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
Summary:
RocksDB allows reusing old `Transaction` objects when creating new ones. Therefore, we need to
reset the transaction's read and commit timestamps back to default values `kMaxTxnTimestamp`.
Otherwise, `CommitAndTryCreateSnapshot()` may fail with "Status::InvalidArgument("Different commit ts specified")".
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10677
Test Plan: make check
Reviewed By: ltamasi
Differential Revision: D39513543
Pulled By: riversand963
fbshipit-source-id: bea01cac149bff3a23a2978fc0c3b198243a6291
Summary:
Change the ```ReadOptions.optimize_multiget_for_io``` flag to default on. It doesn't impact regular MultiGet users as its only applicable when ```ReadOptions.async_io``` is also set to true.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10671
Reviewed By: akankshamahajan15
Differential Revision: D39477439
Pulled By: anand1976
fbshipit-source-id: 47abcdbfa69f9bc60422ab68a238b232e085d4ba
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
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
Summary:
In `db_stress`, DB and expected state files containing changes leading up to a verification failure are often deleted, which makes debugging such failures difficult. On the DB side, flushed WAL files and compacted SST files are marked obsolete and then deleted. Without those files, we cannot pinpoint where a key that failed verification changed unexpectedly. On the expected state side, files for verifying prefix-recoverability in the presence of unsynced data loss are deleted before verification. These include a baseline state file containing the expected state at the time of the last successful verification, and a trace file containing all operations since then. Without those files, we cannot know the sequence of DB operations expected to be recovered.
This PR attempts to address this gap with a new `db_stress` flag: `preserve_unverified_changes`. Setting `preserve_unverified_changes=1` has two effects.
First, prior to startup verification, `db_stress` hardlinks all DB and expected state files in "unverified/" subdirectories of `FLAGS_db` and `FLAGS_expected_values_dir`. The separate directories are needed because the pre-verification opening process deletes files written by the previous `db_stress` run as described above. These "unverified/" subdirectories are cleaned up following startup verification success.
I considered other approaches for preserving DB files through startup verification, like using a read-only DB or preventing deletion of DB files externally, e.g., in the `Env` layer. However, I decided against it since such an approach would not work for expected state files, and I did not want to change the DB management logic. If there were a way to disable DB file deletions before regular DB open, I would have preferred to use that.
Second, `db_stress` attempts to keep all DB and expected state files that were live at some point since the start of the `db_stress` run. This is a bit tricky and involves the following changes.
- Open the DB with `disable_auto_compactions=1` and `avoid_flush_during_recovery=1`
- DisableFileDeletions()
- EnableAutoCompactions()
For this part, too, I would have preferred to use a hypothetical API that disables DB file deletion before regular DB open.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10659
Reviewed By: hx235
Differential Revision: D39407454
Pulled By: ajkr
fbshipit-source-id: 6e981025c7dce147649d2e770728471395a7fa53
Summary:
Sanitize initial_auto_readahead_size if its greater than max_auto_readahead_size in case of async_io
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10660
Test Plan: Ran db_stress with intitial_auto_readahead_size greater than max_auto_readahead_size.
Reviewed By: anand1976
Differential Revision: D39408095
Pulled By: akankshamahajan15
fbshipit-source-id: 07f933242f636cfbc7ccf042e0c8b959a8ec5f3a
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
Summary:
The current integration with folly requires cherry-picking folly source files to include in RocksDB for external CI builds. Its not scaleable as we depend on more features in folly, such as coroutines. This PR adds a dependency from RocksDB to the folly library when ```USE_FOLLY``` or ```USE_COROUTINES``` are set. We build folly using the build scripts in ```third-party/folly```, relying on it to download and build its dependencies. A new ```Makefile``` target, ```build_folly```, is provided to make building folly easier.
A new option, ```USE_FOLLY_LITE``` is added to retain the old model of compiling selected folly sources with RocksDB. This might be useful for short-term development.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10103
Reviewed By: pdillinger
Differential Revision: D38426787
Pulled By: anand1976
fbshipit-source-id: 33bc84abd9fdc7e2567749f02aa1b2494eb62b2f
Summary:
Same as title
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10632
Test Plan: make crash_test -j32
Reviewed By: anand1976
Differential Revision: D39241479
Pulled By: akankshamahajan15
fbshipit-source-id: 5db5b0c007da786bacc1b30d8926d36d6d029b87
Summary:
Expanded `all_params` to include all parameters crash test may set. Previously, `atomic_flush` was not included in `all_params` and thus was not visible to `finalize_and_sanitize()`. The consequence was manual crash test runs could provide unsafe combinations of parameters to `db_stress`. For example, running `db_crashtest.py` with `-atomic_flush=0` could cause `db_stress` to run with `-atomic_flush=0 -disable_wal=1`, which is known to produce inconsistencies across column families.
While expanding `all_params`, I found we cannot have an entry in it for both `db_stress` and `db_crashtest.py`. So I renamed `enable_tiered_storage` to `test_tiered_storage` for `db_crashtest.py`, which appears more conventional anyways.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10654
Reviewed By: hx235
Differential Revision: D39369349
Pulled By: ajkr
fbshipit-source-id: 31d9010c760c868b20d5e9bd78ba75c8ff3ce348
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
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
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
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
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
Summary:
Example flake where CircleCI reports memory at 99% and process gets killed with signal 9 (likely OOM): https://app.circleci.com/pipelines/github/facebook/rocksdb/18085/workflows/bdadbfe6-c40f-4ccb-a5db-fc8c4036f20a/jobs/475628
The previous settings of max_key=25000000, column_families=10, and log2_keys_per_lock=2 resulted in 3GB memory usage just for SharedState. The locks alone consume at least (25000000 keys per CF) * (10 CFs) / (2^2 keys per lock) * (40 bytes per lock) = 2.3GB. This PR reduces it 10x by reducing max_key by that factor.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10639
Reviewed By: cbi42
Differential Revision: D39263804
Pulled By: ajkr
fbshipit-source-id: 9b5565bbafcb21a2f5b487c8364808dea2f0bc0c
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
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
Summary:
Appears possible after 5de98f2 introduced possible lost
updates. Could be related to 2af132c also. Simply ensure no sqrt of
negative.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10586
Test Plan: test added
Reviewed By: ajkr
Differential Revision: D39068391
Pulled By: pdillinger
fbshipit-source-id: 230b214a41e6c9ae91a1ef3e8b2a17b46bbb17c2
Summary:
... because we are frequently seeing the 10m "no output"
timeouts on these
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10627
Test Plan: CI
Reviewed By: hx235
Differential Revision: D39224922
Pulled By: pdillinger
fbshipit-source-id: f54c7adb5de87b2f57ccbc7f4e6c541b9cd37e08
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
Summary:
RocksDB does auto-readahead for iterators on noticing more
than two reads for a table file if user doesn't provide readahead_size and reads are sequential.
A new option num_file_reads_for_auto_readahead is added which can be
configured and indicates after how many sequential reads prefetching should
be start.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10556
Test Plan: Existing and new unit test
Reviewed By: anand1976
Differential Revision: D38947147
Pulled By: akankshamahajan15
fbshipit-source-id: c9eeab495f84a8df7f701c42f04894e46440ad97
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
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
Summary:
**Context/Summary:**
`ExpectedState` is not aware of transaction-related concept so `use_txn=1 ` is not compatible with `sync_fault_injection=1`. Therefore this PR disabled this combination until we expand our correctness testing to transaction related features.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10605
Test Plan:
- Run the following commands to verify `--use_txn` is correctly sanitized
- `python3 ./tools/db_crashtest.py blackbox --use_txn=1 --sync_fault_injection=1 `
- `python3 ./tools/db_crashtest.py blackbox --use_txn=0 --sync_fault_injection=1 `
Reviewed By: ajkr
Differential Revision: D39121287
Pulled By: hx235
fbshipit-source-id: 7d5d6dd32479ea1c07df4f38322650f3a60def9c
Summary:
Right now, when the option migration tool migrates to FIFO compaction, it compacts all the data into one single SST file and move to L0. Although it creates a valid LSM-tree for FIFO, for any data to be deleted for FIFO, the giant file will be deleted, which might make the DB almost empty. There is not good solution for it, because usually we don't have enough information to reconstruct the FIFO LSM-tree. This change changes to a solution that compromises the FIFO condition. We hope the solution is more useable.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10600
Test Plan: Add unit tests for that.
Reviewed By: jay-zhuang
Differential Revision: D39106424
fbshipit-source-id: bdfd852c3b343373765b8d9716fefc08fd27145c
Summary:
Currently, `db_bench` and `db_stress` print the blob cache options even if
a shared block/blob cache is configured, i.e. when they are not actually
in effect. The patch changes this so they are only printed when a separate blob
cache is used.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10614
Test Plan: Tested manually using `db_bench` and `db_stress`.
Reviewed By: akankshamahajan15
Differential Revision: D39144603
Pulled By: ltamasi
fbshipit-source-id: f714304c5d46186f8514746c27ee6f52aa3e4af8
Summary:
This should fix an import issue detected in meta internal tests.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10604
Test Plan: Unit Tests.
Reviewed By: hx235
Differential Revision: D39120414
Pulled By: gitbw95
fbshipit-source-id: dbd016d7f47b9f54aab5ea61e8d3cd79734f46af
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
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
Summary:
Imported a fix to "rocksdb.prefetched.bytes.discarded" stat from https://github.com/facebook/rocksdb/issues/10561, and added a new stat "rocksdb.async.prefetch.abort.micros" to measure time spent waiting for async reads to abort.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10585
Reviewed By: akankshamahajan15
Differential Revision: D39067000
Pulled By: anand1976
fbshipit-source-id: d7cda71abb48017239bd5fd832345a16c7024faf
Summary:
When verification fails for db_stress, print more information about
value read from the db and expected state.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10587
Test Plan:
make check
./db_stress
Reviewed By: akankshamahajan15, hx235
Differential Revision: D39078511
Pulled By: riversand963
fbshipit-source-id: 77ac8ffae01fc3a9b58a02c2e7bbe141e1a18f0b
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
Summary:
https://github.com/facebook/rocksdb/issues/10538 added `TestIterateAgainstExpected()` in `no_batched_ops_test` to verify iterator correctness against the in memory expected state. It is not compatible when run after some other stress tests, e.g. `TestPut()` in `batched_op_stress`, that either do not set expected state when writing to DB or use keys that cannot be parsed by `GetIntVal()`. The assert [here](d17be55aab/db_stress_tool/db_stress_common.h (L520)) could fail. This PR fixed this issue by setting iterator upperbound to `max_key` when `destroy_db_initially=0` to avoid the key space that `batched_op_stress` touches.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10590
Test Plan:
```
# set up DB with batched_op_stress
./db_stress --test_batches_snapshots=1 --verify_iterator_with_expected_state_one_in=1 --max_key_len=3 --max_key=100000000 --skip_verifydb=1 --continuous_verification_interval=0 --writepercent=85 --delpercent=3 --delrangepercent=0 --iterpercent=10 --nooverwritepercent=1 --prefixpercent=0 --readpercent=2 --key_len_percent_dist=1,30,69
# Before this PR, the following test will fail the asserts with error msg like the following
# Assertion failed: (size_key <= key_gen_ctx.weights.size() * sizeof(uint64_t)), function GetIntVal, file db_stress_common.h, line 524.
./db_stress --verify_iterator_with_expected_state_one_in=1 --max_key_len=3 --max_key=100000000 --skip_verifydb=1 --continuous_verification_interval=0 --writepercent=0 --delpercent=3 --delrangepercent=0 --iterpercent=95 --nooverwritepercent=1 --prefixpercent=0 --readpercent=2 --key_len_percent_dist=1,30,69 --destroy_db_initially=0
```
Reviewed By: ajkr
Differential Revision: D39085243
Pulled By: cbi42
fbshipit-source-id: a7dfee2320c330773b623b442d730fd014ec7056
Summary:
FreeBSD doesn't have `JEMALLOC_USABLE_SIZE_CONST` so we need to define
it.
This fixes MariaDB MDEV-20248.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10575
Reviewed By: jay-zhuang
Differential Revision: D39057665
Pulled By: ajkr
fbshipit-source-id: 3874779d12a1dd5036324947f6372e6ad57a7b08
