent writers can fill the active memtable and trigger a switch, adding a new immutable memtable with a higher ID. `MemPurge` then assigns its output memtable the stale ID from mems_.back() (the newest memtable in the original flush batch), which is now lower than the front of the immutable list, violating the ordering assertion in `MemTableListVersion::AddMemTable `.

## Fix

After re-acquiring db_mutex_, use `std::max(mems_.back()->GetID(), imm()->GetLatestMemTableID())` so the output memtable's ID is never lower than any existing immutable memtable. Two `TEST_SYNC_POINT`s are added to the `MemPurge` success path to enable deterministic repro.

Reviewed By: pdillinger

Differential Revision: D94756638

fbshipit-source-id: 2e9e15b4285dc6b996c8744795228180dbd73ed3
2026-03-05 22:32:47 -08:00
Xingbo Wang
2dc6d6f765 Propagate builder error when flush produces empty output (#14418)
Summary:
Propagate builder error when flush produces empty output

When write fault injection causes the table builder to enter an error
state during flush, all subsequent Add() calls return early (ok() is
false), leaving the builder empty (IsEmpty() == true). Previously,
BuildTable() would call builder->Abandon() but not propagate the
builder's error status to 's', leaving it OK. This caused the downstream
key count validation in flush_job.cc to fire a misleading Corruption
error ('Number of keys in flush output SST files does not match...'),
which the stress test harness couldn't identify as a retryable injected
fault error, leading to SafeTerminate().

This started failing recently because ('Separate keys and
values in data blocks', ) introduced a new SST
block format (separate_key_value_in_data_block) that stores keys and
values in separate sections within data blocks. This format requires
additional write operations during Flush() inside the table builder,
increasing the probability that write fault injection
(--write_fault_one_in=128) hits a data block write and puts the builder
into an error state before any entries are committed. The bug in
BuildTable() existed before, but was rarely triggered because the old
interleaved block format had fewer write points susceptible to fault
injection during the critical Add() path.

Fix: After builder->Abandon(), propagate the builder's error status to
's' when the builder is empty due to an internal error. This ensures the
actual IOError from write fault injection is reported, which the stress
test can properly handle via IsErrorInjectedAndRetryable().

The analysis was based on stack trace. However, it would be great
if we could get direct evidence from fault injection.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/14418

Test Plan: Unit test

Reviewed By: hx235

Differential Revision: D95121070

Pulled By: xingbowang

fbshipit-source-id: cfb513bd744ac34ac90cda11c1cbe49a9d0a7c6c
2026-03-05 14:18:08 -08:00
Xingbo Wang
c311362ab6 Reapply "Fix flaky unit test in mempurge. (#14377)" (#14381) (#14385)
Summary:
This reverts commit 4213f9e14a.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/14385

Reviewed By: archang19

Differential Revision: D94367585

Pulled By: xingbowang

fbshipit-source-id: 6c125b23ffa74e4113ef04847ccdefa015d7db35
2026-02-25 12:39:45 -08:00
xingbowang
4213f9e14a Revert "Fix flaky unit test in mempurge. (#14377)" (#14381)
Summary:
This reverts commit e7c3391640.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/14381

Reviewed By: archang19

Differential Revision: D94244056

Pulled By: xingbowang

fbshipit-source-id: 0fffa8ce15dab4ece7b37e3839368fb399cd5734
2026-02-24 10:56:10 -08:00
Xingbo Wang
e7c3391640 Fix flaky unit test in mempurge. (#14377)
Summary:
Add proper synchronization in mempurge unit test to fix flaky test

Pull Request resolved: https://github.com/facebook/rocksdb/pull/14377

Test Plan: Unit test

Reviewed By: nmk70

Differential Revision: D94153290

Pulled By: xingbowang

fbshipit-source-id: 2a2cdcc6f8b5500bb5e68d2d223255cd1a5660b3
2026-02-23 22:55:04 -08:00
Peter Dillinger
d3817f058d Remove deprecated DB::Open raw pointer variants (and more) (#14335)
Summary:
and remove deprecated DB::MaxMemCompactionLevel(). In the process of pushing through a relatively clean refactoring of uses of the old functions, some other minor public APIs are also migrated from raw DB pointers to unique_ptr.

Claude did pretty much all the work, but requiring dozens of prompts to actually push through relatively clean phase out of raw DB pointers from what needed to be touched, and leaving that code in better shape. (Hundreds of `DB*` still remain all over the place even outside C and Java bindings.)

Pull Request resolved: https://github.com/facebook/rocksdb/pull/14335

Test Plan: existing tests; no functional changes intended

Reviewed By: xingbowang, mszeszko-meta

Differential Revision: D93523820

Pulled By: pdillinger

fbshipit-source-id: e4ca22ad81cd2cfe91122d7507d7ca34fe03d043
2026-02-17 23:33:39 -08:00
Pierre Moulon
8b6f98cdb4 Fixing typos in comments and documentation (#14205)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/14205

Fixed various spelling errors throughout RocksDB codebase including:
- assiciated → associated
- disucssion → discussion
- satisifed → satisfied
- supoort → support
- capacit_limit → capacity_limit
- direclty → directly
- diable → disable
- opeartions → operations
- paylaod → payload
- happenning/happended → happening/happened
- intialized/initiallized → initialized
- asynchronosuly → asynchronously
- exisiting → existing
- persitence → persistence
- and several others

These changes are in comments, test code, and documentation only.

Reviewed By: pdillinger

Differential Revision: D89800154

fbshipit-source-id: 1681ec95a687b038c2bad48856f1abb4dbeb42cf
2026-01-02 17:25:57 -08:00
Xingbo Wang
742741b175 Support Super Block Alignment (#13909)
Summary:
Pad block based table based on super block alignment

Pull Request resolved: https://github.com/facebook/rocksdb/pull/13909

Test Plan:
Unit Test

No impact on perf observed due to change in the inner loop of flush.

upstream/main branch 202.15 MB/s
```
for i in `seq 1 10`; do ./db_bench --benchmarks=fillseq -num=10000000 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=1000 -fifo_compaction_allow_compaction=0 -disable_wal -write_buffer_size=12000000 -format_version=7 >> /tmp/x1 2>&1; grep fillseq /tmp/x1 | grep -Po "\d+\.\d+ MB/s" | grep -Po "\d+\.\d+" | awk '{sum+=$1} END {print sum/NR}'
```

After the change without super block alignment 203.44 MB/s
```
for i in `seq 1 10`; do ./db_bench --benchmarks=fillseq -num=10000000 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=1000 -fifo_compaction_allow_compaction=0 -disable_wal -write_buffer_size=12000000 -format_version=7 >> /tmp/x1 2>&1
```

After the change with super block alignment 204.47 MB/s
```
for i in `seq 1 10`; do ./db_bench --benchmarks=fillseq -num=10000000 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=1000 -fifo_compaction_allow_compaction=0 -disable_wal -write_buffer_size=12000000 -format_version=7 --super_block_alignment_size=131072 --super_block_alignment_max_padding_size=4096 >> /tmp/x1 2>&1;
```

Reviewed By: pdillinger

Differential Revision: D83068913

Pulled By: xingbowang

fbshipit-source-id: eecd65088ab3e9dbc7902aab8c2580f1bc8575df
2025-10-01 18:20:35 -07:00
Hui Xiao
613e1a9a38 Verify flush output file record count + minor clean up (#13556)
Summary:
**Context/Summary:**
Similar to 0a43d8a261, this is to verify flush output file contains the exact number of keys (represented by its `TableProperties::num_entries`) as added to table builder for block-based and plain table format. The implementation reuses a temporary compaction stats to record output record and existing input record (with some refactoring)

**Bonus:**
following 0a43d8a261 (r154313564), limit compaction output record count check within block based table and plain table format as well as removing extra test setting; fix some typo

Pull Request resolved: https://github.com/facebook/rocksdb/pull/13556

Test Plan: New test

Reviewed By: jaykorean

Differential Revision: D73229644

Pulled By: hx235

fbshipit-source-id: 2a7796450048b3bcb2d5c38f2b5fc6b53e4aae37
2025-04-23 14:52:56 -07:00
Peter Dillinger
7127119ae9 Refactor SyncWAL and SyncClosedLogs for code sharing (#12707)
Summary:
These functions were very similar and did not make sense for maintaining separately. This is not a pure refactor but I think bringing the behaviors closer together should reduce long term risk of unintentionally divergent behavior. This change is motivated by some forthcoming WAL handling fixes for Checkpoint and Backups.

* Sync() is always used on closed WALs, like the old SyncClosedWals. SyncWithoutFlush() is only used on the active (maybe) WAL. Perhaps SyncWithoutFlush() should be used whenever available, but I don't know which is preferred, as the previous state of the code was inconsistent.
* Syncing the WAL dir is selective based on need, like old SyncWAL, rather than done always like old SyncClosedLogs. This could be a performance improvement that was never applied to SyncClosedLogs but now is. We might still sync the dir more times than necessary in the case of parallel SyncWAL variants, but on a good FileSystem that's probably not too different performance-wise from us implementing something to have threads wait on each other.

Cosmetic changes:

* Rename internal function SyncClosedLogs to SyncClosedWals
* Merging the sync points into the common implementation between the two entry points isn't pretty, but should be fine.

Recommended follow-up:

* Clean up more confusing naming like log_dir_synced_

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12707

Test Plan: existing tests

Reviewed By: anand1976

Differential Revision: D57870856

Pulled By: pdillinger

fbshipit-source-id: 5455fba016d25dd5664fa41b253f18db2ca8919a
2024-05-30 14:53:13 -07:00
yuzhangyu@fb.com
1cfdece85d Run internal cpp modernizer on RocksDB repo (#12398)
Summary:
When internal cpp modernizer attempts to format rocksdb code, it will replace macro `ROCKSDB_NAMESPACE`  with its default definition `rocksdb` when collapsing nested namespace. We filed a feedback for the tool T180254030 and the team filed a bug for this: https://github.com/llvm/llvm-project/issues/83452. At the same time, they suggested us to run the modernizer tool ourselves so future auto codemod attempts will be smaller. This diff contains:

Running
`xplat/scripts/codemod_service/cpp_modernizer.sh`
in fbcode/internal_repo_rocksdb/repo (excluding some directories in utilities/transactions/lock/range/range_tree/lib that has a non meta copyright comment)
without swapping out the namespace macro `ROCKSDB_NAMESPACE`

Followed by RocksDB's own
`make format`
Pull Request resolved: https://github.com/facebook/rocksdb/pull/12398

Test Plan: Auto tests

Reviewed By: hx235

Differential Revision: D54382532

Pulled By: jowlyzhang

fbshipit-source-id: e7d5b40f9b113b60e5a503558c181f080b9d02fa
2024-03-04 10:08:32 -08:00
Peter Dillinger
54cb9c77d9 Prefer static_cast in place of most reinterpret_cast (#12308)
Summary:
The following are risks associated with pointer-to-pointer reinterpret_cast:
* Can produce the "wrong result" (crash or memory corruption). IIRC, in theory this can happen for any up-cast or down-cast for a non-standard-layout type, though in practice would only happen for multiple inheritance cases (where the base class pointer might be "inside" the derived object). We don't use multiple inheritance a lot, but we do.
* Can mask useful compiler errors upon code change, including converting between unrelated pointer types that you are expecting to be related, and converting between pointer and scalar types unintentionally.

I can only think of some obscure cases where static_cast could be troublesome when it compiles as a replacement:
* Going through `void*` could plausibly cause unnecessary or broken pointer arithmetic. Suppose we have
`struct Derived: public Base1, public Base2`.  If we have `Derived*` -> `void*` -> `Base2*` -> `Derived*` through reinterpret casts, this could plausibly work (though technical UB) assuming the `Base2*` is not dereferenced. Changing to static cast could introduce breaking pointer arithmetic.
* Unnecessary (but safe) pointer arithmetic could arise in a case like `Derived*` -> `Base2*` -> `Derived*` where before the Base2 pointer might not have been dereferenced. This could potentially affect performance.

With some light scripting, I tried replacing pointer-to-pointer reinterpret_casts with static_cast and kept the cases that still compile. Most occurrences of reinterpret_cast have successfully been changed (except for java/ and third-party/). 294 changed, 257 remain.

A couple of related interventions included here:
* Previously Cache::Handle was not actually derived from in the implementations and just used as a `void*` stand-in with reinterpret_cast. Now there is a relationship to allow static_cast. In theory, this could introduce pointer arithmetic (as described above) but is unlikely without multiple inheritance AND non-empty Cache::Handle.
* Remove some unnecessary casts to void* as this is allowed to be implicit (for better or worse).

Most of the remaining reinterpret_casts are for converting to/from raw bytes of objects. We could consider better idioms for these patterns in follow-up work.

I wish there were a way to implement a template variant of static_cast that would only compile if no pointer arithmetic is generated, but best I can tell, this is not possible. AFAIK the best you could do is a dynamic check that the void* conversion after the static cast is unchanged.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12308

Test Plan: existing tests, CI

Reviewed By: ltamasi

Differential Revision: D53204947

Pulled By: pdillinger

fbshipit-source-id: 9de23e618263b0d5b9820f4e15966876888a16e2
2024-02-07 10:44:11 -08:00
Peter Dillinger
a771a47a1b Fix leak or crash on failure in automatic atomic flush (#12176)
Summary:
Through code inspection in debugging an apparent leak of ColumnFamilyData in the crash test, I found a case where too few UnrefAndTryDelete() could be called on a cfd. This fixes that case, which would fail like this in the new unit test:

```
db_flush_test: db/column_family.cc:1648:
rocksdb::ColumnFamilySet::~ColumnFamilySet(): Assertion `last_ref' failed.
```

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12176

Test Plan: unit test added

Reviewed By: cbi42

Differential Revision: D52417071

Pulled By: pdillinger

fbshipit-source-id: 4ee33c918409cf9c1968f138e273d3347a6cc8e5
2023-12-26 11:04:25 -08:00
Changyu Bi
d5bc30befa Enforce status checking after Valid() returns false for IteratorWrapper (#11975)
Summary:
... when compiled with ASSERT_STATUS_CHECKED = 1.

The main change is in iterator_wrapper.h. The remaining changes are just fixing existing unit tests. Adding this check to IteratorWrapper gives a good coverage as the class is used in many places, including child iterators under merging iterator, merging iterator under DB iter, file_iter under level iterator, etc. This change can catch the bug fixed in https://github.com/facebook/rocksdb/issues/11782.

Future follow up: enable `ASSERT_STATUS_CHECKED=1` for stress test and for DEBUG_LEVEL=0.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11975

Test Plan:
* `ASSERT_STATUS_CHECKED=1 DEBUG_LEVEL=2 make -j32 J=32 check`
* I tried to run stress test with `ASSERT_STATUS_CHECKED=1`, but there are a lot of existing stress code that ignore status checking, and fail without the change in this PR. So defer that to a follow up task.

Reviewed By: ajkr

Differential Revision: D50383790

Pulled By: cbi42

fbshipit-source-id: 1a28ce0f5fdf1890f93400b26b3b1b3a287624ce
2023-10-18 09:38:38 -07:00
Changyu Bi
0086809601 Fix a bug with atomic_flush that causes DB to stuck after a flush failure (#11872)
Summary:
With atomic_flush=true, a flush job with younger memtables wait for older memtables to be installed before install its memtables. If the flush for older memtables failed, auto-recovery starts a resume thread which can becomes stuck waiting for all background work to finish (including the flush for younger memtables). If a non-recovery flush starts now and tries to flush, it can make the situation worse since it will fail due to background error but never rollback its memtable: 269478ee46/db/db_impl/db_impl_compaction_flush.cc (L725) This prevents any future flush to pick old memtables.

A more detailed repro is in unit test.

This PR fixes this issue by
1. Ensure we rollback memtables if an atomic flush fails due to background error
2. When there is a background error, abort atomic flushes that are waiting for older memtables to be installed
3. Do not schedule non-recovery flushes when there is a background error that stops background work

There was another issue with atomic_flush=true where DB can hang during DB close, see more in #11867. The fix in this PR, specifically fix 2 above, should be enough to resolve it too.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11872

Test Plan: new unit test.

Reviewed By: jowlyzhang

Differential Revision: D49556867

Pulled By: cbi42

fbshipit-source-id: 4a0210ff28a8552a99ece7fbb0f574fd24b4da3f
2023-09-22 16:43:50 -07:00
Changyu Bi
b927ba5936 Rollback other pending memtable flushes when a flush fails (#11865)
Summary:
when atomic_flush=false, there are certain cases where we try to install memtable results with already deleted SST files. This can happen when the following sequence events happen:
```
Start Flush0 for memtable M0 to SST0
Start Flush1 for memtable M1 to SST1
Flush 1 returns OK, but don't install to MANIFEST and let whoever flushes M0 to take care of it
Flush0 finishes with a retryable IOError, it rollbacks M0, (incorrectly) does not rollback M1, and deletes SST0 and SST1
Starts Flush2 for M0, it does not pick up M1 since it thought M1 is flushed
Flush2 writes SST2 and finishes OK, tries to install SST2 and SST1
Error opening SST1 since it's already deleted with an  error message like the following:

IO error: No such file or directory: While open a file for random read: /tmp/rocksdbtest-501/db_flush_test_3577_4230653031040984171/000011.sst: No such file or directory
```

This happens since:
1. We currently only rollback the memtables that we are flushing in a flush job when atomic_flush=false.
2. Pending output SSTs from previous flushes are deleted since a pending file number is released whenever a flush job is finished no matter of flush status: f42e70bf56/db/db_impl/db_impl_compaction_flush.cc (L3161)

This PR fixes the issue by rollback these pending flushes.

There is another issue where if a new flush for new memtable starts and finishes after Flush0 finishes. Its output may also be deleted (see more in unit test). It is fixed by checking bg error status before installing a memtable result, and rollback if there is an error.

There is a more efficient fix where we just don't release the pending file output number for flushes that delegate installation. It is more efficient since it does not have to rewrite the flush output file. With the fix in this PR, we can end up with a giant file if a lot of memtables are being flushed together. However, the more efficient fix is a bit more complicated to implement (requires associating such pending file numbers with flush job/memtables) and is more risky since it changes normal flush code path.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11865

Test Plan: * Added repro unit tests.

Reviewed By: anand1976

Differential Revision: D49484922

Pulled By: cbi42

fbshipit-source-id: 25b536c08f4e02e7f1d0f86571663737d2b5d53d
2023-09-21 15:31:29 -07:00
Changyu Bi
76ed9a3990 Add missing status check when compiling with ASSERT_STATUS_CHECKED=1 (#11686)
Summary:
It seems the flag `-fno-elide-constructors` is incorrectly overwritten in Makefile by 9c2ebcc2c3/Makefile (L243)
Applying the change in PR https://github.com/facebook/rocksdb/issues/11675 shows a lot of missing status checks. This PR adds the missing status checks.

Most of changes are just adding asserts in unit tests. I'll add pr comment around more interesting changes that need review.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11686

Test Plan: change Makefile as in https://github.com/facebook/rocksdb/issues/11675, and run `ASSERT_STATUS_CHECKED=1 TEST_UINT128_COMPAT=1 ROCKSDB_MODIFY_NPHASH=1 LIB_MODE=static OPT="-DROCKSDB_NAMESPACE=alternative_rocksdb_ns" make V=1 -j24 J=24 check`

Reviewed By: hx235

Differential Revision: D48176132

Pulled By: cbi42

fbshipit-source-id: 6758946cfb1c6ff84c4c1e0ca540d05e6fc390bd
2023-08-09 15:46:44 -07:00
Hui Xiao
11cb6af6e5 Fix bug of prematurely excluded CF in atomic flush contains unflushed data that should've been included in the atomic flush (#11148)
Summary:
**Context:**
Atomic flush should guarantee recoverability of all data of seqno up to the max seqno of the flush. It achieves this by ensuring all such data are flushed by the time this atomic flush finishes through `SelectColumnFamiliesForAtomicFlush()`. However, our crash test exposed the following case where an excluded CF from an atomic flush contains unflushed data of seqno less than the max seqno of that atomic flush and loses its data with `WriteOptions::DisableWAL=true` in face of a crash right after the atomic flush finishes .
```
./db_stress --preserve_unverified_changes=1 --reopen=0 --acquire_snapshot_one_in=0 --adaptive_readahead=1 --allow_data_in_errors=True --async_io=1 --atomic_flush=1 --avoid_flush_during_recovery=0 --avoid_unnecessary_blocking_io=0 --backup_max_size=104857600 --backup_one_in=0 --batch_protection_bytes_per_key=0 --block_size=16384 --bloom_bits=15 --bottommost_compression_type=none --bytes_per_sync=262144 --cache_index_and_filter_blocks=0 --cache_size=8388608 --cache_type=lru_cache --charge_compression_dictionary_building_buffer=0 --charge_file_metadata=1 --charge_filter_construction=0 --charge_table_reader=0 --checkpoint_one_in=0 --checksum_type=kXXH3 --clear_column_family_one_in=0 --compact_files_one_in=0 --compact_range_one_in=0 --compaction_pri=1 --compaction_ttl=100 --compression_max_dict_buffer_bytes=134217727 --compression_max_dict_bytes=16384 --compression_parallel_threads=1 --compression_type=lz4hc --compression_use_zstd_dict_trainer=0 --compression_zstd_max_train_bytes=0 --continuous_verification_interval=0 --data_block_index_type=0 --db=$db --db_write_buffer_size=1048576 --delpercent=4 --delrangepercent=1 --destroy_db_initially=0 --detect_filter_construct_corruption=0 --disable_wal=1 --enable_compaction_filter=0 --enable_pipelined_write=0 --expected_values_dir=$exp --fail_if_options_file_error=0 --fifo_allow_compaction=0 --file_checksum_impl=none --flush_one_in=0 --format_version=5 --get_current_wal_file_one_in=0 --get_live_files_one_in=100 --get_property_one_in=0 --get_sorted_wal_files_one_in=0 --index_block_restart_interval=2 --index_type=0 --ingest_external_file_one_in=0 --initial_auto_readahead_size=524288 --iterpercent=10 --key_len_percent_dist=1,30,69 --level_compaction_dynamic_level_bytes=True --long_running_snapshots=1 --manual_wal_flush_one_in=100 --mark_for_compaction_one_file_in=0 --max_auto_readahead_size=0 --max_background_compactions=20 --max_bytes_for_level_base=10485760 --max_key=10000 --max_key_len=3 --max_manifest_file_size=1073741824 --max_write_batch_group_size_bytes=64 --max_write_buffer_number=3 --max_write_buffer_size_to_maintain=0 --memtable_prefix_bloom_size_ratio=0.01 --memtable_protection_bytes_per_key=4 --memtable_whole_key_filtering=0 --memtablerep=skip_list --min_write_buffer_number_to_merge=2 --mmap_read=1 --mock_direct_io=False --nooverwritepercent=1 --num_file_reads_for_auto_readahead=0 --open_files=-1 --open_metadata_write_fault_one_in=0 --open_read_fault_one_in=0 --open_write_fault_one_in=0 --ops_per_thread=100000000 --optimize_filters_for_memory=1 --paranoid_file_checks=1 --partition_filters=0 --partition_pinning=3 --pause_background_one_in=0 --periodic_compaction_seconds=100 --prefix_size=8 --prefixpercent=5 --prepopulate_block_cache=0 --preserve_internal_time_seconds=3600 --progress_reports=0 --read_fault_one_in=32 --readahead_size=16384 --readpercent=50 --recycle_log_file_num=0 --ribbon_starting_level=6 --secondary_cache_fault_one_in=0 --set_options_one_in=10000 --snapshot_hold_ops=100000 --sst_file_manager_bytes_per_sec=104857600 --sst_file_manager_bytes_per_truncate=1048576 --stats_dump_period_sec=10 --subcompactions=1 --sync=0 --sync_fault_injection=0 --target_file_size_base=524288 --target_file_size_multiplier=2 --test_batches_snapshots=0 --top_level_index_pinning=0 --unpartitioned_pinning=1 --use_direct_io_for_flush_and_compaction=0 --use_direct_reads=0 --use_full_merge_v1=0 --use_merge=0 --use_multiget=1 --use_put_entity_one_in=0 --user_timestamp_size=0 --value_size_mult=32 --verify_checksum=1 --verify_checksum_one_in=0 --verify_db_one_in=1000 --verify_sst_unique_id_in_manifest=1 --wal_bytes_per_sync=524288 --wal_compression=none --write_buffer_size=524288 --write_dbid_to_manifest=1 --write_fault_one_in=0 --writepercent=30 &
    pid=$!
    sleep 0.2
    sleep 10
    kill $pid
    sleep 0.2
./db_stress --ops_per_thread=1 --preserve_unverified_changes=1 --reopen=0 --acquire_snapshot_one_in=0 --adaptive_readahead=1 --allow_data_in_errors=True --async_io=1 --atomic_flush=1 --avoid_flush_during_recovery=0 --avoid_unnecessary_blocking_io=0 --backup_max_size=104857600 --backup_one_in=0 --batch_protection_bytes_per_key=0 --block_size=16384 --bloom_bits=15 --bottommost_compression_type=none --bytes_per_sync=262144 --cache_index_and_filter_blocks=0 --cache_size=8388608 --cache_type=lru_cache --charge_compression_dictionary_building_buffer=0 --charge_file_metadata=1 --charge_filter_construction=0 --charge_table_reader=0 --checkpoint_one_in=0 --checksum_type=kXXH3 --clear_column_family_one_in=0 --compact_files_one_in=0 --compact_range_one_in=0 --compaction_pri=1 --compaction_ttl=100 --compression_max_dict_buffer_bytes=134217727 --compression_max_dict_bytes=16384 --compression_parallel_threads=1 --compression_type=lz4hc --compression_use_zstd_dict_trainer=0 --compression_zstd_max_train_bytes=0 --continuous_verification_interval=0 --data_block_index_type=0 --db=$db --db_write_buffer_size=1048576 --delpercent=4 --delrangepercent=1 --destroy_db_initially=0 --detect_filter_construct_corruption=0 --disable_wal=1 --enable_compaction_filter=0 --enable_pipelined_write=0 --expected_values_dir=$exp --fail_if_options_file_error=0 --fifo_allow_compaction=0 --file_checksum_impl=none --flush_one_in=0 --format_version=5 --get_current_wal_file_one_in=0 --get_live_files_one_in=100 --get_property_one_in=0 --get_sorted_wal_files_one_in=0 --index_block_restart_interval=2 --index_type=0 --ingest_external_file_one_in=0 --initial_auto_readahead_size=524288 --iterpercent=10 --key_len_percent_dist=1,30,69 --level_compaction_dynamic_level_bytes=True --long_running_snapshots=1 --manual_wal_flush_one_in=100 --mark_for_compaction_one_file_in=0 --max_auto_readahead_size=0 --max_background_compactions=20 --max_bytes_for_level_base=10485760 --max_key=10000 --max_key_len=3 --max_manifest_file_size=1073741824 --max_write_batch_group_size_bytes=64 --max_write_buffer_number=3 --max_write_buffer_size_to_maintain=0 --memtable_prefix_bloom_size_ratio=0.01 --memtable_protection_bytes_per_key=4 --memtable_whole_key_filtering=0 --memtablerep=skip_list --min_write_buffer_number_to_merge=2 --mmap_read=1 --mock_direct_io=False --nooverwritepercent=1 --num_file_reads_for_auto_readahead=0 --open_files=-1 --open_metadata_write_fault_one_in=0 --open_read_fault_one_in=0 --open_write_fault_one_in=0 --ops_per_thread=100000000 --optimize_filters_for_memory=1 --paranoid_file_checks=1 --partition_filters=0 --partition_pinning=3 --pause_background_one_in=0 --periodic_compaction_seconds=100 --prefix_size=8 --prefixpercent=5 --prepopulate_block_cache=0 --preserve_internal_time_seconds=3600 --progress_reports=0 --read_fault_one_in=32 --readahead_size=16384 --readpercent=50 --recycle_log_file_num=0 --ribbon_starting_level=6 --secondary_cache_fault_one_in=0 --set_options_one_in=10000 --snapshot_hold_ops=100000 --sst_file_manager_bytes_per_sec=104857600 --sst_file_manager_bytes_per_truncate=1048576 --stats_dump_period_sec=10 --subcompactions=1 --sync=0 --sync_fault_injection=0 --target_file_size_base=524288 --target_file_size_multiplier=2 --test_batches_snapshots=0 --top_level_index_pinning=0 --unpartitioned_pinning=1 --use_direct_io_for_flush_and_compaction=0 --use_direct_reads=0 --use_full_merge_v1=0 --use_merge=0 --use_multiget=1 --use_put_entity_one_in=0 --user_timestamp_size=0 --value_size_mult=32 --verify_checksum=1 --verify_checksum_one_in=0 --verify_db_one_in=1000 --verify_sst_unique_id_in_manifest=1 --wal_bytes_per_sync=524288 --wal_compression=none --write_buffer_size=524288 --write_dbid_to_manifest=1 --write_fault_one_in=0 --writepercent=30 &
    pid=$!
    sleep 0.2
    sleep 40
    kill $pid
    sleep 0.2

Verification failed for column family 6 key 0000000000000239000000000000012B0000000000000138 (56622): value_from_db: , value_from_expected: 4A6331754E4F4C4D42434041464744455A5B58595E5F5C5D5253505156575455, msg: Value not found: NotFound:
Crash-recovery verification failed :(
No writes or ops?
Verification failed :(
```

The bug is due to the following:
- When atomic flush is used, an empty CF is legally [excluded](https://github.com/facebook/rocksdb/blob/7.10.fb/db/db_filesnapshot.cc#L39) in `SelectColumnFamiliesForAtomicFlush` as the first step of `DBImpl::FlushForGetLiveFiles` before [passing](https://github.com/facebook/rocksdb/blob/7.10.fb/db/db_filesnapshot.cc#L42) the included CFDs to `AtomicFlushMemTables`.
- But [later](https://github.com/facebook/rocksdb/blob/7.10.fb/db/db_impl/db_impl_compaction_flush.cc#L2133) in `AtomicFlushMemTables`, `WaitUntilFlushWouldNotStallWrites` will [release the db mutex](https://github.com/facebook/rocksdb/blob/7.10.fb/db/db_impl/db_impl_compaction_flush.cc#L2403), during which data@seqno N can be inserted into the excluded CF and data@seqno M can be inserted into one of the included CFs, where M > N.
- However, data@seqno N in an already-excluded CF is thus excluded from this atomic flush while we seqno N is less than seqno M.

**Summary:**
- Replace `SelectColumnFamiliesForAtomicFlush()`-before-`AtomicFlushMemTables()` with `SelectColumnFamiliesForAtomicFlush()`-after-wait-within-`AtomicFlushMemTables()` so we ensure no write affecting the recoverability of this atomic job (i.e, change to max seqno of this atomic flush or insertion of data with less seqno than the max seqno of the atomic flush to excluded CF) can happen after calling `SelectColumnFamiliesForAtomicFlush()`.
- For above, refactored and clarified comments on `SelectColumnFamiliesForAtomicFlush()` and `AtomicFlushMemTables()` for clearer semantics of passed-in CFDs to atomic-flush

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11148

Test Plan:
- New unit test failed before the fix and passes after
- Make check
- Rehearsal stress test

Reviewed By: ajkr

Differential Revision: D42799871

Pulled By: hx235

fbshipit-source-id: 13636b63e9c25c5895857afc36ea580d57f6d644
2023-03-14 16:53:20 -07:00
sdong
4720ba4391 Remove RocksDB LITE (#11147)
Summary:
We haven't been actively mantaining RocksDB LITE recently and the size must have been gone up significantly. We are removing the support.

Most of changes were done through following comments:

unifdef -m -UROCKSDB_LITE `git grep -l ROCKSDB_LITE | egrep '[.](cc|h)'`

by Peter Dillinger. Others changes were manually applied to build scripts, CircleCI manifests, ROCKSDB_LITE is used in an expression and file db_stress_test_base.cc.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11147

Test Plan: See CI

Reviewed By: pdillinger

Differential Revision: D42796341

fbshipit-source-id: 4920e15fc2060c2cd2221330a6d0e5e65d4b7fe2
2023-01-27 13:14:19 -08:00
Hui Xiao
86fa2592be Fix data race on ColumnFamilyData::flush_reason by letting FlushRequest/Job owns flush_reason instead of CFD (#11111)
Summary:
**Context:**
Concurrent flushes on the same CF can set on `ColumnFamilyData::flush_reason` before each other flush finishes. An symptom is one CF has different flush_reason with others though all of them are in an atomic flush  `db_stress: db/db_impl/db_impl_compaction_flush.cc:423: rocksdb::Status rocksdb::DBImpl::AtomicFlushMemTablesToOutputFiles(const rocksdb::autovector<rocksdb::DBImpl::BGFlushArg>&, bool*, rocksdb::JobContext*, rocksdb::LogBuffer*, rocksdb::Env::Priority): Assertion cfd->GetFlushReason() == cfds[0]->GetFlushReason() failed. `

**Summary:**
Suggested by ltamasi, we now refactor and let FlushRequest/Job to own flush_reason as there is no good way to define `ColumnFamilyData::flush_reason` in face of concurrent flushes on the same CF (which wasn't the case a long time ago when `ColumnFamilyData::flush_reason ` first introduced`)

**Tets:**
- new unit test
- make check
- aggressive crash test rehearsal

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11111

Reviewed By: ajkr

Differential Revision: D42644600

Pulled By: hx235

fbshipit-source-id: 8589c8184869d3415e5b780c887f877818a5ebaf
2023-01-24 09:54:04 -08:00
Andrew Kryczka
5cf6ab6f31 Ran clang-format on db/ directory (#10910)
Summary:
Ran `find ./db/ -type f | xargs clang-format -i`. Excluded minor changes it tried to make on db/db_impl/. Everything else it changed was directly under db/ directory. Included minor manual touchups mentioned in PR commit history.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10910

Reviewed By: riversand963

Differential Revision: D40880683

Pulled By: ajkr

fbshipit-source-id: cfe26cda05b3fb9a72e3cb82c286e21d8c5c4174
2022-11-02 14:34:24 -07:00
Yanqin Jin
edda219fc3 Manual flush with wait=false should not stall when writes stopped (#10001)
Summary:
When `FlushOptions::wait` is set to false, manual flush should not stall forever.

If the database has already stopped writes, then the thread calling `DB::Flush()` with
`FlushOptions::wait=false` should not enter the `DBImpl::write_thread_`.

To prevent this, we should do a check at the beginning and return `TryAgain()`

Resolves: https://github.com/facebook/rocksdb/issues/9892

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10001

Reviewed By: siying

Differential Revision: D36422303

Pulled By: siying

fbshipit-source-id: 723bd3065e8edc4f17c82449d0d6b95a2381ac0a
2022-10-04 16:43:01 -07:00
Baptiste Lemaire
5879053fd0 Dynamically changeable MemPurge option (#10011)
Summary:
**Summary**
Make the mempurge option flag a Mutable Column Family option flag. Therefore, the mempurge feature can be dynamically toggled.

**Motivation**
RocksDB users prefer having the ability to switch features on and off without having to close and reopen the DB. This is particularly important if the feature causes issues and needs to be turned off. Dynamically changing a DB option flag does not seem currently possible.
Moreover, with this new change, the MemPurge feature can be toggled on or off independently between column families, which we see as a major improvement.

**Content of this PR**
This PR includes removal of the `experimental_mempurge_threshold` flag as a DB option flag, and its re-introduction as a `MutableCFOption` flag. I updated the code to handle dynamic changes of the flag (in particular inside the `FlushJob` file). Additionally, this PR includes a new test to demonstrate the capacity of the code to toggle the MemPurge feature on and off, as well as the addition in the `db_stress` module of 2 different mempurge threshold values (0.0 and 1.0) that can be randomly changed with the `set_option_one_in` flag. This is useful to stress test the dynamic changes.

**Benchmarking**
I will add numbers to prove that there is no performance impact within the next 12 hours.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10011

Reviewed By: pdillinger

Differential Revision: D36462357

Pulled By: bjlemaire

fbshipit-source-id: 5e3d63bdadf085c0572ecc2349e7dd9729ce1802
2022-06-23 09:42:18 -07:00
sdong
49628c9a83 Use std::numeric_limits<> (#9954)
Summary:
Right now we still don't fully use std::numeric_limits but use a macro, mainly for supporting VS 2013. Right now we only support VS 2017 and up so it is not a problem. The code comment claims that MinGW still needs it. We don't have a CI running MinGW so it's hard to validate. since we now require C++17, it's hard to imagine MinGW would still build RocksDB but doesn't support std::numeric_limits<>.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9954

Test Plan: See CI Runs.

Reviewed By: riversand963

Differential Revision: D36173954

fbshipit-source-id: a35a73af17cdcae20e258cdef57fcf29a50b49e0
2022-05-05 13:08:21 -07:00
Yanqin Jin
6eafdf135a Encode min_log_number_to_keep and delete_wals_before in one version edit (#9766)
Summary:
min_log_number_to_keep denotes that the WALs whose numbers are below
this value **will** be deleted by RocksDB.
delete_wals_before will be used by RocksDB if
track_and_verify_wals_in_manifest is set to true. During recovery,
RocksDB uses the info encoded in delete_wals_before to reconstruct its
knowledge about what WALs to expect existing.
If these two tags are not encoded in the same VersionEdit, then it's
possible for min_log_number_to_keep=100 to exist, but
delete_wals_before=100 to be lost due to power failure. Subsequent
recovery will delete 99.log. If the db crashes again, the following
recovery will expect to see 99.log since there is no
delete_wals_before=100 in the MANIFEST, but the WAL is already deleted.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9766

Test Plan:
First of all, make check.
Second, format compatibility.
SHORT_TEST=1 ./tools/check_format_compatible.sh

Reviewed By: ltamasi

Differential Revision: D35203623

Pulled By: riversand963

fbshipit-source-id: 45623fc4b4b50d299d5e0f9559a3a4c5e9522c8f
2022-03-31 20:00:52 -07:00
Baptiste Lemaire
7bed6595f3 Fix mempurge crash reported in #8958 (#9671)
Summary:
Change the `MemPurge` code to address a failure during a crash test reported in https://github.com/facebook/rocksdb/issues/8958.

### Details and results of the crash investigation:
These failures happened in a specific scenario where the list of immutable tables was composed of 2 or more memtables, and the last memtable was the output of a previous `Mempurge` operation. Because the `PickMemtablesToFlush` function included a sorting of the memtables (previous PR related to the Mempurge project), and because the `VersionEdit` of the flush class is piggybacked onto a single one of these memtables, the `VersionEdit` was not properly selected and applied to the `VersionSet` of the DB. Since the `VersionSet` was not edited properly, the database was losing track of the SST file created during the flush process, which was subsequently deleted (and as you can expect, caused the tests to crash).
The following command consistently failed, which was quite convenient to investigate the issue:
`$ while rm -rf /dev/shm/single_stress && ./db_stress --clear_column_family_one_in=0 --column_families=1 --db=/dev/shm/single_stress --experimental_mempurge_threshold=5.493146827397074 --flush_one_in=10000 --reopen=0 --write_buffer_size=262144 --value_size_mult=33 --max_write_buffer_number=3 -ops_per_thread=10000; do : ; done`

### Solution proposed
The memtables are no longer sorted based on their `memtableID` in the `PickMemtablesToFlush` function. Additionally, the `next_log_number` of the memtable created as an output of the `Mempurge` function now takes in the correct value (the log number of the first memtable being mempurged). Finally, the VersionEdit object of the flush class now takes the maximum `next_log_number` of the stack of memtables being flushed, which doesnt change anything when Mempurge is `off` but becomes necessary when Mempurge is `on`.

### Testing of the solution
The following command no longer fails:
``$ while rm -rf /dev/shm/single_stress && ./db_stress --clear_column_family_one_in=0 --column_families=1 --db=/dev/shm/single_stress --experimental_mempurge_threshold=5.493146827397074 --flush_one_in=10000 --reopen=0 --write_buffer_size=262144 --value_size_mult=33 --max_write_buffer_number=3 -ops_per_thread=10000; do : ; done``
Additionally, I ran `db_crashtest` (`whitebox` and `blackbox`) for 2.5 hours with MemPurge on and did not observe any crash.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9671

Reviewed By: pdillinger

Differential Revision: D34697424

Pulled By: bjlemaire

fbshipit-source-id: d1ab675b361904351ac81a35c184030e52222874
2022-03-10 15:16:55 -08:00
Yanqin Jin
659a16d52b Fix bug causing incorrect data returned by snapshot read (#9648)
Summary:
This bug affects use cases that meet the following conditions
- (has only the default column family or disables WAL) and
- has at least one event listener
- atomic flush is NOT affected.

If the above conditions meet, then RocksDB can release the db mutex before picking all the
existing memtables to flush. In the meantime, a snapshot can be created and db's sequence
number can still be incremented. The upcoming flush will ignore this snapshot.
A later read using this snapshot can return incorrect result.

To fix this issue, we call the listeners callbacks after picking the memtables so that we avoid
creating snapshots during this interval.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9648

Test Plan: make check

Reviewed By: ajkr

Differential Revision: D34555456

Pulled By: riversand963

fbshipit-source-id: 1438981e9f069a5916686b1a0ad7627f734cf0ee
2022-03-02 21:03:14 -08:00
Andrew Kryczka
8ca433f912 Fix test race conditions with OnFlushCompleted() (#9617)
Summary:
We often see flaky tests due to `DB::Flush()` or `DBImpl::TEST_WaitForFlushMemTable()` not waiting until event listeners complete. For example, https://github.com/facebook/rocksdb/issues/9084, https://github.com/facebook/rocksdb/issues/9400, https://github.com/facebook/rocksdb/issues/9528, plus two new ones this week: "EventListenerTest.OnSingleDBFlushTest" and "DBFlushTest.FireOnFlushCompletedAfterCommittedResult". I ran a `make check` with the below race condition-coercing patch and fixed  issues it found besides old BlobDB.

```
 diff --git a/db/db_impl/db_impl_compaction_flush.cc b/db/db_impl/db_impl_compaction_flush.cc
index 0e1864788..aaba68c4a 100644
 --- a/db/db_impl/db_impl_compaction_flush.cc
+++ b/db/db_impl/db_impl_compaction_flush.cc
@@ -861,6 +861,8 @@ void DBImpl::NotifyOnFlushCompleted(
        mutable_cf_options.level0_stop_writes_trigger);
   // release lock while notifying events
   mutex_.Unlock();
+  bg_cv_.SignalAll();
+  sleep(1);
   {
     for (auto& info : *flush_jobs_info) {
       info->triggered_writes_slowdown = triggered_writes_slowdown;
```

The reason I did not fix old BlobDB issues is because it appears to have a fundamental (non-test) issue. In particular, it uses an EventListener to keep track of the files. OnFlushCompleted() could be delayed until even after a compaction involving that flushed file completes, causing the compaction to unexpectedly delete an untracked file.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9617

Test Plan: `make check` including the race condition coercing patch

Reviewed By: hx235

Differential Revision: D34384022

Pulled By: ajkr

fbshipit-source-id: 2652ded39b415277c5d6a628414345223930514e
2022-02-22 12:23:00 -08:00
Levi Tamasi
320d9a8e8a Use a sorted vector instead of a map to store blob file metadata (#9526)
Summary:
The patch replaces `std::map` with a sorted `std::vector` for
`VersionStorageInfo::blob_files_` and preallocates the space
for the `vector` before saving the `BlobFileMetaData` into the
new `VersionStorageInfo` in `VersionBuilder::Rep::SaveBlobFilesTo`.
These changes reduce the time the DB mutex is held while
saving new `Version`s, and using a sorted `vector` also makes
lookups faster thanks to better memory locality.

In addition, the patch introduces helper methods
`VersionStorageInfo::GetBlobFileMetaData` and
`VersionStorageInfo::GetBlobFileMetaDataLB` that can be used by
clients to perform lookups in the `vector`, and does some general
cleanup in the parts of code where blob file metadata are used.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9526

Test Plan:
Ran `make check` and the crash test script for a while.

Performance was tested using a load-optimized benchmark (`fillseq` with vector memtable, no WAL) and small file sizes so that a significant number of files are produced:

```
numactl --interleave=all ./db_bench --benchmarks=fillseq --allow_concurrent_memtable_write=false --level0_file_num_compaction_trigger=4 --level0_slowdown_writes_trigger=20 --level0_stop_writes_trigger=30 --max_background_jobs=8 --max_write_buffer_number=8 --db=/data/ltamasi-dbbench --wal_dir=/data/ltamasi-dbbench --num=800000000 --num_levels=8 --key_size=20 --value_size=400 --block_size=8192 --cache_size=51539607552 --cache_numshardbits=6 --compression_max_dict_bytes=0 --compression_ratio=0.5 --compression_type=lz4 --bytes_per_sync=8388608 --cache_index_and_filter_blocks=1 --cache_high_pri_pool_ratio=0.5 --benchmark_write_rate_limit=0 --write_buffer_size=16777216 --target_file_size_base=16777216 --max_bytes_for_level_base=67108864 --verify_checksum=1 --delete_obsolete_files_period_micros=62914560 --max_bytes_for_level_multiplier=8 --statistics=0 --stats_per_interval=1 --stats_interval_seconds=20 --histogram=1 --memtablerep=skip_list --bloom_bits=10 --open_files=-1 --subcompactions=1 --compaction_style=0 --min_level_to_compress=3 --level_compaction_dynamic_level_bytes=true --pin_l0_filter_and_index_blocks_in_cache=1 --soft_pending_compaction_bytes_limit=167503724544 --hard_pending_compaction_bytes_limit=335007449088 --min_level_to_compress=0 --use_existing_db=0 --sync=0 --threads=1 --memtablerep=vector --allow_concurrent_memtable_write=false --disable_wal=1 --enable_blob_files=1 --blob_file_size=16777216 --min_blob_size=0 --blob_compression_type=lz4 --enable_blob_garbage_collection=1 --seed=<some value>
```

Final statistics before the patch:

```
Cumulative writes: 0 writes, 700M keys, 0 commit groups, 0.0 writes per commit group, ingest: 284.62 GB, 121.27 MB/s
Interval writes: 0 writes, 334K keys, 0 commit groups, 0.0 writes per commit group, ingest: 139.28 MB, 72.46 MB/s
```

With the patch:

```
Cumulative writes: 0 writes, 760M keys, 0 commit groups, 0.0 writes per commit group, ingest: 308.66 GB, 131.52 MB/s
Interval writes: 0 writes, 445K keys, 0 commit groups, 0.0 writes per commit group, ingest: 185.35 MB, 93.15 MB/s
```

Total time to complete the benchmark is 2611 seconds with the patch, down from 2986 secs.

Reviewed By: riversand963

Differential Revision: D34082728

Pulled By: ltamasi

fbshipit-source-id: fc598abf676dce436734d06bb9d2d99a26a004fc
2022-02-09 12:36:43 -08:00
Yanqin Jin
bd513fd075 Add commit marker with timestamp (#9266)
Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9266

This diff adds a new tag `CommitWithTimestamp`. Currently, there is no API to trigger writing
this tag to WAL, thus it is unavailable to users.
This is an ongoing effort to add user-defined timestamp support to write-committed transactions.
This diff also indicates all column families that may potentially participate in the same
transaction must either disable timestamp or have the same timestamp format, since
`CommitWithTimestamp` tag is followed by a single byte-array denoting the commit
timestamp of the transaction. We will enforce this checking in a future diff. We keep this
diff small.

Reviewed By: ltamasi

Differential Revision: D31721350

fbshipit-source-id: e1450811443647feb6ca01adec4c8aaae270ffc6
2021-12-10 11:05:35 -08:00
Yanqin Jin
1e8322c0f5 Fix a bug in FlushJob picking more memtables beyond synced WALs (#9142)
Summary:
After RocksDB 6.19 and before this PR, RocksDB FlushJob may pick more memtables to flush beyond synced WALs.
This can be problematic if there are multiple column families, since it can prematurely advance the flushed column
family's log_number. Should subsequent attempts fail to sync the latest WALs and the database goes
through a recovery, it may detect corrupted WAL number below the flushed column family's log number
and complain about column family inconsistency.
To fix, we record the maximum memtable ID of the column family being flushed. Then we call SyncClosedLogs()
so that all closed WALs at the time when memtable ID is recorded will be synced.
I also disabled a unit test temporarily due to reasons described in https://github.com/facebook/rocksdb/issues/9151

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9142

Test Plan: make check

Reviewed By: ajkr

Differential Revision: D32299956

Pulled By: riversand963

fbshipit-source-id: 0da75888177d91905cf8c9d00605b73afb5970a7
2021-11-19 09:56:00 -08:00
Peter Dillinger
21f8a57f2a Fix TSAN report on MemPurge test (#9115)
Summary:
TSAN reported data race on count variables in MemPurgeBasic
test. This suggests the test could fail if mempurges were slow enough
that they don't complete before the count variables being checked, but
injecting a long sleep into MemPurge (outside DB mutex) confirms that
blocked writes ensure enough mempurges/flushes happen to make the test
pass. All the possible different values on testing should be OK to make
the test pass.

So this change makes the variables atomic so that up-to-date value is
always read and TSAN report suppressed. I have also used `.exchange(0)`
to make the checking less stateful by "popping off" all the accumulated
counts.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9115

Test Plan: updated test, watch for any flakiness

Reviewed By: riversand963

Differential Revision: D32114432

Pulled By: pdillinger

fbshipit-source-id: c985609d39896a0d8f69ebc87b221e688609bdd8
2021-11-02 21:54:29 -07:00
Yanqin Jin
8f4f302316 Attempt to deflake DBFlushTest.FireOnFlushCompletedAfterCommittedResult (#9083)
Summary:
DBFlushTest.FireOnFlushCompletedAfterCommittedResult uses test sync
points to coordinate interleaving of different threads. Before this PR,
the test writes some data to memtable, triggers a manual flush, and
triggers a second manual flush after a first bg flush thread starts
executing. Though unlikely, it is possible for the second bg flush
thread to run faster than the first bg flush thread and deques flush
queue first. In this case, the original test will fail.
The fix is to wait until the first bg flush thread deques the flush
queue before triggering second manual flush.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9083

Test Plan: ./db_flush_test --gtest_filter=DBFlushTest.FireOnFlushCompletedAfterCommittedResult

Reviewed By: jay-zhuang

Differential Revision: D31951239

Pulled By: riversand963

fbshipit-source-id: f32d7cdabe6ad6808fd18e54e663936dc0a9edb4
2021-10-31 22:08:48 -07:00
Yanqin Jin
f72fd58565 Fix atomic flush waiting forever for MANIFEST write (#9034)
Summary:
In atomic flush, concurrent background flush threads will commit to the MANIFEST
one by one, in the order of the IDs of their picked memtables for all included column
families. Each time, a background flush thread decides whether to wait based on two
criteria:
- Is db stopped? If so, don't wait.
- Am I the one to commit the currently earliest memtable? If so, don't wait and ready to go.

When atomic flush was implemented, error writing to or syncing the MANIFEST would
cause the db to be stopped. Therefore, this background thread does not have to check
for the background error while waiting. If there has been such an error, `DBStopped()`
would have been true, and this thread will **not** wait forever.

After we improved error handling, RocksDB may map an IOError while writing to MANIFEST
to a soft error, if there is no WAL. This requires the background threads to check for
background error while waiting. Otherwise, a background flush thread may wait forever.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9034

Test Plan: make check

Reviewed By: zhichao-cao

Differential Revision: D31639225

Pulled By: riversand963

fbshipit-source-id: e9ab07c4d8f2eade238adeefe3e42dd9a5a3ebbd
2021-10-20 21:34:47 -07:00
mrambacher
6924869867 Make SystemClock into a Customizable Class (#8636)
Summary:
Made SystemClock into a Customizable class, complete with CreateFromString.

Cleaned up some of the existing SystemClock implementations that were redundant (NoSleep was the same as the internal one for MockEnv).

Changed MockEnv construction to allow Clock to be passed to the Memory/MockFileSystem.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8636

Reviewed By: zhichao-cao

Differential Revision: D30483360

Pulled By: mrambacher

fbshipit-source-id: cd0e3a876c39f8c98fe13374c06e8edbd5b9f2a1
2021-09-21 09:23:48 -07:00
mrambacher
beed86473a Make MemTableRepFactory into a Customizable class (#8419)
Summary:
This PR does the following:
-> Makes the MemTableRepFactory into a Customizable class and creatable/configurable via CreateFromString
-> Makes the existing implementations compatible with configurations
-> Moves the "SpecialRepFactory" test class into testutil, accessible via the ObjectRegistry or a NewSpecial API

New tests were added to validate the functionality and all existing tests pass.  db_bench and memtablerep_bench were hand-tested to verify the functionality in those tools.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8419

Reviewed By: zhichao-cao

Differential Revision: D29558961

Pulled By: mrambacher

fbshipit-source-id: 81b7229636e4e649a0c914e73ac7b0f8454c931c
2021-09-08 07:46:44 -07:00
Baptiste Lemaire
c625b8d017 Add condition on NotifyOnFlushComplete that FlushJob was not mempurge. Add event listeners to mempurge tests. (#8672)
Summary:
Previously, when a `FlushJob` was redirected to a MemPurge, the function `DBImpl::NotifyOnFlushComplete` was called, which created a series of issues because the JobInfo was not correctly collected from the memtables.
This diff aims at correcting these two issues (`FlushJobInfo` collection in `FlushJob::MemPurge` , no call to `DBImpl::NotifyOnFlushComplete` after successful mempurge).
Event listeners were added to the unit tests to handle these situations.
Surprisingly none of the crashtests caught this issue, I will try to add event listeners to crash tests in the future.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8672

Reviewed By: akankshamahajan15

Differential Revision: D30383109

Pulled By: bjlemaire

fbshipit-source-id: 35a8d4295886923ee4049a6447f00022cb221c73
2021-08-18 17:40:01 -07:00
Baptiste Lemaire
e3a96c4823 Memtable sampling for mempurge heuristic. (#8628)
Summary:
Changes the API of the MemPurge process: the `bool experimental_allow_mempurge` and `experimental_mempurge_policy` flags have been replaced by a `double experimental_mempurge_threshold` option.
This change of API reflects another major change introduced in this PR: the MemPurgeDecider() function now works by sampling the memtables being flushed to estimate the overall amount of useful payload (payload minus the garbage), and then compare this useful payload estimate with the `double experimental_mempurge_threshold` value.
Therefore, when the value of this flag is `0.0` (default value), mempurge is simply deactivated. On the other hand, a value of `DBL_MAX` would be equivalent to always going through a mempurge regardless of the garbage ratio estimate.
At the moment, a `double experimental_mempurge_threshold` value else than 0.0 or `DBL_MAX` is opnly supported`with the `SkipList` memtable representation.
Regarding the sampling, this PR includes the introduction of a `MemTable::UniqueRandomSample` function that collects (approximately) random entries from the memtable by using the new `SkipList::Iterator::RandomSeek()` under the hood, or by iterating through each memtable entry, depending on the target sample size and the total number of entries.
The unit tests have been readapted to support this new API.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8628

Reviewed By: pdillinger

Differential Revision: D30149315

Pulled By: bjlemaire

fbshipit-source-id: 1feef5390c95db6f4480ab4434716533d3947f27
2021-08-10 18:09:03 -07:00