Summary:
Add a new per level counter for block cache hits, increase it by one on every successful attempt to get an entry from cache.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4796
Differential Revision: D13513688
Pulled By: zinoale
fbshipit-source-id: 104df038f1232e3356e162eb2d8ca138e34a8281
Summary:
Previously we were cleaning up range tombstone meta-block by calling `ReleaseCachedEntry`, which wouldn't work if `value != nullptr && cache_handle == nullptr`. This happened at least in the case with mmap reads and block cache both enabled. I noticed `NewDataBlockIterator` intends to handle all these cases, so migrated to that instead of `NewUnfragmentedRangeTombstoneIterator`.
Also changed the table-opening logic to fail on `ReadRangeDelBlock` failure, since that can cause data corruption. Added a test case to verify this behavior. Note the test case does not fail on `TryReopen` because failure to preload table handlers is not considered critical. However, it does fail on any read involving that file since it cannot return correct data.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4810
Differential Revision: D13534296
Pulled By: ajkr
fbshipit-source-id: 55dde1111717cea6ec4bf38418daab81ccef3599
Summary:
Introduce the first CPU timing counter, perf_context.get_cpu_nanos. This opens a door to more CPU counters in the future.
Only Posix Env has it implemented using clock_gettime() with CLOCK_THREAD_CPUTIME_ID. How accurate the counter is depends on the platform.
Make PerfStepTimer to take an Env as an argument, and sometimes pass it in. The direct reason is to make the unit tests to use SpecialEnv where we can ingest logic there. But in long term, this is a good change.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4741
Differential Revision: D13287798
Pulled By: siying
fbshipit-source-id: 090361049d9d5095d1d1a369fe1338d2e2e1c73f
Summary:
To avoid a race on the flag, make it an atomic_bool. This
doesn't seem to significantly affect benchmarks.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4801
Differential Revision: D13523845
Pulled By: abhimadan
fbshipit-source-id: 3bc29f53c50a4e06cd9f8c6232a4bb221868e055
Summary:
This TODO was already addressed, but I forgot to remove it
before landing the PR it came from.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4800
Differential Revision: D13522284
Pulled By: abhimadan
fbshipit-source-id: 7766bc4f5b54e47d355cf26137ef5e86c604472a
Summary:
This PR contains the following fixes:
1. Fixing Makefile to support non-default locations of developer tools
2. Fixing compile error using a patch from https://github.com/facebook/rocksdb/pull/4007
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4687
Differential Revision: D13287263
Pulled By: riversand963
fbshipit-source-id: 4525eb42ba7b6f82af5f9bfb8e52fa4024e27ccc
Summary:
1) `transaction_base.h` overrides from `transaction.h` with a `const boolean do_validate`.
The non-const base declaration, which I cannot see the need for, causes a compilation error on Microsoft Windows.
2) Implicit cast from `double` to `uint64_t` causes a compilation error on Microsoft Windows.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4798
Differential Revision: D13519734
Pulled By: sagar0
fbshipit-source-id: 6e8cb80e9a589b1122e1500c21b8e3a3a472b459
Summary:
in certain cases, we do not perform memtable switching if the active
memtable of the column family is empty. Two exceptions:
1. In manual flush, if cached_recoverable_state_empty_ is false, then we need
to switch memtable due to requirement of transaction.
2. In switch WAL, we need to switch memtable anyway because we have to seal the
memtable if the WAL on which it depends will be closed.
This change can potentially delay the occurence of write stalls because number
of memtables increase more slowly.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4792
Differential Revision: D13499501
Pulled By: riversand963
fbshipit-source-id: 91c9b17ae753578578039f3851667d93610005e1
Summary:
Now that v2 is fully functional, the v1 aggregator is removed.
The v2 aggregator has been renamed.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4778
Differential Revision: D13495930
Pulled By: abhimadan
fbshipit-source-id: 9d69500a60a283e79b6c4fa938fc68a8aa4d40d6
Summary:
RangeDelAggregatorV2 now supports ShouldDelete calls on
snapshot stripes and creation of range tombstone compaction iterators.
RangeDelAggregator is no longer used on any non-test code path, and will
be removed in a future commit.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4758
Differential Revision: D13439254
Pulled By: abhimadan
fbshipit-source-id: fe105bcf8e3d4a2df37a622d5510843cd71b0401
Summary:
The test fails sporadically expecting the DB to be empty after DeleteFilesInRange(..., nullptr, nullptr) call which is not. Debugging shows cases where the files are skipped since they are being compacted. The patch fixes the test by waiting for the last CompactRange to finish before calling DeleteFilesInRange.
Verified by
```
~/gtest-parallel/gtest-parallel ./db_compaction_test --gtest_filter=DBCompactionTest.DeleteFileRange --repeat=10000
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4784
Differential Revision: D13469402
Pulled By: maysamyabandeh
fbshipit-source-id: 3d8f44abe205b82c69f01e7edf27e1f8098248e1
Summary:
options_file_number_ must be written under db::mutex_ sine its read is protected by mutex_ in ::GetLiveFiles(). However currently it is written in ::RenameTempFileToOptionsFile() which according to its contract must be called without holding db::mutex_. The patch fixes the race condition by also acquitting the mutex_ before writing options_file_number_. Also it does that only if the rename of option file is successful.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4780
Differential Revision: D13461411
Pulled By: maysamyabandeh
fbshipit-source-id: 2d5bae96a1f3e969ef2505b737cf2d7ae749787b
Summary:
If one column family is dropped, we should simply skip it and continue to flush
other active ones.
Currently we use Status::ShutdownInProgress to notify caller of column families
being dropped. In the future, we should consider using a different Status code.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4708
Differential Revision: D13378954
Pulled By: riversand963
fbshipit-source-id: 42f248cdf2d32d4c0f677cd39012694b8f1328ca
Summary:
The PR is targeting to resolve the issue of:
https://github.com/facebook/rocksdb/issues/3972#issue-330771918
We have a rocksdb created with leveled-compaction with multiple column families (CFs), some of CFs are using HDD to store big and less frequently accessed data and others are using SSD.
When there are continuously write traffics going on to all CFs, the compaction thread pool is mostly occupied by those slow HDD compactions, which blocks fully utilize SSD bandwidth.
Since atomic write and transaction is needed across CFs, so splitting it to multiple rocksdb instance is not an option for us.
With the compaction thread control, we got 30%+ HDD write throughput gain, and also a lot smooth SSD write since less write stall happening.
ConcurrentTaskLimiter can be shared with multi-CFs across rocksdb instances, so the feature does not only work for multi-CFs scenarios, but also for multi-rocksdbs scenarios, who need disk IO resource control per tenant.
The usage is straight forward:
e.g.:
//
// Enable compaction thread limiter thru ColumnFamilyOptions
//
std::shared_ptr<ConcurrentTaskLimiter> ctl(NewConcurrentTaskLimiter("foo_limiter", 4));
Options options;
ColumnFamilyOptions cf_opt(options);
cf_opt.compaction_thread_limiter = ctl;
...
//
// Compaction thread limiter can be tuned or disabled on-the-fly
//
ctl->SetMaxOutstandingTask(12); // enlarge to 12 tasks
...
ctl->ResetMaxOutstandingTask(); // disable (bypass) thread limiter
ctl->SetMaxOutstandingTask(-1); // Same as above
...
ctl->SetMaxOutstandingTask(0); // full throttle (0 task)
//
// Sharing compaction thread limiter among CFs (to resolve multiple storage perf issue)
//
std::shared_ptr<ConcurrentTaskLimiter> ctl_ssd(NewConcurrentTaskLimiter("ssd_limiter", 8));
std::shared_ptr<ConcurrentTaskLimiter> ctl_hdd(NewConcurrentTaskLimiter("hdd_limiter", 4));
Options options;
ColumnFamilyOptions cf_opt_ssd1(options);
ColumnFamilyOptions cf_opt_ssd2(options);
ColumnFamilyOptions cf_opt_hdd1(options);
ColumnFamilyOptions cf_opt_hdd2(options);
ColumnFamilyOptions cf_opt_hdd3(options);
// SSD CFs
cf_opt_ssd1.compaction_thread_limiter = ctl_ssd;
cf_opt_ssd2.compaction_thread_limiter = ctl_ssd;
// HDD CFs
cf_opt_hdd1.compaction_thread_limiter = ctl_hdd;
cf_opt_hdd2.compaction_thread_limiter = ctl_hdd;
cf_opt_hdd3.compaction_thread_limiter = ctl_hdd;
...
//
// The limiter is disabled by default (or set to nullptr explicitly)
//
Options options;
ColumnFamilyOptions cf_opt(options);
cf_opt.compaction_thread_limiter = nullptr;
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4332
Differential Revision: D13226590
Pulled By: siying
fbshipit-source-id: 14307aec55b8bd59c8223d04aa6db3c03d1b0c1d
Summary:
The test has been failing sporadically probably because the configured compaction options were actually unused. Verified that by the following:
```
~/gtest-parallel/gtest-parallel ./db_compaction_test --gtest_filter=DBCompactionTest.DeleteFileRange --repeat=1000
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4776
Differential Revision: D13441052
Pulled By: maysamyabandeh
fbshipit-source-id: d35075b9e6cef9b9c9d0d571f9cd72ade8eda55d
Summary:
To support the flush/compaction use cases of RangeDelAggregator
in v2, FragmentedRangeTombstoneIterator now supports dropping tombstones
that cannot be read in the compaction output file. Furthermore,
FragmentedRangeTombstoneIterator supports the "snapshot striping" use
case by allowing an iterator to be split by a list of snapshots.
RangeDelAggregatorV2 will use these changes in a follow-up change.
In the process of making these changes, other miscellaneous cleanups
were also done in these files.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4740
Differential Revision: D13287382
Pulled By: abhimadan
fbshipit-source-id: f5aeb03e1b3058049b80c02a558ee48f723fa48c
Summary:
Change the directory where ExternalSSTFileBasicTest* tests run.
**Problem:**
Without this change, I spent considerable time chasing around a non-existent issue as ExternalSSTFileTest.* and ExternalSSTFileBasicTest.* create similar directories.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4766
Differential Revision: D13409384
Pulled By: sagar0
fbshipit-source-id: c33e1f4d505dfa6efbc788d6c57cdb680053ded3
Summary:
It is possible to see a situation like the following when
subcompactions are enabled:
1. A subcompaction boundary is set to `[b, e)`.
2. The first output file in a subcompaction has `c@20` as its smallest key
3. The range tombstone `[a, d)30` is encountered.
4. The tombstone is written to the range-del meta block and the new
smallest key is set to `b@0` (since no keys in this subcompaction's
output can be smaller than `b`).
5. A key `b@10` in a lower level will now reappear, since it is not
covered by the truncated start key `b@0`.
In general, unless the smallest data key in a file has a seqnum of 0, it
is not safe to truncate a tombstone at the start key to have a seqnum of
0, since it can expose keys with a seqnum greater than 0 but less than
the tombstone's actual seqnum.
To fix this, when the lower bound of a file is from the subcompaction
boundaries, we now set the seqnum of an artificially extended smallest
key to the tombstone's seqnum. This is safe because subcompactions
operate over disjoint sets of keys, and the subcompactions that can
experience this problem are not the first subcompaction (which is
unbounded on the left).
Furthermore, there is now an assertion to detect the described anomalous
case.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4723
Differential Revision: D13236188
Pulled By: abhimadan
fbshipit-source-id: a6da6a113f2de1e2ff307ca72e055300c8fe5692
Summary:
1. DBImplReadOnly::GetLiveFiles should not return NotSupported. Instead, it
should call DBImpl::GetLiveFiles(flush_memtable=false).
2. In DBImp::Recover, we should also recover the OPTIONS file name and/or
number so that an immediate subsequent GetLiveFiles will get the correct
OPTIONS name.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4681
Differential Revision: D13069205
Pulled By: riversand963
fbshipit-source-id: 3e6a0174307d06db5a01feb099b306cea1f7f88a
Summary:
When write stall has already been triggered due to number of L0 files reaching
threshold, file ingestion must proceed with its flush without waiting for the
write stall condition to cleared by the compaction because compaction can wait
for ingestion to finish (circular wait).
In order to avoid this wait, we can set `FlushOptions.allow_write_stall` to be
true (default is false). Setting it to false can cause deadlock.
This can happen when the number of compaction threads is low.
Considere the following
```
Time compaction_thread ingestion_thread
| num_running_ingest_file_++
| while(num_running_ingest_file_>0){wait}
| flush
V
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4751
Differential Revision: D13343037
Pulled By: riversand963
fbshipit-source-id: d3b95938814af46ec4c463feff0b50c70bd8b23f
Summary:
Current implementation of `current_over_upper_bound_` fails to take into consideration that keys might be invalid in either base iterator or delta iterator. Calling key() in such scenario will lead to assertion failure and runtime errors.
This PR addresses the bug by adding check for valid keys before calling `IsOverUpperBound()`, also added test coverage for iterate_upper_bound usage in BaseDeltaIterator
Also recommit https://github.com/facebook/rocksdb/pull/4656 (It was reverted earlier due to bugs)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4702
Differential Revision: D13146643
Pulled By: miasantreble
fbshipit-source-id: 6d136929da12d0f2e2a5cea474a8038ec5cdf1d0
Summary:
Full block (use_block_based_builder=false) Bloom filter has clear CPU saving benefits but with limitation of using temp memory when building an SST file proportional to the SST file size. We reduced the chance of having large SST files with multi-level universal compaction. Now we change to a default with better performance.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4735
Differential Revision: D13266674
Pulled By: siying
fbshipit-source-id: 7594a4c3e32568a5a2adce22bb0e46553e55c602
Summary:
**Summary:**
Simplified the code layout by moving FIFOCompactionPicker to a separate file.
**Why?:**
While trying to add ttl functionality to universal compaction, I found that `FIFOCompactionPicker` class and its impl methods to be interspersed between `LevelCompactionPicker` methods which kind-of made the code a little hard to traverse. So I moved `FIFOCompactionPicker` to a separate compaction_picker_fifo.h/cc file, similar to `UniversalCompactionPicker`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4724
Differential Revision: D13227914
Pulled By: sagar0
fbshipit-source-id: 89471766ea67fa4d87664a41c057dd7df4b3d4e3
Summary:
There is a race condition in DBFlushTest.SyncFail, as illustrated below.
```
time thread1 bg_flush_thread
| Flush(wait=false, cfd)
| refs_before=cfd->current()->TEST_refs() PickMemtable calls cfd->current()->Ref()
V
```
The race condition between thread1 getting the ref count of cfd's current
version and bg_flush_thread incrementing the cfd's current version makes it
possible for later assertion on refs_before to fail. Therefore, we add test
sync points to enforce the order and assert on the ref count before and after
PickMemtable is called in bg_flush_thread.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4633
Differential Revision: D12967131
Pulled By: riversand963
fbshipit-source-id: a99d2bacb7869ec5d8d03b24ef2babc0e6ae1a3b
Summary:
there is chance that
* the caller tries to repair the db when holding the db_lock, in
that case the env implementation might not set the `lock`
parameter of Repairer::Run().
* the caller somehow never calls Repairer::Run().
either way, the desctructor of Repair will compare the uninitialized
db_lock_ with nullptr, and tries to unlock it. there is good chance
that the db_lock_ is not nullptr, then boom.
Signed-off-by: Kefu Chai <tchaikov@gmail.com>
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4683
Differential Revision: D13260287
Pulled By: riversand963
fbshipit-source-id: 878a119d2e9f10a0fa17ee62cf3fb24b33d49fa5
Summary:
Removed `one_time_use` flag, which removed the need for some
tests, and changed all `NewRangeTombstoneIterator` methods to return
`FragmentedRangeTombstoneIterators`.
These changes also led to removing `RangeDelAggregatorV2::AddUnfragmentedTombstones`
and one of the `MemTableListVersion::AddRangeTombstoneIterators` methods.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4692
Differential Revision: D13106570
Pulled By: abhimadan
fbshipit-source-id: cbab5432d7fc2d9cdfd8d9d40361a1bffaa8f845
Summary:
If user do not end the trace manually, the tracing will continue which can potential use up all the storage space and cause problem. In this PR, the max trace file size is added to the TraceOptions and user can set the value if they need or the default is 64GB.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4610
Differential Revision: D12893400
Pulled By: zhichao-cao
fbshipit-source-id: acf4b5a6076bb691778bdfbac4864e1006758953
Summary:
Previously, every range tombstone iterator was seeked on every
ShouldDelete call, which quickly degraded performance for long range
scans. This PR improves performance by tracking iterator positions and
only advancing iterators when necessary.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4677
Differential Revision: D13205373
Pulled By: abhimadan
fbshipit-source-id: 80c199dace1e19362a4c61c686bf01913eae87cb
Summary:
We haven't been populating `NO_FILE_CLOSES` since v1.5.8 even though it was never marked as deprecated. Start populating it again. Conveniently `DeleteTableReader` has an unused `void*` argument that we can use...
Blame: 63f216ee0aCloses#4700.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4703
Differential Revision: D13146769
Pulled By: ajkr
fbshipit-source-id: ad8d6fb0493e701f60a165a3bca1787d255be008
Summary:
…ons (#4676)"
This reverts commit b32d087dbb.
`MemoryAllocator` needs to be with `Cache`, since cache entry can
outlive DB and block based table. The cache needs to hold reference to
memory allocator when deleting cache entry.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4697
Differential Revision: D13133490
Pulled By: yiwu-arbug
fbshipit-source-id: 8ef7e8a51263bfd929f892fd062665ff4ce9ce5a
Summary:
The old RangeDelAggregator did expensive pre-processing work
to create a collapsed, binary-searchable representation of range
tombstones. With FragmentedRangeTombstoneIterator, much of this work is
now unnecessary. RangeDelAggregatorV2 takes advantage of this by seeking
in each iterator to find a covering tombstone in ShouldDelete, while
doing minimal work in AddTombstones. The old RangeDelAggregator is still
used during flush/compaction for now, though RangeDelAggregatorV2 will
support those uses in a future PR.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4649
Differential Revision: D13146964
Pulled By: abhimadan
fbshipit-source-id: be29a4c020fc440500c137216fcc1cf529571eb3
Summary:
Since a range tombstone seen at one level will cover all keys
in the range at lower levels, there was a short-circuiting check in Get
that reported a key was not found at most one file after the range
tombstone was discovered. However, this was incorrect for merge
operands, since a deletion might only cover some merge operands,
which implies that the key should be found. This PR fixes this logic in
the Version portion of Get, and removes the logic from the MemTable
portion of Get, since the perforamnce benefit provided there is minimal.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4698
Differential Revision: D13142484
Pulled By: abhimadan
fbshipit-source-id: cbd74537c806032f2bfa564724d01a80df7c8f10
Summary:
WriteBufferManger is not invoked when allocating memory for memtable if the limit is not set even if a cache is passed. It is inconsistent from the comment syas. Fix it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4695
Differential Revision: D13112722
Pulled By: siying
fbshipit-source-id: 0b27eef63867f679cd06033ea56907c0569597f4
Summary:
This is a quick fix for the uninitialized bugs in `LiveFileMetaData` and `SstFileMetaData` that were uncovered in #4686.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4693
Differential Revision: D13113189
Pulled By: ajkr
fbshipit-source-id: 18e798d031d2a59d0b55fc010c135e0126f4042d
Summary:
This fixes an assertion.
An atomic flush can have multiple flush jobs. Some of them may fail. If any of
them fails, we need to rollback all of them.
For the flush jobs that do fail, we already call `RollbackMemTableFlush` in
`FlushJob::Run`. The tricky part is for flush jobs that have completed
successfully. We need to call `RollbackMemTableFlush` for them as well.
The newly added DBAtomicFlushTest.AtomicFlushRollbackSomeJobs will SigAbort
without the corresponding change in AtomicFlushMemTablesToOutputFiles.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4641
Differential Revision: D12943649
Pulled By: riversand963
fbshipit-source-id: c66a4a664a1e0938e938fd41edc5a70c34cdd868
Summary:
Rather than storing a `vector<RangeTombstone>`, we now store a
`vector<RangeTombstoneStack>` and a `vector<SequenceNumber>`. A
`RangeTombstoneStack` contains the start and end keys of a range tombstone
fragment, and indices into the seqnum vector to indicate which sequence
numbers the fragment is located at. The diagram below illustrates an
example:
```
tombstones_: [a, b) [c, e) [h, k)
| \ / \ / |
| \ / \ / |
v v v v
tombstone_seqs_: [ 5 3 10 7 2 8 6 ]
```
This format allows binary searching the tombstone list to use less key
comparisons, which helps in cases where there are many overlapping
tombstones. Also, this format makes it easier to add DBIter-like
semantics to `FragmentedRangeTombstoneIterator` in the future.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4632
Differential Revision: D13053103
Pulled By: abhimadan
fbshipit-source-id: e8220cc712fcf5be4d602913bb23ace8ea5f8ef0
Summary:
DBTest.SanitizeNumThreads Sometimes fails. The test waited for 10ms timeout and expect all threads scheduled to be executed. This can be a source of flakiness. Make a check every 1ms and up to 10s.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4659
Differential Revision: D13074174
Pulled By: siying
fbshipit-source-id: b1d5ff87a326a4fc9eab8d1cc307bbb940dfe70c
Summary:
`GenSubcompactionBoundaries` calls `VersionSet::ApproximateSize` which gets BlockBasedTableReader for every file and seeks in its index block to find `key`'s offset. If the table or index block aren't in memory already, this involves I/O. This can be improved by releasing DB mutex when calling ApproximateSize.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4630
Differential Revision: D13052653
Pulled By: miasantreble
fbshipit-source-id: cae31d46d10d0860fa8a26b8d5154b2d17d1685f
Summary:
Currently transaction iterator does not apply `ReadOptions.iterate_upper_bound` when iterating. This PR attempts to fix the problem by having `BaseDeltaIterator` enforcing the upper bound check when iterator state is changed.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4656
Differential Revision: D13039257
Pulled By: miasantreble
fbshipit-source-id: 909eb9f6b4597a4d80418fb139f32ec82c6ec1d1
Summary:
Per offline discussion with siying, `MemoryAllocator` and `Cache` should be decouple. The idea is that memory allocator handles memory allocation, while cache handle cache policy.
It is normal that external cache libraries pack couple the two components for better optimization. If we want to integrate with such library in the future, we can make a wrapper of the library implementing both `Cache` and `MemoryAllocator` interface.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4676
Differential Revision: D13047662
Pulled By: yiwu-arbug
fbshipit-source-id: cd42e246d80ab600b4de47d073f7d2db308ce6dd
Summary:
We used to have a bug, which caused every block to be read twice, and none of our tests caught it. Add a very simply unit test to make sure that when reading a data block, we only issue one pread against the SST file.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4657
Differential Revision: D13005260
Pulled By: siying
fbshipit-source-id: 03167b554ad2451192b1707415536d7d05e9026c
Summary:
he ratio of num_deletions to num_entries of a level can be useful to determine if a manual compaction needs to be triggered on a level.
Also refer #3980
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4623
Differential Revision: D13045744
Pulled By: sagar0
fbshipit-source-id: 71f3c8e363a8ffd194ec3bb0ed0b69612231f0b3
Summary:
Currently, `Statistics` can record tick by `recordTick()` whose second parameter is an `uint64_t`.
That means tick can only increase.
If we want to reduce tick, we have to work around like `RecordTick(statistics_, NO_ITERATORS, uint64_t(-1));`.
That's kind of a hack.
So, this PR divide `NO_ITERATORS` into two counters `NO_ITERATOR_CREATED` and `NO_ITERATOR_DELETE`, making the counters increase only.
Fixes#3013 .
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4498
Differential Revision: D10395010
Pulled By: sagar0
fbshipit-source-id: cfb523b22a37411c794b4e9da090f1ae30293db2
Alexander Zinoviev