Commit Graph

5118 Commits

Author SHA1 Message Date
Changyu Bi be04a3b6cd Fix data race in accessing `cached_range_tombstone_` (#10680)
Summary:
fix a data race introduced in https://github.com/facebook/rocksdb/issues/10547 (P5295241720), first reported by pdillinger. The race is between the `std::atomic_load_explicit` in NewRangeTombstoneIteratorInternal and the `std::atomic_store_explicit` in MemTable::Add() that operate on `cached_range_tombstone_`. P5295241720 shows that `atomic_store_explicit` initializes some mutex which `atomic_load_explicit` could be trying to call `lock()` on at the same time. This fix moves the initialization to memtable constructor.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10680

Test Plan: `USE_CLANG=1 COMPILE_WITH_TSAN=1 make -j24 whitebox_crash_test`

Reviewed By: ajkr

Differential Revision: D39528696

Pulled By: cbi42

fbshipit-source-id: ee740841044438e18ad2b8ea567444dd542dd8e2
2022-09-14 20:50:10 -07:00
anand76 bb9a6d4e4b Bypass a MultiGet test when async_io is used (#10669)
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/10669

Reviewed By: akankshamahajan15

Differential Revision: D39492658

Pulled By: anand1976

fbshipit-source-id: abef79808e30762654680f7dd7e46487c631febc
2022-09-14 09:59:54 -07:00
Levi Tamasi 06ab0a8b40 Add wide-column support to iterators (#10670)
Summary:
The patch extends the iterator API with a new `columns` method which
can be used to retrieve all wide columns for the current key. Similarly to
the `Get` and `GetEntity` APIs, the classic `value` API returns the value
of the default (anonymous) column for wide-column entities, and `columns`
returns an entity with a single default column for plain old key-values.
(The goal here is to maintain the invariant that `value()` is the same as
the value of the default column in `columns()`.) The patch also involves a
smaller refactoring: historically, `value()` was implemented using a bunch
of conditions, that is, the `Slice` to be returned was decided based on the
direction of the iteration, whether a merge had been done etc. when the
method was called; with the patch, the value to be exposed is stored in a
member `Slice value_` when the iterator lands on a new key, and `value()`
simply returns this `Slice`.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10670

Test Plan: Ran `make check` and a simple blackbox crash test.

Reviewed By: riversand963

Differential Revision: D39475551

Pulled By: ltamasi

fbshipit-source-id: 29e7a6ed9ef340841aab36803b832b7c8f668b0b
2022-09-13 21:01:36 -07:00
Changyu Bi f291eefb02 Cache fragmented range tombstone list for mutable memtables (#10547)
Summary:
Each read from memtable used to read and fragment all the range tombstones into a `FragmentedRangeTombstoneList`. https://github.com/facebook/rocksdb/issues/10380 improved the inefficient here by caching a `FragmentedRangeTombstoneList` with each immutable memtable. This PR extends the caching to mutable memtables. The fragmented range tombstone can be constructed in either read (This PR) or write path (https://github.com/facebook/rocksdb/issues/10584). With both implementation, each `DeleteRange()` will invalidate the cache, and the difference is where the cache is re-constructed.`CoreLocalArray` is used to store the cache with each memtable so that multi-threaded reads can be efficient. More specifically, each core will have a shared_ptr to a shared_ptr pointing to the current cache. Each read thread will only update the reference count in its core-local shared_ptr, and this is only needed when reading from mutable memtables.

The choice between write path and read path is not an easy one: they are both improvement compared to no caching in the current implementation, but they favor different operations and could cause regression in the other operation (read vs write). The write path caching in (https://github.com/facebook/rocksdb/issues/10584) leads to a cleaner implementation, but I chose the read path caching here to avoid significant regression in write performance when there is a considerable amount of range tombstones in a single memtable (the number from the benchmark below suggests >1000 with concurrent writers). Note that even though the fragmented range tombstone list is only constructed in `DeleteRange()` operations, it could block other writes from proceeding, and hence affects overall write performance.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10547

Test Plan:
- TestGet() in stress test is updated in https://github.com/facebook/rocksdb/issues/10553 to compare Get() result against expected state: `./db_stress_branch --readpercent=57 --prefixpercent=4 --writepercent=25 -delpercent=5 --iterpercent=5 --delrangepercent=4`
- Perf benchmark: tested read and write performance where a memtable has 0, 1, 10, 100 and 1000 range tombstones.
```
./db_bench --benchmarks=fillrandom,readrandom --writes_per_range_tombstone=200 --max_write_buffer_number=100 --min_write_buffer_number_to_merge=100 --writes=200000 --reads=100000 --disable_auto_compactions --max_num_range_tombstones=1000
```
Write perf regressed since the cost of constructing fragmented range tombstone list is shifted from every read to a single write. 6cbe5d8e172dc5f1ef65c9d0a6eedbd9987b2c72 is included in the last column as a reference to see performance impact on multi-thread reads if `CoreLocalArray` is not used.

micros/op averaged over 5 runs: first 4 columns are for fillrandom, last 4 columns are for readrandom.
|   |fillrandom main           | write path caching          | read path caching          |memtable V3 (https://github.com/facebook/rocksdb/issues/10308)     | readrandom main            | write path caching           | read path caching            |memtable V3      |
|---   |---  |---   |---   |---   | ---   |           ---   |  ---   |  ---   |
| 0                    |6.35                           |6.15                           |5.82                           |6.12                           |2.24                           |2.26                           |2.03                           |2.07                           |
| 1                    |5.99                           |5.88                           |5.77                           |6.28                           |2.65                           |2.27                           |2.24                           |2.5                            |
| 10                   |6.15                           |6.02                           |5.92                           |5.95                           |5.15                           |2.61                           |2.31                           |2.53                           |
| 100                  |5.95                           |5.78                           |5.88                           |6.23                           |28.31                          |2.34                           |2.45                           |2.94                           |
| 100 25 threads       |52.01                          |45.85                          |46.18                          |47.52                          |35.97                          |3.34                           |3.34                           |3.56                           |
| 1000                 |6.0                            |7.07                           |5.98                           |6.08                           |333.18                         |2.86                           |2.7                            |3.6                            |
| 1000 25 threads      |52.6                           |148.86                         |79.06                          |45.52                          |473.49                         |3.66                           |3.48                           |4.38                           |

  - Benchmark performance of`readwhilewriting` from https://github.com/facebook/rocksdb/issues/10552, 100 range tombstones are written: `./db_bench --benchmarks=readwhilewriting --writes_per_range_tombstone=500 --max_write_buffer_number=100 --min_write_buffer_number_to_merge=100 --writes=100000 --reads=500000 --disable_auto_compactions --max_num_range_tombstones=10000 --finish_after_writes`

readrandom micros/op:
|  |main            |write path caching           |read path caching            |memtable V3      |
|---|---|---|---|---|
| single thread        |48.28                          |1.55                           |1.52                           |1.96                           |
| 25 threads           |64.3                           |2.55                           |2.67                           |2.64                           |

Reviewed By: ajkr

Differential Revision: D38895410

Pulled By: cbi42

fbshipit-source-id: 930bfc309dd1b2f4e8e9042f5126785bba577559
2022-09-13 20:07:28 -07:00
Hui Xiao f79b3d19a7 Inject spurious wakeup and sleep before acquiring db mutex to expose race condition (#10291)
Summary:
**Context/Summary:**
Previous experience with bugs and flaky tests taught us there exist features in RocksDB vulnerable to race condition caused by acquiring db mutex at a particular timing. This PR aggressively exposes those vulnerable features by injecting spurious wakeup and sleep to cause acquiring db mutex at various timing in order to expose such race condition

**Testing:**
- `COERCE_CONTEXT_SWITCH=1 make -j56 check / make -j56 db_stress` should reveal
    - flaky tests caused by db mutex related race condition
       - Reverted https://github.com/facebook/rocksdb/pull/9528
       - A/B testing on `COMPILE_WITH_TSAN=1 make -j56 listener_test` w/ and w/o `COERCE_CONTEXT_SWITCH=1` followed by `./listener_test --gtest_filter=EventListenerTest.MultiCF --gtest_repeat=10`
       - `COERCE_CONTEXT_SWITCH=1` can cause expected test failure (i.e, expose target TSAN data race error) within 10 run while the other couldn't.
       - This proves our injection can expose flaky tests caused by db mutex related race condition faster.
    -  known or new race-condition-type of internal bug by continuously running this PR
- Performance
   - High ops-threads time: COERCE_CONTEXT_SWITCH=1 regressed by 4 times slower (2:01.16 vs 0:22.10 elapsed ). This PR will be run as a separate CI job so this regression won't affect any existing job.
```
TEST_TMPDIR=$db /usr/bin/time ./db_stress \
--ops_per_thread=100000 --expected_values_dir=$exp --clear_column_family_one_in=0 \
--write_buffer_size=524288 —target_file_size_base=524288 —ingest_external_file_one_in=100 —compact_files_one_in=1000 —compact_range_one_in=1000
```
  - Start-up time:  COERCE_CONTEXT_SWITCH=1 didn't regress by 25% (0:01.51 vs 0:01.29 elapsed)
```
TEST_TMPDIR=$db ./db_stress -ops_per_thread=100000000 -expected_values_dir=$exp --clear_column_family_one_in=0 & sleep 120; pkill -9 db_stress

TEST_TMPDIR=$db /usr/bin/time ./db_stress \
--ops_per_thread=1 -reopen=0 --expected_values_dir=$exp --clear_column_family_one_in=0 --destroy_db_initially=0
```

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10291

Reviewed By: ajkr

Differential Revision: D39231182

Pulled By: hx235

fbshipit-source-id: 7ab6695430460e0826727fd8c66679b32b3e44b6
2022-09-12 13:55:23 -07:00
Yanqin Jin 3d67d79154 Fix overlapping check by excluding timestamp (#10615)
Summary:
With user-defined timestamp, checking overlapping should exclude
timestamp part from key. This has already been done for range checking
for files in sstableKeyCompare(), but not yet done when checking with
concurrent compactions.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10615

Test Plan:
(Will add more tests)

make check
(Repro seems easier with this commit sha: git checkout 78bbdef530)
rm -rf /dev/shm/rocksdb/* &&
mkdir /dev/shm/rocksdb/rocksdb_crashtest_expected &&
./db_stress
--allow_data_in_errors=True --clear_column_family_one_in=0
--continuous_verification_interval=0 --data_block_index_type=1
--db=/dev/shm/rocksdb//rocksdb_crashtest_blackbox --delpercent=5
--delrangepercent=0
--expected_values_dir=/dev/shm/rocksdb//rocksdb_crashtest_expected
--iterpercent=0 --max_background_compactions=20
--max_bytes_for_level_base=10485760 --max_key=25000000
--max_write_batch_group_size_bytes=1048576 --nooverwritepercent=1
--ops_per_thread=1000000 --paranoid_file_checks=1 --partition_filters=0
--prefix_size=8 --prefixpercent=5 --readpercent=30 --reopen=0
--snapshot_hold_ops=100000 --subcompactions=1 --compaction_pri=3
--target_file_size_base=65536 --target_file_size_multiplier=2
--test_batches_snapshots=0 --test_cf_consistency=0 --use_multiget=1
--user_timestamp_size=8 --value_size_mult=32 --verify_checksum=1
--write_buffer_size=65536 --writepercent=60 -disable_wal=1

Reviewed By: akankshamahajan15

Differential Revision: D39146797

Pulled By: riversand963

fbshipit-source-id: 7fca800026ca6219220100b8b6cf84d907828163
2022-09-08 13:03:07 -07:00
Levi Tamasi fe56cb9aa0 Eliminate some allocations/copies around the blob cache (#10647)
Summary:
Historically, `BlobFileReader` has returned the blob(s) read from the file
in the `PinnableSlice` provided by the client. This interface was
preserved when caching was implemented for blobs, which meant that
the blob data was copied multiple times when caching was in use: first,
into the client-provided `PinnableSlice` (by `BlobFileReader::SaveValue`),
and then, into the object stored in the cache (by `BlobSource::PutBlobIntoCache`).
The patch eliminates these copies and the related allocations by changing
`BlobFileReader` so it returns its results in the form of heap-allocated `BlobContents`
objects that can be directly inserted into the cache. The allocations backing
these `BlobContents` objects are made using the blob cache's allocator if the
blobs are to be inserted into the cache (i.e. if a cache is configured and the
`fill_cache` read option is set). Note: this PR focuses on the common case when
blobs are compressed; some further small optimizations are possible for uncompressed
blobs.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10647

Test Plan: `make check`

Reviewed By: riversand963

Differential Revision: D39335185

Pulled By: ltamasi

fbshipit-source-id: 464503d60a5520d654c8273ffb8efd5d1bcd7b36
2022-09-08 12:40:18 -07:00
Peter Dillinger 6de7081cf3 Always verify SST unique IDs on SST file open (#10532)
Summary:
Although we've been tracking SST unique IDs in the DB manifest
unconditionally, checking has been opt-in and with an extra pass at DB::Open
time. This changes the behavior of `verify_sst_unique_id_in_manifest` to
check unique ID against manifest every time an SST file is opened through
table cache (normal DB operations), replacing the explicit pass over files
at DB::Open time. This change also enables the option by default and
removes the "EXPERIMENTAL" designation.

One possible criticism is that the option no longer ensures the integrity
of a DB at Open time. This is far from an all-or-nothing issue. Verifying
the IDs of all SST files hardly ensures all the data in the DB is readable.
(VerifyChecksum is supposed to do that.) Also, with
max_open_files=-1 (default, extremely common), all SST files are
opened at DB::Open time anyway.

Implementation details:
* `VerifySstUniqueIdInManifest()` functions are the extra/explicit pass
that is now removed.
* Unit tests that manipulate/corrupt table properties have to opt out of
this check, because that corrupts the "actual" unique id. (And even for
testing we don't currently have a mechanism to set "no unique id"
in the in-memory file metadata for new files.)
* A lot of other unit test churn relates to (a) default checking on, and
(b) checking on SST open even without DB::Open (e.g. on flush)
* Use `FileMetaData` for more `TableCache` operations (in place of
`FileDescriptor`) so that we have access to the unique_id whenever
we might need to open an SST file. **There is the possibility of
performance impact because we can no longer use the more
localized `fd` part of an `FdWithKeyRange` but instead follow the
`file_metadata` pointer. However, this change (possible regression)
is only done for `GetMemoryUsageByTableReaders`.**
* Removed a completely unnecessary constructor overload of
`TableReaderOptions`

Possible follow-up:
* Verification only happens when opening through table cache. Are there
more places where this should happen?
* Improve error message when there is a file size mismatch vs. manifest
(FIXME added in the appropriate place).
* I'm not sure there's a justification for `FileDescriptor` to be distinct from
`FileMetaData`.
* I'm skeptical that `FdWithKeyRange` really still makes sense for
optimizing some data locality by duplicating some data in memory, but I
could be wrong.
* An unnecessary overload of NewTableReader was recently added, in
the public API nonetheless (though unusable there). It should be cleaned
up to put most things under `TableReaderOptions`.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10532

Test Plan:
updated unit tests

Performance test showing no significant difference (just noise I think):
`./db_bench -benchmarks=readwhilewriting[-X10] -num=3000000 -disable_wal=1 -bloom_bits=8 -write_buffer_size=1000000 -target_file_size_base=1000000`
Before: readwhilewriting [AVG 10 runs] : 68702 (± 6932) ops/sec
After: readwhilewriting [AVG 10 runs] : 68239 (± 7198) ops/sec

Reviewed By: jay-zhuang

Differential Revision: D38765551

Pulled By: pdillinger

fbshipit-source-id: a827a708155f12344ab2a5c16e7701c7636da4c2
2022-09-07 22:52:42 -07:00
Bo Wang d490bfcdb6 Avoid recompressing cold block in CompressedSecondaryCache (#10527)
Summary:
**Summary:**
When a block is firstly `Lookup` from the secondary cache, we just insert a dummy block in the primary cache (charging the actual size of the block) and don’t erase the block from the secondary cache. A standalone handle is returned from `Lookup`. Only if the block is hit again, we erase it from the secondary cache and add it into the primary cache.

When a block is firstly evicted from the primary cache to the secondary cache, we just insert a dummy block (size 0) in the secondary cache. When the block is evicted again, it is treated as a hot block and is inserted into the secondary cache.

**Implementation Details**
Add a new state of LRUHandle: The handle is never inserted into the LRUCache (both hash table and LRU list) and it doesn't experience the above three states. The entry can be freed when refs becomes 0.  (refs >= 1 && in_cache == false && IS_STANDALONE == true)

The behaviors of  `LRUCacheShard::Lookup()` are updated if the secondary_cache is CompressedSecondaryCache:
1. If a handle is found in primary cache:
  1.1. If the handle's value is not nullptr, it is returned immediately.
  1.2. If the handle's value is nullptr, this means the handle is a dummy one. For a dummy handle, if it was retrieved from secondary cache, it may still exist in secondary cache.
    - 1.2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr.
    - 1.2.2. If the handle from secondary cache is valid, erase it from the secondary cache and add it into the primary cache.
2. If a handle is not found in primary cache:
  2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr.
  2.2.  If the handle from secondary cache is valid, insert a dummy block in the primary cache (charging the actual size of the block)  and return a standalone handle.

The behaviors of `LRUCacheShard::Promote()` are updated as follows:
1. If `e->sec_handle` has value, one of the following steps can happen:
  1.1. Insert a dummy handle and return a standalone handle to caller when `secondary_cache_` is `CompressedSecondaryCache` and e is a standalone handle.
  1.2. Insert the item into the primary cache and return the handle to caller.
  1.3. Exception handling.
3. If `e->sec_handle` has no value, mark the item as not in cache and charge the cache as its only metadata that'll shortly be released.

The behavior of  `CompressedSecondaryCache::Insert()` is updated:
1. If a block is evicted from the primary cache for the first time, a dummy item is inserted.
4. If a dummy item is found for a block, the block is inserted into the secondary cache.

The behavior of  `CompressedSecondaryCache:::Lookup()` is updated:
1. If a handle is not found or it is a dummy item, a nullptr is returned.
2. If `erase_handle` is true, the handle is erased.

The behaviors of  `LRUCacheShard::Release()` are adjusted for the standalone handles.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10527

Test Plan:
1. stress tests.
5. unit tests.
6. CPU profiling for db_bench.

Reviewed By: siying

Differential Revision: D38747613

Pulled By: gitbw95

fbshipit-source-id: 74a1eba7e1957c9affb2bd2ae3e0194584fa6eca
2022-09-07 19:00:27 -07:00
Levi Tamasi c8543296ca Support custom allocators for the blob cache (#10628)
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/10628

Test Plan: `make check`

Reviewed By: akankshamahajan15

Differential Revision: D39228165

Pulled By: ltamasi

fbshipit-source-id: 591fdff08db400b170b26f0165551f86d33c1dbf
2022-09-06 13:31:48 -07:00
Andrew Kryczka 5a97e6b1d2 Deflake blob caching tests (#10636)
Summary:
Example failure:

```
db/blob/db_blob_basic_test.cc:226: Failure
Expected equality of these values:
  i
    Which is: 1
  num_blobs
    Which is: 5
```

I can't repro locally, but it looks like the 2KB cache is too small to guarantee no eviction happens between loading all the data into cache and reading from `kBlockCacheTier`. This 2KB setting appears to have come from a test where the cached entries are pinned, where it makes sense to have a small setting. However, such a small setting makes less sense when the blocks are evictable but must remain cached per the test's expectation. This PR increases the capacity setting to 2MB for those cases.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10636

Reviewed By: cbi42

Differential Revision: D39250976

Pulled By: ajkr

fbshipit-source-id: 769309f9a19cfac20b67b927805c8df5c1d2d1f5
2022-09-06 13:01:05 -07:00
Andrew Kryczka 1ffadbe9fc Deflake DBErrorHandlingFSTest.*WALWriteError (#10642)
Summary:
Example flake: https://app.circleci.com/pipelines/github/facebook/rocksdb/17660/workflows/7a891875-f07b-4a67-b204-eaa7ca9f9aa2/jobs/467496

The test could get stuck in out-of-space due to a callback executing `SetFilesystemActive(false /* active */)` after the test executed `SetFilesystemActive(true /* active */)`. This could happen because background info logging went through the SyncPoint callback "WritableFileWriter::Append:BeforePrepareWrite", probably unintentionally. The solution of this PR is to call `ClearAllCallBacks()` to wait for any such pending callbacks to drain before calling `SetFilesystemActive(true /* active */)`

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10642

Reviewed By: cbi42

Differential Revision: D39265381

Pulled By: ajkr

fbshipit-source-id: 9a2f4916ab19726c8fb4b3a3b590b1b9ed93de1b
2022-09-06 12:59:02 -07:00
Andrew Kryczka fe5fbe32cb Deflake DBBlockCacheTest1.WarmCacheWithBlocksDuringFlush (#10635)
Summary:
Previously, automatic compaction could be triggered prior to the test invoking CompactRange(). It could lead to the following flaky failure:

```
/root/project/db/db_block_cache_test.cc:753: Failure
Expected equality of these values:
  1 + kNumBlocks
    Which is: 11
  options.statistics->getTickerCount(BLOCK_CACHE_INDEX_ADD)
    Which is: 10
```

A sequence leading to this failure was:

* Automatic compaction
  * files [1] [2] trivially moved
  * files [3] [4] [5] [6] trivially moved
* CompactRange()
  * files [7] [8] [9] trivially moved
  * file [10] trivially moved

In such a case, the index/filter block adds that the test expected did not happen since there were no new files.

This PR just tweaks settings to ensure the `CompactRange()` produces one new file.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10635

Reviewed By: cbi42

Differential Revision: D39250869

Pulled By: ajkr

fbshipit-source-id: a3c94c49069e28c49c40b4b80dae0059739d19fd
2022-09-04 14:55:09 -07:00
Changyu Bi 30bc495c03 Skip swaths of range tombstone covered keys in merging iterator (2022 edition) (#10449)
Summary:
Delete range logic is moved from `DBIter` to `MergingIterator`, and `MergingIterator` will seek to the end of a range deletion if possible instead of scanning through each key and check with `RangeDelAggregator`.

With the invariant that a key in level L (consider memtable as the first level, each immutable and L0 as a separate level) has a larger sequence number than all keys in any level >L, a range tombstone `[start, end)` from level L covers all keys in its range in any level >L. This property motivates optimizations in iterator:
- in `Seek(target)`, if level L has a range tombstone `[start, end)` that covers `target.UserKey`, then for all levels > L, we can do Seek() on `end` instead of `target` to skip some range tombstone covered keys.
- in `Next()/Prev()`, if the current key is covered by a range tombstone `[start, end)` from level L, we can do `Seek` to `end` for all levels > L.

This PR implements the above optimizations in `MergingIterator`. As all range tombstone covered keys are now skipped in `MergingIterator`, the range tombstone logic is removed from `DBIter`. The idea in this PR is similar to https://github.com/facebook/rocksdb/issues/7317, but this PR leaves `InternalIterator` interface mostly unchanged. **Credit**: the cascading seek optimization and the sentinel key (discussed below) are inspired by [Pebble](https://github.com/cockroachdb/pebble/blob/master/merging_iter.go) and suggested by ajkr in https://github.com/facebook/rocksdb/issues/7317. The two optimizations are mostly implemented in `SeekImpl()/SeekForPrevImpl()` and `IsNextDeleted()/IsPrevDeleted()` in `merging_iterator.cc`. See comments for each method for more detail.

One notable change is that the minHeap/maxHeap used by `MergingIterator` now contains range tombstone end keys besides point key iterators. This helps to reduce the number of key comparisons. For example, for a range tombstone `[start, end)`, a `start` and an `end` `HeapItem` are inserted into the heap. When a `HeapItem` for range tombstone start key is popped from the minHeap, we know this range tombstone becomes "active" in the sense that, before the range tombstone's end key is popped from the minHeap, all the keys popped from this heap is covered by the range tombstone's internal key range `[start, end)`.

Another major change, *delete range sentinel key*, is made to `LevelIterator`. Before this PR, when all point keys in an SST file are iterated through in `MergingIterator`, a level iterator would advance to the next SST file in its level. In the case when an SST file has a range tombstone that covers keys beyond the SST file's last point key, advancing to the next SST file would lose this range tombstone. Consequently, `MergingIterator` could return keys that should have been deleted by some range tombstone. We prevent this by pretending that file boundaries in each SST file are sentinel keys. A `LevelIterator` now only advance the file iterator once the sentinel key is processed.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10449

Test Plan:
- Added many unit tests in db_range_del_test
- Stress test: `./db_stress --readpercent=5 --prefixpercent=19 --writepercent=20 -delpercent=10 --iterpercent=44 --delrangepercent=2`
- Additional iterator stress test is added to verify against iterators against expected state: https://github.com/facebook/rocksdb/issues/10538. This is based on ajkr's previous attempt https://github.com/facebook/rocksdb/pull/5506#issuecomment-506021913.

```
python3 ./tools/db_crashtest.py blackbox --simple --write_buffer_size=524288 --target_file_size_base=524288 --max_bytes_for_level_base=2097152 --compression_type=none --max_background_compactions=8 --value_size_mult=33 --max_key=5000000 --interval=10 --duration=7200 --delrangepercent=3 --delpercent=9 --iterpercent=25 --writepercent=60 --readpercent=3 --prefixpercent=0 --num_iterations=1000 --range_deletion_width=100 --verify_iterator_with_expected_state_one_in=1
```

- Performance benchmark: I used a similar setup as in the blog [post](http://rocksdb.org/blog/2018/11/21/delete-range.html) that introduced DeleteRange, "a database with 5 million data keys, and 10000 range tombstones (ignoring those dropped during compaction) that were written in regular intervals after 4.5 million data keys were written".  As expected, the performance with this PR depends on the range tombstone width.
```
# Setup:
TEST_TMPDIR=/dev/shm ./db_bench_main --benchmarks=fillrandom --writes=4500000 --num=5000000
TEST_TMPDIR=/dev/shm ./db_bench_main --benchmarks=overwrite --writes=500000 --num=5000000 --use_existing_db=true --writes_per_range_tombstone=50

# Scan entire DB
TEST_TMPDIR=/dev/shm ./db_bench_main --benchmarks=readseq[-X5] --use_existing_db=true --num=5000000 --disable_auto_compactions=true

# Short range scan (10 Next())
TEST_TMPDIR=/dev/shm/width-100/ ./db_bench_main --benchmarks=seekrandom[-X5] --use_existing_db=true --num=500000 --reads=100000 --seek_nexts=10 --disable_auto_compactions=true

# Long range scan(1000 Next())
TEST_TMPDIR=/dev/shm/width-100/ ./db_bench_main --benchmarks=seekrandom[-X5] --use_existing_db=true --num=500000 --reads=2500 --seek_nexts=1000 --disable_auto_compactions=true
```
Avg over of 10 runs (some slower tests had fews runs):

For the first column (tombstone), 0 means no range tombstone, 100-10000 means width of the 10k range tombstones, and 1 means there is a single range tombstone in the entire DB (width is 1000). The 1 tombstone case is to test regression when there's very few range tombstones in the DB, as no range tombstone is likely to take a different code path than with range tombstones.

- Scan entire DB

| tombstone width | Pre-PR ops/sec | Post-PR ops/sec | ±% |
| ------------- | ------------- | ------------- |  ------------- |
| 0 range tombstone    |2525600 (± 43564)    |2486917 (± 33698)    |-1.53%               |
| 100   |1853835 (± 24736)    |2073884 (± 32176)    |+11.87%              |
| 1000  |422415 (± 7466)      |1115801 (± 22781)    |+164.15%             |
| 10000 |22384 (± 227)        |227919 (± 6647)      |+918.22%             |
| 1 range tombstone      |2176540 (± 39050)    |2434954 (± 24563)    |+11.87%              |
- Short range scan

| tombstone width | Pre-PR ops/sec | Post-PR ops/sec | ±% |
| ------------- | ------------- | ------------- |  ------------- |
| 0  range tombstone   |35398 (± 533)        |35338 (± 569)        |-0.17%               |
| 100   |28276 (± 664)        |31684 (± 331)        |+12.05%              |
| 1000  |7637 (± 77)          |25422 (± 277)        |+232.88%             |
| 10000 |1367                 |28667                |+1997.07%            |
| 1 range tombstone      |32618 (± 581)        |32748 (± 506)        |+0.4%                |

- Long range scan

| tombstone width | Pre-PR ops/sec | Post-PR ops/sec | ±% |
| ------------- | ------------- | ------------- |  ------------- |
| 0 range tombstone     |2262 (± 33)          |2353 (± 20)          |+4.02%               |
| 100   |1696 (± 26)          |1926 (± 18)          |+13.56%              |
| 1000  |410 (± 6)            |1255 (± 29)          |+206.1%              |
| 10000 |25                   |414                  |+1556.0%             |
| 1 range tombstone   |1957 (± 30)          |2185 (± 44)          |+11.65%              |

- Microbench does not show significant regression: https://gist.github.com/cbi42/59f280f85a59b678e7e5d8561e693b61

Reviewed By: ajkr

Differential Revision: D38450331

Pulled By: cbi42

fbshipit-source-id: b5ef12e8d8c289ed2e163ccdf277f5039b511fca
2022-09-02 09:51:19 -07:00
Levi Tamasi b07217da04 Pin the newly cached blob after insert (#10625)
Summary:
With the current code, when a blob isn't found in the cache and gets read
from the blob file and then inserted into the cache, the application gets
passed the self-contained `PinnableSlice` resulting from the blob file read.
The patch changes this so that the `PinnableSlice` pins the cache entry
instead in this case.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10625

Test Plan: `make check`

Reviewed By: pdillinger

Differential Revision: D39220904

Pulled By: ltamasi

fbshipit-source-id: cb9c62881e3523b1e9f614e00bf503bac2fe3b0a
2022-09-01 16:25:46 -07:00
anand76 5fbcc8c54d Update MULTIGET_IO_BATCH_SIZE for non-async MultiGet (#10622)
Summary:
This stat was only getting updated in the async (coroutine) version of MultiGet.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10622

Reviewed By: akankshamahajan15

Differential Revision: D39188790

Pulled By: anand1976

fbshipit-source-id: 7e231507f65fc94c8a006c38f79dfba182a2c24a
2022-08-31 21:03:52 -07:00
Changyu Bi 3a75219e5d Validate option `memtable_protection_bytes_per_key` (#10621)
Summary:
sanity check value for option `memtable_protection_bytes_per_key` in `ColumnFamilyData::ValidateOptions()`.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10621

Test Plan: `make check`, added unit test in ColumnFamilyTest.

Reviewed By: ajkr

Differential Revision: D39180133

Pulled By: cbi42

fbshipit-source-id: 009e0da3ccb332d1c9e14d20193304610bd4eb8a
2022-08-31 17:47:07 -07:00
Levi Tamasi 01e88dfeb4 Support using cache warming with the secondary blob cache (#10603)
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/10603

Test Plan: `make check`

Reviewed By: riversand963

Differential Revision: D39117952

Pulled By: ltamasi

fbshipit-source-id: 5e956fa2fc18974876a5c87686acb50718e0edb7
2022-08-30 17:03:45 -07:00
Hui Xiao 8a85946f58 Add missing mutex when reading from shared variable bg_bottom_compaction_scheduled_, bg_compaction_scheduled_ (#10610)
Summary:
**Context/Summary:**
According to https://github.com/facebook/rocksdb/blob/7.6.fb/db/compaction/compaction_job.h#L328-L332, any reading in the form of `*bg_compaction_scheduled_` , `*bg_bottom_compaction_scheduled_` should be protected by mutex, which isn't the case for some assert statement. This leads to a data race that can be repro-ed by the following command (command coming soon)

```
db=/dev/shm/rocksdb_crashtest_blackbox
exp=/dev/shm/rocksdb_crashtest_expected
rm -rf $db $exp
mkdir -p $exp

./db_stress --clear_column_family_one_in=0 --column_families=1 --db=$db --delpercent=10 --delrangepercent=0 --destroy_db_initially=1 --expected_values_dir=$exp --iterpercent=0 --key_len_percent_dist=1,30,69 --max_key=1000000 --max_key_len=3 --prefixpercent=0 --readpercent=0 --reopen=0 --ops_per_thread=100000000 --value_size_mult=32 --writepercent=90  --compaction_pri=4 --use_txn=1 --level_compaction_dynamic_level_bytes=True  --compaction_ttl=0  --compact_files_one_in=1000000 --compact_range_one_in=1000000 --value_size_mult=32 --verify_db_one_in=1000  --write_buffer_size=65536 --mark_for_compaction_one_file_in=10 --max_background_compactions=20 --max_key=25000000 --max_key_len=3 --max_write_buffer_number=3 --max_write_buffer_size_to_maintain=2097152 --target_file_size_base=2097152 --target_file_size_multiplier=2
```
```
WARNING: ThreadSanitizer: data race (pid=73424)
  Read of size 4 at 0x7b8c0000151c by thread T13:
    #0 ReleaseSubcompactionResources internal_repo_rocksdb/repo/db/compaction/compaction_job.cc:390 (db_stress+0x630aa3)
    https://github.com/facebook/rocksdb/issues/1 rocksdb::CompactionJob::Run() internal_repo_rocksdb/repo/db/compaction/compaction_job.cc:741 (db_stress+0x630aa3)
    https://github.com/facebook/rocksdb/issues/2 rocksdb::DBImpl::BackgroundCompaction(bool*, rocksdb::JobContext*, rocksdb::LogBuffer*, rocksdb::DBImpl::PrepickedCompaction*, rocksdb::Env::Priority) internal_repo_rocksdb/repo/db/db_impl/db_impl_compaction_flush.cc:3436 (db_stress+0x60b2cc)
    https://github.com/facebook/rocksdb/issues/3 rocksdb::DBImpl::BackgroundCallCompaction(rocksdb::DBImpl::PrepickedCompaction*, rocksdb::Env::Priority) internal_repo_rocksdb/repo/db/db_impl/db_impl_compaction_flush.cc:2950 (db_stress+0x606d79)
    https://github.com/facebook/rocksdb/issues/4 rocksdb::DBImpl::BGWorkCompaction(void*) internal_repo_rocksdb/repo/db/db_impl/db_impl_compaction_flush.cc:2693 (db_stress+0x60356a)

  Previous write of size 4 at 0x7b8c0000151c by thread T12 (mutexes: write M438955329917552448):
    #0 rocksdb::DBImpl::BackgroundCallCompaction(rocksdb::DBImpl::PrepickedCompaction*, rocksdb::Env::Priority) internal_repo_rocksdb/repo/db/db_impl/db_impl_compaction_flush.cc:3018 (db_stress+0x6072a1)
    https://github.com/facebook/rocksdb/issues/1 rocksdb::DBImpl::BGWorkCompaction(void*) internal_repo_rocksdb/repo/db/db_impl/db_impl_compaction_flush.cc:2693 (db_stress+0x60356a)

Location is heap block of size 6720 at 0x7b8c00000000 allocated by main thread:
    #0 operator new(unsigned long, std::align_val_t) <null> (db_stress+0xbab5bb)
    https://github.com/facebook/rocksdb/issues/1 rocksdb::DBImpl::Open(rocksdb::DBOptions const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::vector<rocksdb::ColumnFamilyDescriptor, std::allocator<rocksdb::ColumnFamilyDescriptor> > const&, std::vector<rocksdb::ColumnFamilyHandle*, std::allocator<rocksdb::ColumnFamilyHandle*> >*, rocksdb::DB**, bool, bool) internal_repo_rocksdb/repo/db/db_impl/db_impl_open.cc:1811 (db_stress+0x69769a)
    https://github.com/facebook/rocksdb/issues/2 rocksdb::TransactionDB::Open(rocksdb::DBOptions const&, rocksdb::TransactionDBOptions const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::vector<rocksdb::ColumnFamilyDescriptor, std::allocator<rocksdb::ColumnFamilyDescriptor> > const&, std::vector<rocksdb::ColumnFamilyHandle*, std::allocator<rocksdb::ColumnFamilyHandle*> >*, rocksdb::TransactionDB**) internal_repo_rocksdb/repo/utilities/transactions/pessimistic_transaction_db.cc:258 (db_stress+0x8ae1f4)
    https://github.com/facebook/rocksdb/issues/3 rocksdb::StressTest::Open(rocksdb::SharedState*) internal_repo_rocksdb/repo/db_stress_tool/db_stress_test_base.cc:2611 (db_stress+0x32b927)
    https://github.com/facebook/rocksdb/issues/4 rocksdb::StressTest::InitDb(rocksdb::SharedState*) internal_repo_rocksdb/repo/db_stress_tool/db_stress_test_base.cc:290 (db_stress+0x34712c)
```
This PR added all the missing mutex that should've been in place

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10610

Test Plan:
- Past repro command
- Existing CI

Reviewed By: riversand963

Differential Revision: D39143016

Pulled By: hx235

fbshipit-source-id: 51dd4db55ad306f3dbda5d0dd54d6f2513cf70f2
2022-08-30 16:24:01 -07:00
Yanqin Jin 7c0838e65e Use std::make_unique when possible (#10578)
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/10578

Test Plan: make check

Reviewed By: ajkr

Differential Revision: D39064748

Pulled By: riversand963

fbshipit-source-id: c7c135b7b713608edb14614846050ece6d4cc59d
2022-08-29 19:09:29 -07:00
Hui Xiao e484b81eee Sync dir containing CURRENT after RenameFile on CURRENT as much as possible (#10573)
Summary:
**Context:**
Below crash test revealed a bug that directory containing CURRENT file (short for `dir_contains_current_file` below) was not always get synced after a new CURRENT is created and being called with `RenameFile` as part of the creation.

This bug exposes a risk that such un-synced directory containing the updated CURRENT can’t survive a host crash (e.g, power loss) hence get corrupted. This then will be followed by a recovery from a corrupted CURRENT that we don't want.

The root-cause is that a nullptr `FSDirectory* dir_contains_current_file` sometimes gets passed-down to `SetCurrentFile()` hence in those case `dir_contains_current_file->FSDirectory::FsyncWithDirOptions()` will be skipped  (which otherwise will internally call`Env/FS::SyncDic()` )
```
./db_stress --acquire_snapshot_one_in=10000 --adaptive_readahead=1 --allow_data_in_errors=True --avoid_unnecessary_blocking_io=0 --backup_max_size=104857600 --backup_one_in=100000 --batch_protection_bytes_per_key=8 --block_size=16384 --bloom_bits=134.8015470676662 --bottommost_compression_type=disable --cache_size=8388608 --checkpoint_one_in=1000000 --checksum_type=kCRC32c --clear_column_family_one_in=0 --compact_files_one_in=1000000 --compact_range_one_in=1000000 --compaction_pri=2 --compaction_ttl=100 --compression_max_dict_buffer_bytes=511 --compression_max_dict_bytes=16384 --compression_type=zstd --compression_use_zstd_dict_trainer=1 --compression_zstd_max_train_bytes=65536 --continuous_verification_interval=0 --data_block_index_type=0 --db=$db --db_write_buffer_size=1048576 --delpercent=5 --delrangepercent=0 --destroy_db_initially=0 --disable_wal=0 --enable_compaction_filter=0 --enable_pipelined_write=1 --expected_values_dir=$exp --fail_if_options_file_error=1 --file_checksum_impl=none --flush_one_in=1000000 --get_current_wal_file_one_in=0 --get_live_files_one_in=1000000 --get_property_one_in=1000000 --get_sorted_wal_files_one_in=0 --index_block_restart_interval=4 --ingest_external_file_one_in=0 --iterpercent=10 --key_len_percent_dist=1,30,69 --level_compaction_dynamic_level_bytes=True --mark_for_compaction_one_file_in=10 --max_background_compactions=20 --max_bytes_for_level_base=10485760 --max_key=10000 --max_key_len=3 --max_manifest_file_size=16384 --max_write_batch_group_size_bytes=64 --max_write_buffer_number=3 --max_write_buffer_size_to_maintain=0 --memtable_prefix_bloom_size_ratio=0.001 --memtable_protection_bytes_per_key=1 --memtable_whole_key_filtering=1 --mmap_read=1 --nooverwritepercent=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_pinning=2 --pause_background_one_in=1000000 --periodic_compaction_seconds=0 --prefix_size=5 --prefixpercent=5 --prepopulate_block_cache=1 --progress_reports=0 --read_fault_one_in=1000 --readpercent=45 --recycle_log_file_num=0 --reopen=0 --ribbon_starting_level=999 --secondary_cache_fault_one_in=32 --secondary_cache_uri=compressed_secondary_cache://capacity=8388608 --set_options_one_in=10000 --snapshot_hold_ops=100000 --sst_file_manager_bytes_per_sec=0 --sst_file_manager_bytes_per_truncate=0 --subcompactions=3 --sync_fault_injection=1 --target_file_size_base=2097 --target_file_size_multiplier=2 --test_batches_snapshots=1 --top_level_index_pinning=1 --use_full_merge_v1=1 --use_merge=1 --value_size_mult=32 --verify_checksum=1 --verify_checksum_one_in=1000000 --verify_db_one_in=100000 --verify_sst_unique_id_in_manifest=1 --wal_bytes_per_sync=524288 --write_buffer_size=4194 --writepercent=35
```

```
stderr:
WARNING: prefix_size is non-zero but memtablerep != prefix_hash
db_stress: utilities/fault_injection_fs.cc:748: virtual rocksdb::IOStatus rocksdb::FaultInjectionTestFS::RenameFile(const std::string &, const std::string &, const rocksdb::IOOptions &, rocksdb::IODebugContext *): Assertion `tlist.find(tdn.second) == tlist.end()' failed.`
```

**Summary:**
The PR ensured the non-test path pass down a non-null dir containing CURRENT (which is by current RocksDB assumption just db_dir) by doing the following:
- Renamed `directory_to_fsync` as `dir_contains_current_file` in `SetCurrentFile()` to tighten the association between this directory and CURRENT file
- Changed `SetCurrentFile()` API to require `dir_contains_current_file` being passed-in, instead of making it by default nullptr.
    -  Because `SetCurrentFile()`'s `dir_contains_current_file` is passed down from `VersionSet::LogAndApply()` then `VersionSet::ProcessManifestWrites()` (i.e, think about this as a chain of 3 functions related to MANIFEST update), these 2 functions also got refactored to require `dir_contains_current_file`
- Updated the non-test-path callers of these 3 functions to obtain and pass in non-nullptr `dir_contains_current_file`, which by current assumption of RocksDB, is the `FSDirectory* db_dir`.
    - `db_impl` path will obtain `DBImpl::directories_.getDbDir()` while others with no access to such `directories_` are obtained on the fly by creating such object `FileSystem::NewDirectory(..)` and manage it by unique pointers to ensure short life time.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10573

Test Plan:
- `make check`
- Passed the repro db_stress command
- For future improvement, since we currently don't assert dir containing CURRENT to be non-nullptr due to https://github.com/facebook/rocksdb/pull/10573#pullrequestreview-1087698899, there is still chances that future developers mistakenly pass down nullptr dir containing CURRENT thus resulting skipped sync dir and cause the bug again. Therefore a smarter test (e.g, such as quoted from ajkr  "(make) unsynced data loss to be dropping files corresponding to unsynced directory entries") is still needed.

Reviewed By: ajkr

Differential Revision: D39005886

Pulled By: hx235

fbshipit-source-id: 336fb9090d0cfa6ca3dd580db86268007dde7f5a
2022-08-29 17:35:21 -07:00
Levi Tamasi 7818560194 Add a dedicated cache entry role for blobs (#10601)
Summary:
The patch adds a dedicated cache entry role for blob values and switches
to a registered deleter so that blobs show up as a separate bucket
(as opposed to "Misc") in the cache occupancy statistics, e.g.

```
Block cache entry stats(count,size,portion): DataBlock(133515,531.73 MB,13.6866%) BlobValue(1824855,3.10 GB,81.7071%) Misc(1,0.00 KB,0%)
```

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10601

Test Plan: Ran `make check` and tested the cache occupancy statistics using `db_bench`.

Reviewed By: riversand963

Differential Revision: D39107915

Pulled By: ltamasi

fbshipit-source-id: 8446c3b190a41a144030df73f318eeda4398c125
2022-08-29 16:11:59 -07:00
Peter Dillinger c5afbbfe4b Don't wait for indirect flush in read-only DB (#10569)
Summary:
Some APIs for getting live files, which are used by Checkpoint
and BackupEngine, can optionally trigger and wait for a flush. These
would deadlock when used on a read-only DB. Here we fix that by assuming
the user wants the overall operation to succeed and is OK without
flushing (because the DB is read-only).

Follow-up work: the same or other issues can be hit by directly invoking
some DB functions that are clearly not appropriate for read-only
instance, but are not covered by overrides in DBImplReadOnly and
CompactedDBImpl. These should be fixed to avoid similar problems on
accidental misuse. (Long term, it would be nice to have a DBReadOnly
class without those members, like BackupEngineReadOnly.)

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10569

Test Plan: tests updated to catch regression (hang before the fix)

Reviewed By: riversand963

Differential Revision: D38995759

Pulled By: pdillinger

fbshipit-source-id: f5f8bc7123e13cb45bd393dd974d7d6eda20bc68
2022-08-29 13:36:23 -07:00
Levi Tamasi 23376aa576 Improve the accounting of memory used by cached blobs (#10583)
Summary:
The patch improves the bookkeeping around the memory usage of
cached blobs in two ways: 1) it uses `malloc_usable_size`, which accounts
for allocator bin sizes etc., and 2) it also considers the memory usage
of the `BlobContents` object in addition to the blob itself. Note: some unit
tests had been relying on the cache charge being equal to the size of the
cached blob; these were updated.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10583

Test Plan: `make check`

Reviewed By: riversand963

Differential Revision: D39060680

Pulled By: ltamasi

fbshipit-source-id: 3583adce2b4ce6e84861f3fadccbfd2e5a3cc482
2022-08-26 15:53:08 -07:00
Jay Zhuang d9e71fb2c5 Fix periodic_task unable to re-register the same task type (#10379)
Summary:
Timer has a limitation that it cannot re-register a task with the same name,
because the cancel only mark the task as invalid and wait for the Timer thread
to clean it up later, before the task is cleaned up, the same task name cannot
be added. Which makes the task option update likely to fail, which basically
cancel and re-register the same task name. Change the periodic task name to a
random unique id and store it in periodic_task_scheduler.

Also refactor the `periodic_work` to `periodic_task` to make each job function
as a `task`.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10379

Test Plan: unittests

Reviewed By: ajkr

Differential Revision: D38000615

Pulled By: jay-zhuang

fbshipit-source-id: e4135f9422e3b53aaec8eda54f4e18ce633a279e
2022-08-25 18:52:37 -07:00
Levi Tamasi 3f57d84af4 Introduce a dedicated class to represent blob values (#10571)
Summary:
The patch introduces a new class called `BlobContents`, which represents
a single uncompressed blob value. We currently use `std::string` for this
purpose; `BlobContents` is somewhat smaller but the primary reason for a
dedicated class is that it enables certain improvements and optimizations
like eliding a copy when inserting a blob into the cache, using custom
allocators, or more control over and better accounting of the memory usage
of cached blobs (see https://github.com/facebook/rocksdb/issues/10484).
(We plan to implement these in subsequent PRs.)

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10571

Test Plan: `make check`

Reviewed By: riversand963

Differential Revision: D39000965

Pulled By: ltamasi

fbshipit-source-id: f296eddf9dec4fc3e11cad525b462bdf63c78f96
2022-08-25 16:45:48 -07:00
Andrew Kryczka 7ad4b38617 Ensure writes to WAL tail during `FlushWAL(true /* sync */)` will be synced (#10560)
Summary:
WAL append and switch can both happen between `FlushWAL(true /* sync */)`'s sync operations and its call to `MarkLogsSynced()`. We permit this since locks need to be released for the sync operations. Such an appended/switched WAL is both inactive and incompletely synced at the time `MarkLogsSynced()` processes it.

Prior to this PR, `MarkLogsSynced()` assumed all inactive WALs were fully synced and removed them from consideration for future syncs. That was wrong in the scenario described above and led to the latest append(s) never being synced. This PR changes `MarkLogsSynced()` to only remove inactive WALs from consideration for which all flushed data has been synced.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10560

Test Plan: repro unit test for the scenario described above. Without this PR, it fails on "key2" not found

Reviewed By: riversand963

Differential Revision: D38957391

Pulled By: ajkr

fbshipit-source-id: da77175eba97ff251a4219b227b3bb2d4843ed26
2022-08-25 12:53:46 -07:00
muthukrishnan.s 79ed4be80f Add get_name, get_id for column family handle in C API (#10499)
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/10499

Reviewed By: hx235

Differential Revision: D38523859

Pulled By: ajkr

fbshipit-source-id: 268bba1fcce4a3e20c51e498a79d7b476f663aea
2022-08-24 13:49:02 -07:00
Levi Tamasi 78bbdef530 Fix a typo in BlobSecondaryCacheTest (#10566)
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/10566

Test Plan: `make check`

Reviewed By: riversand963

Differential Revision: D38989926

Pulled By: ltamasi

fbshipit-source-id: 6402635fe745e4e7eb3083ef9ad9f04c0177d762
2022-08-24 13:08:43 -07:00
EdvardD 6e93d24935 Expose set_checksum function to C api (#10537)
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/10537

Reviewed By: hx235

Differential Revision: D38797662

Pulled By: ajkr

fbshipit-source-id: a8db723c3eb9d5592cd78f8be7e442e4826686ad
2022-08-23 14:59:27 -07:00
Chen Lixiang 9593fd1c82 Fix wrong compression type and options in universal compaction picker (#10515)
Summary:
In UniversalCompactionBuilder::PickCompactionToReduceSortedRuns, we passed start_level to get compression type and options. I think that is wrong and we should use output_level instead.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10515

Reviewed By: hx235

Differential Revision: D38611335

Pulled By: ajkr

fbshipit-source-id: bb860caed4b6c6bbde8f75fc50cf875a9f04723d
2022-08-23 14:58:02 -07:00
anand76 35cdd3e71e MultiGet async IO across multiple levels (#10535)
Summary:
This PR exploits parallelism in MultiGet across levels. It applies only to the coroutine version of MultiGet. Previously, MultiGet file reads from SST files in the same level were parallelized. With this PR, MultiGet batches with keys distributed across multiple levels are read in parallel. This is accomplished by splitting the keys not present in a level (determined by bloom filtering) into a separate batch, and processing the new batch in parallel with the original batch.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10535

Test Plan:
1. Ensure existing MultiGet unit tests pass, updating them as necessary
2. New unit tests - TODO
3. Run stress test - TODO

No noticeable regression (<1%) without async IO -
Without PR: `multireadrandom :       7.261 micros/op 1101724 ops/sec 60.007 seconds 66110936 operations;  571.6 MB/s (8168992 of 8168992 found)`
With PR: `multireadrandom :       7.305 micros/op 1095167 ops/sec 60.007 seconds 65717936 operations;  568.2 MB/s (8271992 of 8271992 found)`

For a fully cached DB, but with async IO option on, no regression observed (<1%) -
Without PR: `multireadrandom :       5.201 micros/op 1538027 ops/sec 60.005 seconds 92288936 operations;  797.9 MB/s (11540992 of 11540992 found) `
With PR: `multireadrandom :       5.249 micros/op 1524097 ops/sec 60.005 seconds 91452936 operations;  790.7 MB/s (11649992 of 11649992 found) `

Reviewed By: akankshamahajan15

Differential Revision: D38774009

Pulled By: anand1976

fbshipit-source-id: c955e259749f1c091590ade73105b3ee46cd0007
2022-08-19 16:52:52 -07:00
Levi Tamasi 81388b36e0 Add support for wide-column point lookups (#10540)
Summary:
The patch adds a new API `GetEntity` that can be used to perform
wide-column point lookups. It also extends the `Get` code path and
the `MemTable` / `MemTableList` and `Version` / `GetContext` logic
accordingly so that wide-column entities can be served from both
memtables and SSTs. If the result of a lookup is a wide-column entity
(`kTypeWideColumnEntity`), it is passed to the application in deserialized
form; if it is a plain old key-value (`kTypeValue`), it is presented as a
wide-column entity with a single default (anonymous) column.
(In contrast, regular `Get` returns plain old key-values as-is, and
returns the value of the default column for wide-column entities, see
https://github.com/facebook/rocksdb/issues/10483 .)

The result of `GetEntity` is a self-contained `PinnableWideColumns` object.
`PinnableWideColumns` contains a `PinnableSlice`, which either stores the
underlying data in its own buffer or holds on to a cache handle. It also contains
a `WideColumns` instance, which indexes the contents of the `PinnableSlice`,
so applications can access the values of columns efficiently.

There are several pieces of functionality which are currently not supported
for wide-column entities: there is currently no `MultiGetEntity` or wide-column
iterator; also, `Merge` and `GetMergeOperands` are not supported, and there
is no `GetEntity` implementation for read-only and secondary instances.
We plan to implement these in future PRs.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10540

Test Plan: `make check`

Reviewed By: akankshamahajan15

Differential Revision: D38847474

Pulled By: ltamasi

fbshipit-source-id: 42311a34ccdfe88b3775e847a5e2a5296e002b5b
2022-08-19 11:51:12 -07:00
Andrew Kryczka 91166012c8 Prevent a case of WriteBufferManager flush thrashing (#6364)
Summary:
Previously, the flushes triggered by `WriteBufferManager` could affect
the same CF repeatedly if it happens to get consecutive writes. Such
flushes are not particularly useful for reducing memory usage since
they switch nearly-empty memtables to immutable while they've just begun
filling their first arena block. In fact they may not even reduce the
mutable memory count if they involve replacing one mutable memtable containing
one arena block with a new mutable memtable containing one arena block.
Further, if such switches happen even a few times before a flush finishes,
the immutable memtable limit will be reached and writes will stall.

This PR adds a heuristic to not switch memtables to immutable for CFs
that already have one or more immutable memtables awaiting flush. There
is a memory usage regression if the user continues writing to the same
CF, that DB does not have any CFs eligible for switching, flushes
are not finishing, and the `WriteBufferManager` was constructed with
`allow_stall=false`. Before, it would grow by switching nearly empty
memtables until writes stall. Now, it would grow by filling memtables
until writes stall. This feels like an acceptable behavior change because
users who prefer to stall over violate the memory limit should be using
`allow_stall=true`, which is unaffected by this PR.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/6364

Test Plan:
- Command:

`rm -rf /dev/shm/dbbench/ && TEST_TMPDIR=/dev/shm ./db_bench -benchmarks=fillrandom -num_multi_db=8 -num_column_families=2 -write_buffer_size=4194304 -db_write_buffer_size=16777216 -compression_type=none -statistics=true -target_file_size_base=4194304 -max_bytes_for_level_base=16777216`

- `rocksdb.db.write.stall` count before this PR: 175
- `rocksdb.db.write.stall` count after this PR: 0

Reviewed By: jay-zhuang

Differential Revision: D20167197

Pulled By: ajkr

fbshipit-source-id: 4a64064e9bc33d57c0a35f15547542d0191d0cb7
2022-08-17 15:53:40 -07:00
anand76 65814a4ae6 Fix range deletion handling in async MultiGet (#10534)
Summary:
The fix in https://github.com/facebook/rocksdb/issues/10513 was not complete w.r.t range deletion handling. It didn't handle the case where a file with a range tombstone covering a key also overlapped another key in the batch. In that case, ```mget_range``` would be non-empty. However, ```mget_range``` would only have the second key and, therefore, the first key would be skipped when iterating through the range tombstones in ```TableCache::MultiGet```.

Test plan -
1. Add a unit test
2. Run stress tests

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10534

Reviewed By: akankshamahajan15

Differential Revision: D38773880

Pulled By: anand1976

fbshipit-source-id: dae491dbe52e18bbce5179b77b63f20771a66c00
2022-08-17 13:51:39 -07:00
Gang Liao 275cd80cdb Add a blob-specific cache priority (#10461)
Summary:
RocksDB's `Cache` abstraction currently supports two priority levels for items: high (used for frequently accessed/highly valuable SST metablocks like index/filter blocks) and low (used for SST data blocks). Blobs are typically lower-value targets for caching than data blocks, since 1) with BlobDB, data blocks containing blob references conceptually form an index structure which has to be consulted before we can read the blob value, and 2) cached blobs represent only a single key-value, while cached data blocks generally contain multiple KVs. Since we would like to make it possible to use the same backing cache for the block cache and the blob cache, it would make sense to add a new, lower-than-low cache priority level (bottom level) for blobs so data blocks are prioritized over them.

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

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10461

Reviewed By: siying

Differential Revision: D38672823

Pulled By: ltamasi

fbshipit-source-id: 90cf7362036563d79891f47be2cc24b827482743
2022-08-12 17:59:06 -07:00
sdong bc575c614c Fix two extra headers (#10525)
Summary:
Fix copyright for two more extra headers to make internal tool happy.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10525

Reviewed By: jay-zhuang

Differential Revision: D38661390

fbshipit-source-id: ab2d055bfd145dfe82b5bae7a6c25cc338c8de94
2022-08-12 15:54:35 -07:00
Changyu Bi fd165c869d Add memtable per key-value checksum (#10281)
Summary:
Append per key-value checksum to internal key. These checksums are verified on read paths including Get, Iterator and during Flush. Get and Iterator will return `Corruption` status if there is a checksum verification failure. Flush will make DB become read-only upon memtable entry checksum verification failure.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10281

Test Plan:
- Added new unit test cases: `make check`
- Benchmark on memtable insert
```
TEST_TMPDIR=/dev/shm/memtable_write ./db_bench -benchmarks=fillseq -disable_wal=true -max_write_buffer_number=100 -num=10000000 -min_write_buffer_number_to_merge=100

# avg over 10 runs
Baseline: 1166936 ops/sec
memtable 2 bytes kv checksum : 1.11674e+06 ops/sec (-4%)
memtable 2 bytes kv checksum + write batch 8 bytes kv checksum: 1.08579e+06 ops/sec (-6.95%)
write batch 8 bytes kv checksum: 1.17979e+06 ops/sec (+1.1%)
```
-  Benchmark on only memtable read: ops/sec dropped 31% for `readseq` due to time spend on verifying checksum.
ops/sec for `readrandom` dropped ~6.8%.
```
# Readseq
sudo TEST_TMPDIR=/dev/shm/memtable_read ./db_bench -benchmarks=fillseq,readseq"[-X20]" -disable_wal=true -max_write_buffer_number=100 -num=10000000 -min_write_buffer_number_to_merge=100

readseq [AVG    20 runs] : 7432840 (± 212005) ops/sec;  822.3 (± 23.5) MB/sec
readseq [MEDIAN 20 runs] : 7573878 ops/sec;  837.9 MB/sec

With -memtable_protection_bytes_per_key=2:

readseq [AVG    20 runs] : 5134607 (± 119596) ops/sec;  568.0 (± 13.2) MB/sec
readseq [MEDIAN 20 runs] : 5232946 ops/sec;  578.9 MB/sec

# Readrandom
sudo TEST_TMPDIR=/dev/shm/memtable_read ./db_bench -benchmarks=fillrandom,readrandom"[-X10]" -disable_wal=true -max_write_buffer_number=100 -num=1000000 -min_write_buffer_number_to_merge=100
readrandom [AVG    10 runs] : 140236 (± 3938) ops/sec;    9.8 (± 0.3) MB/sec
readrandom [MEDIAN 10 runs] : 140545 ops/sec;    9.8 MB/sec

With -memtable_protection_bytes_per_key=2:
readrandom [AVG    10 runs] : 130632 (± 2738) ops/sec;    9.1 (± 0.2) MB/sec
readrandom [MEDIAN 10 runs] : 130341 ops/sec;    9.1 MB/sec
```

- Stress test: `python3 -u tools/db_crashtest.py whitebox --duration=1800`

Reviewed By: ajkr

Differential Revision: D37607896

Pulled By: cbi42

fbshipit-source-id: fdaefb475629d2471780d4a5f5bf81b44ee56113
2022-08-12 13:51:32 -07:00
Peter Dillinger 86a1e3e0e7 Derive cache keys from SST unique IDs (#10394)
Summary:
... so that cache keys can be derived from DB manifest data
before reading the file from storage--so that every part of the file
can potentially go in a persistent cache.

See updated comments in cache_key.cc for technical details. Importantly,
the new cache key encoding uses some fancy but efficient math to pack
data into the cache key without depending on the sizes of the various
pieces. This simplifies some existing code creating cache keys, like
cache warming before the file size is known.

This should provide us an essentially permanent mapping between SST
unique IDs and base cache keys, with the ability to "upgrade" SST
unique IDs (and thus cache keys) with new SST format_versions.

These cache keys are of similar, perhaps indistinguishable quality to
the previous generation. Before this change (see "corrected" days
between collision):

```
./cache_bench -stress_cache_key -sck_keep_bits=43
18 collisions after 2 x 90 days, est 10 days between (1.15292e+19 corrected)
```

After this change (keep 43 bits, up through 50, to validate "trajectory"
is ok on "corrected" days between collision):
```
19 collisions after 3 x 90 days, est 14.2105 days between (1.63836e+19 corrected)
16 collisions after 5 x 90 days, est 28.125 days between (1.6213e+19 corrected)
15 collisions after 7 x 90 days, est 42 days between (1.21057e+19 corrected)
15 collisions after 17 x 90 days, est 102 days between (1.46997e+19 corrected)
15 collisions after 49 x 90 days, est 294 days between (2.11849e+19 corrected)
15 collisions after 62 x 90 days, est 372 days between (1.34027e+19 corrected)
15 collisions after 53 x 90 days, est 318 days between (5.72858e+18 corrected)
15 collisions after 309 x 90 days, est 1854 days between (1.66994e+19 corrected)
```

However, the change does modify (probably weaken) the "guaranteed unique" promise from this

> SST files generated in a single process are guaranteed to have unique cache keys, unless/until number session ids * max file number = 2**86

to this (see https://github.com/facebook/rocksdb/issues/10388)

> With the DB id limitation, we only have nice guaranteed unique cache keys for files generated in a single process until biggest session_id_counter and offset_in_file reach combined 64 bits

I don't think this is a practical concern, though.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10394

Test Plan: unit tests updated, see simulation results above

Reviewed By: jay-zhuang

Differential Revision: D38667529

Pulled By: pdillinger

fbshipit-source-id: 49af3fe7f47e5b61162809a78b76c769fd519fba
2022-08-12 13:49:49 -07:00
Peter Dillinger 9fa5c146d7 LOG more info on oldest snapshot and sequence numbers (#10454)
Summary:
The info LOG file does not currently give any direct
information about the existence of old, live snapshots, nor how to
estimate wall time from a sequence number within the scope of LOG
history. This change addresses both with:
* Logging smallest and largest seqnos for generated SST files, which can
help associate sequence numbers with write time (based on flushes).
* Logging oldest_snapshot_seqno for each compaction, which (along with
that seqno info) helps us to determine how much old data might be kept
around for old (leaked?) snapshots. Including the date here I thought might
be excessive.

I wanted to log the date and seqno of the oldest snapshot with periodic
stats, but the current structure of the code doesn't really support that
because `DumpDBStats` doesn't have access to the DB object.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10454

Test Plan:
manual inspect LOG from
`KEEP_DB=1 ./db_basic_test --gtest_filter=*CompactBetweenSnapshots*`

Reviewed By: ajkr

Differential Revision: D38326948

Pulled By: pdillinger

fbshipit-source-id: 294918ffc04a419844146cd826045321b4d5c038
2022-08-12 13:08:50 -07:00
sdong 2297769b38 Fix regression issue of too large score (#10518)
Summary:
https://github.com/facebook/rocksdb/pull/10057 caused a regression bug: since the base level size is not adjusted based on L0 size anymore, L0 score might become very large. This makes compaction heavily favor L0->L1 compaction against L1->L2 compaction, and cause in some cases, data stuck in L1 without being moved down. We fix calculating a score of L0 by size(L0)/size(L1) in the case where L0 is large..

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10518

Test Plan: run db_bench against data on tmpfs and watch the behavior of data stuck in L1 goes away.

Reviewed By: ajkr

Differential Revision: D38603145

fbshipit-source-id: 4949e52dc28b54aacfe08417c6e6cc7e40a27225
2022-08-11 17:10:36 -07:00
sherriiiliu 4753e5a2e9 Fix wrong value passed in compaction filter in BlobDB (#10391)
Summary:
New blobdb has a bug in compaction filter, where `blob_value_` is not reset for next iterated key. This will cause blob_value_ not empty and previous value read from blob is passed into the filter function for next key, even if its value is not in blob. Fixed by reseting regardless of key type.

Test Case:
Add `FilterByValueLength` test case in `DBBlobCompactionTest`

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10391

Reviewed By: riversand963

Differential Revision: D38629900

Pulled By: ltamasi

fbshipit-source-id: 47d23ff2e5ec697958a210db9e6ceeb8b2fc49fa
2022-08-11 13:55:28 -07:00
sdong 9277569ba3 Add some missing headers (#10519)
Summary:
Some files miss headers. Also some headers are irregular. Fix them to make an internal checkup tool happy.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10519

Reviewed By: jay-zhuang

Differential Revision: D38603291

fbshipit-source-id: 13b1bbd6d48f5ee15ba20da67544396de48238f1
2022-08-11 12:45:50 -07:00
Jay Zhuang 5d3aefb682 Migrate to docker for CI run (#10496)
Summary:
Moved linux builds to using docker to avoid CI instability caused by dependency installation site down.
Added the `Dockerfile` which is used to build the image.
The build time is also significantly reduced, because no dependencies installation and with using 2xlarge+ instance for slow build (like tsan test).
Also fixed a few issues detected while building this:
* `DestoryDB()` Status not checked for a few tests
* nullptr might be used in `inlineskiplist.cc`

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10496

Test Plan: CI

Reviewed By: ajkr

Differential Revision: D38554200

Pulled By: jay-zhuang

fbshipit-source-id: 16e8fb2bf07b9c84bb27fb18421c4d54f2f248fd
2022-08-10 17:34:38 -07:00
Guido Tagliavini Ponce a0798f6f92 Enable ClockCache in DB block cache test (#10482)
Summary:
A test in db_block_cache_test.cc was skipping ClockCache due to the 16-byte key length requirement. We fixed this. Along the way, we fixed a bug in ApplyToSomeEntries, which assumed the function being applied could modify handle metadata, and thus took an exclusive reference. This is incompatible with calls that need to inspect every element (including externally referenced ones) to gather stats.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10482

Test Plan: ``make -j24 check``

Reviewed By: anand1976

Differential Revision: D38553073

Pulled By: guidotag

fbshipit-source-id: 0ed63fed4d3b89e5056b35b7091fce579f5647ae
2022-08-10 13:57:52 -07:00
sdong 911c0208b9 WritableFileWriter tries to skip operations after failure (#10489)
Summary:
A flag in WritableFileWriter is introduced to remember error has happened. Subsequent operations will fail with an assertion. Those operations, except Close() are not supposed to be called anyway. This change will help catch bug in tests and stress tests and limit damage of a potential bug of continue writing to a file after a failure.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10489

Test Plan: Fix existing unit tests and watch crash tests for a while.

Reviewed By: anand1976

Differential Revision: D38473277

fbshipit-source-id: 09aafb971e56cfd7f9ef92ad15b883f54acf1366
2022-08-10 10:19:20 -07:00
Yanqin Jin fee2c472d0 Include minimal contextual information in `CompactionIterator` (#10505)
Summary:
The main purpose is to make debugging easier without sacrificing performance.

Instead of using a boolean variable for `CompactionIterator::valid_`, we can extend it to an `uint8_t`,
using the LSB to denote if the compaction iterator is valid and 4 additional bits to denote where
the iterator is set valid inside `NextFromInput()`. Therefore, when the control flow reaches
`PrepareOutput()` and hits assertion there, we can have a better idea of what has gone wrong.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10505

Test Plan:
make check
```
TEST_TMPDIR=/dev/shm/rocksdb time ./db_bench -compression_type=none -write_buffer_size=1073741824 -benchmarks=fillseq,flush
```
The above command has a 'flush' benchmark which uses `CompactionIterator`.  I haven't observed any CPU regression or drop in throughput or latency increase.

Reviewed By: ltamasi

Differential Revision: D38551615

Pulled By: riversand963

fbshipit-source-id: 1250848fc118bb753d71fa9ff8ba840df999f5e0
2022-08-09 17:07:24 -07:00
anand76 0b02960d8c Fix MultiGet range deletion handling and a memory leak (#10513)
Summary:
This PR fixes 2 bugs introduced in https://github.com/facebook/rocksdb/issues/10432 -
1. If the bloom filter returned a negative result for all MultiGet keys in a file, the range tombstones in that file were being ignored, resulting in incorrect results if those tombstones covered a key in a higher level.
2. If all the keys in a file were filtered out in `TableCache::MultiGetFilter`, the table cache handle was not being released.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10513

Test Plan: Add a new unit test that fails without this fix

Reviewed By: akankshamahajan15

Differential Revision: D38548739

Pulled By: anand1976

fbshipit-source-id: a741a1e25d2e991d63f038100f126c2dc404a87c
2022-08-09 14:44:47 -07:00
Levi Tamasi 06b04127a8 Reset blob value as soon as it's not needed in DBIter (#10490)
Summary:
We have recently added caching support to BlobDB, and separately,
implemented an optimization where reading blobs from the cache
results in the cache handle being transferred to the target `PinnableSlice`
(as opposed to the contents getting copied). With these changes,
it makes sense to reset the `PinnableSlice` storing the blob value in
`DBIter` as soon as we move to a different iterator position to prevent
us from holding on to the cache handle any longer than necessary.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10490

Test Plan: `make check`

Reviewed By: akankshamahajan15

Differential Revision: D38473630

Pulled By: ltamasi

fbshipit-source-id: 84c045ffac76436c6152fd0f5775b007f4051386
2022-08-09 11:39:57 -07:00
Levi Tamasi 24bcab7d5d Make queries return the value of the default column for wide-column entities (#10483)
Summary:
The patch adds support for wide-column entities to the existing query
APIs (`Get`, `MultiGet`, and iterator). Namely, when during a query a
wide-column entity is encountered, we will return the value of the default
(anonymous) column as the result. Later, we plan to add wide-column
specific query APIs which will enable retrieving entire wide-column entities
or a subset of their columns.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10483

Test Plan: `make check`

Reviewed By: riversand963

Differential Revision: D38441881

Pulled By: ltamasi

fbshipit-source-id: 6444e79a31aff2470e866698e3a97985bc2b3543
2022-08-08 16:10:08 -07:00
Jay Zhuang 3f763763aa Change `bottommost_temperture` to `last_level_temperture` (#10471)
Summary:
Change tiered compaction feature from `bottommost_temperture` to
`last_level_temperture`. The old option is kept for migration purpose only,
which is behaving the same as `last_level_temperture` and it will be removed in
the next release.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10471

Test Plan: CI

Reviewed By: siying

Differential Revision: D38450621

Pulled By: jay-zhuang

fbshipit-source-id: cc1cdf8bad409376fec0152abc0a64fb72a91527
2022-08-08 14:36:34 -07:00
Jay Zhuang 375534752a Improve universal compaction picker for tiered compaction (#10467)
Summary:
Current universal compaction picker may cause extra size amplification
compaction if there're more hot data on penultimate level. Improve the picker
to skip the last level for size amp calculation if tiered compaction is
enabled, which can
1. avoid extra unnecessary size amp compaction;
2. typically cold tier (the last level) is not size constrained, so skip size
   amp for cold tier is intended;

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10467

Test Plan: CI and added unittest

Reviewed By: siying

Differential Revision: D38391350

Pulled By: jay-zhuang

fbshipit-source-id: 103c0731c05e0a7e8f267e9e829d022328be25d2
2022-08-08 14:34:36 -07:00
Levi Tamasi 0cc9e98bbb Respect fill_cache when reading blobs in DBIter (#10492)
Summary:
Similarly to https://github.com/facebook/rocksdb/pull/10457, we now have
to explicitly set the `fill_cache` read option when reading blobs in
`DBIter` to prevent the cache from getting polluted by queries with
`fill_cache` set to false. (Before we added support for a blob cache,
the setting had not made any difference either way.)

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10492

Test Plan: `make check`

Reviewed By: akankshamahajan15

Differential Revision: D38476121

Pulled By: ltamasi

fbshipit-source-id: ea5c5e252f83e4a4e2c74156b37d40308d7e0c80
2022-08-08 08:26:33 -07:00
Burton Li e446bc65e6 Remove local static string (#8103)
Summary:
Local static string is not friendly to Jemalloc arena aware implementation, as it will be allocated on the arena of the first caller, which causes crash if the allocated arena gets refunded earlier.

P.S. A Jemalloc arena aware implementation is each rocksdb instance only use certain Jemalloc arenas, and arena will be refunded after associated DB instance is destroyed.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8103

Reviewed By: ajkr

Differential Revision: D38477235

Pulled By: ltamasi

fbshipit-source-id: a58d32cb647ed64c144b4736fb2d5db27c2c28f9
2022-08-05 23:03:51 -07:00
Jay Zhuang edae671ce0 Re-enable SuggestCompactRangeTest and add Universal Compaction test (#10473)
Summary:
The feature `SuggestCompactRange()` is still experimental. Just
re-add the test back.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10473

Test Plan: CI

Reviewed By: akankshamahajan15

Differential Revision: D38427153

Pulled By: jay-zhuang

fbshipit-source-id: 0b4491c947cbce6c18ff147b167e3c678633129a
2022-08-05 13:16:58 -07:00
Hui Xiao 56dbcb4f72 Deflake ChargeFileMetadataTestWithParam/ChargeFileMetadataTestWithParam.Basic/0 (#10481)
Summary:
**Context/summary:**
`ChargeFileMetadataTestWithParam/ChargeFileMetadataTestWithParam.Basic/0 ` relies on `DBImpl::BackgroundCallCompaction:PurgedObsoleteFiles` happens before verifying `EXPECT_EQ(file_metadata_charge_only_cache->GetCacheCharge(),
              1 * CacheReservationManagerImpl<
                      CacheEntryRole::kFileMetadata>::GetDummyEntrySize());` or `EXPECT_EQ(file_metadata_charge_only_cache->GetCacheCharge(), 0);` to ensure appropriate cache reservation release is done before checking.

However, this might not be the case under some timing delay and spurious wake-up as coerced below.

```
 diff --git a/db/db_impl/db_impl_compaction_flush.cc b/db/db_impl/db_impl_compaction_flush.cc
index 4378f3212..3e4f60853 100644
 --- a/db/db_impl/db_impl_compaction_flush.cc
+++ b/db/db_impl/db_impl_compaction_flush.cc
@@ -2989,6 +2989,8 @@ void DBImpl::BackgroundCallCompaction(PrepickedCompaction* prepicked_compaction,
     if (job_context.HaveSomethingToClean() ||
         job_context.HaveSomethingToDelete() || !log_buffer.IsEmpty()) {
       mutex_.Unlock();
+      bg_cv_.SignalAll();
+      usleep(1000);
         // Have to flush the info logs before bg_compaction_scheduled_--
        // because if bg_flush_scheduled_ becomes 0 and the lock is
        // released, the deconstructor of DB can kick in and destroy all the
        // states of DB so info_log might not be available after that point.
        // It also applies to access other states that DB owns.
        log_buffer.FlushBufferToLog();
        if (job_context.HaveSomethingToDelete()) {
          PurgeObsoleteFiles(job_context);
          TEST_SYNC_POINT("DBImpl::BackgroundCallCompaction:PurgedObsoleteFiles");
        }
```

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10481

Test Plan:
The test of interest failed often at the above coercion:

After fix, the test of interest passed at the above coercion:

Reviewed By: jay-zhuang

Differential Revision: D38438256

Pulled By: hx235

fbshipit-source-id: de80ecdb250174f00e7c2f5e4d952695ed56f51e
2022-08-05 12:58:07 -07:00
Changyu Bi 9d77bf8f7b Fragment memtable range tombstone in the write path (#10380)
Summary:
- Right now each read fragments the memtable range tombstones https://github.com/facebook/rocksdb/issues/4808. This PR explores the idea of fragmenting memtable range tombstones in the write path and reads can just read this cached fragmented tombstone without any fragmenting cost. This PR only does the caching for immutable memtable, and does so right before a memtable is added to an immutable memtable list. The fragmentation is done without holding mutex to minimize its performance impact.
- db_bench is updated to print out the number of range deletions executed if there is any.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10380

Test Plan:
- CI, added asserts in various places to check whether a fragmented range tombstone list should have been constructed.
- Benchmark: as this PR only optimizes immutable memtable path, the number of writes in the benchmark is chosen such  an immutable memtable is created and range tombstones are in that memtable.

```
single thread:
./db_bench --benchmarks=fillrandom,readrandom --writes_per_range_tombstone=1 --max_write_buffer_number=100 --min_write_buffer_number_to_merge=100 --writes=500000 --reads=100000 --max_num_range_tombstones=100

multi_thread
./db_bench --benchmarks=fillrandom,readrandom --writes_per_range_tombstone=1 --max_write_buffer_number=100 --min_write_buffer_number_to_merge=100 --writes=15000 --reads=20000 --threads=32 --max_num_range_tombstones=100
```
Commit 99cdf16464 is included in benchmark result. It was an earlier attempt where tombstones are fragmented for each write operation. Reader threads share it using a shared_ptr which would slow down multi-thread read performance as seen in benchmark results.
Results are averaged over 5 runs.

Single thread result:
| Max # tombstones  | main fillrandom micros/op | 99cdf16464 | Post PR | main readrandom micros/op |  99cdf16464 | Post PR |
| ------------- | ------------- |------------- |------------- |------------- |------------- |------------- |
| 0    |6.68     |6.57     |6.72     |4.72     |4.79     |4.54     |
| 1    |6.67     |6.58     |6.62     |5.41     |4.74     |4.72     |
| 10   |6.59     |6.5      |6.56     |7.83     |4.69     |4.59     |
| 100  |6.62     |6.75     |6.58     |29.57    |5.04     |5.09     |
| 1000 |6.54     |6.82     |6.61     |320.33   |5.22     |5.21     |

32-thread result: note that "Max # tombstones" is per thread.
| Max # tombstones  | main fillrandom micros/op | 99cdf16464 | Post PR | main readrandom micros/op |  99cdf16464 | Post PR |
| ------------- | ------------- |------------- |------------- |------------- |------------- |------------- |
| 0    |234.52   |260.25   |239.42   |5.06     |5.38     |5.09     |
| 1    |236.46   |262.0    |231.1    |19.57    |22.14    |5.45     |
| 10   |236.95   |263.84   |251.49   |151.73   |21.61    |5.73     |
| 100  |268.16   |296.8    |280.13   |2308.52  |22.27    |6.57     |

Reviewed By: ajkr

Differential Revision: D37916564

Pulled By: cbi42

fbshipit-source-id: 05d6d2e16df26c374c57ddcca13a5bfe9d5b731e
2022-08-05 12:02:33 -07:00
anand76 bf4532eb5c Break TableReader MultiGet into filter and lookup stages (#10432)
Summary:
This PR is the first step in enhancing the coroutines MultiGet to be able to lookup a batch in parallel across levels. By having a separate TableReader function for probing the bloom filters, we can quickly figure out which overlapping keys from a batch are definitely not in the file and can move on to the next level.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10432

Reviewed By: akankshamahajan15

Differential Revision: D38245910

Pulled By: anand1976

fbshipit-source-id: 3d20db2350378c3fe6f086f0c7ba5ff01d7f04de
2022-08-04 12:51:57 -07:00
Yanqin Jin 538df26fcc Deflake DBWALTest.RaceInstallFlushResultsWithWalObsoletion (#10456)
Summary:
Existing DBWALTest.RaceInstallFlushResultsWithWalObsoletion test relies
on a specific interleaving of two background flush threads. We call them
bg1 and bg2, and assume bg1 starts to install flush results ahead of
bg2. After bg1 enters `ProcessManifestWrites`, bg1 waits for bg2 to also
enter `MemTableList::TryInstallMemtableFlushResults()` before bg1 can
proceed with MANIFEST write. However, if bg2 called `SyncClosedLogs()`
and needed to commit to the MANIFEST but falls behind bg1, then bg2
needs to wait for bg1 to finish writing to MANIFEST. This is a circular
dependency.

Fix this by allowing bg2 to start only after bg1 grabs the chance to
sync the WAL and commit to MANIFEST.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10456

Test Plan:
1. make check

2. export TEST_TMPDIR=/dev/shm && gtest-parallel -r 1000 -w 32 ./db_wal_test --gtest_filter=DBWALTest.RaceInstallFlushResultsWithWalObsoletion

Reviewed By: ltamasi

Differential Revision: D38391856

Pulled By: riversand963

fbshipit-source-id: 55f647d5b94e534c008a4dd2fb082675ddf58c96
2022-08-04 12:14:28 -07:00
Andrew Kryczka 504fe4de80 Avoid allocations/copies for large `GetMergeOperands()` results (#10458)
Summary:
This PR avoids allocations and copies for the result of `GetMergeOperands()` when the average operand size is at least 256 bytes and the total operands size is at least 32KB. The `GetMergeOperands()` already included `PinnableSlice` but was calling `PinSelf()` (i.e., allocating and copying) for each operand. When this optimization takes effect, we instead call `PinSlice()` to skip that allocation and copy. Resources are pinned in order for the `PinnableSlice` to point to valid memory even after `GetMergeOperands()` returns.

The pinned resources include a referenced `SuperVersion`, a `MergingContext`, and a `PinnedIteratorsManager`. They are bundled into a `GetMergeOperandsState`. We use `SharedCleanablePtr` to share that bundle among all `PinnableSlice`s populated by `GetMergeOperands()`. That way, the last `PinnableSlice` to be `Reset()` will cleanup the bundle, including unreferencing the `SuperVersion`.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10458

Test Plan:
- new DB level test
- measured benefit/regression in a number of memtable scenarios

Setup command:
```
$ ./db_bench -benchmarks=mergerandom -merge_operator=StringAppendOperator -num=$num -writes=16384 -key_size=16 -value_size=$value_sz -compression_type=none -write_buffer_size=1048576000
```

Benchmark command:
```
./db_bench -threads=$threads -use_existing_db=true -avoid_flush_during_recovery=true -write_buffer_size=1048576000 -benchmarks=readrandomoperands -merge_operator=StringAppendOperator -num=$num -duration=10
```

Worst regression is when a key has many tiny operands:

- Parameters: num=1 (implying 16384 operands per key), value_sz=8, threads=1
- `GetMergeOperands()` latency increases 682 micros -> 800 micros (+17%)

The regression disappears into the noise (<1% difference) if we remove the `Reset()` loop and the size counting loop. The former is arguably needed regardless of this PR as the convention in `Get()` and `MultiGet()` is to `Reset()` the input `PinnableSlice`s at the start. The latter could be optimized to count the size as we accumulate operands rather than after the fact.

Best improvement is when a key has large operands and high concurrency:

- Parameters: num=4 (implying 4096 operands per key), value_sz=2KB, threads=32
- `GetMergeOperands()` latency decreases 11492 micros -> 437 micros (-96%).

Reviewed By: cbi42

Differential Revision: D38336578

Pulled By: ajkr

fbshipit-source-id: 48146d127e04cb7f2d4d2939a2b9dff3aba18258
2022-08-04 00:42:13 -07:00
mpoeter bef3127b00 Fix race in ExitAsBatchGroupLeader with pipelined writes (#9944)
Summary:
Resolves https://github.com/facebook/rocksdb/issues/9692

This PR adds a unit test that reproduces the race described in https://github.com/facebook/rocksdb/issues/9692 and an according fix.

The unit test does not have any assertions, because I could not find a reliable and save way to assert that the writers list does not form a cycle. So with the old (buggy) code, the test would simply hang, while with the fix the test passes successfully.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9944

Reviewed By: pdillinger

Differential Revision: D36134604

Pulled By: riversand963

fbshipit-source-id: ef636c5a79ddbef18658ab2f19ca9210a427324a
2022-08-02 14:52:10 -07:00
Peter Dillinger 27f3af5966 Fix serious FSDirectory use-after-Close bug (missing fsync) (#10460)
Summary:
TL;DR: due to a recent change, if you drop a column family,
often that DB will no longer fsync after writing new SST files
to remaining or new column families, which could lead to data
loss on power loss.

More bug detail:
The intent of https://github.com/facebook/rocksdb/issues/10049 was to Close FSDirectory objects at
DB::Close time rather than waiting for DB object destruction.
Unfortunately, it also closes shared FSDirectory objects on
DropColumnFamily (& destroy remaining handles), which can lead
to use-after-Close on FSDirectory shared with remaining column
families. Those "uses" are only Fsyncs (or redundant Closes). In
the default Posix filesystem, an Fsync on a closed FSDirectory is a
quiet no-op. Consequently (under most configurations), if you drop
a column family, that DB will no longer fsync after writing new SST
files to column families sharing the same directory (true under most
configurations).

More fix detail:
Basically, this removes unnecessary Close ops on destroying
ColumnFamilyData. We let `shared_ptr` take care of calling the
destructor at the right time. If the intent was to require Close be
called before destroying FSDirectory, that was not made clear by the
author of FileSystem and was not at all enforced by https://github.com/facebook/rocksdb/issues/10049, which
could have added `assert(fd_ == -1)` to `~PosixDirectory()` but did
not. To keep this fix simple, we relax the unit test for https://github.com/facebook/rocksdb/issues/10049 to allow
timely destruction of FSDirectory to suffice as Close (in
CountedFileSystem). Added a TODO to revisit that.

Also in this PR:
* Added a TODO to share FSDirectory instances between DB and its column
families. (Already shared among column families.)
* Made DB::Close attempt to close all its open FSDirectory objects even
if there is a failure in closing one. Also code clean-up around this
logic.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10460

Test Plan:
add an assert to check for use-after-Close. With that
existing tests can detect the misuse. With fix, tests pass (except noted
relaxing of unit test for https://github.com/facebook/rocksdb/issues/10049)

Reviewed By: ajkr

Differential Revision: D38357922

Pulled By: pdillinger

fbshipit-source-id: d42079cadbedf0a969f03389bf586b3b4e1f9137
2022-08-02 10:54:32 -07:00
Levi Tamasi cc8ded6152 Do not put blobs read during compaction into cache (#10457)
Summary:
During compaction, blobs are currently read using the default
`ReadOptions`, which has the `fill_cache` flag set to true. Earlier,
this didn't make any difference since we didn't have a blob cache;
however, now we have to explicitly set this flag to false to avoid
polluting the cache during compaction.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10457

Test Plan: `make check`

Reviewed By: riversand963

Differential Revision: D38333528

Pulled By: ltamasi

fbshipit-source-id: 5b4d49a1e39543bee73c7df2aa9194fb101875e2
2022-08-01 19:49:05 -07:00
Yanqin Jin fbfcf5cbcd Remove unused fields from FileMetaData (temporarily) (#10443)
Summary:
FileMetaData::[min|max]_timestamp are not currently being used or
tracked by RocksDB, even when user-defined timestamp is enabled. Each of
them is a std::string which can occupy 32 bytes. Remove them for now.
They may be added back when we have a pressing need for them. When we do
add them back, consider store them in a more compact way, e.g. one
boolean flag and a byte array of size 16.

Per file min/max timestamp bounds are available as table properties.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10443

Test Plan: make check

Reviewed By: pdillinger

Differential Revision: D38292275

Pulled By: riversand963

fbshipit-source-id: 841dc4e855ad8f8481c80cb020603de9607c9c94
2022-08-01 17:56:13 -07:00
Akanksha Mahajan 56463d443d Provide support for subcompactions with user-defined timestamps (#10344)
Summary:
The subcompaction logic currently picks file boundaries as subcompaction boundaries. This is not compatible with user-defined timestamps because of two issues.
Issue1: ReadOptions.iterate_lower_bound and ReadOptions.iterate_upper_bound contains timestamps which results in assertion failure as BlockBasedTableIterator expects bounds to be without timestamps. As result, because of wrong comparison end key is returned as user_key resulting in assertion failure.
Issue2: Since it might result in two keys that only differ by user timestamp getting processed by two different subcompactions (and thus two different CompactionIterator state machines), which in turn can cause data correction issues.

This PR provide support to reenable subcompactions with user-defined timestamps.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10344

Test Plan:
Added new unit test
- Without fix for Issue1 unit test MultipleSubCompactions fails with error:
```
db_with_timestamp_compaction_test: ./db/compaction/clipping_iterator.h:247: void rocksdb::ClippingIterat│
or::AssertBounds(): Assertion `!valid_ || !end_ || cmp_->Compare(key(), *end_) < 0' failed.
Received signal 6 (Aborted)                                                                             │
#0   /usr/local/fbcode/platform009/lib/libc.so.6(gsignal+0x100) [0x7f8fbbbfe530] db_with_timestamp_compaction_test: ./db/compaction/clipping_iterator.h:247: void rocksdb::ClippingIterator::AssertBounds(): Assertion `!valid_ || !end_ || cmp_->Compare(key(), *end_) < 0' failed.
Aborted (core dumped)
```
Ran stress test
`make crash_test_with_ts -j32`

Reviewed By: riversand963

Differential Revision: D38220841

Pulled By: akankshamahajan15

fbshipit-source-id: 5d5cae2bd37fcaeba1e77fce0a69070ad4158ccb
2022-07-31 11:39:16 -07:00
Peter Dillinger 65036e4217 Revert "Add a blob-specific cache priority (#10309)" (#10434)
Summary:
This reverts commit 8d178090be
because of a clear performance regression seen in internal dashboard
https://fburl.com/unidash/tpz75iee

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10434

Reviewed By: ltamasi

Differential Revision: D38256373

Pulled By: pdillinger

fbshipit-source-id: 134aa00f50dd7b1bbe037c227884a351342ec44b
2022-07-29 07:18:15 -07:00
Andrew Kryczka c7ccbb33a6 Allow manual compactions to run in parallel by default (#10317)
Summary:
This PR changes the default value of
`CompactRangeOptions::exclusive_manual_compaction` from true to false so
manual `CompactRange()`s can run in parallel with other compactions. I
believe no artificial parallelism restriction is the intuitive behavior
so feel the old default value is a trap, which I have fallen into
several times, including yesterday.
`CompactRangeOptions::exclusive_manual_compaction == false` has been
used in both our correctness test and in production for years so should
be reasonably safe.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10317

Reviewed By: jay-zhuang

Differential Revision: D37659392

Pulled By: ajkr

fbshipit-source-id: 504915e978bbe300b79483d064070c75e93d91e5
2022-07-28 17:07:36 -07:00
Jay Zhuang 87649d3288 Best efforts recovery to skip empty MANIFEST (#10416)
Summary:
Skip empty MANIFEST fie during best_efforts_recovery.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10416

Test Plan: make failed db_stress test pass

Reviewed By: riversand963

Differential Revision: D38126273

Pulled By: jay-zhuang

fbshipit-source-id: 4498d322b09eaa194dd2cbf9c683d62ab54bfb01
2022-07-27 20:16:38 -07:00
Gang Liao 8d178090be Add a blob-specific cache priority (#10309)
Summary:
RocksDB's `Cache` abstraction currently supports two priority levels for items: high (used for frequently accessed/highly valuable SST metablocks like index/filter blocks) and low (used for SST data blocks). Blobs are typically lower-value targets for caching than data blocks, since 1) with BlobDB, data blocks containing blob references conceptually form an index structure which has to be consulted before we can read the blob value, and 2) cached blobs represent only a single key-value, while cached data blocks generally contain multiple KVs. Since we would like to make it possible to use the same backing cache for the block cache and the blob cache, it would make sense to add a new, lower-than-low cache priority level (bottom level) for blobs so data blocks are prioritized over them.

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

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10309

Reviewed By: ltamasi

Differential Revision: D38211655

Pulled By: gangliao

fbshipit-source-id: 65ef33337db4d85277cc6f9782d67c421ad71dd5
2022-07-27 19:09:24 -07:00
Jay Zhuang 6a0010eb46 ldb to display public unique id and dump work with key range (#10417)
Summary:
2 ldb command improvements:
1. `ldb manifest_dump --verbose` display both the internal unique id and public id. which is useful to manually check sst_unique_id between manifest and SST;
2. `ldb dump` has `--from/to` option, but not working. Add support for that.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10417

Test Plan:
run the command locally
```
$ ldb manifest_dump --path=MANIFEST-000026 --verbose
...
AddFile: 0 18 1023 'bar' seq:6, type:1 .. 'foo' seq:5, type:1 oldest_ancester_time:1658787615 file_creation_time:1658787615 file_checksum: file_checksum_func_name: Unknown unique_id(internal): {8800772265202404198,16149248642318466463} public_unique_id: F3E0A029B631D7D4-6E402DE08E771780
```
```
$ ldb dump --path=000036.sst --from=key000006 --to=key000009
Sst file format: block-based
'key000006' seq:2411, type:1 => value6
'key000007' seq:2412, type:1 => value7
'key000008' seq:2413, type:1 => value8
...
```

Reviewed By: ajkr

Differential Revision: D38136140

Pulled By: jay-zhuang

fbshipit-source-id: 8be6eeaa07ff9f089e33011ebe90fd0b69d33bf3
2022-07-26 20:40:18 -07:00
Zichen Zhu c945a9a664 Allow sufficient subcompactions under round-robin compaction priority (#10422)
Summary:
Allow sufficient subcompactions can be used when the number of input files is less than `max_subcompactions` under round-robin compaction priority.

Test Case:
Add `RoundRobinWithoutAdditionalResources` into `db_compaction_test`

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10422

Reviewed By: ajkr

Differential Revision: D38186545

Pulled By: littlepig2013

fbshipit-source-id: b8e5098306f1e5b9561dfafafc8300a38f7fe88e
2022-07-26 20:37:34 -07:00
Jay Zhuang 3134471457 Deflake FlushStaleColumnFamilies test (#10409)
Summary:
Make the Stale Flush test more robust by explicitly checking the target CF is
flushed.  Currently it's flaky because the default CF may have more than 3
SSTs.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10409

Test Plan:
the test more likely to fail on a resource limited host:
```
gtest-parallel ./column_family_test --gtest_filter=FormatDef/ColumnFamilyTest.FlushStaleColumnFamilies/0 -r 1000 -w 100
```

Reviewed By: ajkr

Differential Revision: D38116383

Pulled By: jay-zhuang

fbshipit-source-id: e27cc56f76f14d0936504f126104e3d87e3d0d5f
2022-07-26 12:50:27 -07:00
Changyu Bi 2fc6df37d6 Add checksum handshake for WAL fragment decompression (#10339)
Summary:
If WAL compression is enabled, WAL fragment decompression results are concatenated together in `log::Reader::ReadPhysicalRecord()`. This PR adds checksum handshake to protect memory corruption during the copying process.

`checksum` is renamed to `record_checksum` in `ReadRecord()` to differentiate it from `checksum_` flag that specifies whether CRC32C checksum is verified.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10339

Test Plan: added checksum verification in log_test.cc, `make check -j32`.

Reviewed By: ajkr

Differential Revision: D37763734

Pulled By: cbi42

fbshipit-source-id: c4faa7c76b9ff1df35026edf31adfe4b47ae3154
2022-07-25 16:27:26 -07:00
Zichen Zhu 8860fc902a Support subcmpct using reserved resources for round-robin priority (#10341)
Summary:
Earlier implementation of round-robin priority can only pick one file at a time and disallows parallel compactions within the same level. In this PR, round-robin compaction policy will expand towards more input files with respecting some additional constraints, which are summarized as follows:
 * Constraint 1: We can only pick consecutive files
   - Constraint 1a: When a file is being compacted (or some input files are being compacted after expanding), we cannot choose it and have to stop choosing more files
   - Constraint 1b: When we reach the last file (with the largest keys), we cannot choose more files (the next file will be the first one with small keys)
 * Constraint 2: We should ensure the total compaction bytes (including the overlapped files from the next level) is no more than `mutable_cf_options_.max_compaction_bytes`
 * Constraint 3: We try our best to pick as many files as possible so that the post-compaction level size can be just less than `MaxBytesForLevel(start_level_)`
 * Constraint 4: If trivial move is allowed, we reuse the logic of `TryNonL0TrivialMove()` instead of expanding files with Constraint 3

More details can be found in `LevelCompactionBuilder::SetupOtherFilesWithRoundRobinExpansion()`.

The above optimization accelerates the process of moving the compaction cursor, in which the write-amp can be further reduced. While a large compaction may lead to high write stall, we break this large compaction into several subcompactions **regardless of** the `max_subcompactions` limit.  The number of subcompactions for round-robin compaction priority is determined through the following steps:
* Step 1: Initialized against `max_output_file_limit`, the number of input files in the start level, and also the range size limit `ranges.size()`
* Step 2: Call `AcquireSubcompactionResources()`when max subcompactions is not sufficient, but we may or may not obtain desired resources, additional number of resources is stored in `extra_num_subcompaction_threads_reserved_`). Subcompaction limit is changed and update `num_planned_subcompactions` with `GetSubcompactionLimit()`
* Step 3: Call `ShrinkSubcompactionResources()` to ensure extra resources can be released (extra resources may exist for round-robin compaction when the number of actual number of subcompactions is less than the number of planned subcompactions)

More details can be found in `CompactionJob::AcquireSubcompactionResources()`,`CompactionJob::ShrinkSubcompactionResources()`, and `CompactionJob::ReleaseSubcompactionResources()`.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10341

Test Plan: Add `CompactionPriMultipleFilesRoundRobin[1-3]` unit test in `compaction_picker_test.cc` and `RoundRobinSubcompactionsAgainstResources.SubcompactionsUsingResources/[0-4]`, `RoundRobinSubcompactionsAgainstPressureToken.PressureTokenTest/[0-1]` in `db_compaction_test.cc`

Reviewed By: ajkr, hx235

Differential Revision: D37792644

Pulled By: littlepig2013

fbshipit-source-id: 7fecb7c4ffd97b34bbf6e3b760b2c35a772a0657
2022-07-24 11:12:44 -07:00
sdong 252bea405e Improve SubCompaction Partitioning (#10393)
Summary:
Unit tests still haven't been fixed. Also need to add more tests. But I ran some simple fillrandom db_bench and the partitioning feels reasonable.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10393

Test Plan:
1. Make sure existing tests pass. This should cover some basic sub compaction logic to be correct and the partitioning result is reasonable;
2. Add a new unit test to ApproximateKeyAnchors()
3. Run some db_bench with max_subcompaction = 4 and watch the compaction is indeed partitioned evenly.

Reviewed By: jay-zhuang

Differential Revision: D38043783

fbshipit-source-id: 085008e0f85f9b7c5abff7800307618320efb19f
2022-07-23 17:38:49 -07:00
Jay Zhuang fcccc412d7 Remove Travis CI (#10407)
Summary:
Travis CI is depreciated and haven't been maintained for some time.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10407

Reviewed By: ajkr

Differential Revision: D38078382

Pulled By: jay-zhuang

fbshipit-source-id: f42057f2f41f722bdce56bf195f67a94835191fb
2022-07-22 20:16:45 -07:00
Yu Zhao 00540916 bfc737da21 fix typos in some code and comment (#10139)
Summary:
Minor issue, I just found a few typos on db_test and column_family while reading the code. And I have this PR opened to contribute.  :)

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10139

Reviewed By: ajkr

Differential Revision: D38007098

Pulled By: jay-zhuang

fbshipit-source-id: 511947b32424c34348184691216640f32c410fb1
2022-07-22 19:25:52 -07:00
Andrew Kryczka 7b44724205 Fix WAL compression fragmentation test (#10402)
Summary:
Previously the "Fragmentation" test didn't cover fragmentation because the WAL data was compressible into trivial size. This PR changes it to use random data so the post-compression size is large enough to require fragmentation.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10402

Reviewed By: cbi42

Differential Revision: D38065596

Pulled By: ajkr

fbshipit-source-id: 0d5f89ca14d33546501a74b5d4fafbadc28a46a7
2022-07-22 11:05:55 -07:00
Jun He 5cf18c7634 Fix build error due to uninitialized read_req (#10312)
Summary:
GCC-12 has strick check on variables, and thus
build fails when it finds read_req is not properly
initialized (-Werror=maybe-uninitialized). Add
default value to fix this.

Change-Id: Ib8a9085e2d613ee7b943b58a6a58e1bc351725d7
Signed-off-by: Jun He <jun.he@arm.com>

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10312

Reviewed By: riversand963

Differential Revision: D37656997

Pulled By: ajkr

fbshipit-source-id: fe47492c913b34b3a03c04beeec9ec57831dcaff
2022-07-22 09:24:13 -07:00
LIU HU 8885b0537b Fix underflow in FIFOCompactionPicker (#10386)
Summary:
Fix https://github.com/facebook/rocksdb/issues/10133

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10386

Reviewed By: riversand963

Differential Revision: D38067265

Pulled By: ajkr

fbshipit-source-id: 3a99a98ac5d7ac37581b5b636fbfa7901563d834
2022-07-22 09:20:35 -07:00
Wallace 1e9bf25f61 Do not hold mutex when write keys if not necessary (#7516)
Summary:
## Problem Summary
RocksDB will acquire the global mutex of db instance for every time when user calls `Write`.  When RocksDB schedules a lot of compaction jobs,   it will compete the mutex with write thread and it will hurt the write performance.

## Problem Solution:
I want to use log_write_mutex to replace the global mutex in most case so that we do not acquire it in write-thread unless there is a write-stall event or a write-buffer-full event occur.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7516

Test Plan:
1. make check
2. CI
3. COMPILE_WITH_TSAN=1 make db_stress
make crash_test
make crash_test_with_multiops_wp_txn
make crash_test_with_multiops_wc_txn
make crash_test_with_atomic_flush

Reviewed By: siying

Differential Revision: D36908702

Pulled By: riversand963

fbshipit-source-id: 59b13881f4f5c0a58fd3ca79128a396d9cd98efe
2022-07-21 13:35:36 -07:00
Gang Liao 0b6bc101ba Charge blob cache usage against the global memory limit (#10321)
Summary:
To help service owners to manage their memory budget effectively, we have been working towards counting all major memory users inside RocksDB towards a single global memory limit (see e.g. https://github.com/facebook/rocksdb/wiki/Write-Buffer-Manager#cost-memory-used-in-memtable-to-block-cache). The global limit is specified by the capacity of the block-based table's block cache, and is technically implemented by inserting dummy entries ("reservations") into the block cache. The goal of this task is to support charging the memory usage of the new blob cache against this global memory limit when the backing cache of the blob cache and the block cache are different.

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

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10321

Reviewed By: ltamasi

Differential Revision: D37913590

Pulled By: gangliao

fbshipit-source-id: eaacf23907f82dc7d18964a3f24d7039a2937a72
2022-07-18 23:26:57 -07:00
Jay Zhuang 18a61a1734 Fix seqno->time worker not scheduled with multi DB instances (#10383)
Summary:
`PeriodicWorkScheduler` is a global singleton, which were used to store per-instance setting `record_seqno_time_cadence_`. Move that to db_impl.h which is per-instance.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10383

Reviewed By: siying

Differential Revision: D37928009

Pulled By: jay-zhuang

fbshipit-source-id: e517754f4a9db98798ac04f72033d4b517f734e9
2022-07-18 19:08:39 -07:00
Andrew Kryczka 25cc564ff7 Make RateLimiter not Customizable (#10378)
Summary:
(PR created for informational/testing purposes only.)

- Fixes lost dynamic updates to GenericRateLimiter bandwidth using `SetBytesPerSecond()`
- Benefit over #10374 is eliminating race conditions with Configurable framework.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10378

Reviewed By: pdillinger

Differential Revision: D37914865

fbshipit-source-id: d4f566d60ec9726d26932388c61671adf0ee0f30
2022-07-18 14:48:42 -07:00
Gang Liao ec4ebeff30 Support prepopulating/warming the blob cache (#10298)
Summary:
Many workloads have temporal locality, where recently written items are read back in a short period of time. When using remote file systems, this is inefficient since it involves network traffic and higher latencies. Because of this, we would like to support prepopulating the blob cache during flush.

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

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10298

Reviewed By: ltamasi

Differential Revision: D37908743

Pulled By: gangliao

fbshipit-source-id: 9feaed234bc719d38f0c02975c1ad19fa4bb37d1
2022-07-17 07:13:59 -07:00
sg20180546 f5ef36a29a add sstfilewriter_delete_range (#10314)
Summary:
I add C API
db/c.cc
rocksdb_sstfilewriter_delete_range

and test it , PASS.
 can you review it ? ajkr

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10314

Reviewed By: riversand963

Differential Revision: D37657236

Pulled By: ajkr

fbshipit-source-id: c3b758daa36fbd9133210b011716914dff311278
2022-07-16 19:35:46 -07:00
Gang Liao 95ef007adc Support using secondary cache with the blob cache (#10349)
Summary:
RocksDB supports a two-level cache hierarchy (see https://rocksdb.org/blog/2021/05/27/rocksdb-secondary-cache.html), where items evicted from the primary cache can be spilled over to the secondary cache, or items from the secondary cache can be promoted to the primary one. We have a CacheLib-based non-volatile secondary cache implementation that can be used to improve read latencies and reduce the amount of network bandwidth when using distributed file systems. In addition, we have recently implemented a compressed secondary cache that can be used as a replacement for the OS page cache when e.g. direct I/O is used. The goals of this task are to add support for using a secondary cache with the blob cache and to measure the potential performance gains using `db_bench`.

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

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10349

Reviewed By: ltamasi

Differential Revision: D37896773

Pulled By: gangliao

fbshipit-source-id: 7804619ce4a44b73d9e11ad606640f9385969c84
2022-07-16 03:54:37 -07:00
Jay Zhuang faa0f9723c Tiered compaction: integrate Seqno time mapping with per key placement (#10370)
Summary:
Using the Sequence number to time mapping to decide if a key is hot or not in
compaction and place it in the corresponding level.

Note: the feature is not complete, level compaction will run indefinitely until
all penultimate level data is cold and small enough to not trigger compaction.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10370

Test Plan:
CI
* Run basic db_bench for universal compaction manually

Reviewed By: siying

Differential Revision: D37892338

Pulled By: jay-zhuang

fbshipit-source-id: 792bbd91b1ccc2f62b5d14c53118434bcaac4bbe
2022-07-15 19:01:30 -07:00
Jay Zhuang fb579a221c Remove fixed TODO (#10241)
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/10241

Reviewed By: gitbw95

Differential Revision: D37369726

Pulled By: jay-zhuang

fbshipit-source-id: 1e94f0e2433aee42e9871043fa434291ce948eac
2022-07-15 14:47:36 -07:00
Jay Zhuang dcb6a3be4e Add helper function to get debug type name (#10243)
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/10243

Reviewed By: riversand963

Differential Revision: D37370236

Pulled By: jay-zhuang

fbshipit-source-id: 6e7a6fadf45fdfb5afe97b3f6fe4acf1260d4a86
2022-07-15 14:42:00 -07:00
Jay Zhuang 69a18b9bad VerifySstUniqueIds status is overrided for multi CFs (#10247)
Summary:
There's bug that basically we only report the last CF's
VerifySstUniqueIds() result:
https://github.com/facebook/rocksdb/pull/9990#discussion_r877268810

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10247

Test Plan: CI

Reviewed By: pdillinger

Differential Revision: D37384265

Pulled By: jay-zhuang

fbshipit-source-id: d462ad0eab39c9145c45a3db9c45539d5d76f7dd
2022-07-15 11:50:30 -07:00
Jay Zhuang a3acf2ef87 Add seqno to time mapping (#10338)
Summary:
Which will be used for tiered storage to preclude hot data from
compacting to the cold tier (the last level).
Internally, adding seqno to time mapping. A periodic_task is scheduled
to record the current_seqno -> current_time in certain cadence. When
memtable flush, the mapping informaiton is stored in sstable property.
During compaction, the mapping information are merged and get the
approximate time of sequence number, which is used to determine if a key
is recently inserted or not and preclude it from the last level if it's
recently inserted (within the `preclude_last_level_data_seconds`).

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10338

Test Plan: CI

Reviewed By: siying

Differential Revision: D37810187

Pulled By: jay-zhuang

fbshipit-source-id: 6953be7a18a99de8b1cb3b162d712f79c2b4899f
2022-07-14 21:49:34 -07:00
sdong c8b20d469d Make InternalKeyComparator not configurable (#10342)
Summary:
InternalKeyComparator is an internal class which is a simple wrapper of Comparator. https://github.com/facebook/rocksdb/pull/8336 made Comparator customizeable. As a side effect, internal key comparator was made configurable too. This introduces overhead to this simple wrapper. For example, every InternalKeyComparator will have an std::vector attached to it, which consumes memory and possible allocation overhead too.
We remove InternalKeyComparator from being customizable by making InternalKeyComparator not a subclass of Comparator.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10342

Test Plan: Run existing CI tests and make sure it doesn't fail

Reviewed By: riversand963

Differential Revision: D37771351

fbshipit-source-id: 917256ee04b2796ed82974549c734fb6c4d8ccee
2022-07-14 10:09:31 -07:00
Jay Zhuang 6ce0b2ca34 Tiered Compaction: per key placement support (#9964)
Summary:
Support per_key_placement for last level compaction, which will
be used for tiered compaction.
* compaction iterator reports which level a key should output to;
* compaction get the output level information and check if it's safe to
  output the data to penultimate level;
* all compaction output files will be installed.
* extra internal compaction stats added for penultimate level.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9964

Test Plan:
* Unittest
* db_bench, no significate difference: https://gist.github.com/jay-zhuang/3645f8fb97ec0ab47c10704bb39fd6e4
* microbench manual compaction no significate difference: https://gist.github.com/jay-zhuang/ba679b3e89e24992615ee9eef310e6dd
* run the db_stress multiple times (not covering the new feature) looks good (internal: https://fburl.com/sandcastle/9w84pp2m)

Reviewed By: ajkr

Differential Revision: D36249494

Pulled By: jay-zhuang

fbshipit-source-id: a96da57c8031c1df83e4a7a8567b657a112b80a3
2022-07-13 20:54:49 -07:00
Changyu Bi 5f9fe7f21e Added WAL compression checksum (#10319)
Summary:
Enabled zstd checksum flag in StreamingCompress so that WAL (de)compreression is protected by a checksum per compression frame.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10319

Test Plan:
- `make check`
- WAL perf: average ops/sec over 10 runs is 161226 pre PR and 159635 post PR (1% drop).
```
sudo TEST_TMPDIR=/dev/shm/memtable_write ./db_bench_checksum -benchmarks=fillseq -max_write_buffer_number=100 -num=1000000 -min_write_buffer_number_to_merge=10 -wal_compression=zstd
```

Reviewed By: ajkr

Differential Revision: D37673311

Pulled By: cbi42

fbshipit-source-id: 9f34a3bfc2a82e5c80b1ec63bb339a7465108ec9
2022-07-13 15:29:20 -07:00
Guido Tagliavini Ponce 9645e66fc9 Temporarily return a LRUCache from NewClockCache (#10351)
Summary:
ClockCache is still in experimental stage, and currently fails some pre-release fbcode tests. See https://www.internalfb.com/diff/D37772011. API calls to construct ClockCache are done via the function NewClockCache. For now, NewClockCache calls will return an LRUCache (with appropriate arguments), which is stable.

The idea that NewClockCache returns nullptr was also floated, but this would be interpreted as unsupported cache, and a default LRUCache would be constructed instead, potentially causing a performance regression that is harder to identify.

A new version of the NewClockCache function was created for our internal tests.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10351

Test Plan: ``make -j24 check`` and re-run the pre-release tests.

Reviewed By: pdillinger

Differential Revision: D37802685

Pulled By: guidotag

fbshipit-source-id: 0a8d10612ff21e576f7360cb13e20bc36e244972
2022-07-13 08:45:44 -07:00
Yanqin Jin b283f041f5 Stop tracking syncing live WAL for performance (#10330)
Summary:
With https://github.com/facebook/rocksdb/issues/10087, applications calling `SyncWAL()` or writing with `WriteOptions::sync=true` can suffer
from performance regression. This PR reverts to original behavior of tracking the syncing of closed WALs.
After we revert back to old behavior, recovery, whether kPointInTime or kAbsoluteConsistency, may fail to
detect corruption in synced WALs if the corruption is in the live WAL.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10330

Test Plan:
make check

Before https://github.com/facebook/rocksdb/issues/10087
```bash
fillsync     :     750.269 micros/op 1332 ops/sec 75.027 seconds 100000 operations;    0.1 MB/s (100 ops)
fillsync     :     776.492 micros/op 1287 ops/sec 77.649 seconds 100000 operations;    0.1 MB/s (100 ops)
fillsync [AVG 2 runs] : 1310 (± 44) ops/sec;    0.1 (± 0.0) MB/sec
fillsync     :     805.625 micros/op 1241 ops/sec 80.563 seconds 100000 operations;    0.1 MB/s (100 ops)
fillsync [AVG 3 runs] : 1287 (± 51) ops/sec;    0.1 (± 0.0) MB/sec
fillsync [AVG    3 runs] : 1287 (± 51) ops/sec;    0.1 (± 0.0) MB/sec
fillsync [MEDIAN 3 runs] : 1287 ops/sec;    0.1 MB/sec
```

Before this PR and after https://github.com/facebook/rocksdb/issues/10087
```bash
fillsync     :    1479.601 micros/op 675 ops/sec 147.960 seconds 100000 operations;    0.1 MB/s (100 ops)
fillsync     :    1626.080 micros/op 614 ops/sec 162.608 seconds 100000 operations;    0.1 MB/s (100 ops)
fillsync [AVG 2 runs] : 645 (± 59) ops/sec;    0.1 (± 0.0) MB/sec
fillsync     :    1588.402 micros/op 629 ops/sec 158.840 seconds 100000 operations;    0.1 MB/s (100 ops)
fillsync [AVG 3 runs] : 640 (± 35) ops/sec;    0.1 (± 0.0) MB/sec
fillsync [AVG    3 runs] : 640 (± 35) ops/sec;    0.1 (± 0.0) MB/sec
fillsync [MEDIAN 3 runs] : 629 ops/sec;    0.1 MB/sec
```

After this PR
```bash
fillsync     :     749.621 micros/op 1334 ops/sec 74.962 seconds 100000 operations;    0.1 MB/s (100 ops)
fillsync     :     865.577 micros/op 1155 ops/sec 86.558 seconds 100000 operations;    0.1 MB/s (100 ops)
fillsync [AVG 2 runs] : 1244 (± 175) ops/sec;    0.1 (± 0.0) MB/sec
fillsync     :     845.837 micros/op 1182 ops/sec 84.584 seconds 100000 operations;    0.1 MB/s (100 ops)
fillsync [AVG 3 runs] : 1223 (± 109) ops/sec;    0.1 (± 0.0) MB/sec
fillsync [AVG    3 runs] : 1223 (± 109) ops/sec;    0.1 (± 0.0) MB/sec
fillsync [MEDIAN 3 runs] : 1182 ops/sec;    0.1 MB/sec
```

Reviewed By: ajkr

Differential Revision: D37725212

Pulled By: riversand963

fbshipit-source-id: 8fa7d13b3c7662be5d56351c42caf3266af937ae
2022-07-12 17:16:57 -07:00
sdong 769b156e65 Remove customized naming from InternalKeyComparator (#10343)
Summary:
InternalKeyComparator is a thin wrapper around user comparator. Storing a string for name is relatively expensive to this small wrapper for both CPU and memory usage. Try to remove it.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10343

Test Plan: Run existing tests

Reviewed By: ajkr

Differential Revision: D37772469

fbshipit-source-id: d2d106a8d022193058fd7f6b220108e3d94aca34
2022-07-12 13:30:35 -07:00
Yanqin Jin 7e2004a123 Remove unused variables (#10327)
Summary:
As title.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10327

Test Plan: make check

Reviewed By: gitbw95

Differential Revision: D37699040

Pulled By: riversand963

fbshipit-source-id: 305a88628907a47dea53c4d9aec9c2f5bb9b58df
2022-07-11 13:55:23 -07:00
Gang Liao c987eb4712 Eliminate the copying of blobs when serving reads from the cache (#10297)
Summary:
The blob cache enables an optimization on the read path: when a blob is found in the cache, we can avoid copying it into the buffer provided by the application. Instead, we can simply transfer ownership of the cache handle to the target `PinnableSlice`. (Note: this relies on the `Cleanable` interface, which is implemented by `PinnableSlice`.)

This has the potential to save a lot of CPU, especially with large blob values.

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

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10297

Reviewed By: riversand963

Differential Revision: D37640311

Pulled By: gangliao

fbshipit-source-id: 92de0e35cc703d06c87c5c1861cc2899ec52234a
2022-07-06 18:57:29 -07:00