1330 Commits (b6ec3328af25290fe1190b1d3f20503b76ed9ff7)

Author	SHA1	Message	Date
Peter Dillinger	9d0cae7104	Eliminate unnecessary (slow) block cache Ref()ing in MultiGet (#9899) ... Summary: When MultiGet() determines that multiple query keys can be served by examining the same data block in block cache (one Lookup()), each PinnableSlice referring to data in that data block needs to hold on to the block in cache so that they can be released at arbitrary times by the API user. Historically this is accomplished with extra calls to Ref() on the Handle from Lookup(), with each PinnableSlice cleanup calling Release() on the Handle, but this creates extra contention on the block cache for the extra Ref()s and Release()es, especially because they hit the same cache shard repeatedly. In the case of merge operands (possibly more cases?), the problem was compounded by doing an extra Ref()+eventual Release() for each merge operand for a key reusing a block (which could be the same key!), rather than one Ref() per key. (Note: the non-shared case with `biter` was already one per key.) This change optimizes MultiGet not to rely on these extra, contentious Ref()+Release() calls by instead, in the shared block case, wrapping the cache Release() cleanup in a refcounted object referenced by the PinnableSlices, such that after the last wrapped reference is released, the cache entry is Release()ed. Relaxed atomic refcounts should be much faster than mutex-guarded Ref() and Release(), and much less prone to a performance cliff when MultiGet() does a lot of block sharing. Note that I did not use std::shared_ptr, because that would require an extra indirection object (shared_ptr itself new/delete) in order to associate a ref increment/decrement with a Cleanable cleanup entry. (If I assumed it was the size of two pointers, I could do some hackery to make it work without the extra indirection, but that's too fragile.) Some details: * Fixed (removed) extra block cache tracing entries in cases of cache entry reuse in MultiGet, but it's likely that in some other cases traces are missing (XXX comment inserted) * Moved existing implementations for cleanable.h from iterator.cc to new cleanable.cc * Improved API comments on Cleanable * Added a public SharedCleanablePtr class to cleanable.h in case others could benefit from the same pattern (potentially many Cleanables and/or smart pointers referencing a shared Cleanable) * Add a typedef for MultiGetContext::Mask * Some variable renaming for clarity Pull Request resolved: https://github.com/facebook/rocksdb/pull/9899 Test Plan: Added unit tests for SharedCleanablePtr. Greatly enhanced ability of existing tests to detect cache use-after-free. * Release PinnableSlices from MultiGet as they are read rather than in bulk (in db_test_util wrapper). * In ASAN build, default to using a trivially small LRUCache for block_cache so that entries are immediately erased when unreferenced. (Updated two tests that depend on caching.) New ASAN testsuite running time seems OK to me. If I introduce a bug into my implementation where we skip the shared cleanups on block reuse, ASAN detects the bug in `db_basic_test *MultiGet*`. If I remove either of the above testing enhancements, the bug is not detected. Consider for follow-up work: manipulate or randomize ordering of PinnableSlice use and release from MultiGet db_test_util wrapper. But in typical cases, natural ordering gives pretty good functional coverage. Performance test: In the extreme (but possible) case of MultiGetting the same or adjacent keys in a batch, throughput can improve by an order of magnitude. `./db_bench -benchmarks=multireadrandom -db=/dev/shm/testdb -readonly -num=5 -duration=10 -threads=20 -multiread_batched -batch_size=200` Before ops/sec, num=5: 1,384,394 Before ops/sec, num=500: 6,423,720 After ops/sec, num=500: 10,658,794 After ops/sec, num=5: 16,027,257 Also note that previously, with high parallelism, having query keys concentrated in a single block was worse than spreading them out a bit. Now concentrated in a single block is faster than spread out, which is hopefully consistent with natural expectation. Random query performance: with num=1000000, over 999 x 10s runs running before & after simultaneously (each -threads=12): Before: multireadrandom [AVG 999 runs] : 1088699 (± 7344) ops/sec; 120.4 (± 0.8 ) MB/sec After: multireadrandom [AVG 999 runs] : 1090402 (± 7230) ops/sec; 120.6 (± 0.8 ) MB/sec Possibly better, possibly in the noise. Reviewed By: anand1976 Differential Revision: D35907003 Pulled By: pdillinger fbshipit-source-id: bbd244d703649a8ca12d476f2d03853ed9d1a17e	3 years ago
Akanksha Mahajan	3653029dda	Add stats related to async prefetching (#9845) ... Summary: Add stats PREFETCHED_BYTES_DISCARDED and POLL_WAIT_MICROS. PREFETCHED_BYTES_DISCARDED records number of prefetched bytes discarded by FilePrefetchBuffer. POLL_WAIT_MICROS records the time taken by underling file_system Poll API. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9845 Test Plan: Update existing tests Reviewed By: anand1976 Differential Revision: D35909694 Pulled By: akankshamahajan15 fbshipit-source-id: e009ef940bb9ed72c9446f5529095caabb8a1e36	3 years ago
Hui Xiao	a5063c8931	Fix issue of opening too many files in BlockBasedTableReaderCapMemoryTest.CapMemoryUsageUnderCacheCapacity (#9869) ... Summary: **Context:** Unit test for https://github.com/facebook/rocksdb/pull/9748 keeps opening new files to see whether the new feature is able to correctly constrain the opening based on block cache capacity. However, the unit test has two places written inefficiently that can lead to opening too many new files relative to underlying operating system/file system constraint, even before hitting the block cache capacity: (1) [opened_table_reader_num < 2 * max_table_reader_num](https://github.com/facebook/rocksdb/pull/9748/files?show-viewed-files=true&file-filters%5B%5D=#diff-ec9f5353e317df71093094734ba29193b94a998f0f9c9af924e4c99692195eeaR438), which can leads to 1200 + open files because of (2) below (2) NewLRUCache(6 * CacheReservationManagerImpl<CacheEntryRole::kBlockBasedTableReader>::GetDummyEntrySize()) in [here](https://github.com/facebook/rocksdb/pull/9748/files?show-viewed-files=true&file-filters%5B%5D=#diff-ec9f5353e317df71093094734ba29193b94a998f0f9c9af924e4c99692195eeaR364) Therefore we see CI failures like this on machine with a strict open file limit ~1000 (see the "table_1021" naming in following error msg) https://app.circleci.com/pipelines/github/facebook/rocksdb/12886/workflows/75524682-3fa4-41ee-9a61-81827b51d99b/jobs/345270 ``` fs_->NewWritableFile(path, foptions, &file, nullptr) IO error: While open a file for appending: /dev/shm/rocksdb.Jedwt/run-block_based_table_reader_test-CapMemoryUsageUnderCacheCapacity-BlockBasedTableReaderCapMemoryTest.CapMemoryUsageUnderCacheCapacity-0/block_based_table_reader_test_1668910_829492452552920927/**table_1021**: Too many open files ``` **Summary:** - Revised the test more efficiently on the above 2 places, including using 1.1 instead 2 in the threshold and lowering down the block cache capacity a bit - Renamed some variables for clarity Pull Request resolved: https://github.com/facebook/rocksdb/pull/9869 Test Plan: - Manual inspection of max opened table reader in all test case, which is around ~389 - Circle CI to see if error is gone Reviewed By: ajkr Differential Revision: D35752655 Pulled By: hx235 fbshipit-source-id: 8a0953d39d561babfa4257b8ed8550bb21b04839	3 years ago
Akanksha Mahajan	0c7f455f85	Make initial auto readahead_size configurable (#9836) ... Summary: Make initial auto readahead_size configurable Pull Request resolved: https://github.com/facebook/rocksdb/pull/9836 Test Plan: Added new unit test Ran regression: Without change: ``` ./db_bench -use_existing_db=true -db=/tmp/prefix_scan_prefetch_main -benchmarks="seekrandom" -key_size=32 -value_size=512 -num=5000000 -use_direct_reads=true -seek_nexts=327680 -duration=120 -ops_between_duration_checks=1 Initializing RocksDB Options from the specified file Initializing RocksDB Options from command-line flags RocksDB: version 7.0 Date: Thu Mar 17 13:11:34 2022 CPU: 24 * Intel Core Processor (Broadwell) CPUCache: 16384 KB Keys: 32 bytes each (+ 0 bytes user-defined timestamp) Values: 512 bytes each (256 bytes after compression) Entries: 5000000 Prefix: 0 bytes Keys per prefix: 0 RawSize: 2594.0 MB (estimated) FileSize: 1373.3 MB (estimated) Write rate: 0 bytes/second Read rate: 0 ops/second Compression: Snappy Compression sampling rate: 0 Memtablerep: SkipListFactory Perf Level: 1 ------------------------------------------------ DB path: [/tmp/prefix_scan_prefetch_main] seekrandom : 483618.390 micros/op 2 ops/sec; 338.9 MB/s (249 of 249 found) ``` With this change: ``` ./db_bench -use_existing_db=true -db=/tmp/prefix_scan_prefetch_main -benchmarks="seekrandom" -key_size=32 -value_size=512 -num=5000000 -use_direct_reads=true -seek_nexts=327680 -duration=120 -ops_between_duration_checks=1 Set seed to 1649895440554504 because --seed was 0 Initializing RocksDB Options from the specified file Initializing RocksDB Options from command-line flags RocksDB: version 7.2 Date: Wed Apr 13 17:17:20 2022 CPU: 24 * Intel Core Processor (Broadwell) CPUCache: 16384 KB Keys: 32 bytes each (+ 0 bytes user-defined timestamp) Values: 512 bytes each (256 bytes after compression) Entries: 5000000 Prefix: 0 bytes Keys per prefix: 0 RawSize: 2594.0 MB (estimated) FileSize: 1373.3 MB (estimated) Write rate: 0 bytes/second Read rate: 0 ops/second Compression: Snappy Compression sampling rate: 0 Memtablerep: SkipListFactory Perf Level: 1 ------------------------------------------------ DB path: [/tmp/prefix_scan_prefetch_main] ... finished 100 ops seekrandom : 476892.488 micros/op 2 ops/sec; 344.6 MB/s (252 of 252 found) ``` Reviewed By: anand1976 Differential Revision: D35632815 Pulled By: akankshamahajan15 fbshipit-source-id: c8057a88f9294c9d03b1d434b03affe02f74d796	3 years ago
Peter Dillinger	efd035164b	Meta-internal folly integration with F14FastMap (#9546) ... Summary: Especially after updating to C++17, I don't see a compelling case for *requiring* any folly components in RocksDB. I was able to purge the existing hard dependencies, and it can be quite difficult to strip out non-trivial components from folly for use in RocksDB. (The prospect of doing that on F14 has changed my mind on the best approach here.) But this change creates an optional integration where we can plug in components from folly at compile time, starting here with F14FastMap to replace std::unordered_map when possible (probably no public APIs for example). I have replaced the biggest CPU users of std::unordered_map with compile-time pluggable UnorderedMap which will use F14FastMap when USE_FOLLY is set. USE_FOLLY is always set in the Meta-internal buck build, and a simulation of that is in the Makefile for public CI testing. A full folly build is not needed, but checking out the full folly repo is much simpler for getting the dependency, and anything else we might want to optionally integrate in the future. Some picky details: * I don't think the distributed mutex stuff is actually used, so it was easy to remove. * I implemented an alternative to `folly::constexpr_log2` (which is much easier in C++17 than C++11) so that I could pull out the hard dependencies on `ConstexprMath.h` * I had to add noexcept move constructors/operators to some types to make F14's complainUnlessNothrowMoveAndDestroy check happy, and I added a macro to make that easier in some common cases. * Updated Meta-internal buck build to use folly F14Map (always) No updates to HISTORY.md nor INSTALL.md as this is not (yet?) considered a production integration for open source users. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9546 Test Plan: CircleCI tests updated so that a couple of them use folly. Most internal unit & stress/crash tests updated to use Meta-internal latest folly. (Note: they should probably use buck but they currently use Makefile.) Example performance improvement: when filter partitions are pinned in cache, they are tracked by PartitionedFilterBlockReader::filter_map_ and we can build a test that exercises that heavily. Build DB with ``` TEST_TMPDIR=/dev/shm/rocksdb ./db_bench -benchmarks=fillrandom -num=10000000 -disable_wal=1 -write_buffer_size=30000000 -bloom_bits=16 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=10000 -fifo_compaction_allow_compaction=0 -partition_index_and_filters ``` and test with (simultaneous runs with & without folly, ~20 times each to see convergence) ``` TEST_TMPDIR=/dev/shm/rocksdb ./db_bench_folly -readonly -use_existing_db -benchmarks=readrandom -num=10000000 -bloom_bits=16 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=10000 -fifo_compaction_allow_compaction=0 -partition_index_and_filters -duration=40 -pin_l0_filter_and_index_blocks_in_cache ``` Average ops/s no folly: 26229.2 Average ops/s with folly: 26853.3 (+2.4%) Reviewed By: ajkr Differential Revision: D34181736 Pulled By: pdillinger fbshipit-source-id: ffa6ad5104c2880321d8a1aa7187e00ab0d02e94	3 years ago
Akanksha Mahajan	63e68a4e77	Enable async prefetching for ReadOptions.readahead_size (#9827) ... Summary: Currently async prefetching is enabled for implicit internal auto readahead in FilePrefetchBuffer if `ReadOptions.async_io` is set. This PR enables async prefetching for `ReadOptions.readahead_size` when `ReadOptions.async_io` is set true. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9827 Test Plan: Update unit test Reviewed By: anand1976 Differential Revision: D35552129 Pulled By: akankshamahajan15 fbshipit-source-id: d9f9a96672852a591375a21eef15355cf3289f5c	3 years ago
Hui Xiao	f337542948	Fix a bug of TEST_SetRandomTableProperties due to non-zero padding between fields in TableProperties struct (#9812) ... Summary: Context: https://github.com/facebook/rocksdb/pull/9748#discussion_r843134214 reveals an issue with TEST_SetRandomTableProperties when non-zero padding is used between the last string field and first non-string field in TableProperties. Fixed by https://github.com/facebook/rocksdb/pull/9748#discussion_r843244375 Pull Request resolved: https://github.com/facebook/rocksdb/pull/9812 Test Plan: No production code changes and rely on existing CI Reviewed By: ajkr Differential Revision: D35423680 Pulled By: hx235 fbshipit-source-id: fd855eef3d32771bb79c65bd7012ab8bb3c400ab	3 years ago
Peter Dillinger	8ce7cea93f	Tests for filter compatibility (#9773) ... Summary: This change adds two unit tests that would each catch the regression fixed in https://github.com/facebook/rocksdb/issues/9736 * TableMetaIndexKeys - detects any churn in metaindex block keys generated by SST files using standard db_test_util configurations. * BloomFilterCompatibility - this detects if any common built-in FilterPolicy configurations fail to read filters generated by another. (The regression bug caused NewRibbonFilterPolicy not to read filters from NewBloomFilterPolicy and vice-versa.) This replaces some previous tests that didn't really appear to be testing much of anything except basic data correctness, which doesn't tell you a filter is being used. Light refactoring in meta_blocks.cc/h to support inspecting metaindex keys. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9773 Test Plan: this is the test. Verified that 7.0.2 fails both tests and 7.0.3 passes. With backporting for intentional API changes in 7.0, 6.29 also passes. Reviewed By: ajkr Differential Revision: D35236248 Pulled By: pdillinger fbshipit-source-id: 493dfe9ad7e27524bf7c6c1af8a4b8c31bc6ef5a	3 years ago
Hui Xiao	49623f9c8e	Account memory of big memory users in BlockBasedTable in global memory limit (#9748) ... Summary: **Context:** Through heap profiling, we discovered that `BlockBasedTableReader` objects can accumulate and lead to high memory usage (e.g, `max_open_file = -1`). These memories are currently not saved, not tracked, not constrained and not cache evict-able. As a first step to improve this, similar to https://github.com/facebook/rocksdb/pull/8428, this PR is to track an estimate of `BlockBasedTableReader` object's memory in block cache and fail future creation if the memory usage exceeds the available space of cache at the time of creation. **Summary:** - Approximate big memory users (`BlockBasedTable::Rep` and `TableProperties` )' memory usage in addition to the existing estimated ones (filter block/index block/un-compression dictionary) - Charge all of these memory usages to block cache on `BlockBasedTable::Open()` and release them on `~BlockBasedTable()` as there is no memory usage fluctuation of concern in between - Refactor on CacheReservationManager (and its call-sites) to add concurrent support for BlockBasedTable used in this PR. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9748 Test Plan: - New unit tests - db bench: `OpenDb` : **-0.52% in ms** - Setup `./db_bench -benchmarks=fillseq -db=/dev/shm/testdb -disable_auto_compactions=1 -write_buffer_size=1048576` - Repeated run with pre-change w/o feature and post-change with feature, benchmark `OpenDb`: `./db_bench -benchmarks=readrandom -use_existing_db=1 -db=/dev/shm/testdb -reserve_table_reader_memory=true (remove this when running w/o feature) -file_opening_threads=3 -open_files=-1 -report_open_timing=true| egrep 'OpenDb:'` #-run | (feature-off) avg milliseconds | std milliseconds | (feature-on) avg milliseconds | std milliseconds | change (%) -- | -- | -- | -- | -- | -- 10 | 11.4018 | 5.95173 | 9.47788 | 1.57538 | -16.87382694 20 | 9.23746 | 0.841053 | 9.32377 | 1.14074 | 0.9343477536 40 | 9.0876 | 0.671129 | 9.35053 | 1.11713 | 2.893283155 80 | 9.72514 | 2.28459 | 9.52013 | 1.0894 | -2.108041632 160 | 9.74677 | 0.991234 | 9.84743 | 1.73396 | 1.032752389 320 | 10.7297 | 5.11555 | 10.547 | 1.97692 | **-1.70275031** 640 | 11.7092 | 2.36565 | 11.7869 | 2.69377 | **0.6635807741** - db bench on write with cost to cache in WriteBufferManager (just in case this PR's CRM refactoring accidentally slows down anything in WBM) : `fillseq` : **+0.54% in micros/op** `./db_bench -benchmarks=fillseq -db=/dev/shm/testdb -disable_auto_compactions=1 -cost_write_buffer_to_cache=true -write_buffer_size=10000000000 | egrep 'fillseq'` #-run | (pre-PR) avg micros/op | std micros/op | (post-PR) avg micros/op | std micros/op | change (%) -- | -- | -- | -- | -- | -- 10 | 6.15 | 0.260187 | 6.289 | 0.371192 | 2.260162602 20 | 7.28025 | 0.465402 | 7.37255 | 0.451256 | 1.267813605 40 | 7.06312 | 0.490654 | 7.13803 | 0.478676 | **1.060579461** 80 | 7.14035 | 0.972831 | 7.14196 | 0.92971 | **0.02254791432** - filter bench: `bloom filter`: **-0.78% in ms/key** - ` ./filter_bench -impl=2 -quick -reserve_table_builder_memory=true | grep 'Build avg'` #-run | (pre-PR) avg ns/key | std ns/key | (post-PR) ns/key | std ns/key | change (%) -- | -- | -- | -- | -- | -- 10 | 26.4369 | 0.442182 | 26.3273 | 0.422919 | **-0.4145720565** 20 | 26.4451 | 0.592787 | 26.1419 | 0.62451 | **-1.1465262** - Crash test `python3 tools/db_crashtest.py blackbox --reserve_table_reader_memory=1 --cache_size=1` killed as normal Reviewed By: ajkr Differential Revision: D35136549 Pulled By: hx235 fbshipit-source-id: 146978858d0f900f43f4eb09bfd3e83195e3be28	3 years ago
Akanksha Mahajan	36bc3da97f	Fix segfault in FilePrefetchBuffer with async_io enabled (#9777) ... Summary: If FilePrefetchBuffer object is destroyed and then later Poll() calls callback on object which has been destroyed, it gives segfault on accessing destroyed object. It was caught after adding unit tests that tests Posix implementation of ReadAsync and Poll APIs. This PR also updates and fixes existing IOURing tests which were not running locally because RocksDbIOUringEnable function wasn't defined and IOUring was disabled for those tests Pull Request resolved: https://github.com/facebook/rocksdb/pull/9777 Test Plan: Added new unit test Reviewed By: anand1976 Differential Revision: D35254002 Pulled By: akankshamahajan15 fbshipit-source-id: 68e80054ffb14ae25c255920ebc6548ca5f130a1	3 years ago
Alan Paxton	b6ad0d958f	Fb 9718 verify checksums is ignored (#9767) ... Summary: Fixes https://github.com/facebook/rocksdb/issues/9718 The verify_checksums flag of read_options should be passed to the read options used by the BlockFetcher in a couple of cases where it is not at present. It will now happen (but did not, previously) on iteration and on [multi]get, where a fetcher is created as part of the iterate/get call. This may result in much better performance in a few workloads where the client chooses to remove verification. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9767 Reviewed By: mrambacher Differential Revision: D35218986 Pulled By: jay-zhuang fbshipit-source-id: 329d29764bb70fbc7f2673440bc46c107a813bc8	3 years ago
myasuka	98130c5a26	Enable READ_BLOCK_COMPACTION_MICROS to track stats (#9722) ... Summary: After commit [d642c60](d642c60bdc), the stats `READ_BLOCK_COMPACTION_MICROS` cannot record any compaction read duration, and it always report zero. This PR targets to distinguish `READ_BLOCK_COMPACTION_MICROS` with `READ_BLOCK_GET_MICROS` so that `READ_BLOCK_COMPACTION_MICROS` could record the correct stats. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9722 Reviewed By: ajkr Differential Revision: D35021870 Pulled By: jay-zhuang fbshipit-source-id: f1a804994265e51465de64c2a08f2e0eeb6fc5a3	3 years ago
Peter Dillinger	91687d70ea	Fix a major performance bug in 7.0 re: filter compatibility (#9736) ... Summary: Bloom filters generated by pre-7.0 releases are not read by 7.0.x releases (and vice-versa) due to changes to FilterPolicy::Name() in https://github.com/facebook/rocksdb/issues/9590. This can severely impact read performance and read I/O on upgrade or downgrade with existing DB, but not data correctness. To fix, we go back using the old, unified name in SST metadata but (for a while anyway) recognize the aliases that could be generated by early 7.0.x releases. This unfortunately requires a public API change to avoid interfering with all the good changes from https://github.com/facebook/rocksdb/issues/9590, but the API change only affects users with custom FilterPolicy, which should be very few. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9736 Test Plan: manual Generate DBs with ``` ./db_bench.7.0 -db=/dev/shm/rocksdb.7.0 -bloom_bits=10 -cache_index_and_filter_blocks=1 -benchmarks=fillrandom -num=10000000 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=10000 -fifo_compaction_allow_compaction=0 ``` and similar. Compare with ``` for IMPL in 6.29 7.0 fixed; do for DB in 6.29 7.0 fixed; do echo "Testing $IMPL on $DB:"; ./db_bench.$IMPL -db=/dev/shm/rocksdb.$DB -use_existing_db -readonly -bloom_bits=10 -benchmarks=readrandom -num=10000000 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=10000 -fifo_compaction_allow_compaction=0 -duration=10 2>&1 | grep micros/op; done; done ``` Results: ``` Testing 6.29 on 6.29: readrandom : 34.381 micros/op 29085 ops/sec; 3.2 MB/s (291999 of 291999 found) Testing 6.29 on 7.0: readrandom : 190.443 micros/op 5249 ops/sec; 0.6 MB/s (52999 of 52999 found) Testing 6.29 on fixed: readrandom : 40.148 micros/op 24907 ops/sec; 2.8 MB/s (249999 of 249999 found) Testing 7.0 on 6.29: readrandom : 229.430 micros/op 4357 ops/sec; 0.5 MB/s (43999 of 43999 found) Testing 7.0 on 7.0: readrandom : 33.348 micros/op 29986 ops/sec; 3.3 MB/s (299999 of 299999 found) Testing 7.0 on fixed: readrandom : 152.734 micros/op 6546 ops/sec; 0.7 MB/s (65999 of 65999 found) Testing fixed on 6.29: readrandom : 32.024 micros/op 31224 ops/sec; 3.5 MB/s (312999 of 312999 found) Testing fixed on 7.0: readrandom : 33.990 micros/op 29390 ops/sec; 3.3 MB/s (294999 of 294999 found) Testing fixed on fixed: readrandom : 28.714 micros/op 34825 ops/sec; 3.9 MB/s (348999 of 348999 found) ``` Just paying attention to order of magnitude of ops/sec (short test durations, lots of noise), it's clear that with the fix we can read <= 6.29 & >= 7.0 at full speed, where neither 6.29 nor 7.0 can on both. And 6.29 release can properly read fixed DB at full speed. Reviewed By: siying, ajkr Differential Revision: D35057844 Pulled By: pdillinger fbshipit-source-id: a46893a6af4bf084375ebe4728066d00eb08f050	3 years ago
gitbw95	8102690a52	Update Cache::Release param from force_erase to erase_if_last_ref (#9728) ... Summary: The param name force_erase may be misleading, since the handle is erased only if it has last reference even if the param is set true. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9728 Reviewed By: pdillinger Differential Revision: D35038673 Pulled By: gitbw95 fbshipit-source-id: 0d16d1e8fed17b97eba7fb53207119332f659a5f	3 years ago
Akanksha Mahajan	49a10feb21	Provide implementation to prefetch data asynchronously in FilePrefetchBuffer (#9674) ... Summary: In FilePrefetchBuffer if reads are sequential, after prefetching call ReadAsync API to prefetch data asynchronously so that in next prefetching data will be available. Data prefetched asynchronously will be readahead_size/2. It uses two buffers, one for synchronous prefetching and one for asynchronous. In case, the data is overlapping, the data is copied from both buffers to third buffer to make it continuous. This feature is under ReadOptions::async_io and is under experimental. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9674 Test Plan: 1. Add new unit tests 2. Run **db_stress** to make sure nothing crashes. - Normal prefetch without `async_io` ran successfully: ``` export CRASH_TEST_EXT_ARGS=" --async_io=0" make crash_test -j ``` 3. **Run Regressions**. i) Main branch without any change for normal prefetching with async_io disabled: ``` ./db_bench -db=/tmp/prefix_scan_prefetch_main -benchmarks="fillseq" -key_size=32 -value_size=512 -num=5000000 - use_direct_io_for_flush_and_compaction=true -target_file_size_base=16777216 ``` ``` ./db_bench -use_existing_db=true -db=/tmp/prefix_scan_prefetch_main -benchmarks="seekrandom" -key_size=32 -value_size=512 -num=5000000 -use_direct_reads=true -seek_nexts=327680 -duration=120 -ops_between_duration_checks=1 Initializing RocksDB Options from the specified file Initializing RocksDB Options from command-line flags RocksDB: version 7.0 Date: Thu Mar 17 13:11:34 2022 CPU: 24 * Intel Core Processor (Broadwell) CPUCache: 16384 KB Keys: 32 bytes each (+ 0 bytes user-defined timestamp) Values: 512 bytes each (256 bytes after compression) Entries: 5000000 Prefix: 0 bytes Keys per prefix: 0 RawSize: 2594.0 MB (estimated) FileSize: 1373.3 MB (estimated) Write rate: 0 bytes/second Read rate: 0 ops/second Compression: Snappy Compression sampling rate: 0 Memtablerep: SkipListFactory Perf Level: 1 ------------------------------------------------ DB path: [/tmp/prefix_scan_prefetch_main] seekrandom : 483618.390 micros/op 2 ops/sec; 338.9 MB/s (249 of 249 found) ``` ii) normal prefetching after changes with async_io disable: ``` ./db_bench -use_existing_db=true -db=/tmp/prefix_scan_prefetch_withchange -benchmarks="seekrandom" -key_size=32 -value_size=512 -num=5000000 -use_direct_reads=true -seek_nexts=327680 -duration=120 -ops_between_duration_checks=1 Initializing RocksDB Options from the specified file Initializing RocksDB Options from command-line flags RocksDB: version 7.0 Date: Thu Mar 17 14:11:31 2022 CPU: 24 * Intel Core Processor (Broadwell) CPUCache: 16384 KB Keys: 32 bytes each (+ 0 bytes user-defined timestamp) Values: 512 bytes each (256 bytes after compression) Entries: 5000000 Prefix: 0 bytes Keys per prefix: 0 RawSize: 2594.0 MB (estimated) FileSize: 1373.3 MB (estimated) Write rate: 0 bytes/second Read rate: 0 ops/second Compression: Snappy Compression sampling rate: 0 Memtablerep: SkipListFactory Perf Level: 1 ------------------------------------------------ DB path: [/tmp/prefix_scan_prefetch_withchange] seekrandom : 471347.227 micros/op 2 ops/sec; 348.1 MB/s (255 of 255 found) ``` Reviewed By: anand1976 Differential Revision: D34731543 Pulled By: akankshamahajan15 fbshipit-source-id: 8e23aa93453d5fe3c672b9231ad582f60207937f	3 years ago
Peter Dillinger	cff0d1e8e6	New backup meta schema, with file temperatures (#9660) ... Summary: The primary goal of this change is to add support for backing up and restoring (applying on restore) file temperature metadata, without committing to either the DB manifest or the FS reported "current" temperatures being exclusive "source of truth". To achieve this goal, we need to add temperature information to backup metadata, which requires updated backup meta schema. Fortunately I prepared for this in https://github.com/facebook/rocksdb/issues/8069, which began forward compatibility in version 6.19.0 for this kind of schema update. (Previously, backup meta schema was not extensible! Making this schema update public will allow some other "nice to have" features like taking backups with hard links, and avoiding crc32c checksum computation when another checksum is already available.) While schema version 2 is newly public, the default schema version is still 1. Until we change the default, users will need to set to 2 to enable features like temperature data backup+restore. New metadata like temperature information will be ignored with a warning in versions before this change and since 6.19.0. The metadata is considered ignorable because a functioning DB can be restored without it. Some detail: * Some renaming because "future schema" is now just public schema 2. * Initialize some atomics in TestFs (linter reported) * Add temperature hint support to SstFileDumper (used by BackupEngine) Pull Request resolved: https://github.com/facebook/rocksdb/pull/9660 Test Plan: related unit test majorly updated for the new functionality, including some shared testing support for tracking temperatures in a FS. Some other tests and testing hooks into production code also updated for making the backup meta schema change public. Reviewed By: ajkr Differential Revision: D34686968 Pulled By: pdillinger fbshipit-source-id: 3ac1fa3e67ee97ca8a5103d79cc87d872c1d862a	3 years ago
ehds@qq.com	60422f1676	Replace GetUserKey with ExtractUserKey (#9664) ... Summary: Replace `GetUserKey` with `ExtractUserKey` Pull Request resolved: https://github.com/facebook/rocksdb/pull/9664 Reviewed By: jay-zhuang Differential Revision: D34673571 Pulled By: ajkr fbshipit-source-id: 5acf7d0d1a45efce0ccbe505991acf76c9cdc461	3 years ago
Jay Zhuang	36aec94d85	`compression_per_level` should be used for flush and changeable (#9658) ... Summary: - Make `compression_per_level` dynamical changeable with `SetOptions`; - Fix a bug that `compression_per_level` is not used for flush; Pull Request resolved: https://github.com/facebook/rocksdb/pull/9658 Test Plan: CI Reviewed By: ajkr Differential Revision: D34700749 Pulled By: jay-zhuang fbshipit-source-id: a23b9dfa7ad03d393c1d71781d19e91de796f49c	3 years ago
Hui Xiao	4a776d81cc	Dynamic toggling of BlockBasedTableOptions::detect_filter_construct_corruption (#9654) ... Summary: **Context/Summary:** As requested, `BlockBasedTableOptions::detect_filter_construct_corruption` can now be dynamically configured using `DB::SetOptions` after this PR Pull Request resolved: https://github.com/facebook/rocksdb/pull/9654 Test Plan: - New unit test Reviewed By: pdillinger Differential Revision: D34622609 Pulled By: hx235 fbshipit-source-id: c06773ef3d029e6bf1724d3a72dffd37a8ec66d9	3 years ago
sdong	33742c2a9f	Remove BlockBasedTableOptions.hash_index_allow_collision (#9454) ... Summary: BlockBasedTableOptions.hash_index_allow_collision is already deprecated and has no effect. Delete it for preparing 7.0 release. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9454 Test Plan: Run all existing tests. Reviewed By: ajkr Differential Revision: D33805827 fbshipit-source-id: ed8a436d1d083173ec6aef2a762ba02e1eefdc9d	3 years ago
Andrew Kryczka	0a89cea5f5	Handle failures in block-based table size/offset approximation (#9615) ... Summary: In crash test with fault injection, we were seeing stack traces like the following: ``` https://github.com/facebook/rocksdb/issues/3 0x00007f75f763c533 in __GI___assert_fail (assertion=assertion@entry=0x1c5b2a0 "end_offset >= start_offset", file=file@entry=0x1c580a0 "table/block_based/block_based_table_reader.cc", line=line@entry=3245, function=function@entry=0x1c60e60 "virtual uint64_t rocksdb::BlockBasedTable::ApproximateSize(const rocksdb::Slice&, const rocksdb::Slice&, rocksdb::TableReaderCaller)") at assert.c:101 https://github.com/facebook/rocksdb/issues/4 0x00000000010ea9b4 in rocksdb::BlockBasedTable::ApproximateSize (this=<optimized out>, start=..., end=..., caller=<optimized out>) at table/block_based/block_based_table_reader.cc:3224 https://github.com/facebook/rocksdb/issues/5 0x0000000000be61fb in rocksdb::TableCache::ApproximateSize (this=0x60f0000161b0, start=..., end=..., fd=..., caller=caller@entry=rocksdb::kCompaction, internal_comparator=..., prefix_extractor=...) at db/table_cache.cc:719 https://github.com/facebook/rocksdb/issues/6 0x0000000000c3eaec in rocksdb::VersionSet::ApproximateSize (this=<optimized out>, v=<optimized out>, f=..., start=..., end=..., caller=<optimized out>) at ./db/version_set.h:850 https://github.com/facebook/rocksdb/issues/7 0x0000000000c6ebc3 in rocksdb::VersionSet::ApproximateSize (this=<optimized out>, options=..., v=v@entry=0x621000047500, start=..., end=..., start_level=start_level@entry=0, end_level=<optimized out>, caller=<optimized out>) at db/version_set.cc:5657 https://github.com/facebook/rocksdb/issues/8 0x000000000166e894 in rocksdb::CompactionJob::GenSubcompactionBoundaries (this=<optimized out>) at ./include/rocksdb/options.h:1869 https://github.com/facebook/rocksdb/issues/9 0x000000000168c526 in rocksdb::CompactionJob::Prepare (this=this@entry=0x7f75f3ffcf00) at db/compaction/compaction_job.cc:546 ``` The problem occurred in `ApproximateSize()` when the index `Seek()` for the first `ApproximateDataOffsetOf()` encountered an I/O error, while the second `Seek()` did not. In the old code that scenario caused `start_offset == data_size` , thus it was easy to trip the assertion that `end_offset >= start_offset`. The fix is to set `start_offset == 0` when the first index `Seek()` fails, and `end_offset == data_size` when the second index `Seek()` fails. I doubt these give an "on average correct" answer for how this function is used, but I/O errors in index seeks are hopefully rare, it looked consistent with what was already there, and it was easier to calculate. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9615 Test Plan: run the repro command for a while and stopped seeing coredumps - ``` $ while ! ./db_stress --block_size=128 --cache_size=32768 --clear_column_family_one_in=0 --column_families=1 --continuous_verification_interval=0 --db=/dev/shm/rocksdb_crashtest --delpercent=4 --delrangepercent=1 --destroy_db_initially=0 --expected_values_dir=/dev/shm/rocksdb_crashtest_expected --index_type=2 --iterpercent=10 --kill_random_test=18887 --max_key=1000000 --max_bytes_for_level_base=2048576 --nooverwritepercent=1 --open_files=-1 --open_read_fault_one_in=32 --ops_per_thread=1000000 --prefixpercent=5 --read_fault_one_in=0 --readpercent=45 --reopen=0 --skip_verifydb=1 --subcompactions=2 --target_file_size_base=524288 --test_batches_snapshots=0 --value_size_mult=32 --write_buffer_size=524288 --writepercent=35 ; do : ; done ``` Reviewed By: pdillinger Differential Revision: D34383069 Pulled By: ajkr fbshipit-source-id: fac26c3b20ea962e75387515ba5f2724dc48719f	3 years ago
mrambacher	30b08878d8	Make FilterPolicy Customizable (#9590) ... Summary: Make FilterPolicy into a Customizable class. Allow new FilterPolicy to be discovered through the ObjectRegistry Pull Request resolved: https://github.com/facebook/rocksdb/pull/9590 Reviewed By: pdillinger Differential Revision: D34327367 Pulled By: mrambacher fbshipit-source-id: 37e7edac90ec9457422b72f359ab8ef48829c190	3 years ago
Andrew Kryczka	54fb2a8975	Change type of cache buffer passed to `Cache::CreateCallback()` to `const void*` (#9595) ... Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/9595 Reviewed By: riversand963 Differential Revision: D34329906 Pulled By: ajkr fbshipit-source-id: 508601856fa9bee4d40f4a68d14d333ef2143d40	3 years ago
Peter Dillinger	725833a424	Hide FilterBits{Builder,Reader} from public API (#9592) ... Summary: We don't have any evidence of people using these to build custom filters. The recommended way of customizing filter handling is to defer to various built-in policies based on FilterBuildingContext (e.g. to build Monkey filtering policy). With old API, we have evidence of people modifying keys going into filter, but most cases of that can be handled with prefix_extractor. Having FilterBitsBuilder+Reader in the public API is an ogoing hinderance to code evolution (e.g. recent new Finish and MaybePostVerify), and so this change removes them from the public API for 7.0. Maybe they will come back in some form later, but lacking evidence of them providing value in the public API, we want to take back more freedom to evolve these. With this moved to internal-only, there is no rush to clean up the complex Finish signatures, or add memory allocator support, but doing so is much easier with them out of public API, for example to use CacheAllocationPtr without exposing it in the public API. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9592 Test Plan: cosmetic changes only Reviewed By: hx235 Differential Revision: D34315470 Pulled By: pdillinger fbshipit-source-id: 03e03bb66a72c73df2c464d2dbbbae906dd8f99b	3 years ago
Andrew Kryczka	babe56ddba	Add rate limiter priority to ReadOptions (#9424) ... Summary: Users can set the priority for file reads associated with their operation by setting `ReadOptions::rate_limiter_priority` to something other than `Env::IO_TOTAL`. Rate limiting `VerifyChecksum()` and `VerifyFileChecksums()` is the motivation for this PR, so it also includes benchmarks and minor bug fixes to get that working. `RandomAccessFileReader::Read()` already had support for rate limiting compaction reads. I changed that rate limiting to be non-specific to compaction, but rather performed according to the passed in `Env::IOPriority`. Now the compaction read rate limiting is supported by setting `rate_limiter_priority = Env::IO_LOW` on its `ReadOptions`. There is no default value for the new `Env::IOPriority` parameter to `RandomAccessFileReader::Read()`. That means this PR goes through all callers (in some cases multiple layers up the call stack) to find a `ReadOptions` to provide the priority. There are TODOs for cases I believe it would be good to let user control the priority some day (e.g., file footer reads), and no TODO in cases I believe it doesn't matter (e.g., trace file reads). The API doc only lists the missing cases where a file read associated with a provided `ReadOptions` cannot be rate limited. For cases like file ingestion checksum calculation, there is no API to provide `ReadOptions` or `Env::IOPriority`, so I didn't count that as missing. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9424 Test Plan: - new unit tests - new benchmarks on ~50MB database with 1MB/s read rate limit and 100ms refill interval; verified with strace reads are chunked (at 0.1MB per chunk) and spaced roughly 100ms apart. - setup command: `./db_bench -benchmarks=fillrandom,compact -db=/tmp/testdb -target_file_size_base=1048576 -disable_auto_compactions=true -file_checksum=true` - benchmarks command: `strace -ttfe pread64 ./db_bench -benchmarks=verifychecksum,verifyfilechecksums -use_existing_db=true -db=/tmp/testdb -rate_limiter_bytes_per_sec=1048576 -rate_limit_bg_reads=1 -rate_limit_user_ops=true -file_checksum=true` - crash test using IO_USER priority on non-validation reads with https://github.com/facebook/rocksdb/issues/9567 reverted: `python3 tools/db_crashtest.py blackbox --max_key=1000000 --write_buffer_size=524288 --target_file_size_base=524288 --level_compaction_dynamic_level_bytes=true --duration=3600 --rate_limit_bg_reads=true --rate_limit_user_ops=true --rate_limiter_bytes_per_sec=10485760 --interval=10` Reviewed By: hx235 Differential Revision: D33747386 Pulled By: ajkr fbshipit-source-id: a2d985e97912fba8c54763798e04f006ccc56e0c	3 years ago
Peter Dillinger	1e403a0c6c	Fix assertion failure in FastLocalBloomBitsBuilder (#9585) ... Summary: As in ``` db_stress: table/block_based/filter_policy.cc:316: rocksdb::{anonymous}::FastLocalBloomBitsBuilder::FastLocalBloomBitsBuilder(int, std::atomic<long int>*, std::shared_ptr<rocksdb::CacheReservationManager>, bool): Assertion `millibits_per_key >= 1000' failed. ``` This assertion failure was actually happening with our RibbonFilterPolicy which falls back to Bloom for some cases, often for flush, but was missing new special logic to skip generating filter for 0 bits per key case. Fixed by adding the logic in other builtin FilterPolicy implementations. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9585 Test Plan: Updated db_bloom_filter_test to do more integration testing of the RibbonFilterPolicy ("auto Ribbon") class, incl regression test this with SkipFilterOnEssentiallyZeroBpk Reviewed By: ajkr Differential Revision: D34295101 Pulled By: pdillinger fbshipit-source-id: 3488eb207fc1d67bbbd1301313714aa1b6406e6e	3 years ago
Peter Dillinger	8c681087c7	Refactor FilterPolicies toward Customizable (#9567) ... Summary: Some changes to make it easier to make FilterPolicy customizable. Especially, create distinct classes for the different testing-only and user-facing built-in FilterPolicy modes. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9567 Test Plan: tests updated, with no intended difference in functionality tested. No difference in test performance seen as a result of moving to string-based filter type configuration. Reviewed By: mrambacher Differential Revision: D34234694 Pulled By: pdillinger fbshipit-source-id: 8a94931a9e04c3bcca863a4f524cfd064aaf0122	3 years ago
Peter Dillinger	479eb1aad6	Hide deprecated, inefficient block-based filter from public API (#9535) ... Summary: This change removes the ability to configure the deprecated, inefficient block-based filter in the public API. Options that would have enabled it now use "full" (and optionally partitioned) filters. Existing block-based filters can still be read and used, and a "back door" way to build them still exists, for testing and in case of trouble. About the only way this removal would cause an issue for users is if temporary memory for filter construction greatly increases. In HISTORY.md we suggest a few possible mitigations: partitioned filters, smaller SST files, or setting reserve_table_builder_memory=true. Or users who have customized a FilterPolicy using the CreateFilter/KeyMayMatch mechanism removed in https://github.com/facebook/rocksdb/issues/9501 will have to upgrade their code. (It's long past time for people to move to the new builder/reader customization interface.) This change also introduces some internal-use-only configuration strings for testing specific filter implementations while bypassing some compatibility / intelligence logic. This is intended to hint at a path toward making FilterPolicy Customizable, but it also gives us a "back door" way to configure block-based filter. Aside: updated db_bench so that -readonly implies -use_existing_db Pull Request resolved: https://github.com/facebook/rocksdb/pull/9535 Test Plan: Unit tests updated. Specifically, * BlockBasedTableTest.BlockReadCountTest is tweaked to validate the back door configuration interface and ignoring of `use_block_based_builder`. * BlockBasedTableTest.TracingGetTest is migrated from testing block-based filter access pattern to full filter access patter, by re-ordering some things. * Options test (pretty self-explanatory) Performance test - create with `./db_bench -db=/dev/shm/rocksdb1 -bloom_bits=10 -cache_index_and_filter_blocks=1 -benchmarks=fillrandom -num=10000000 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=10000 -fifo_compaction_allow_compaction=0` with and without `-use_block_based_filter`, which creates a DB with 21 SST files in L0. Read with `./db_bench -db=/dev/shm/rocksdb1 -readonly -bloom_bits=10 -cache_index_and_filter_blocks=1 -benchmarks=readrandom -num=10000000 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=10000 -fifo_compaction_allow_compaction=0 -duration=30` Without -use_block_based_filter: readrandom 464 ops/sec, 689280 KB DB With -use_block_based_filter: readrandom 169 ops/sec, 690996 KB DB No consistent difference with fillrandom Reviewed By: jay-zhuang Differential Revision: D34153871 Pulled By: pdillinger fbshipit-source-id: 31f4a933c542f8f09aca47fa64aec67832a69738	3 years ago
Peter Dillinger	68a9c186d0	FilterPolicy API changes for 7.0 (#9501) ... Summary: * Inefficient block-based filter is no longer customizable in the public API, though (for now) can still be enabled. * Removed deprecated FilterPolicy::CreateFilter() and FilterPolicy::KeyMayMatch() * Removed `rocksdb_filterpolicy_create()` from C API * Change meaning of nullptr return from GetBuilderWithContext() from "use block-based filter" to "generate no filter in this case." This is a cleaner solution to the proposal in https://github.com/facebook/rocksdb/issues/8250. * Also, when user specifies bits_per_key < 0.5, we now round this down to "no filter" because we expect a filter with >= 80% FP rate is unlikely to be worth the CPU cost of accessing it (esp with cache_index_and_filter_blocks=1 or partition_filters=1). * bits_per_key >= 0.5 and < 1.0 is still rounded up to 1.0 (for 62% FP rate) * This also gives us some support for configuring filters from OPTIONS file as currently saved: `filter_policy=rocksdb.BuiltinBloomFilter`. Opening from such an options file will enable reading filters (an improvement) but not writing new ones. (See Customizable follow-up below.) * Also removed deprecated functions * FilterBitsBuilder::CalculateNumEntry() * FilterPolicy::GetFilterBitsBuilder() * NewExperimentalRibbonFilterPolicy() * Remove default implementations of * FilterBitsBuilder::EstimateEntriesAdded() * FilterBitsBuilder::ApproximateNumEntries() * FilterPolicy::GetBuilderWithContext() * Remove support for "filter_policy=experimental_ribbon" configuration string. * Allow "filter_policy=bloomfilter:n" without bool to discourage use of block-based filter. Some pieces for https://github.com/facebook/rocksdb/issues/9389 Likely follow-up (later PRs): * Refactoring toward FilterPolicy Customizable, so that we can generate filters with same configuration as before when configuring from options file. * Remove support for user enabling block-based filter (ignore `bool use_block_based_builder`) * Some months after this change, we could even remove read support for block-based filter, because it is not critical to DB data preservation. * Make FilterBitsBuilder::FinishV2 to avoid `using FilterBitsBuilder::Finish` mess and add support for specifying a MemoryAllocator (for cache warming) Pull Request resolved: https://github.com/facebook/rocksdb/pull/9501 Test Plan: A number of obsolete tests deleted and new tests or test cases added or updated. Reviewed By: hx235 Differential Revision: D34008011 Pulled By: pdillinger fbshipit-source-id: a39a720457c354e00d5b59166b686f7f59e392aa	3 years ago
satyajanga	036bbab6f7	Use the comparator from the sst file table properties in sst_dump_tool (#9491) ... Summary: We introduced a new Comparator for timestamp in user keys. In the sst_dump_tool by default we use BytewiseComparator to read sst files. This change allows us to read comparator_name from table properties in meta data block and use it to read. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9491 Test Plan: added unittests for new functionality. make check   Reviewed By: riversand963 Differential Revision: D33993614 Pulled By: satyajanga fbshipit-source-id: 4b5cf938e6d2cb3931d763bef5baccc900b8c536	3 years ago
Hui Xiao	920386f2b7	Detect (new) Bloom/Ribbon Filter construction corruption (#9342) ... Summary: Note: rebase on and merge after https://github.com/facebook/rocksdb/pull/9349, https://github.com/facebook/rocksdb/pull/9345, (optional) https://github.com/facebook/rocksdb/pull/9393 **Context:** (Quoted from pdillinger) Layers of information during new Bloom/Ribbon Filter construction in building block-based tables includes the following: a) set of keys to add to filter b) set of hashes to add to filter (64-bit hash applied to each key) c) set of Bloom indices to set in filter, with duplicates d) set of Bloom indices to set in filter, deduplicated e) final filter and its checksum This PR aims to detect corruption (e.g, unexpected hardware/software corruption on data structures residing in the memory for a long time) from b) to e) and leave a) as future works for application level. - b)'s corruption is detected by verifying the xor checksum of the hash entries calculated as the entries accumulate before being added to the filter. (i.e, `XXPH3FilterBitsBuilder::MaybeVerifyHashEntriesChecksum()`) - c) - e)'s corruption is detected by verifying the hash entries indeed exists in the constructed filter by re-querying these hash entries in the filter (i.e, `FilterBitsBuilder::MaybePostVerify()`) after computing the block checksum (except for PartitionFilter, which is done right after each `FilterBitsBuilder::Finish` for impl simplicity - see code comment for more). For this stage of detection, we assume hash entries are not corrupted after checking on b) since the time interval from b) to c) is relatively short IMO. Option to enable this feature of detection is `BlockBasedTableOptions::detect_filter_construct_corruption` which is false by default. **Summary:** - Implemented new functions `XXPH3FilterBitsBuilder::MaybeVerifyHashEntriesChecksum()` and `FilterBitsBuilder::MaybePostVerify()` - Ensured hash entries, final filter and banding and their [cache reservation ](https://github.com/facebook/rocksdb/issues/9073) are released properly despite corruption - See [Filter.construction.artifacts.release.point.pdf ](https://github.com/facebook/rocksdb/files/7923487/Design.Filter.construction.artifacts.release.point.pdf) for high-level design - Bundled and refactored hash entries's related artifact in XXPH3FilterBitsBuilder into `HashEntriesInfo` for better control on lifetime of these artifact during `SwapEntires`, `ResetEntries` - Ensured RocksDB block-based table builder calls `FilterBitsBuilder::MaybePostVerify()` after constructing the filter by `FilterBitsBuilder::Finish()` - When encountering such filter construction corruption, stop writing the filter content to files and mark such a block-based table building non-ok by storing the corruption status in the builder. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9342 Test Plan: - Added new unit test `DBFilterConstructionCorruptionTestWithParam.DetectCorruption` - Included this new feature in `DBFilterConstructionReserveMemoryTestWithParam.ReserveMemory` as this feature heavily touch ReserveMemory's impl - For fallback case, I run `./filter_bench -impl=3 -detect_filter_construct_corruption=true -reserve_table_builder_memory=true -strict_capacity_limit=true -quick -runs 10 | grep 'Build avg'` to make sure nothing break. - Added to `filter_bench`: increased filter construction time by **30%**, mostly by `MaybePostVerify()` - FastLocalBloom - Before change: `./filter_bench -impl=2 -quick -runs 10 | grep 'Build avg'`: **28.86643s** - After change: - `./filter_bench -impl=2 -detect_filter_construct_corruption=false -quick -runs 10 | grep 'Build avg'` (expect a tiny increase due to MaybePostVerify is always called regardless): **27.6644s (-4% perf improvement might be due to now we don't drop bloom hash entry in `AddAllEntries` along iteration but in bulk later, same with the bypassing-MaybePostVerify case below)** - `./filter_bench -impl=2 -detect_filter_construct_corruption=true -quick -runs 10 | grep 'Build avg'` (expect acceptable increase): **34.41159s (+20%)** - `./filter_bench -impl=2 -detect_filter_construct_corruption=true -quick -runs 10 | grep 'Build avg'` (by-passing MaybePostVerify, expect minor increase): **27.13431s (-6%)** - Standard128Ribbon - Before change: `./filter_bench -impl=3 -quick -runs 10 | grep 'Build avg'`: **122.5384s** - After change: - `./filter_bench -impl=3 -detect_filter_construct_corruption=false -quick -runs 10 | grep 'Build avg'` (expect a tiny increase due to MaybePostVerify is always called regardless - verified by removing MaybePostVerify under this case and found only +-1ns difference): **124.3588s (+2%)** - `./filter_bench -impl=3 -detect_filter_construct_corruption=true -quick -runs 10 | grep 'Build avg'`(expect acceptable increase): **159.4946s (+30%)** - `./filter_bench -impl=3 -detect_filter_construct_corruption=true -quick -runs 10 | grep 'Build avg'`(by-passing MaybePostVerify, expect minor increase) : **125.258s (+2%)** - Added to `db_stress`: `make crash_test`, `./db_stress --detect_filter_construct_corruption=true` - Manually smoke-tested: manually corrupted the filter construction in some db level tests with basic PUT and background flush. As expected, the error did get returned to users in subsequent PUT and Flush status. Reviewed By: pdillinger Differential Revision: D33746928 Pulled By: hx235 fbshipit-source-id: cb056426be5a7debc1cd16f23bc250f36a08ca57	3 years ago
Peter Dillinger	f6d7ec1d02	Ignore `total_order_seek` in DB::Get (#9427) ... Summary: Apparently setting total_order_seek=true for DB::Get was intended to allow accurate read semantics if the current prefix extractor doesn't match what was used to generate SST files on disk. But since prefix_extractor was made a mutable option in 5.14.0, we have been able to detect this case and provide the correct semantics regardless of the total_order_seek option. Since that time, the option has only made Get() slower in a reasonably common case: prefix_extractor unchanged and whole_key_filtering=false. So this change primarily removes unnecessary effect of total_order_seek on Get. Also cleans up some related comments. Also adds a -total_order_seek option to db_bench and canonicalizes handling of ReadOptions in db_bench so that command line options have the expected association with library features. (There is potential for change in regression test behavior, but the old behavior is likely indefensible, or some other inconsistency would need to be fixed.) TODO in follow-up work: there should be no reason for Get() to depend on current prefix extractor at all. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9427 Test Plan: Unit tests updated. Performance (using db_bench update) Create 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 -whole_key_filtering=0` Test with and without `-total_order_seek` on `TEST_TMPDIR=/dev/shm/rocksdb ./db_bench -use_existing_db -readonly -benchmarks=readrandom -num=10000000 -duration=40 -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` Before this change, total_order_seek=false: 25188 ops/sec Before this change, total_order_seek=true: 1222 ops/sec (~20x slower) After this change, total_order_seek=false: 24570 ops/sec After this change, total_order_seek=true: 25012 ops/sec (indistinguishable) Reviewed By: siying Differential Revision: D33753458 Pulled By: pdillinger fbshipit-source-id: bf892f34907a5e407d9c40bd4d42f0adbcbe0014	3 years ago
Peter Dillinger	ea89c77f27	Fix major bug with MultiGet, DeleteRange, and memtable Bloom (#9453) ... 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	3 years ago
Hui Xiao	11d7329503	Clarify status-handling logic in BlockBasedTableBuilder::WriteRawBlock (#9393) ... Summary: **Context:** Inside `BlockBasedTableBuilder::WriteRawBlock`, there are multiple places that change local variables `io_s` and `s` while depend on them. This PR attempts to clarify the relevant logics so that it's easier to read and add places of changing these local variables later (like https://github.com/facebook/rocksdb/pull/9342.) without changing the current behavior. **Summary:** - Shorten the lifetime of local var `io_s` and `s` as much as possible to avoid if-else branches by early return **Test** - Reasoned against original behavior to verify new changes do not break existing behaviors. - Rely on CI tests since we are not changing current behavior. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9393 Reviewed By: pdillinger Differential Revision: D33626095 Pulled By: hx235 fbshipit-source-id: 6184d1e1d85d2650d16617c449971988d062ed3f	3 years ago
sdong	5d10a53b42	Not try to finish index builder after errors (#9426) ... Summary: Right now, when error happens in block based table reader, we still call index_builder->Finish(), this causes one assertion in one stress test: db_stress: table/block_based/index_builder.cc:202: virtual rocksdb::Status rocksdb::PartitionedIndexBuilder::Finish(rocksdb::IndexBuilder::IndexBlocks*, const rocksdb::BlockHandle&): Assertion `sub_index_builder_ == nullptr' failed. This unlikely causes any corruption as we would finally abandon the file, but the code is confusing and it is hard to understand what would happen. Changing the behavior. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9426 Test Plan: Run existing tests Reviewed By: pdillinger Differential Revision: D33751929 fbshipit-source-id: 3c916b9444a4171010fc53df40496570bef5ae7a	3 years ago
Peter Dillinger	fc9d4071f0	Fast path for detecting unchanged prefix_extractor (#9407) ... 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	3 years ago
Peter Dillinger	ffe1e4b820	Make some FilterPolicy deprecations more clear (#9403) ... Summary: The old block-based filter has been deprecated for years, but this makes that more clear by marking the functions specific to it and logging a warning when the feature is used. It is deprecated because of performance. In that old design, you have to binary search through the full SST index before a bloom filter query, which is much more expensive than a bloom query itself. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9403 Test Plan: Used db_bench with and without -use_block_based_filter, running at the same time TEST_TMPDIR=/dev/shm/rocksdb ./db_bench -benchmarks=fillrandom,readrandom -num=10000000 -duration=20 -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 No significant difference in construction time but 3x slower readrandom with -use_block_based_filter: readrandom : 100.517 micros/op 9948 ops/sec; 1.1 MB/s vs. readrandom : 33.368 micros/op 29968 ops/sec; 3.3 MB/s Also saw deprecation message (just once) in LOG only with -use_block_based_filter Reviewed By: ajkr Differential Revision: D33673202 Pulled By: pdillinger fbshipit-source-id: 99f6f0eff619408d9e5f7ef546954ed0be6c7a5b	3 years ago
Si Ke	93b1de4f45	Enable db_test running in Centos 32 bit OS and Alpine 32 bit OS (#9294) ... Summary: Closes https://github.com/facebook/rocksdb/issues/9271 Pull Request resolved: https://github.com/facebook/rocksdb/pull/9294 Reviewed By: riversand963, hx235 Differential Revision: D33586002 Pulled By: pdillinger fbshipit-source-id: 3d1a2fa71023e108613ff03dbd37a5f954fc4920	3 years ago
mrambacher	1973fcba11	Restore Regex support for ObjectLibrary::Register, rename new APIs to allow old one to be deprecated in the future (#9362) ... 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	3 years ago
Hui Xiao	9110685e8c	Release cache reservation of hash entries of the fall-back Ribbon Filter earlier (#9345) ... 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	3 years ago
Hui Xiao	fb0a76a9e2	Always check previous conditionally unchecked status due to shortcut evaluation in BlockBasedTableBuilder::WriteIndexBlock (#9349) ... Summary: Note: part of https://github.com/facebook/rocksdb/pull/9342 **Context/Summary:** Due to shortcut evaluation in `ok() && s.IsIncomplete()`, status `s` remains unchecked if `ok()==false`, which is the case in https://app.circleci.com/pipelines/github/facebook/rocksdb/10718/workflows/429f7ad4-6b9a-446b-b9b3-710d51b90409/jobs/265508 revealed by the change in the corresponding PR https://github.com/facebook/rocksdb/pull/9342. As suggested by reviewers, separation and clarification of status checking for partitioned index building from general table building status is added. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9349 Test Plan: - The newly added if-else code is an equivalent translation of the existing logic plus always checking the conditionally unchecked status so relying on existing tests should be fine - https://github.com/facebook/rocksdb/pull/9342's `[build-linux-shared_lib-alt_namespace-status_checked](https://app.circleci.com/pipelines/github/facebook/rocksdb/10721/workflows/a200efe0-d545-4075-8c42-26dd3dc00f27/jobs/265625)` test should now pass after rebasing on this change Reviewed By: pdillinger Differential Revision: D33377223 Pulled By: hx235 fbshipit-source-id: cb81da9709ae9185e9cea89776e3012e915d6ef9	3 years ago
mrambacher	1c39b7952b	Remove/Reduce use of Regex in ObjectRegistry/Library (#9264) ... 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	3 years ago
mrambacher	9a116ab4b4	Add NewMetaDataIterator method (#8692) ... Summary: Fixes a problem where the iterator for metadata was being treated as a non-user key when in fact it was a user key. This led to a problem where the property keys could not be searched for correctly. The main exposure of this problem was that the HashIndexReader could not get the "prefixes" property correctly, resulting in the failure of retrieval/creation of the BlockPrefixIndex. Added BlockBasedTableTest.SeekMetaBlocks test to validate this condition. Fixing this condition exposed two other tests (SeekWithPrefixLongerThanKey, MultiGetPrefixFilter) that passed incorrectly previously and now failed. Updated those two tests to pass. Not sure if the tests are functionally correct/still appropriate, but made them pass... Pull Request resolved: https://github.com/facebook/rocksdb/pull/8692 Reviewed By: riversand963 Differential Revision: D33119539 Pulled By: mrambacher fbshipit-source-id: 658969fe9265f73dc184dab97cc3f4eaed2d881a	3 years ago
mrambacher	423538a816	Make MemoryAllocator into a Customizable class (#8980) ... Summary: - Make MemoryAllocator and its implementations into a Customizable class. - Added a "DefaultMemoryAllocator" which uses new and delete - Added a "CountedMemoryAllocator" that counts the number of allocs and free - Updated the existing tests to use these new allocators - Changed the memkind allocator test into a generic test that can test the various allocators. - Added tests for creating all of the allocators - Added tests to verify/create the JemallocNodumpAllocator using its options. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8980 Reviewed By: zhichao-cao Differential Revision: D32990403 Pulled By: mrambacher fbshipit-source-id: 6fdfe8218c10dd8dfef34344a08201be1fa95c76	3 years ago
Peter Dillinger	0050a73a4f	New stable, fixed-length cache keys (#9126) ... 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	3 years ago
Akanksha Mahajan	96d0773a11	Update prepopulate_block_cache logic to support block-based filter (#9300) ... Summary: Update prepopulate_block_cache logic to support block-based filter during insertion in block cache Pull Request resolved: https://github.com/facebook/rocksdb/pull/9300 Test Plan: CircleCI tests, make crash_test -j64 Reviewed By: pdillinger Differential Revision: D33132018 Pulled By: akankshamahajan15 fbshipit-source-id: 241deabab8645bda704728e572d6de6354df18b2	3 years ago
Peter Dillinger	e92a0ed040	Optimize & clean up footer code (#9280) ... Summary: Again, ahead of planned changes in https://github.com/facebook/rocksdb/issues/9058. This change improves performance (vs. pre-https://github.com/facebook/rocksdb/issues/9240 baseline) by separating a FooterBuilder from Footer, where FooterBuilder includes (inline owns) the serialized data so that it can be stack allocated. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9280 Test Plan: existing tests + performance testing below Extreme case performance testing as in https://github.com/facebook/rocksdb/issues/9240 with TEST_TMPDIR=/dev/shm/ ./db_bench -benchmarks=fillseq -memtablerep=vector -allow_concurrent_memtable_write=false -num=30000000 (Each is ops/s averaged over 50 runs, run simultaneously with competing configuration for load fairness) Pre-https://github.com/facebook/rocksdb/issues/9240 baseline (f577458): 436389 With https://github.com/facebook/rocksdb/issues/9240 (653c392): 417946 (-4.2% vs. baseline) This change: 443762 (+1.7% vs. baseline) Reviewed By: ajkr Differential Revision: D33077220 Pulled By: pdillinger fbshipit-source-id: 7eaa6499589aac1693414a758e8c799216c5016c	3 years ago
Peter Dillinger	653c392e47	More refactoring ahead of footer & meta changes (#9240) ... 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	3 years ago
Akanksha Mahajan	9e4d56f2c9	Fix segmentation fault in table_options.prepopulate_block_cache when used with partition_filters (#9263) ... Summary: When table_options.prepopulate_block_cache is set to BlockBasedTableOptions::PrepopulateBlockCache::kFlushOnly and table_options.partition_filters is also set true, then there is segmentation failure when top level filter is fetched because its entered with wrong type in cache. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9263 Test Plan: Updated unit tests; Ran db_stress: make crash_test -j32 Reviewed By: pdillinger Differential Revision: D32936566 Pulled By: akankshamahajan15 fbshipit-source-id: 8bd79e53830d3e3c1bb79787e1ffbc3cb46d4426	3 years ago
Hui Xiao	9daf07305c	Replace TableProperties::properties_offsets map with external_sst_file_global_seqno_offset (#9212) ... Summary: **Context:** Searching `TableProperties::properties_offsets` across the codebase reveals that internally it is only used to find the external SST file's global seqno offeset. Therefore we can narrow it down and replace this map property with a uint64_t property `external_sst_file_global_seqno_offset` to save memory usage related to table properties. Note: - See PR comments for discussion about potential impact on existing external usage of `TableProperties::properties_offsets` - See PR comments for discussion on keeping external SST file global seqno's offset VS using a simple flag indicating seqno's existence. **Summary:** - Replaced `TableProperties::properties_offsets` with `TableProperties::external_sst_file_global_seqno_offset` Pull Request resolved: https://github.com/facebook/rocksdb/pull/9212 Test Plan: - Relied on existing tests should be sufficient since `TableProperties::properties_offsets` existed before and should already be tested. Reviewed By: ajkr Differential Revision: D32665941 Pulled By: hx235 fbshipit-source-id: 718e44617346dc4f3b1276ee953e61c196277795	3 years ago