Summary:
Disallow `immutable_db_opts.use_direct_io_for_flush_and_compaction == true` and
`mutable_db_opts.writable_file_max_buffer_size == 0`, since it causes `WritableFileWriter::Append()`
to loop forever and does not make much sense in direct IO.
This combination of options itself does not make much sense: asking RocksDB to do direct IO but not allowing
RocksDB to allocate a buffer. We should detect this false combination and warn user early, no matter whether
the application is running on a platform that supports direct IO or not. In the case of platform **not** supporting
direct IO, it's ok if the user learns about this and then finds that direct IO is not supported.
One tricky thing: the constructor of `WritableFileWriter` is being used in our unit tests, and it's impossible
to return status code from constructor. Since we do not throw, I put an assertion for now. Fortunately,
the constructor is not exposed to external applications.
Closing https://github.com/facebook/rocksdb/issues/7109
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9348
Test Plan: make check
Reviewed By: ajkr
Differential Revision: D33371924
Pulled By: riversand963
fbshipit-source-id: 2a3701ab541cee23bffda8a36cdf37b2d235edfa
Summary:
MemTable::MultiGet was not considering range tombstones before
querying Bloom filter. This means range tombstones would be skipped for
keys (or prefixes) with no other entries in the memtable. This could cause
old values for a key (in SST files) to still show up until the range tombstone
covering it has been flushed.
This is fixed by essentially disabling the memtable Bloom filter when there
are any range tombstones. (This could be better optimized in the future, but
good enough for now.)
Did some other cleanup/optimization in the same code to (more than) offset
the cost of checking on range tombstones in more cases. There is now
notable improvement when memtable_whole_key_filtering and prefix_extractor
are used together (unusual), and this makes MultiGet closer to the Get
implementation.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9453
Test Plan:
new unit test added. Added memtable Bloom to crash test.
Performance testing
--------------------
Build WAL-only DB (recovers to memtable):
```
TEST_TMPDIR=/dev/shm/rocksdb ./db_bench -benchmarks=fillrandom -num=1000000 -write_buffer_size=250000000
```
Query test command, to maximize sensitivity to the changed code:
```
TEST_TMPDIR=/dev/shm/rocksdb ./db_bench -use_existing_db -readonly -benchmarks=multireadrandom -num=10000000 -write_buffer_size=250000000 -memtable_bloom_size_ratio=0.015 -multiread_batched -batch_size=24 -threads=8 -memtable_whole_key_filtering=$MWKF -prefix_size=$PXS
```
(Note -num here is 10x larger for mostly memtable misses)
Before & after run simultaneously, average over 10 iterations per data point, ops/sec.
MWKF=0 PXS=0 (Bloom disabled)
Before: 5724844
After: 6722066
MWKF=0 PXS=7 (prefixes hardly unique; Bloom not useful)
Before: 9981319
After: 10237990
MWKF=0 PXS=8 (prefixes unique; Bloom useful)
Before: 12081715
After: 12117603
MWKF=1 PXS=0 (whole key Bloom useful)
Before: 11944354
After: 12096085
MWKF=1 PXS=7 (whole key Bloom useful in new version; prefixes not useful in old version)
Before: 9444299
After: 11826029
MWKF=1 PXS=7 (whole key Bloom useful in new version; prefixes useful in old version)
Before: 11784465
After: 11778591
Only in this last case is the 'before' *slightly* faster, perhaps because hashing prefixes is slightly faster than hashing whole keys. Otherwise, 'after' is faster.
Reviewed By: ajkr
Differential Revision: D33805025
Pulled By: pdillinger
fbshipit-source-id: 597523cae4f4eafdf6ae6bb2bc6cb46f83b017bf
Summary:
1. Removed the options from the Capped/Fixed SliceTransforms. Instead these classes are created with id.number. This allows the GetID() id to be calculated and stored at class construction time. This change puts the construction back to similar to how it was prior to the Customizable changes for SliceTransform.
2. Improve the performance of AsString by using the ID only if there are no option properties (which is the case for all of the builtin transforms).
Ran tests of calling AsString in a loop 5M times and found approximately a 10x performance increase vs the original code.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9401
Reviewed By: pdillinger
Differential Revision: D33668672
Pulled By: mrambacher
fbshipit-source-id: d0075912c6ece8ed754ee543bc6b0b49a169b309
Summary:
Regexes are considered potentially problematic for use in
registering RocksDB extensions, so we are removing
ObjectLibrary::Register() and the Regex public API it depended on (now
unused).
In reference to https://github.com/facebook/rocksdb/issues/9389
Why?
* The power of Regexes can make it hard to reason about which extension
will match what. (The replacement API isn't perfect, but we are at least
"holding the line" on patterns we have seen in practice.)
* It is easy to make regexes that don't quite mean what you think they
mean, such as forgetting that the `.` in `foo.bar` can match any character
or that matching is nondeterministic, as in `a🅱️42` matching `.*:[0-9]+`.
* Some regexes and implementations can have disastrously bad
performance. This might not be much practical concern for ObjectLibray
here, but we don't want to encourage potentially dangerous further use
in production code. (Testing code is fine. See TestRegex.)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9439
Test Plan: CI
Reviewed By: mrambacher
Differential Revision: D33792342
Pulled By: pdillinger
fbshipit-source-id: 4f64dcb04764e639162c8977a5fa196f67754cec
Summary:
Fixes a major performance regression in 6.26, where
extra CPU is spent in SliceTransform::AsString when reads involve
a prefix_extractor (Get, MultiGet, Seek). Common case performance
is now better than 6.25.
This change creates a "fast path" for verifying that the current prefix
extractor is unchanged and compatible with what was used to
generate a table file. This fast path detects the common case by
pointer comparison on the current prefix_extractor and a "known
good" prefix extractor (if applicable) that is saved at the time the
table reader is opened. The "known good" prefix extractor is saved
as another shared_ptr copy (in an existing field, however) to ensure
the pointer is not recycled.
When the prefix_extractor has changed to a different instance but
same compatible configuration (rare, odd), performance is still a
regression compared to 6.25, but this is likely acceptable because
of the oddity of such a case. The performance of incompatible
prefix_extractor is essentially unchanged.
Also fixed a minor case (ForwardIterator) where a prefix_extractor
could be used via a raw pointer after being freed as a shared_ptr,
if replaced via SetOptions.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9407
Test Plan:
## Performance
Populate DB with `TEST_TMPDIR=/dev/shm/rocksdb ./db_bench -benchmarks=fillrandom -num=10000000 -disable_wal=1 -write_buffer_size=10000000 -bloom_bits=16 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=10000 -fifo_compaction_allow_compaction=0 -prefix_size=12`
Running head-to-head comparisons simultaneously with `TEST_TMPDIR=/dev/shm/rocksdb ./db_bench -use_existing_db -readonly -benchmarks=seekrandom -num=10000000 -duration=20 -disable_wal=1 -bloom_bits=16 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=10000 -fifo_compaction_allow_compaction=0 -prefix_size=12`
Below each is compared by ops/sec vs. baseline which is version 6.25 (multiple baseline runs because of variable machine load)
v6.26: 4833 vs. 6698 (<- major regression!)
v6.27: 4737 vs. 6397 (still)
New: 6704 vs. 6461 (better than baseline in common case)
Disabled fastpath: 4843 vs. 6389 (e.g. if prefix extractor instance changes but is still compatible)
Changed prefix size (no usable filter) in new: 787 vs. 5927
Changed prefix size (no usable filter) in new & baseline: 773 vs. 784
Reviewed By: mrambacher
Differential Revision: D33677812
Pulled By: pdillinger
fbshipit-source-id: 571d9711c461fb97f957378a061b7e7dbc4d6a76
Summary:
As title.
This is part of an fb-internal task.
First, remove all `using namespace` statements if applicable.
Next, utilize multiple build platforms and see if anything is broken.
Should anything become broken, fix the compilation errors with as little extra change as possible.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9369
Test Plan:
internal build and make check
make clean && make static_lib && cd examples && make all
Reviewed By: pdillinger
Differential Revision: D33517260
Pulled By: riversand963
fbshipit-source-id: 3fc4ce6402a073421dfd9a9b2d1c79441dca7a40
Summary:
In order to support old-style regex function registration, restored the original "Register<T>(string, Factory)" method using regular expressions. The PatternEntry methods were left in place but renamed to AddFactory. The goal is to allow for the deprecation of the original regex Registry method in an upcoming release.
Added modes to the PatternEntry kMatchZeroOrMore and kMatchAtLeastOne to match * or +, respectively (kMatchAtLeastOne was the original behavior).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9362
Reviewed By: pdillinger
Differential Revision: D33432562
Pulled By: mrambacher
fbshipit-source-id: ed88ab3f9a2ad0d525c7bd1692873f9bb3209d02
Summary:
Note: rebase on and merge after https://github.com/facebook/rocksdb/pull/9349, as part of https://github.com/facebook/rocksdb/pull/9342
**Context:**
https://github.com/facebook/rocksdb/pull/9073 charged the hash entries' memory in block cache with `CacheReservationHandle`. However, in the edge case where Ribbon Filter falls back to Bloom Filter and swaps its hash entries to the embedded bloom filter object, the handles associated with those entries are not swapped and thus not released as soon as those entries are cleared during Bloom Filter's finish process.
Although this is a minor issue since RocksDB internal calls `FilterBitsBuilder->Reset()` right after `FilterBitsBuilder->Finish()` on the main path, which releases all the cache reservation related to both the Ribbon Filter and its embedded Bloom Filter, it still worths this fix to avoid confusion.
**Summary:**
- Swapped the `CacheReservationHandle` associated with the hash entries on Ribbon Filter's fallback
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9345
Test Plan: - Added a unit test to verify the number of cache reservation after clearing hash entries, which failed before the change and now succeeds
Reviewed By: pdillinger
Differential Revision: D33377225
Pulled By: hx235
fbshipit-source-id: 7487f4c40dfb6ee7928232021f93ef2c5329cffa
Summary:
Added new ObjectLibrary::Entry classes to replace/reduce the use of Regex. For simple factories that only do name matching, there are "StringEntry" and "AltStringEntry" classes. For classes that use some semblance of regular expressions, there is a PatternEntry class that can match a name and prefixes. There is also a class for Customizable::IndividualId format matches.
Added tests for the new derivative classes and got all unit tests to pass.
Resolves https://github.com/facebook/rocksdb/issues/9225.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9264
Reviewed By: pdillinger
Differential Revision: D33062001
Pulled By: mrambacher
fbshipit-source-id: c2d2143bd2d38bdf522705c8280c35381b135c03
Summary:
in hope to get rockdb compiled with GCC-11 without warning
* util/bloom_test: init a variable before using it
to silence the GCC warning like
```
util/bloom_test.cc:1253:31: error: ‘<anonymous>’ may be used uninitialized [-Werror=maybe-uninitialized]
1253 | Slice key_slice{key_bytes, 8};
| ^
...
include/rocksdb/slice.h:41:3: note: by argument 2 of type ‘const char*’ to ‘rocksdb::Slice::Slice(const char*, size_t)’ declared here
41 | Slice(const char* d, size_t n) : data_(d), size_(n) {}
| ^~~~~
util/bloom_test.cc:1249:3: note: ‘<anonymous>’ declared here
1249 | };
| ^
cc1plus: all warnings being treated as errors
```
* cmake: add find_package(uring ...)
find liburing in a more consistent way. also it is the encouraged way for finding a library.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9286
Reviewed By: mrambacher
Differential Revision: D33165241
Pulled By: jay-zhuang
fbshipit-source-id: 9f3487e11b4e40fd8f1c97c8facb24a190e5ce31
Summary:
This change standardizes on a new 16-byte cache key format for
block cache (incl compressed and secondary) and persistent cache (but
not table cache and row cache).
The goal is a really fast cache key with practically ideal stability and
uniqueness properties without external dependencies (e.g. from FileSystem).
A fixed key size of 16 bytes should enable future optimizations to the
concurrent hash table for block cache, which is a heavy CPU user /
bottleneck, but there appears to be measurable performance improvement
even with no changes to LRUCache.
This change replaces a lot of disjointed and ugly code handling cache
keys with calls to a simple, clean new internal API (cache_key.h).
(Preserving the old cache key logic under an option would be very ugly
and likely negate the performance gain of the new approach. Complete
replacement carries some inherent risk, but I think that's acceptable
with sufficient analysis and testing.)
The scheme for encoding new cache keys is complicated but explained
in cache_key.cc.
Also: EndianSwapValue is moved to math.h to be next to other bit
operations. (Explains some new include "math.h".) ReverseBits operation
added and unit tests added to hash_test for both.
Fixes https://github.com/facebook/rocksdb/issues/7405 (presuming a root cause)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9126
Test Plan:
### Basic correctness
Several tests needed updates to work with the new functionality, mostly
because we are no longer relying on filesystem for stable cache keys
so table builders & readers need more context info to agree on cache
keys. This functionality is so core, a huge number of existing tests
exercise the cache key functionality.
### Performance
Create db with
`TEST_TMPDIR=/dev/shm ./db_bench -bloom_bits=10 -benchmarks=fillrandom -num=3000000 -partition_index_and_filters`
And test performance with
`TEST_TMPDIR=/dev/shm ./db_bench -readonly -use_existing_db -bloom_bits=10 -benchmarks=readrandom -num=3000000 -duration=30 -cache_index_and_filter_blocks -cache_size=250000 -threads=4`
using DEBUG_LEVEL=0 and simultaneous before & after runs.
Before ops/sec, avg over 100 runs: 121924
After ops/sec, avg over 100 runs: 125385 (+2.8%)
### Collision probability
I have built a tool, ./cache_bench -stress_cache_key to broadly simulate host-wide cache activity
over many months, by making some pessimistic simplifying assumptions:
* Every generated file has a cache entry for every byte offset in the file (contiguous range of cache keys)
* All of every file is cached for its entire lifetime
We use a simple table with skewed address assignment and replacement on address collision
to simulate files coming & going, with quite a variance (super-Poisson) in ages. Some output
with `./cache_bench -stress_cache_key -sck_keep_bits=40`:
```
Total cache or DBs size: 32TiB Writing 925.926 MiB/s or 76.2939TiB/day
Multiply by 9.22337e+18 to correct for simulation losses (but still assume whole file cached)
```
These come from default settings of 2.5M files per day of 32 MB each, and
`-sck_keep_bits=40` means that to represent a single file, we are only keeping 40 bits of
the 128-bit cache key. With file size of 2\*\*25 contiguous keys (pessimistic), our simulation
is about 2\*\*(128-40-25) or about 9 billion billion times more prone to collision than reality.
More default assumptions, relatively pessimistic:
* 100 DBs in same process (doesn't matter much)
* Re-open DB in same process (new session ID related to old session ID) on average
every 100 files generated
* Restart process (all new session IDs unrelated to old) 24 times per day
After enough data, we get a result at the end:
```
(keep 40 bits) 17 collisions after 2 x 90 days, est 10.5882 days between (9.76592e+19 corrected)
```
If we believe the (pessimistic) simulation and the mathematical generalization, we would need to run a billion machines all for 97 billion days to expect a cache key collision. To help verify that our generalization ("corrected") is robust, we can make our simulation more precise with `-sck_keep_bits=41` and `42`, which takes more running time to get enough data:
```
(keep 41 bits) 16 collisions after 4 x 90 days, est 22.5 days between (1.03763e+20 corrected)
(keep 42 bits) 19 collisions after 10 x 90 days, est 47.3684 days between (1.09224e+20 corrected)
```
The generalized prediction still holds. With the `-sck_randomize` option, we can see that we are beating "random" cache keys (except offsets still non-randomized) by a modest amount (roughly 20x less collision prone than random), which should make us reasonably comfortable even in "degenerate" cases:
```
197 collisions after 1 x 90 days, est 0.456853 days between (4.21372e+18 corrected)
```
I've run other tests to validate other conditions behave as expected, never behaving "worse than random" unless we start chopping off structured data.
Reviewed By: zhichao-cao
Differential Revision: D33171746
Pulled By: pdillinger
fbshipit-source-id: f16a57e369ed37be5e7e33525ace848d0537c88f
Summary:
I'm working on a new format_version=6 to support context
checksum (https://github.com/facebook/rocksdb/issues/9058) and this includes much of the refactoring and test
updates to support that change.
Test coverage data and manual inspection agree on dead code in
block_based_table_reader.cc (removed).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9240
Test Plan:
tests enhanced to cover more cases etc.
Extreme case performance testing indicates small % regression in fillseq (w/ compaction), though CPU profile etc. doesn't suggest any explanation. There is enhanced correctness checking in Footer::DecodeFrom, but this should be negligible.
TEST_TMPDIR=/dev/shm/ ./db_bench -benchmarks=fillseq -memtablerep=vector -allow_concurrent_memtable_write=false -num=30000000 -checksum_type=1 --disable_wal={false,true}
(Each is ops/s averaged over 50 runs, run simultaneously with competing configuration for load fairness)
Before w/ wal: 454512
After w/ wal: 444820 (-2.1%)
Before w/o wal: 1004560
After w/o wal: 998897 (-0.6%)
Since this doesn't modify WAL code, one would expect real effects to be larger in w/o wal case.
This regression will be corrected in a follow-up PR.
Reviewed By: ajkr
Differential Revision: D32813769
Pulled By: pdillinger
fbshipit-source-id: 444a244eabf3825cd329b7d1b150cddce320862f
Summary:
Add a new API in listener.h that notifies about IOErrors on
Read/Write/Append/Flush etc. The API reports about IOStatus, filename, Operation
name, offset and length.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9177
Test Plan: Added new unit tests
Reviewed By: anand1976
Differential Revision: D32470627
Pulled By: akankshamahajan15
fbshipit-source-id: 189a717033590ae227b3beae8b1e7e185e4cdc12
Summary:
Note: This PR is the 4th part of a bigger PR stack (https://github.com/facebook/rocksdb/pull/9073) and will rebase/merge only after the first three PRs (https://github.com/facebook/rocksdb/pull/9070, https://github.com/facebook/rocksdb/pull/9071, https://github.com/facebook/rocksdb/pull/9130) merge.
**Context:**
Similar to https://github.com/facebook/rocksdb/pull/8428, this PR is to track memory usage during (new) Bloom Filter (i.e,FastLocalBloom) and Ribbon Filter (i.e, Ribbon128) construction, moving toward the goal of [single global memory limit using block cache capacity](https://github.com/facebook/rocksdb/wiki/Projects-Being-Developed#improving-memory-efficiency). It also constrains the size of the banding portion of Ribbon Filter during construction by falling back to Bloom Filter if that banding is, at some point, larger than the available space in the cache under `LRUCacheOptions::strict_capacity_limit=true`.
The option to turn on this feature is `BlockBasedTableOptions::reserve_table_builder_memory = true` which by default is set to `false`. We [decided](https://github.com/facebook/rocksdb/pull/9073#discussion_r741548409) not to have separate option for separate memory user in table building therefore their memory accounting are all bundled under one general option.
**Summary:**
- Reserved/released cache for creation/destruction of three main memory users with the passed-in `FilterBuildingContext::cache_res_mgr` during filter construction:
- hash entries (i.e`hash_entries`.size(), we bucket-charge hash entries during insertion for performance),
- banding (Ribbon Filter only, `bytes_coeff_rows` +`bytes_result_rows` + `bytes_backtrack`),
- final filter (i.e, `mutable_buf`'s size).
- Implementation details: in order to use `CacheReservationManager::CacheReservationHandle` to account final filter's memory, we have to store the `CacheReservationManager` object and `CacheReservationHandle` for final filter in `XXPH3BitsFilterBuilder` as well as explicitly delete the filter bits builder when done with the final filter in block based table.
- Added option fo run `filter_bench` with this memory reservation feature
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9073
Test Plan:
- Added new tests in `db_bloom_filter_test` to verify filter construction peak cache reservation under combination of `BlockBasedTable::Rep::FilterType` (e.g, `kFullFilter`, `kPartitionedFilter`), `BloomFilterPolicy::Mode`(e.g, `kFastLocalBloom`, `kStandard128Ribbon`, `kDeprecatedBlock`) and `BlockBasedTableOptions::reserve_table_builder_memory`
- To address the concern for slow test: tests with memory reservation under `kFullFilter` + `kStandard128Ribbon` and `kPartitionedFilter` take around **3000 - 6000 ms** and others take around **1500 - 2000 ms**, in total adding **20000 - 25000 ms** to the test suit running locally
- Added new test in `bloom_test` to verify Ribbon Filter fallback on large banding in FullFilter
- Added test in `filter_bench` to verify that this feature does not significantly slow down Bloom/Ribbon Filter construction speed. Local result averaged over **20** run as below:
- FastLocalBloom
- baseline `./filter_bench -impl=2 -quick -runs 20 | grep 'Build avg'`:
- **Build avg ns/key: 29.56295** (DEBUG_LEVEL=1), **29.98153** (DEBUG_LEVEL=0)
- new feature (expected to be similar as above)`./filter_bench -impl=2 -quick -runs 20 -reserve_table_builder_memory=true | grep 'Build avg'`:
- **Build avg ns/key: 30.99046** (DEBUG_LEVEL=1), **30.48867** (DEBUG_LEVEL=0)
- new feature of RibbonFilter with fallback (expected to be similar as above) `./filter_bench -impl=2 -quick -runs 20 -reserve_table_builder_memory=true -strict_capacity_limit=true | grep 'Build avg'` :
- **Build avg ns/key: 31.146975** (DEBUG_LEVEL=1), **30.08165** (DEBUG_LEVEL=0)
- Ribbon128
- baseline `./filter_bench -impl=3 -quick -runs 20 | grep 'Build avg'`:
- **Build avg ns/key: 129.17585** (DEBUG_LEVEL=1), **130.5225** (DEBUG_LEVEL=0)
- new feature (expected to be similar as above) `./filter_bench -impl=3 -quick -runs 20 -reserve_table_builder_memory=true | grep 'Build avg' `:
- **Build avg ns/key: 131.61645** (DEBUG_LEVEL=1), **132.98075** (DEBUG_LEVEL=0)
- new feature of RibbonFilter with fallback (expected to be a lot faster than above due to fallback) `./filter_bench -impl=3 -quick -runs 20 -reserve_table_builder_memory=true -strict_capacity_limit=true | grep 'Build avg'` :
- **Build avg ns/key: 52.032965** (DEBUG_LEVEL=1), **52.597825** (DEBUG_LEVEL=0)
- And the warning message of `"Cache reservation for Ribbon filter banding failed due to cache full"` is indeed logged to console.
Reviewed By: pdillinger
Differential Revision: D31991348
Pulled By: hx235
fbshipit-source-id: 9336b2c60f44d530063da518ceaf56dac5f9df8e
Summary:
`pthread_setname_np()` fails on attempts to assign oversized names like
"rocksdb:bottom10", which resulted in some thread name updates being
lost. We do not need the ID suffix so I removed it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9165
Test Plan:
```
$ TEST_TMPDIR=/dev/shm ./db_bench -benchmarks=fillrandom -max_background_flushes=123 -max_background_compactions=456 -num_bottom_pri_threads=789 -duration=60
```
While above is running:
```
$ ps -o 'comm' -Lp `pidof db_bench` | grep '^rocksdb:' | sort | uniq -c
789 rocksdb:bottom
123 rocksdb:high
456 rocksdb:low
```
Reviewed By: pdillinger
Differential Revision: D32415077
Pulled By: ajkr
fbshipit-source-id: a0e013101e26a78bc5eca73509293ef4bf22254f
Summary:
**Context:**
Some existing internal calls of `GenericRateLimiter::Request()` in backupable_db.cc and newly added internal calls in https://github.com/facebook/rocksdb/pull/8722/ do not make sure `bytes <= GetSingleBurstBytes()` as required by rate_limiter https://github.com/facebook/rocksdb/blob/master/include/rocksdb/rate_limiter.h#L47.
**Impacts of this bug include:**
(1) In debug build, when `GenericRateLimiter::Request()` requests bytes greater than `GenericRateLimiter:: kMinRefillBytesPerPeriod = 100` byte, process will crash due to assertion failure. See https://github.com/facebook/rocksdb/pull/9063#discussion_r737034133 and for possible scenario
(2) In production build, although there will not be the above crash due to disabled assertion, the bug can lead to a request of small bytes being blocked for a long time by a request of same priority with insanely large bytes from a different thread. See updated https://github.com/facebook/rocksdb/wiki/Rate-Limiter ("Notice that although....the maximum bytes that can be granted in a single request have to be bounded...") for more info.
There is an on-going effort to move rate-limiting to file wrapper level so rate limiting in `BackupEngine` and this PR might be made obsolete in the future.
**Summary:**
- Implemented loop-calling `GenericRateLimiter::Request()` with `bytes <= GetSingleBurstBytes()` as a static private helper function `BackupEngineImpl::LoopRateLimitRequestHelper`
-- Considering make this a util function in `RateLimiter` later or do something with `RateLimiter::RequestToken()`
- Replaced buggy internal callers with this helper function wherever requested byte is not pre-limited by `GetSingleBurstBytes()`
- Removed the minimum refill bytes per period enforced by `GenericRateLimiter` since it is useless and prevents testing `GenericRateLimiter` for extreme case with small refill bytes per period.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9063
Test Plan:
- Added a new test that failed the assertion before this change and now passes
- It exposed bugs in [the write during creation in `CopyOrCreateFile()`](df7cc66e17/utilities/backupable/backupable_db.cc (L2034-L2043)), [the read of table properties in `GetFileDbIdentities()`](df7cc66e17/utilities/backupable/backupable_db.cc (L2372-L2378)), [some read of metadata in `BackupMeta::LoadFromFile()`](df7cc66e17/utilities/backupable/backupable_db.cc (L2726))
- Passing Existing tests
Reviewed By: ajkr
Differential Revision: D31824535
Pulled By: hx235
fbshipit-source-id: d2b3dea7a64e2a4b1e6a59fca322f0800a4fcbcc
Summary:
Context:
Surprisingly, there isn't any sanitization against negative `int64_t bytes` in `GenericRateLimiter::Request(int64_t bytes, const Env::IOPriority pri, Statistics* stats)`. A negative `bytes` can be passed in and incorrectly increases `available_bytes_` by subtracting the negative `bytes` from `available_bytes_`, such as [here](https://github.com/facebook/rocksdb/blob/main/util/rate_limiter.cc#L138) and [here](https://github.com/facebook/rocksdb/blob/main/util/rate_limiter.cc#L283), which are incorrect behaviors.
- Sanitized negative request bytes by rounding it up to 0
- Added notes to public and internal API
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9112
Test Plan: - Rely on existing tests
Reviewed By: ajkr
Differential Revision: D32085364
Pulled By: hx235
fbshipit-source-id: b1b6066b2dd5ffc7bcbfb07069ca65a33578251b
Summary:
Directory fsync might be expensive on btrfs and it may not be needed.
Here are 4 directory fsync cases:
1. creating a new file: dir-fsync is not needed on btrfs, as long as the
new file itself is synced.
2. renaming a file: dir-fsync is not needed if the renamed file is
synced. So an API `FsyncAfterFileRename(filename, ...)` is provided
to sync the file on btrfs. By default, it just calls dir-fsync.
3. deleting files: dir-fsync is forced by set
`IOOptions.force_dir_fsync = true`
4. renaming multiple files (like backup and checkpoint): dir-fsync is
forced, the same as above.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8903
Test Plan: run tests on btrfs and non btrfs
Reviewed By: ajkr
Differential Revision: D30885059
Pulled By: jay-zhuang
fbshipit-source-id: dd2730b31580b0bcaedffc318a762d7dbf25de4a
Summary:
This PR adds support for building on s390x including updating travis CI. It uses the previous work in https://github.com/facebook/rocksdb/pull/6168 and adds some more changes to get all current tests (make check and jni tests) to pass. The tests were run with snappy, lz4, bzip2 and zstd all compiled in.
There are a few pieces still needed to get the travis build working that I don't think I can do. adamretter is this something you could help with?
1. A prebuilt https://rocksdb-deps.s3-us-west-2.amazonaws.com/cmake/cmake-3.14.5-Linux-s390x.deb package
2. A https://hub.docker.com/r/evolvedbinary/rocksjava s390x image
Not sure if there is more required for travis. Happy to help in any way I can.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8962
Reviewed By: mrambacher
Differential Revision: D31802198
Pulled By: pdillinger
fbshipit-source-id: 683511466fa6b505f85ba5a9964a268c6151f0c2
Summary:
Adds changes to DBOptions (comparable to ColumnFamilyOptions) to allow some option values to be ignored on rehydration from the Options file. This is necessary for some customizable classes that were not registered with the ObjectRegistry but are saved/restored from the Options file.
All tests pass. Will run check_format_compatible.sh shortly.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9045
Reviewed By: zhichao-cao
Differential Revision: D31761664
Pulled By: mrambacher
fbshipit-source-id: 300c2251639cce2b223481c3bb2a63877b1f3766
Summary:
* New public header unique_id.h and function GetUniqueIdFromTableProperties
which computes a universally unique identifier based on table properties
of table files from recent RocksDB versions.
* Generation of DB session IDs is refactored so that they are
guaranteed unique in the lifetime of a process running RocksDB.
(SemiStructuredUniqueIdGen, new test included.) Along with file numbers,
this enables SST unique IDs to be guaranteed unique among SSTs generated
in a single process, and "better than random" between processes.
See https://github.com/pdillinger/unique_id
* In addition to public API producing 'external' unique IDs, there is a function
for producing 'internal' unique IDs, with functions for converting between the
two. In short, the external ID is "safe" for things people might do with it, and
the internal ID enables more "power user" features for the future. Specifically,
the external ID goes through a hashing layer so that any subset of bits in the
external ID can be used as a hash of the full ID, while also preserving
uniqueness guarantees in the first 128 bits (bijective both on first 128 bits
and on full 192 bits).
Intended follow-up:
* Use the internal unique IDs in cache keys. (Avoid conflicts with https://github.com/facebook/rocksdb/issues/8912) (The file offset can be XORed into
the third 64-bit value of the unique ID.)
* Publish the external unique IDs in FileStorageInfo (https://github.com/facebook/rocksdb/issues/8968)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8990
Test Plan:
Unit tests added, and checking of unique ids in stress test.
NOTE in stress test we do not generate nearly enough files to thoroughly
stress uniqueness, but the test trims off pieces of the ID to check for
uniqueness so that we can infer (with some assumptions) stronger
properties in the aggregate.
Reviewed By: zhichao-cao, mrambacher
Differential Revision: D31582865
Pulled By: pdillinger
fbshipit-source-id: 1f620c4c86af9abe2a8d177b9ccf2ad2b9f48243
Summary:
There were three implementations of VectorIterator (util/vector_iterator, test_util/testutil.h and LoggingForwardVectorIterator). Merged them into one class to increase code coverage/testing and reduce duplication.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8901
Reviewed By: pdillinger
Differential Revision: D31022673
Pulled By: mrambacher
fbshipit-source-id: 8e3acbd2dfd60b4df609d02cc72846de2389d531
Summary:
This header file was including everything and the kitchen sink when it did not need to. This resulted in many places including this header when they needed other pieces instead.
Cleaned up this header to only include what was needed and fixed up the remaining code to include what was now missing.
Hopefully, this sort of code hygiene cleanup will speed up the builds...
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8930
Reviewed By: pdillinger
Differential Revision: D31142788
Pulled By: mrambacher
fbshipit-source-id: 6b45de3f300750c79f751f6227dece9cfd44085d
Summary:
Made SliceTransform into a Customizable class.
Would be nice to write a test that stored and used a custom transform in an SST table.
There are a set of tests (DBBlockFliterTest.PrefixExtractor*, SamePrefixTest.InDomainTest, PrefixTest.PrefixAndWholeKeyTest that run the same with or without a SliceTransform/PrefixFilter. Is this expected?
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8641
Reviewed By: zhichao-cao
Differential Revision: D31142793
Pulled By: mrambacher
fbshipit-source-id: bb08672fccbfdc263dcae21f25a62307e1facda1
Summary:
Context:
After more discussion, a fix in https://github.com/facebook/rocksdb/issues/8938 might turn out to be too restrictive for the case where `GetTotalPendingRequests` might be invoked on RateLimiter classes that does not support the recently added API `RateLimiter::GetTotalPendingRequests` (https://github.com/facebook/rocksdb/issues/8890) due to the `assert(false)` in https://github.com/facebook/rocksdb/issues/8938. Furthermore, sentinel value like `-1` proposed in https://github.com/facebook/rocksdb/issues/8938 is easy to be ignored and unchecked. Therefore we decided to adopt `Status::NotSupported()`, which is also a convention of adding new API to public header in RocksDB.
- Changed return value type of `RateLimiter::GetTotalPendingRequests` in related declaration/definition
- Passed in pointer argument to hold the output instead of returning it as before
- Adapted to the changes above in calling `RateLimiter::GetTotalPendingRequests` in test
- Minor improvement to `TEST_F(RateLimiterTest, GetTotalPendingRequests)`: added failure message for assertion and replaced repetitive statements with a loop
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8950
Reviewed By: ajkr, pdillinger
Differential Revision: D31128450
Pulled By: hx235
fbshipit-source-id: 282ac9c4f3dacaa0aec6d0a993161f77ad47a040
Summary:
Made SystemClock into a Customizable class, complete with CreateFromString.
Cleaned up some of the existing SystemClock implementations that were redundant (NoSleep was the same as the internal one for MockEnv).
Changed MockEnv construction to allow Clock to be passed to the Memory/MockFileSystem.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8636
Reviewed By: zhichao-cao
Differential Revision: D30483360
Pulled By: mrambacher
fbshipit-source-id: cd0e3a876c39f8c98fe13374c06e8edbd5b9f2a1
Summary:
- Fixed a bug in `RateLimiterTest.GeneratePriorityIterationOrder` that the callbacks in this test were not called starting from `i = 1`. Fix by increasing `rate_bytes_per_sec` and requested bytes.
- The bug is due to the previous `rate_bytes_per_sec` was set too small, resulting in `refill_bytes_per_period` less than `kMinRefillBytesPerPeriod`. Hence the actual `refill_bytes_per_period` was equal to `kMinRefillBytesPerPeriod` due to the logic [here](https://github.com/facebook/rocksdb/blob/main/util/rate_limiter.cc#L302-L303) and it ended up being greater than the previously set requested bytes. Therefore starting from `i = 1`, `RefillBytesAndGrantRequests()` and `GeneratePriorityIterationOrder` won't be called and the test callbacks was not triggered to execute the assertion.
- Added internal flag to assert callbacks are called in `RateLimiterTest.GeneratePriorityIterationOrder` to prevent any future changes defeat the purpose of the test [as suggested](https://github.com/facebook/rocksdb/pull/8890#discussion_r704915134)
- Increased `rate_bytes_per_sec` and bytes of each request in `RateLimiterTest.GetTotalBytesThrough`, `RateLimiterTest.GetTotalRequests`, `RateLimiterTest.GetTotalPendingRequests` to trigger the "long path" of execution (i.e, the one trigger RefillBytesAndGrantRequests()) to increase test coverage
- This increased the running time of the three tests, see test plan for time difference running locally
- Cleared up sync point effects after each test by calling `SyncPoint::GetInstance()->DisableProcessing();` and `SyncPoint::GetInstance()->ClearAllCallBacks();` in `~RateLimiterTest()` [as suggested](https://github.com/facebook/rocksdb/pull/8595/files#r697534279)
- It's fine to call these two methods even when `EnableProcessing()` or `SetCallBack()` is not called in the test or is already cleaned up. In those cases, calling these two functions in destructor is effectively no-op.
- This will allow cleaning up sync point effects of previous test even when the previous test failed in assertion.
- Added missing `SyncPoint::GetInstance()->DisableProcessing();` and `SyncPoint::GetInstance()->ClearCallBacks(..);` in existing tests for completeness
- Called `SyncPoint::GetInstance()->DisableProcessing();` and `SyncPoint::GetInstance()->ClearCallBacks(..);` in loop in `RateLimiterTest.GeneratePriorityIterationOrder` for completeness
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8904
Test Plan:
- Passing existing tests
- To verify the 1st change, run `RateLimiterTest.GeneratePriorityIterationOrder` with assertions of callbacks are indeed called under original `rate_bytes_per_sec` and request byte and under updated `rate_bytes_per_sec` and request byte. The former will fail the assertion while the latter succeeds.
- Here is the increased test time due to the 3rd change mentioned above in the summary. The relevant 3 tests mentioned in total increase the test time by 6s (~6000/33848 = 17.7% of the original total test time), which IMO is acceptable for better test coverage through running the "long path".
- current (run on branch rate_limiter_ut_improve locally)
[ RUN ] RateLimiterTest.GetTotalBytesThrough
[ OK ] RateLimiterTest.GetTotalBytesThrough (3000 ms)
[ RUN ] RateLimiterTest.GetTotalRequests
[ OK ] RateLimiterTest.GetTotalRequests (3001 ms)
[ RUN ] RateLimiterTest.GetTotalPendingRequests
[ OK ] RateLimiterTest.GetTotalPendingRequests (0 ms)
...
[----------] 10 tests from RateLimiterTest (43349 ms total)
[----------] Global test environment tear-down
[==========] 10 tests from 1 test case ran. (43349 ms total)
[ PASSED ] 10 tests.
- previous (run on branch main locally)
[ RUN ] RateLimiterTest.GetTotalBytesThrough
[ OK ] RateLimiterTest.GetTotalBytesThrough (0 ms)
[ RUN ] RateLimiterTest.GetTotalRequests
[ OK ] RateLimiterTest.GetTotalRequests (0 ms)
[ RUN ] RateLimiterTest.GetTotalPendingRequests
[ OK ] RateLimiterTest.GetTotalPendingRequests (0 ms)
...
[----------] 10 tests from RateLimiterTest (33848 ms total)
[----------] Global test environment tear-down
[==========] 10 tests from 1 test case ran. (33848 ms total)
[ PASSED ] 10 tests.
Reviewed By: ajkr
Differential Revision: D30872544
Pulled By: hx235
fbshipit-source-id: ff894f5c1a4bef70e8e407d53b00be45f776b3e4
Summary:
It's always annoying to find a header does not include its own
dependencies and only works when included after other includes. This
change adds `make check-headers` which validates that each header can
be included at the top of a file. Some headers are excluded e.g. because
of platform or external dependencies.
rocksdb_namespace.h had to be re-worked slightly to enable checking for
failure to include it. (ROCKSDB_NAMESPACE is a valid namespace name.)
Fixes mostly involve adding and cleaning up #includes, but for
FileTraceWriter, a constructor was out-of-lined to make a forward
declaration sufficient.
This check is not currently run with `make check` but is added to
CircleCI build-linux-unity since that one is already relatively fast.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8893
Test Plan: existing tests and resolving issues detected by new check
Reviewed By: mrambacher
Differential Revision: D30823300
Pulled By: pdillinger
fbshipit-source-id: 9fff223944994c83c105e2e6496d24845dc8e572
Summary:
Context/Summary:
As users requested, a public API RateLimiter::GetTotalPendingRequests() is added to expose the total number of pending requests for bytes in the rate limiter, which is the size of the request queue of that priority (or of all priorities, if IO_TOTAL is interested) at the time when this API is called.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8890
Test Plan:
- Passing added new unit tests
- Passing existing unit tests
Reviewed By: ajkr
Differential Revision: D30815500
Pulled By: hx235
fbshipit-source-id: 2dfa990f651c1c47378b6215c751ad76a5824300
Summary:
* Consolidate use of std::regex for testing to testharness.cc, to
minimize Facebook linters constantly flagging uses in non-production
code.
* Improve syntax and error messages for asserting some string matches a
regex in tests.
* Add a public Regex wrapper class to encapsulate existing usage in
ObjectRegistry.
* Remove unnecessary include <regex>
* Put warnings that use of Regex in production code could cause bad
performance or stack overflow.
Intended follow-up work:
* Replace std::regex with another underlying implementation like RE2
* Improve ObjectRegistry interface in terms of possibly confusing literal
string matching vs. regex and in terms of reporting invalid regex.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8740
Test Plan:
tests updated, basic unit test for public Regex, and some manual
testing of temporary changes to see example error messages:
utilities/backupable/backupable_db_test.cc:917: Failure
000010_1162373755_138626.blob (child.name)
does not match regex
[0-9]+_[0-9]+_[0-9]+[.]blobHAHAHA (pattern)
db/db_basic_test.cc:74: Failure
R3SHSBA8C4U0CIMV2ZB0 (sid3)
does not match regex [0-9A-Z]{20}HAHAHA
Reviewed By: mrambacher
Differential Revision: D30706246
Pulled By: pdillinger
fbshipit-source-id: ba845e8f563ccad39bdb58f44f04e9da8f78c3fd
Summary:
Old typedef syntax is confusing
Most but not all changes with
perl -pi -e 's/typedef (.*) ([a-zA-Z0-9_]+);/using $2 = $1;/g' list_of_files
make format
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8751
Test Plan: existing
Reviewed By: zhichao-cao
Differential Revision: D30745277
Pulled By: pdillinger
fbshipit-source-id: 6f65f0631c3563382d43347896020413cc2366d9
Summary:
* FullKey and ParseFullKey appear to serve no purpose in the public API
(or anything else) so removed. Only use in one test updated.
* NumberToString serves no purpose vs. ToString so removed, numerous
calls updated
* Remove unnecessary forward declarations in metadata.h by re-arranging
class definitions.
* Remove some unneeded semicolons
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8736
Test Plan: existing tests
Reviewed By: mrambacher
Differential Revision: D30700039
Pulled By: pdillinger
fbshipit-source-id: 1e436a576f511a6ed8b4d97af7cc8216bc729af2
Summary:
Context:
An extra IO_USER priority in rate limiter allows users to optionally charge WAL writes / SST reads to rate limiter at this priority level, which then has higher priority than IO_HIGH and IO_LOW. With an extra IO_USER priority, it allows users to better specify the relative urgency/importance among different requests in rate limiter. As a consequence, IO resource management can better prioritize and limit resource based on user's need.
The IO_USER is implemented as superior priority in GenericRateLimiter, in the sense that its request queue will always be iterated first without being constrained to fairness. The reason is that the notion of fairness is only meaningful in helping lower priorities in background IO (i.e, IO_HIGH/MID/LOW) to gain some fair chance to run so that it does not block foreground IO (i.e, the ones that are charged at the level of IO_USER). As we can see, the ultimate goal here is to not blocking foreground IO at IO_USER level, which justifies the superiority of IO_USER.
Similar benefits exist for IO_MID priority.
- Rewrote the logic of deciding the order of iterating request queues of high/low priorities to include the extra user/mid priority w/o affecting the existing behavior (see PR's [comment](https://github.com/facebook/rocksdb/pull/8595/files#r678749331))
- Included the request queue of user-pri/mid-pri in the code path of next-leader-candidate signaling and GenericRateLimiter's destructor
- Included the extra user/mid-pri in bookkeeping data structures: total_bytes_through_ and total_requests_
- Re-written the previous impl of explicitly iterating priorities with a loop from Env::IO_LOW to Env::IO_TOTAL
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8595
Test Plan:
- passed existing rate_limiter_test.cc
- passed added unit tests in rate_limiter_test.cc
- run performance test to verify performance with only high/low requests is not affected by this change
- Set-up command:
`TEST_TMPDIR=/dev/shm ./db_bench --benchmarks=fillrandom --duration=5 --compression_type=none --num=100000000 --disable_auto_compactions=true --write_buffer_size=1048576 --writable_file_max_buffer_size=65536 --target_file_size_base=1048576 --max_bytes_for_level_base=4194304 --level0_slowdown_writes_trigger=$(((1 << 31) - 1)) --level0_stop_writes_trigger=$(((1 << 31) - 1))`
- Test command:
`TEST_TMPDIR=/dev/shm ./db_bench --benchmarks=overwrite --use_existing_db=true --disable_wal=true --duration=30 --compression_type=none --num=100000000 --write_buffer_size=1048576 --writable_file_max_buffer_size=65536 --target_file_size_base=1048576 --max_bytes_for_level_base=4194304 --level0_slowdown_writes_trigger=$(((1 << 31) - 1)) --level0_stop_writes_trigger=$(((1 << 31) - 1)) --statistics=true --rate_limiter_bytes_per_sec=1048576 --rate_limiter_refill_period_us=1000 --threads=32 |& grep -E '(flush|compact)\.write\.bytes'`
- Before (on branch upstream/master):
`rocksdb.compact.write.bytes COUNT : 4014162`
`rocksdb.flush.write.bytes COUNT : 26715832`
rocksdb.flush.write.bytes/rocksdb.compact.write.bytes ~= 6.66
- After (on branch rate_limiter_user_pri):
`rocksdb.compact.write.bytes COUNT : 3807822`
`rocksdb.flush.write.bytes COUNT : 26098659`
rocksdb.flush.write.bytes/rocksdb.compact.write.bytes ~= 6.85
Reviewed By: ajkr
Differential Revision: D30577783
Pulled By: hx235
fbshipit-source-id: 0881f2705ffd13ecd331256bde7e8ec874a353f4
Summary:
Env::GenerateUniqueId() works fine on Windows and on POSIX
where /proc/sys/kernel/random/uuid exists. Our other implementation is
flawed and easily produces collision in a new multi-threaded test.
As we rely more heavily on DB session ID uniqueness, this becomes a
serious issue.
This change combines several individually suitable entropy sources
for reliable generation of random unique IDs, with goal of uniqueness
and portability, not cryptographic strength nor maximum speed.
Specifically:
* Moves code for getting UUIDs from the OS to port::GenerateRfcUuid
rather than in Env implementation details. Callers are now told whether
the operation fails or succeeds.
* Adds an internal API GenerateRawUniqueId for generating high-quality
128-bit unique identifiers, by combining entropy from three "tracks":
* Lots of info from default Env like time, process id, and hostname.
* std::random_device
* port::GenerateRfcUuid (when working)
* Built-in implementations of Env::GenerateUniqueId() will now always
produce an RFC 4122 UUID string, either from platform-specific API or
by converting the output of GenerateRawUniqueId.
DB session IDs now use GenerateRawUniqueId while DB IDs (not as
critical) try to use port::GenerateRfcUuid but fall back on
GenerateRawUniqueId with conversion to an RFC 4122 UUID.
GenerateRawUniqueId is declared and defined under env/ rather than util/
or even port/ because of the Env dependency.
Likely follow-up: enhance GenerateRawUniqueId to be faster after the
first call and to guarantee uniqueness within the lifetime of a single
process (imparting the same property onto DB session IDs).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8708
Test Plan:
A new mini-stress test in env_test checks the various public
and internal APIs for uniqueness, including each track of
GenerateRawUniqueId individually. We can't hope to verify anywhere close
to 128 bits of entropy, but it can at least detect flaws as bad as the
old code. Serial execution of the new tests takes about 350 ms on
my machine.
Reviewed By: zhichao-cao, mrambacher
Differential Revision: D30563780
Pulled By: pdillinger
fbshipit-source-id: de4c9ff4b2f581cf784fcedb5f39f16e5185c364
Summary:
With expected use for a 128-bit hash, xxhash library is
upgraded to current dev (2c611a76f914828bed675f0f342d6c4199ffee1e)
as of Aug 6 so that we can use production version of XXH3_128bits
as new Hash128 function (added in hash128.h).
To make this work, however, we have to carve out the "preview" version
of XXH3 that is used in new SST Bloom and Ribbon filters, since that
will not get maintenance in xxhash releases. I have consolidated all the
relevant code into xxph3.h and made it "inline only" (no .cc file). The
working name for this hash function is changed from XXH3p to XXPH3
(XX Preview Hash) because the latter is easier to get working with no
symbol name conflicts between the headers.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8634
Test Plan:
no expected change in existing functionality. For Hash128,
added some unit tests based on those for Hash64 to ensure some basic
properties and that the values do not change accidentally.
Reviewed By: zhichao-cao
Differential Revision: D30173490
Pulled By: pdillinger
fbshipit-source-id: 06aa542a7a28b353bc2c865b9b2f8bdfe44158e4
Summary:
This is essentially resurrection and fixing of the part of
https://github.com/facebook/rocksdb/issues/8198 that was reverted in https://github.com/facebook/rocksdb/issues/8212, using data added in https://github.com/facebook/rocksdb/issues/8246. Basically,
when configuring Ribbon filter, you can specify an LSM level before which
Bloom will be used instead of Ribbon. But Bloom is only considered for
Leveled and Universal compaction styles and file going into a known LSM
level. This way, SST file writer, FIFO compaction, etc. use Ribbon filter as
you would expect with NewRibbonFilterPolicy.
So that this can be controlled with a single int value and so that flushes
can be distinguished from intra-L0, we consider flush to go to level -1 for
the purposes of this option. (Explained in API comment.)
I also expect the most common and recommended Ribbon configuration to
use Bloom during flush, to minimize slowing down writes and because according
to my estimates, Ribbon only pays off if the structure lives in memory for
more than an hour. Thus, I have changed the default for NewRibbonFilterPolicy
to be this mild hybrid configuration. I don't really want to add something like
NewHybridFilterPolicy because at least the mild hybrid configuration (Bloom for
flush, Ribbon otherwise) should be considered a natural choice.
C APIs also updated, but because they don't support overloading,
rocksdb_filterpolicy_create_ribbon is kept pure ribbon for clarity and
rocksdb_filterpolicy_create_ribbon_hybrid must be called for a hybrid
configuration. While touching C API, I changed bits per key options from
int to double.
BuiltinFilterPolicy is needed so that LevelThresholdFilterPolicy doesn't inherit
unused fields from BloomFilterPolicy.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8679
Test Plan: new + updated tests, including crash test
Reviewed By: jay-zhuang
Differential Revision: D30445797
Pulled By: pdillinger
fbshipit-source-id: 6f5aeddfd6d79f7e55493b563c2d1d2d568892e1
Summary:
Extends https://github.com/facebook/rocksdb/issues/8659 to work for ingested external SST files, even
the same file ingested into different DBs sharing a block cache.
Note: These new cache keys are currently only enabled when FileSystem
does not provide GetUniqueId. For now, they are typically larger,
so slightly less efficient.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8669
Test Plan: Extended unit test
Reviewed By: zhichao-cao
Differential Revision: D30398532
Pulled By: pdillinger
fbshipit-source-id: 1f13e2af4b8bfff5741953a69466e9589fbc23c7
Summary:
`GenericRateLimiter` slow path handles requests that cannot be satisfied
immediately. Such requests enter a queue, and their thread stays in `Request()`
until they are granted or the rate limiter is stopped. These threads are
responsible for unblocking themselves. The work to do so is split into two main
duties.
(1) Waiting for the next refill time.
(2) Refilling the bytes and granting requests.
Prior to this PR, the slow path logic involved a leader election algorithm to
pick one thread to perform (1) followed by (2). It elected the thread whose
request was at the front of the highest priority non-empty queue since that
request was most likely to be granted. This algorithm was efficient in terms of
reducing intermediate wakeups, which is a thread waking up only to resume
waiting after finding its request is not granted. However, the conceptual
complexity of this algorithm was too high. It took me a long time to draw a
timeline to understand how it works for just one edge case yet there were so
many.
This PR drops the leader election to reduce conceptual complexity. Now, the two
duties can be performed by whichever thread acquires the lock first. The risk
of this change is increasing the number of intermediate wakeups, however, we
took steps to mitigate that.
- `wait_until_refill_pending_` flag ensures only one thread performs (1). This\
prevents the thundering herd problem at the next refill time. The remaining\
threads wait on their condition variable with an unbounded duration -- thus we\
must remember to notify them to ensure forward progress.
- (1) is typically done by a thread at the front of a queue. This is trivial\
when the queues are initially empty as the first choice that arrives must be\
the only entry in its queue. When queues are initially non-empty, we achieve\
this by having (2) notify a thread at the front of a queue (preferring higher\
priority) to perform the next duty.
- We do not require any additional wakeup for (2). Typically it will just be\
done by the thread that finished (1).
Combined, the second and third bullet points above suggest the refill/granting
will typically be done by a request at the front of its queue. This is
important because one wakeup is saved when a granted request happens to be in an
already running thread.
Note there are a few cases that still lead to intermediate wakeup, however. The
first two are existing issues that also apply to the old algorithm, however, the
third (including both subpoints) is new.
- No request may be granted (only possible when rate limit dynamically\
decreases).
- Requests from a different queue may be granted.
- (2) may be run by a non-front request thread causing it to not be granted even\
if some requests in that same queue are granted. It can happen for a couple\
(unlikely) reasons.
- A new request may sneak in and grab the lock at the refill time, before the\
thread finishing (1) can wake up and grab it.
- A new request may sneak in and grab the lock and execute (1) before (2)'s\
chosen candidate can wake up and grab the lock. Then that non-front request\
thread performing (1) can carry over to perform (2).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8602
Test Plan:
- Use existing tests. The edge cases listed in the comment are all performance\
related; I could not really think of any related to correctness. The logic\
looks the same whether a thread wakes up/finishes its work early/on-time/late,\
or whether the thread is chosen vs. "steals" the work.
- Verified write throughput and CPU overhead are basically the same with and\
without this change, even in a rate limiter heavy workload:
Test command:
```
$ rm -rf /dev/shm/dbbench/ && TEST_TMPDIR=/dev/shm /usr/bin/time ./db_bench -benchmarks=fillrandom -num_multi_db=64 -num_low_pri_threads=64 -num_high_pri_threads=64 -write_buffer_size=262144 -target_file_size_base=262144 -max_bytes_for_level_base=1048576 -rate_limiter_bytes_per_sec=16777216 -key_size=24 -value_size=1000 -num=10000 -compression_type=none -rate_limiter_refill_period_us=1000
```
Results before this PR:
```
fillrandom : 108.463 micros/op 9219 ops/sec; 9.0 MB/s
7.40user 8.84system 1:26.20elapsed 18%CPU (0avgtext+0avgdata 256140maxresident)k
```
Results after this PR:
```
fillrandom : 108.108 micros/op 9250 ops/sec; 9.0 MB/s
7.45user 8.23system 1:26.68elapsed 18%CPU (0avgtext+0avgdata 255688maxresident)k
```
Reviewed By: hx235
Differential Revision: D30048013
Pulled By: ajkr
fbshipit-source-id: 6741bba9d9dfbccab359806d725105817fef818b
Summary: UBSAN revealed a pointer underflow when `LZ4HC_init_internal` is called with a null `start`.
Reviewed By: ajkr
Differential Revision: D30181874
fbshipit-source-id: ca9bbac1a85c58782871d7f153af733b000cc66c
Summary:
This draining mechanism should not be run during `JoinThreads()` because it can detach threads that will be joined. Joining detached threads would throw an exception.
With this PR, we skip draining when `JoinThreads()` has already decided what threads to `join()`, so the threads will exit naturally once the work queue empties.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8635
Test Plan: verified it unblocked using `WaitForJobsAndJoinAllThreads()` in https://github.com/facebook/rocksdb/issues/8611.
Reviewed By: riversand963
Differential Revision: D30174587
Pulled By: ajkr
fbshipit-source-id: 144966398a607987e0763c7152a0f653fdbf3c8b
Summary:
Context:
As need for new feature of resource management using RocksDB's rate limiter like [https://github.com/facebook/rocksdb/issues/8595](https://github.com/facebook/rocksdb/pull/8595) arises, it is about time to re-learn our rate limiter and make this learning process easier for others by improving its readability. The comment/assertion/one extra else-branch are added based on my best understanding toward the rate_limiter.cc and rate_limiter_test.cc up to date after giving it a hard read.
- Add code comments/assertion/one extra else-branch (that is not affecting existing behavior, see PR comment) to describe how leader-election works under multi-thread settings in GenericRateLimiter::Request()
- Add code comments to describe a non-obvious trick during clean-up of rate limiter destructor
- Add code comments to explain more about the starvation being fixed in GenericRateLimiter::Refill() through partial byte-granting
- Add code comments to the rate limiter's setup in a complicated unit test in rate_limiter_test
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8596
Test Plan: - passed existing rate_limiter_test.cc
Reviewed By: ajkr
Differential Revision: D29982590
Pulled By: hx235
fbshipit-source-id: c3592986bb5b0c90d8229fe44f425251ec7e8a0a
Summary:
Calling the GetImpl function could leave reference to a local
callback function in a field of a parameter struct. As this is
performance-critical code, I'm not going to attempt to sanitize this
code too much, but make the existing hack a bit cleaner by reverting
what it overwrites in the input struct.
Added SaveAndRestore utility class to make that easier.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8590
Test Plan:
added unit test for SaveAndRestore; existing tests for
GetImpl
Reviewed By: riversand963
Differential Revision: D29947983
Pulled By: pdillinger
fbshipit-source-id: 2f608853f970bc06724e834cc84dcc4b8599ddeb
Summary:
The PerThreadDBPath has already specified a slash. It does not need to be specified when initializing the test path.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8555
Reviewed By: ajkr
Differential Revision: D29758399
Pulled By: jay-zhuang
fbshipit-source-id: 6d2b878523e3e8580536e2829cb25489844d9011
Summary:
Rare TSAN and valgrind failures are caused by unnecessary
reading of a field on the TaskLimiterToken::limiter_ for an assertion
after the token has been released and the limiter destroyed. To simplify
we can simply destroy the token before triggering DB shutdown
(potentially destroying the limiter). This makes the ReleaseOnce logic
unnecessary.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8567
Test Plan: watch for more failures in CI
Reviewed By: ajkr
Differential Revision: D29811795
Pulled By: pdillinger
fbshipit-source-id: 135549ebb98fe4f176d1542ed85d5bd6350a40b3
Summary:
Fixed a few MSVC (VCToolsVersion=14.0) build errors and warnings
* `DEFINE_string` is a macro and VC compiler complains that it cannot put [ifdef-inside-define](https://stackoverflow.com/questions/5586429/ifdef-inside-define)
* `sleep()` is not a recognizable function. Use `FLAGS_env->SleepForMicroseconds` instead
* Define precise type in comparison to avoid mismatch warning
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8519
Reviewed By: jay-zhuang
Differential Revision: D29683086
fbshipit-source-id: 8c80941472089f8daba84ae29597e75e603850e4
Summary:
In PR https://github.com/facebook/rocksdb/issues/7523 , checksum handoff is introduced in RocksDB for WAL, Manifest, and SST files. When user enable checksum handoff for a certain type of file, before the data is written to the lower layer storage system, we calculate the checksum (crc32c) of each piece of data and pass the checksum down with the data, such that data verification can be down by the lower layer storage system if it has the capability. However, it cannot cover the whole lifetime of the data in the memory and also it potentially introduces extra checksum calculation overhead.
In this PR, we introduce a new interface in WritableFileWriter::Append, which allows the caller be able to pass the data and the checksum (crc32c) together. In this way, WritableFileWriter can directly use the pass-in checksum (crc32c) to generate the checksum of data being passed down to the storage system. It saves the calculation overhead and achieves higher protection coverage. When a new checksum is added with the data, we use Crc32cCombine https://github.com/facebook/rocksdb/issues/8305 to combine the existing checksum and the new checksum. To avoid the segmenting of data by rate-limiter before it is stored, rate-limiter is called enough times to accumulate enough credits for a certain write. This design only support Manifest and WAL which use log_writer in the current stage.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8412
Test Plan: make check, add new testing cases.
Reviewed By: anand1976
Differential Revision: D29151545
Pulled By: zhichao-cao
fbshipit-source-id: 75e2278c5126cfd58393c67b1efd18dcc7a30772
