Summary:
cache_bench wasn't generating 16B keys, which are necessary for FastLRUCache. Also:
- Added asserts in cache_bench, which is assuming that inserts never fail. When they fail (for example, if we used keys of the wrong size), memory allocated to the values will becomes leaked, and eventually the program crashes.
- Move kCacheKeySize to the right spot.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10234

Test Plan:
``make -j24 check``. Also, run cache_bench with FastLRUCache and check that memory usage doesn't blow up:
``./cache_bench -cache_type=fast_lru_cache -num_shard_bits=6 -skewed=true \
                        -lookup_insert_percent=100 -lookup_percent=0 -insert_percent=0 -erase_percent=0 \
                        -populate_cache=true -cache_size=1073741824 -ops_per_thread=10000000 \
                        -value_bytes=8192 -resident_ratio=1 -threads=16``

Reviewed By: pdillinger

Differential Revision: D37382949

Pulled By: guidotag

fbshipit-source-id: b697a942ebb215de5d341f98dc8566763436ba9b

Summary:
When a key is "out of domain" for the prefix_extractor (no
prefix assigned) then the Bloom filter is not queried. PerfContext
was counting this as a Bloom "hit" while Statistics doesn't count this
as a prefix Bloom checked. I think it's more accurate to call it neither
hit nor miss, so changing the counting to make it PerfContext coounting
more like Statistics.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10244

Test Plan:
tests updates and expanded (Get and MultiGet). Iterator test
coverage of the change will come in next PR

Reviewed By: bjlemaire

Differential Revision: D37371297

Pulled By: pdillinger

fbshipit-source-id: fed132fba6a92b2314ab898d449fce2d1586c157

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

Summary:
In order to facilitate correctness and performance testing, we would like to add the new blob cache to our stress test tool `db_stress` and our continuously running crash test script `db_crashtest.py`, as well as our synthetic benchmarking tool `db_bench` and the BlobDB performance testing script `run_blob_bench.sh`.
As part of this task, we would also like to utilize these benchmarking tools to get some initial performance numbers about the effectiveness of caching blobs.

This PR is a part of https://github.com/facebook/rocksdb/issues/10156

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10202

Reviewed By: ltamasi

Differential Revision: D37325739

Pulled By: gangliao

fbshipit-source-id: deb65d0d414502270dd4c324d987fd5469869fa8

Summary:
Fix typo in comments and code.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10233

Test Plan: Existing unit tests should pass.

Reviewed By: jay-zhuang, anand1976

Differential Revision: D37356702

Pulled By: gitbw95

fbshipit-source-id: 32c019adcc6dcc95a9882b38147a310091368e51

Summary:
* Add metadata related structs and functions in C API, including
  - `rocksdb_get_column_family_metadata()` and `rocksdb_get_column_family_metadata_cf()`
     that returns `rocksdb_column_family_metadata_t`.
  - `rocksdb_column_family_metadata_t` and its get functions & destroy function.
  - `rocksdb_level_metadata_t` and its and its get functions & destroy function.
  - `rocksdb_file_metadata_t` and its and get functions & destroy functions.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10207

Test Plan:
Extend the existing c_test.c to include additional checks for column_family_metadata
inside CheckCompaction.

Reviewed By: riversand963

Differential Revision: D37305209

Pulled By: ajkr

fbshipit-source-id: 0a5183206353acde145f5f9b632c3bace670aa6e

Summary:
Recently merged CI benchmark scripts were failing.

There has clearly been a major revision of the fields of benchmark output. The upload script expects and sanity-checks the existence of some fields (changes date to conform to OpenSearch format)..., so the script needs to change.

Also add a bit more exception checking to make it more obvious when this happens again.

We have deleted the existing report.tsv from the benchmark machine. An existing report.tsv is appended to by default, so that if the fields change, later rows no longer match the header. This makes for an upload that dies half way through the report file, when the format no longer matches the header.

Re-instate the config.yml for running the benchmarks, so we can once again test it in situ.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10120

Reviewed By: pdillinger

Differential Revision: D37314908

Pulled By: jay-zhuang

fbshipit-source-id: 34f5243fee694b75c6838eb55d3398e4273254b2

Summary:
Even after https://github.com/facebook/rocksdb/issues/10069, `BackupEngineTest.Concurrency` is still flaky with decreased probability of failure.

Repro steps as follows
```bash
make backup_engine_test
gtest-parallel -r 1000 -w 64 ./backup_engine_test --gtest_filter=BackupEngineTest.Concurrency
```

The first two commits of this PR demonstrate how the test is flaky. https://github.com/facebook/rocksdb/issues/10069 handles the case in which
`Rename()` file returns `IOError` with subcode `PathNotFound`, and `CreateLoggerFromOptions()`
allows the operation to succeed, as expected by the test. However, `BackupEngineTest` uses
`RemapFileSystem` on top of `ChrootFileSystem` which can return `NotFound` instead of `IOError`.

This behavior is different from `Env::Default()` which returns PathNotFound if the src of `rename()`
does not exist. We should make the behaviors of the test Env/FS match a real Env/FS.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10228

Test Plan:
```bash
make check
gtest-parallel -r 1000 -w 64 ./backup_engine_test --gtest_filter=BackupEngineTest.Concurrency
```

Reviewed By: pdillinger

Differential Revision: D37337241

Pulled By: riversand963

fbshipit-source-id: 07a53115e424467b55a731866e571f0ad4c6635d

Summary:
https://github.com/facebook/rocksdb/issues/9984 changes the behavior of RocksDB: if logger creation failed during `SanitizeOptions()`,
`DB::Open()` will fail. However, since `SanitizeOptions()` is called in `DBImpl::DBImpl()`, we cannot
directly expose the error to caller without some additional work.
This is a first version proposal which:
- Adds a new member `init_logger_creation_s` to `DBImpl` to store the result of init logger creation
- Checks the error during `DB::Open()` and return it to caller if non-ok

This is not very ideal. We can alternatively move the logger creation logic out of the `SanitizeOptions()`.
Since `SanitizeOptions()` is used in other places, we need to check whether this change breaks anything
in case other callers of `SanitizeOptions()` assumes that a logger should be created.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10223

Test Plan: make check

Reviewed By: pdillinger

Differential Revision: D37321717

Pulled By: riversand963

fbshipit-source-id: 58042358a86369d606549dd9938933dd47591c4b

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/10180

Reviewed By: pdillinger

Differential Revision: D37182037

Pulled By: riversand963

fbshipit-source-id: a8dc865b86e2249beb7a543c317e94a14781e910

Summary:
There was a bug in the MultiGet enhancement in https://github.com/facebook/rocksdb/issues/9899 with data
block hash index, which was not caught because data block hash index was
never added to stress tests. This change fixes both issues.

Fixes https://github.com/facebook/rocksdb/issues/10186

I intend to pick this into the 7.4.0 release candidate

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10220

Test Plan:
Failure quickly reproduces in crash test with
kDataBlockBinaryAndHash, and does not seem to with the fix. Reproducing
the failure with a unit test I believe would be too tricky and fragile
to be worthwhile.

Reviewed By: anand1976

Differential Revision: D37315647

Pulled By: pdillinger

fbshipit-source-id: 9f648265bba867275edc752f7a56611a59401cba

Summary:
So that DBImpl::RecoverLogFiles do not have to deal with implementation
details of WalFilter.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10214

Test Plan: make check

Reviewed By: ajkr

Differential Revision: D37299122

Pulled By: riversand963

fbshipit-source-id: acf1a80f1ef75da393d375f55968b2f3ac189816

Summary:
Update LZ4 library for platform009.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10224

Test Plan: Current unit tests should pass.

Reviewed By: anand1976

Differential Revision: D37321801

Pulled By: gitbw95

fbshipit-source-id: 8a3d3019d9f7478ac737176f2d2f443c0159829e

Summary:
Add `kRoundRobin` as a compaction priority. The implementation is as follows.

- Define a cursor as the smallest Internal key in the successor of the selected file. Add `vector<InternalKey> compact_cursor_` into `VersionStorageInfo` where each element (`InternalKey`) in `compact_cursor_` represents a cursor. In round-robin compaction policy, we just need to select the first file (assuming files are sorted) and also has the smallest InternalKey larger than/equal to the cursor. After a file is chosen, we create a new `Fsize` vector which puts the selected file is placed at the first position in `temp`, the next cursor is then updated as the smallest InternalKey in successor of the selected file (the above logic is implemented in `SortFileByRoundRobin`).
- After a compaction succeeds, typically `InstallCompactionResults()`, we choose the next cursor for the input level and save it to `edit`. When calling `LogAndApply`, we save the next cursor with its level into some local variable and finally apply the change to `vstorage` in `SaveTo` function.
- Cursors are persist pair by pair (<level, InternalKey>) in `EncodeTo` so that they can be reconstructed when reopening. An empty cursor will not be encoded to MANIFEST

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10107

Test Plan: add unit test (`CompactionPriRoundRobin`) in `compaction_picker_test`, add `kRoundRobin` priority in `CompactionPriTest` from `db_compaction_test`, and add `PersistRoundRobinCompactCursor` in `db_compaction_test`

Reviewed By: ajkr

Differential Revision: D37316037

Pulled By: littlepig2013

fbshipit-source-id: 9f481748190ace416079139044e00df2968fb1ee

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/10221

Reviewed By: hx235

Differential Revision: D37316280

Pulled By: riversand963

fbshipit-source-id: 062781acec2f36beebc62003bcc8ec280488d572

Summary:
In FastLRUCache, we replace the current chained per-shard hash table by an open-addressing hash table. In particular, this allows us to preallocate all handles.

Because all handles are preallocated, this implementation doesn't support strict_capacity_limit = false (i.e., allowing insertions beyond the predefined capacity). This clashes with current assumptions of some tests, namely two tests in cache_test and the crash tests. We have disabled these for now.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10194

Test Plan: ``make -j24 check``

Reviewed By: pdillinger

Differential Revision: D37296770

Pulled By: guidotag

fbshipit-source-id: 232ff1b8260331d868ebf4e3e5d8ad709390b0ad

Summary:
There is currently no caching mechanism for blobs, which is not ideal especially when the database resides on remote storage (where we cannot rely on the OS page cache). As part of this task, we would like to make it possible for the application to configure a blob cache.
In this task, we formally introduced the blob source to RocksDB.  BlobSource is a new abstraction layer that provides universal access to blobs, regardless of whether they are in the blob cache, secondary cache, or (remote) storage. Depending on user settings, it always fetch blobs from multi-tier cache and storage with minimal cost.

Note: The new `MultiGetBlob()` implementation is not included in the current PR. To go faster, we aim to create a separate PR for it in parallel!

This PR is a part of https://github.com/facebook/rocksdb/issues/10156

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10198

Reviewed By: ltamasi

Differential Revision: D37294735

Pulled By: gangliao

fbshipit-source-id: 9cb50422d9dd1bc03798501c2778b6c7520c7a1e

Summary:
One consistency check in SaveTo() is dupilcated with the one within Apply(). Remove one of then in release mode to reduce time spent in DB mutex.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10169

Test Plan: Run existing tests and see nothing breaks.

Reviewed By: ltamasi

Differential Revision: D37157821

fbshipit-source-id: 73b89443a20b43362ff66d10b9212022034a8234

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/10211

Test Plan: `make check`

Reviewed By: riversand963

Differential Revision: D37294067

Pulled By: ltamasi

fbshipit-source-id: 3b26f1964746ba4e3654579cb07cd975a29c7319

Summary:
include "include/rocksdb/blah.h" is messing up some internal
builds vs. include "rocksdb/blah." This fixes the bad case and adds a
check for future instances.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10213

Test Plan: back-port to 7.4 release candidate and watch internal build

Reviewed By: hx235

Differential Revision: D37296202

Pulled By: pdillinger

fbshipit-source-id: d7cc6b2c57d858dff0444f19320d83c8b4f9b185

Summary:
Forgotten in https://github.com/facebook/rocksdb/issues/10204

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10209

Test Plan: local run with SHORT_TEST=1

Reviewed By: hx235

Differential Revision: D37284028

Pulled By: pdillinger

fbshipit-source-id: 631c1969906d002acc930662dcd5eefc0c758429

Summary:
Update HISTORY.md and version.h

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10204

Test Plan: version bump only

Reviewed By: ajkr

Differential Revision: D37271866

Pulled By: pdillinger

fbshipit-source-id: 0ccaa2af36648a5b6017c172a7826a244e1aec93

Summary:
Planned for Sunday 6/19

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10196

Test Plan: no code

Reviewed By: akankshamahajan15

Differential Revision: D37244857

Pulled By: pdillinger

fbshipit-source-id: afbf4aa201983b3c01c16b5f55c68f2325d17421

Summary:
This bug was discovered after write batch checksum verification before WAL is added (https://github.com/facebook/rocksdb/issues/10114) and stress test with write batch checksum protection is turned on (https://github.com/facebook/rocksdb/issues/10037). In this [line](https://github.com/facebook/rocksdb/blob/d5d8920f2cfd06d1803b0976acbe8b564b88b6b1/db/write_batch.cc#L2887), the number of checksums may not be consistent with `batch->Count()`. This PR fixes this issue.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10201

Test Plan:
```
./db_stress --batch_protection_bytes_per_key=8 --destroy_db_initially=1 --max_key=100000 --use_txn=1
```

Reviewed By: ajkr

Differential Revision: D37260799

Pulled By: cbi42

fbshipit-source-id: ff8dce7dcce295d689333bc9d892d17a843bf0ea

Summary:
`FlushWAL(true /* sync */)` is used internally and for manual WAL sync. It had a bug when used together with `track_and_verify_wals_in_manifest` where the synced size tracked in MANIFEST was larger than the number of bytes actually synced.

The bug could be repro'd almost immediately with the following crash test command: `python3 tools/db_crashtest.py blackbox --simple --write_buffer_size=524288 --max_bytes_for_level_base=2097152 --target_file_size_base=524288 --duration=3600 --interval=10 --sync_fault_injection=1 --disable_wal=0 --checkpoint_one_in=1000 --max_key=10000 --value_size_mult=33`.

An example error message produced by the above command is shown below. The error sometimes arose from the checkpoint and other times arose from the main stress test DB.

```
Corruption: Size mismatch: WAL (log number: 119) in MANIFEST is 27938 bytes , but actually is 27859 bytes on disk.
```

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10185

Test Plan:
- repro unit test
- the above crash test command no longer finds the error. It does find a different error after a while longer such as "Corruption: WAL file 481 required by manifest but not in directory list"

Reviewed By: riversand963

Differential Revision: D37200993

Pulled By: ajkr

fbshipit-source-id: 98e0071c1a89f4d009888512ed89f9219779ae5f

Summary:
**Context/Summary:**
https://github.com/facebook/rocksdb/pull/9424 added rate-limiting support for user reads, which does not include batched `MultiGet()`s that call `RandomAccessFileReader::MultiRead()`. The reason is that it's harder (compared with RandomAccessFileReader::Read()) to implement the ideal rate-limiting where we first call `RateLimiter::RequestToken()` for allowed bytes to multi-read and then consume those bytes by satisfying as many requests in `MultiRead()` as possible. For example, it can be tricky to decide whether we want partially fulfilled requests within one `MultiRead()` or not.

However, due to a recent urgent user request, we decide to pursue an elementary (but a conditionally ineffective) solution where we accumulate enough rate limiter requests toward the total bytes needed by one `MultiRead()` before doing that `MultiRead()`. This is not ideal when the total bytes are huge as we will actually consume a huge bandwidth from rate-limiter causing a burst on disk. This is not what we ultimately want with rate limiter. Therefore a follow-up work is noted through TODO comments.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10159

Test Plan:
- Modified existing unit test `DBRateLimiterOnReadTest/DBRateLimiterOnReadTest.NewMultiGet`
- Traced the underlying system calls `io_uring_enter` and verified they are 10 seconds apart from each other correctly under the setting of  `strace -ftt -e trace=io_uring_enter ./db_bench -benchmarks=multireadrandom -db=/dev/shm/testdb2 -readonly -num=50 -threads=1 -multiread_batched=1 -batch_size=100 -duration=10 -rate_limiter_bytes_per_sec=200 -rate_limiter_refill_period_us=1000000 -rate_limit_bg_reads=1 -disable_auto_compactions=1 -rate_limit_user_ops=1` where each `MultiRead()` read about 2000 bytes (inspected by debugger) and the rate limiter grants 200 bytes per seconds.
- Stress test:
   - Verified `./db_stress (-test_cf_consistency=1/test_batches_snapshots=1) -use_multiget=1 -cache_size=1048576 -rate_limiter_bytes_per_sec=10241024 -rate_limit_bg_reads=1 -rate_limit_user_ops=1` work

Reviewed By: ajkr, anand1976

Differential Revision: D37135172

Pulled By: hx235

fbshipit-source-id: 73b8e8f14761e5d4b77235dfe5d41f4eea968bcd

Summary:
There is currently no caching mechanism for blobs, which is not ideal especially when the database resides on remote storage (where we cannot rely on the OS page cache). As part of this task, we would like to make it possible for the application to configure a blob cache.
In this task, we added a new abstraction layer `BlobSource` to retrieve blobs from either blob cache or raw blob file. Note: For simplicity, the current PR only includes `GetBlob()`.  `MultiGetBlob()` will be included in the next PR.

This PR is a part of https://github.com/facebook/rocksdb/issues/10156

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10178

Reviewed By: ltamasi

Differential Revision: D37250507

Pulled By: gangliao

fbshipit-source-id: 3fc4a55a0cea955a3147bdc7dba06430e377259b

Summary:
folly DistributedMutex is faster than standard mutexes though
imposes some static obligations on usage. See
https://github.com/facebook/folly/blob/main/folly/synchronization/DistributedMutex.h
for details. Here we use this alternative for our Cache implementations
(especially LRUCache) for better locking performance, when RocksDB is
compiled with folly.

Also added information about which distributed mutex implementation is
being used to cache_bench output and to DB LOG.

Intended follow-up:
* Use DMutex in more places, perhaps improving API to support non-scoped
locking
* Fix linking with fbcode compiler (needs ROCKSDB_NO_FBCODE=1 currently)

Credit: Thanks Siying for reminding me about this line of work that was previously
left unfinished.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10179

Test Plan:
for correctness, existing tests. CircleCI config updated.
Also Meta-internal buck build updated.

For performance, ran simultaneous before & after cache_bench. Out of three
comparison runs, the middle improvement to ops/sec was +21%:

Baseline: USE_CLANG=1 DEBUG_LEVEL=0 make -j24 cache_bench (fbcode
compiler)

```
Complete in 20.201 s; Rough parallel ops/sec = 1584062
Thread ops/sec = 107176

Operation latency (ns):
Count: 32000000 Average: 9257.9421  StdDev: 122412.04
Min: 134  Median: 3623.0493  Max: 56918500
Percentiles: P50: 3623.05 P75: 10288.02 P99: 30219.35 P99.9: 683522.04 P99.99: 7302791.63
```

New: (add USE_FOLLY=1)

```
Complete in 16.674 s; Rough parallel ops/sec = 1919135  (+21%)
Thread ops/sec = 135487

Operation latency (ns):
Count: 32000000 Average: 7304.9294  StdDev: 108530.28
Min: 132  Median: 3777.6012  Max: 91030902
Percentiles: P50: 3777.60 P75: 10169.89 P99: 24504.51 P99.9: 59721.59 P99.99: 1861151.83
```

Reviewed By: anand1976

Differential Revision: D37182983

Pulled By: pdillinger

fbshipit-source-id: a17eb05f25b832b6a2c1356f5c657e831a5af8d1

Summary:
Ribbon micro-bench needs updating after re-numbering
`BloomLikeFilterPolicy::GetAllFixedImpls()` entries. (CircleCI nightly
failure.)

Also fixed memory leaks while using ASAN to validate my fix. (I assume
the leaks weren't intentional for some performance characteristic.)

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10195

Test Plan: run with ASAN

Reviewed By: jay-zhuang

Differential Revision: D37244459

Pulled By: pdillinger

fbshipit-source-id: 5a363e10de3c4c9c88099c937e3dc3b4cf24fd30

Summary:
Added an option, `WriteOptions::protection_bytes_per_key`, that controls how many bytes per key we use for integrity protection in `WriteBatch`. It takes effect when `WriteBatch::GetProtectionBytesPerKey() == 0`.

Currently the only supported value is eight. Invoking a user API with it set to any other nonzero value will result in `Status::NotSupported` returned to the user.

There is also a bug fix for integrity protection with `inplace_callback`, where we forgot to take into account the possible change in varint length when calculating KV checksum for the final encoded buffer.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10037

Test Plan:
- Manual
  - Set default value of `WriteOptions::protection_bytes_per_key` to eight and ran `make check -j24`
  - Enabled in MyShadow for 1+ week
- Automated
  - Unit tests have a `WriteMode` that enables the integrity protection via `WriteOptions`
  - Crash test - in most cases, use `WriteOptions::protection_bytes_per_key` to enable integrity protection

Reviewed By: cbi42

Differential Revision: D36614569

Pulled By: ajkr

fbshipit-source-id: 8650087ceac9b61b560f1e5fafe5e1baf9c725fb

Summary:
.. between https://github.com/facebook/rocksdb/issues/10184 and https://github.com/facebook/rocksdb/issues/10122 not detected by source control,
leading to non-compiling code.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10192

Test Plan: updated test

Reviewed By: hx235

Differential Revision: D37231921

Pulled By: pdillinger

fbshipit-source-id: fa21488716f4c006b111b8c4127d71c757c935c3

Summary:
Update HISTORY.md for https://github.com/facebook/rocksdb/issues/10114: write batch checksum verification before writing to WAL.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10189

Reviewed By: ajkr

Differential Revision: D37226366

Pulled By: cbi42

fbshipit-source-id: cd2f076961abc35f35783e0f2cc3beda68cdb446

Summary:
There was an interesting code path not covered by testing that
is difficult to replicate in a unit test, which is now covered using a
sync point. Specifically, the case of table_prefix_extractor == null and
!need_upper_bound_check in `BlockBasedTable::PrefixMayMatch`, which
can happen if table reader is open before extractor is registered with global
object registry, but is later registered and re-set with SetOptions. (We
don't have sufficient testing control over object registry to set that up
repeatedly.)

Also, this function has been renamed to `PrefixRangeMayMatch` for clarity
vs. other functions that are not the same.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10122

Test Plan: unit tests expanded

Reviewed By: siying

Differential Revision: D36944834

Pulled By: pdillinger

fbshipit-source-id: 9e52d9da1929a3e42bbc230fcdc3599949de7bdb

Summary:
In https://github.com/facebook/rocksdb/issues/9535, release 7.0, we hid the old block-based filter from being created using
the public API, because of its inefficiency. Although we normally maintain read compatibility
on old DBs forever, filters are not required for reading a DB, only for optimizing read
performance. Thus, it should be acceptable to remove this code and the substantial
maintenance burden it carries as useful features are developed and validated (such
as user timestamp).

This change completely removes the code for reading and writing the old block-based
filters, net removing about 1370 lines of code no longer needed. Options removed from
testing / benchmarking tools. The prior existence is only evident in a couple of places:
* `CacheEntryRole::kDeprecatedFilterBlock` - We can update this public API enum in
a major release to minimize source code incompatibilities.
* A warning is logged when an old table file is opened that used the old block-based
filter. This is provided as a courtesy, and would be a pain to unit test, so manual testing
should suffice. Unfortunately, sst_dump does not tell you whether a file uses
block-based filter, and the structure of the code makes it very difficult to fix.
* To detect that case, `kObsoleteFilterBlockPrefix` (renamed from `kFilterBlockPrefix`)
for metaindex is maintained (for now).

Other notes:
* In some cases where numbers are associated with filter configurations, we have had to
update the assigned numbers so that they all correspond to something that exists.
* Fixed potential stat counting bug by assuming `filter_checked = false` for cases
like `filter == nullptr` rather than assuming `filter_checked = true`
* Removed obsolete `block_offset` and `prefix_extractor` parameters from several
functions.
* Removed some unnecessary checks `if (!table_prefix_extractor() && !prefix_extractor)`
because the caller guarantees the prefix extractor exists and is compatible

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10184

Test Plan:
tests updated, manually test new warning in LOG using base version to
generate a DB

Reviewed By: riversand963

Differential Revision: D37212647

Pulled By: pdillinger

fbshipit-source-id: 06ee020d8de3b81260ffc36ad0c1202cbf463a80

Summary:
Add a couple of stats to help users estimate the impact of potential MultiGet perf improvements -
1. NUM_LEVEL_READ_PER_MULTIGET - A histogram stat for number of levels that required MultiGet to read from a file
2. MULTIGET_COROUTINE_COUNT - A ticker stat to count the number of times the coroutine version of MultiGetFromSST was used

The NUM_DATA_BLOCKS_READ_PER_LEVEL stat is obsoleted as it doesn't provide useful information for MultiGet optimization.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10182

Reviewed By: akankshamahajan15

Differential Revision: D37213296

Pulled By: anand1976

fbshipit-source-id: 5d2b7708017c0e278578ae4bffac3926f6530efb

Summary:
In CompactionIterator code, there are multiple places where the process
will abort in dbg mode before logging the error message describing the
cause. This PR changes only the logging behavior for compaction iterator so
that error message is written to LOG before the process aborts in debug
mode.

Also updated the triggering condition for an assertion for single delete with
user-defined timestamp.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10183

Test Plan: make check

Reviewed By: akankshamahajan15

Differential Revision: D37190218

Pulled By: riversand963

fbshipit-source-id: 741bb007067be7cfbe94ac9e530ad4b2b339c009

Summary:
This PR adds few optimizations for async_io for shorter scans.
1.  If async_io is enabled, seek would create FilePrefetchBuffer object to fetch the data asynchronously. However `FilePrefetchbuffer::num_file_reads_` wasn't taken into consideration if it calls Next after Seek and would go for Prefetching.  This PR fixes that and Next will go for prefetching only if `FilePrefetchbuffer::num_file_reads_` is greater than 2 along with if blocks are sequential. This scenario is only for implicit auto readahead.
2. For seek, when it calls TryReadFromCacheAsync to poll it makes async call as well because TryReadFromCacheAsync flow wasn't changed. So I updated to return after poll instead of further prefetching any data.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10140

Test Plan:
1. Added a unit test
                  2. Ran crash_test with async_io = 1 to make sure nothing crashes.

Reviewed By: anand1976

Differential Revision: D37042242

Pulled By: akankshamahajan15

fbshipit-source-id: b8e6b7cb2ee0886f37a8f53951948b9084e8ffda

Summary:
A consequence of https://github.com/facebook/rocksdb/issues/9990 was requiring a non-empty DB ID to generate
new SST files. But if the DB ID is not tracked in the manifest and the IDENTITY file
is somehow truncated to 0 bytes, then an empty DB ID would be assigned, leading
to crash. This change ensures a non-empty DB ID is assigned and set in the
IDENTITY file.

Also,
* Some light refactoring to clean up the logic
* (I/O efficiency) If the ID is tracked in the manifest and already matches the
IDENTITY file, don't needlessly overwrite the file.
* (Debugging) Log the DB ID to info log on open, because sometimes IDENTITY
can change if DB is moved around (though it would be unusual for info log to
be copied/moved without IDENTITY file)

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10173

Test Plan: unit tests expanded/updated

Reviewed By: ajkr

Differential Revision: D37176545

Pulled By: pdillinger

fbshipit-source-id: a9b414cd35bfa33de48af322a36c24538d50bef1

Summary:
Fix existing usage of non-ASCII and add a check to prevent
future use. Added `-n` option to greps to provide line numbers.

Alternative to https://github.com/facebook/rocksdb/issues/10147

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10164

Test Plan:
used new checker to find & fix cases, manually check
db_bench output is preserved

Reviewed By: akankshamahajan15

Differential Revision: D37148792

Pulled By: pdillinger

fbshipit-source-id: 68c8b57e7ab829369540d532590bf756938855c7

Summary:
Context: WriteBatch can have key-value checksums when it was created `with protection_bytes_per_key > 0`.
This PR added checksum verification for write batches before they are written to WAL.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10114

Test Plan:
- Added new unit tests to db_kv_checksum_test.cc: `make check -j32`
- benchmark on performance regression: `./db_bench --benchmarks=fillrandom[-X20] -db=/dev/shm/test_rocksdb -write_batch_protection_bytes_per_key=8`
  - Pre-PR:
`
fillrandom [AVG    20 runs] : 198875 (± 3006) ops/sec;   22.0 (± 0.3) MB/sec
`
  - Post-PR:
`
fillrandom [AVG    20 runs] : 196487 (± 2279) ops/sec;   21.7 (± 0.3) MB/sec
`
  Mean regressed about 1% (198875 -> 196487 ops/sec).

Reviewed By: ajkr

Differential Revision: D36917464

Pulled By: cbi42

fbshipit-source-id: 29beb74edf65f04b1a890b4f650d873dc7ed790d