394 Commits (cc23b46da146bdc6a8ffd789fae7b81330ee17e4)

Author	SHA1	Message	Date
anand76	57997ddaaf	Multi file concurrency in MultiGet using coroutines and async IO (#9968) ... Summary: This PR implements a coroutine version of batched MultiGet in order to concurrently read from multiple SST files in a level using async IO, thus reducing the latency of the MultiGet. The API from the user perspective is still synchronous and single threaded, with the RocksDB part of the processing happening in the context of the caller's thread. In Version::MultiGet, the decision is made whether to call synchronous or coroutine code. A good way to review this PR is to review the first 4 commits in order - de773b3, 70c2f70, 10b50e1, and 377a597 - before reviewing the rest. TODO: 1. Figure out how to build it in CircleCI (requires some dependencies to be installed) 2. Do some stress testing with coroutines enabled No regression in synchronous MultiGet between this branch and main - ``` ./db_bench -use_existing_db=true --db=/data/mysql/rocksdb/prefix_scan -benchmarks="readseq,multireadrandom" -key_size=32 -value_size=512 -num=5000000 -batch_size=64 -multiread_batched=true -use_direct_reads=false -duration=60 -ops_between_duration_checks=1 -readonly=true -adaptive_readahead=true -threads=16 -cache_size=10485760000 -async_io=false -multiread_stride=40000 -statistics ``` Branch - ```multireadrandom : 4.025 micros/op 3975111 ops/sec 60.001 seconds 238509056 operations; 2062.3 MB/s (14767808 of 14767808 found)``` Main - ```multireadrandom : 3.987 micros/op 4013216 ops/sec 60.001 seconds 240795392 operations; 2082.1 MB/s (15231040 of 15231040 found)``` More benchmarks in various scenarios are given below. The measurements were taken with ```async_io=false``` (no coroutines) and ```async_io=true``` (use coroutines). For an IO bound workload (with every key requiring an IO), the coroutines version shows a clear benefit, being ~2.6X faster. For CPU bound workloads, the coroutines version has ~6-15% higher CPU utilization, depending on how many keys overlap an SST file. 1. Single thread IO bound workload on remote storage with sparse MultiGet batch keys (~1 key overlap/file) - No coroutines - ```multireadrandom : 831.774 micros/op 1202 ops/sec 60.001 seconds 72136 operations; 0.6 MB/s (72136 of 72136 found)``` Using coroutines - ```multireadrandom : 318.742 micros/op 3137 ops/sec 60.003 seconds 188248 operations; 1.6 MB/s (188248 of 188248 found)``` 2. Single thread CPU bound workload (all data cached) with ~1 key overlap/file - No coroutines - ```multireadrandom : 4.127 micros/op 242322 ops/sec 60.000 seconds 14539384 operations; 125.7 MB/s (14539384 of 14539384 found)``` Using coroutines - ```multireadrandom : 4.741 micros/op 210935 ops/sec 60.000 seconds 12656176 operations; 109.4 MB/s (12656176 of 12656176 found)``` 3. Single thread CPU bound workload with ~2 key overlap/file - No coroutines - ```multireadrandom : 3.717 micros/op 269000 ops/sec 60.000 seconds 16140024 operations; 139.6 MB/s (16140024 of 16140024 found)``` Using coroutines - ```multireadrandom : 4.146 micros/op 241204 ops/sec 60.000 seconds 14472296 operations; 125.1 MB/s (14472296 of 14472296 found)``` 4. CPU bound multi-threaded (16 threads) with ~4 key overlap/file - No coroutines - ```multireadrandom : 4.534 micros/op 3528792 ops/sec 60.000 seconds 211728728 operations; 1830.7 MB/s (12737024 of 12737024 found) ``` Using coroutines - ```multireadrandom : 4.872 micros/op 3283812 ops/sec 60.000 seconds 197030096 operations; 1703.6 MB/s (12548032 of 12548032 found) ``` Pull Request resolved: https://github.com/facebook/rocksdb/pull/9968 Reviewed By: akankshamahajan15 Differential Revision: D36348563 Pulled By: anand1976 fbshipit-source-id: c0ce85a505fd26ebfbb09786cbd7f25202038696	3 years ago
Jay Zhuang	c6d326d3d7	Track SST unique id in MANIFEST and verify (#9990) ... Summary: Start tracking SST unique id in MANIFEST, which is used to verify with SST properties to make sure the SST file is not overwritten or misplaced. A DB option `try_verify_sst_unique_id` is introduced to enable/disable the verification, if enabled, it opens all SST files during DB-open to read the unique_id from table properties (default is false), so it's recommended to use it with `max_open_files = -1` to pre-open the files. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9990 Test Plan: unittests, format-compatible test, mini-crash Reviewed By: anand1976 Differential Revision: D36381863 Pulled By: jay-zhuang fbshipit-source-id: 89ea2eb6b35ed3e80ead9c724eb096083eaba63f	3 years ago
sdong	49628c9a83	Use std::numeric_limits<> (#9954) ... Summary: Right now we still don't fully use std::numeric_limits but use a macro, mainly for supporting VS 2013. Right now we only support VS 2017 and up so it is not a problem. The code comment claims that MinGW still needs it. We don't have a CI running MinGW so it's hard to validate. since we now require C++17, it's hard to imagine MinGW would still build RocksDB but doesn't support std::numeric_limits<>. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9954 Test Plan: See CI Runs. Reviewed By: riversand963 Differential Revision: D36173954 fbshipit-source-id: a35a73af17cdcae20e258cdef57fcf29a50b49e0	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
sdong	e03f8a0c12	L0 Subcompaction to trim input files (#9802) ... Summary: When sub compaction is decided for L0->L1 compaction, most of the cases, all L0 files will be involved in all sub compactions. However, it is not always the case. When files are generally (but not strictly) inserted in sequential order, there can be a subset of L0 files invovled. Yet RocksDB always open all those L0 files, and build an iterator, read many of the files' first of last block with expensive readahead. We trim some input files to reduce overhead a little bit. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9802 Test Plan: Add a unit test to cover this case and manually validate the behavior while running the test. Reviewed By: ajkr Differential Revision: D35371031 fbshipit-source-id: 701ed7375b5cbe41672e93b38fe8a1503dad08b6	3 years ago
Peter Dillinger	cad809978a	Fix heap use-after-free race with DropColumnFamily (#9730) ... Summary: Although ColumnFamilySet comments say that DB mutex can be freed during iteration, as long as you hold a ref while releasing DB mutex, this is not quite true because UnrefAndTryDelete might delete cfd right before it is needed to get ->next_ for the next iteration of the loop. This change solves the problem by making a wrapper class that makes such iteration easier while handling the tricky details of UnrefAndTryDelete on the previous cfd only after getting next_ in operator++. FreeDeadColumnFamilies should already have been obsolete; this removes it for good. Similarly, ColumnFamilySet::iterator doesn't need to check for cfd with 0 refs, because those are immediately deleted. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9730 Test Plan: was reported with ASAN on unit tests like DBLogicalBlockSizeCacheTest.CreateColumnFamily (very rare); keep watching Reviewed By: ltamasi Differential Revision: D35038143 Pulled By: pdillinger fbshipit-source-id: 0a5478d5be96c135343a00603711b7df43ae19c9	3 years ago
Yanqin Jin	e0c84aa0dc	Fix a race condition in WAL tracking causing DB open failure (#9715) ... Summary: There is a race condition if WAL tracking in the MANIFEST is enabled in a database that disables 2PC. The race condition is between two background flush threads trying to install flush results to the MANIFEST. Consider an example database with two column families: "default" (cfd0) and "cf1" (cfd1). Initially, both column families have one mutable (active) memtable whose data backed by 6.log. 1. Trigger a manual flush for "cf1", creating a 7.log 2. Insert another key to "default", and trigger flush for "default", creating 8.log 3. BgFlushThread1 finishes writing 9.sst 4. BgFlushThread2 finishes writing 10.sst ``` Time BgFlushThread1 BgFlushThread2 | mutex_.Lock() | precompute min_wal_to_keep as 6 | mutex_.Unlock() | mutex_.Lock() | precompute min_wal_to_keep as 6 | join MANIFEST write queue and mutex_.Unlock() | write to MANIFEST | mutex_.Lock() | cfd1->log_number = 7 | Signal bg_flush_2 and mutex_.Unlock() | wake up and mutex_.Lock() | cfd0->log_number = 8 | FindObsoleteFiles() with job_context->log_number == 7 | mutex_.Unlock() | PurgeObsoleteFiles() deletes 6.log V ``` As shown in the above, BgFlushThread2 thinks that the min wal to keep is 6.log because "cf1" has unflushed data in 6.log (cf1.log_number=6). Similarly, BgThread1 thinks that min wal to keep is also 6.log because "default" has unflushed data (default.log_number=6). No WAL deletion will be written to MANIFEST because 6 is equal to `versions_->wals_.min_wal_number_to_keep`, due to https://github.com/facebook/rocksdb/blob/7.1.fb/db/memtable_list.cc#L513:L514. The bg flush thread that finishes last will perform file purging. `job_context.log_number` will be evaluated as 7, i.e. the min wal that contains unflushed data, causing 6.log to be deleted. However, MANIFEST thinks 6.log should still exist. If you close the db at this point, you won't be able to re-open it if `track_and_verify_wal_in_manifest` is true. We must handle the case of multiple bg flush threads, and it is difficult for one bg flush thread to know the correct min wal number until the other bg flush threads have finished committing to the manifest and updated the `cfd::log_number`. To fix this issue, we rename an existing variable `min_log_number_to_keep_2pc` to `min_log_number_to_keep`, and use it to track WAL file deletion in non-2pc mode as well. This variable is updated only 1) during recovery with mutex held, or 2) in the MANIFEST write thread. `min_log_number_to_keep` means RocksDB will delete WALs below it, although there may be WALs above it which are also obsolete. Formally, we will have [min_wal_to_keep, max_obsolete_wal]. During recovery, we make sure that only WALs above max_obsolete_wal are checked and added back to `alive_log_files_`. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9715 Test Plan: ``` make check ``` Also ran stress test below (with asan) to make sure it completes successfully. ``` TEST_TMPDIR=/dev/shm/rocksdb OPT=-g ASAN_OPTIONS=disable_coredump=0 \ CRASH_TEST_EXT_ARGS=--compression_type=zstd SKIP_FORMAT_BUCK_CHECKS=1 \ make J=52 -j52 blackbox_asan_crash_test ``` Reviewed By: ltamasi Differential Revision: D34984412 Pulled By: riversand963 fbshipit-source-id: c7b21a8d84751bb55ea79c9f387103d21b231005	3 years ago
Yanqin Jin	3bd150c442	Print information about all column families when using ldb (#9719) ... Summary: Before this PR, the following command prints only the default column family's information in the end: ``` ldb --db=. --hex manifest_dump --verbose ``` We should print all column families instead. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9719 Test Plan: `make check` makes sure nothing breaks. Generate a DB, use the above command to verify all column families are printed. Reviewed By: akankshamahajan15 Differential Revision: D34992453 Pulled By: riversand963 fbshipit-source-id: de1d38c4539cd89f74e1a6240ad7a6e2416bf198	3 years ago
Hui Xiao	443d8ef094	Fix PinSelf() read-after-free in DB::GetMergeOperands() (#9507) ... Summary: **Context:** Running the new test `DBMergeOperandTest.MergeOperandReadAfterFreeBug` prior to this fix surfaces the read-after-free bug of PinSef() as below: ``` READ of size 8 at 0x60400002529d thread T0 https://github.com/facebook/rocksdb/issues/5 0x7f199a in rocksdb::PinnableSlice::PinSelf(rocksdb::Slice const&) include/rocksdb/slice.h:171 https://github.com/facebook/rocksdb/issues/6 0x7f199a in rocksdb::DBImpl::GetImpl(rocksdb::ReadOptions const&, rocksdb::Slice const&, rocksdb::DBImpl::GetImplOptions&) db/db_impl/db_impl.cc:1919 https://github.com/facebook/rocksdb/issues/7 0x540d63 in rocksdb::DBImpl::GetMergeOperands(rocksdb::ReadOptions const&, rocksdb::ColumnFamilyHandle*, rocksdb::Slice const&, rocksdb::PinnableSlice*, rocksdb::GetMergeOperandsOptions*, int*) db/db_impl/db_impl.h:203 freed by thread T0 here: https://github.com/facebook/rocksdb/issues/3 0x1191399 in rocksdb::cache_entry_roles_detail::RegisteredDeleter<rocksdb::Block, (rocksdb::CacheEntryRole)0>::Delete(rocksdb::Slice const&, void*) cache/cache_entry_roles.h:99 https://github.com/facebook/rocksdb/issues/4 0x719348 in rocksdb::LRUHandle::Free() cache/lru_cache.h:205 https://github.com/facebook/rocksdb/issues/5 0x71047f in rocksdb::LRUCacheShard::Release(rocksdb::Cache::Handle*, bool) cache/lru_cache.cc:547 https://github.com/facebook/rocksdb/issues/6 0xa78f0a in rocksdb::Cleanable::DoCleanup() include/rocksdb/cleanable.h:60 https://github.com/facebook/rocksdb/issues/7 0xa78f0a in rocksdb::Cleanable::Reset() include/rocksdb/cleanable.h:38 https://github.com/facebook/rocksdb/issues/8 0xa78f0a in rocksdb::PinnedIteratorsManager::ReleasePinnedData() db/pinned_iterators_manager.h:71 https://github.com/facebook/rocksdb/issues/9 0xd0c21b in rocksdb::PinnedIteratorsManager::~PinnedIteratorsManager() db/pinned_iterators_manager.h:24 https://github.com/facebook/rocksdb/issues/10 0xd0c21b in rocksdb::Version::Get(rocksdb::ReadOptions const&, rocksdb::LookupKey const&, rocksdb::PinnableSlice*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*, rocksdb::Status*, rocksdb::MergeContext*, unsigned long*, bool*, bool*, unsigned long*, rocksdb::ReadCallback*, bool*, bool) db/pinned_iterators_manager.h:22 https://github.com/facebook/rocksdb/issues/11 0x7f0fdf in rocksdb::DBImpl::GetImpl(rocksdb::ReadOptions const&, rocksdb::Slice const&, rocksdb::DBImpl::GetImplOptions&) db/db_impl/db_impl.cc:1886 https://github.com/facebook/rocksdb/issues/12 0x540d63 in rocksdb::DBImpl::GetMergeOperands(rocksdb::ReadOptions const&, rocksdb::ColumnFamilyHandle*, rocksdb::Slice const&, rocksdb::PinnableSlice*, rocksdb::GetMergeOperandsOptions*, int*) db/db_impl/db_impl.h:203 previously allocated by thread T0 here: https://github.com/facebook/rocksdb/issues/1 0x1239896 in rocksdb::AllocateBlock(unsigned long, **rocksdb::MemoryAllocator*)** memory/memory_allocator.h:35 https://github.com/facebook/rocksdb/issues/2 0x1239896 in rocksdb::BlockFetcher::CopyBufferToHeapBuf() table/block_fetcher.cc:171 https://github.com/facebook/rocksdb/issues/3 0x1239896 in rocksdb::BlockFetcher::GetBlockContents() table/block_fetcher.cc:206 https://github.com/facebook/rocksdb/issues/4 0x122eae5 in rocksdb::BlockFetcher::ReadBlockContents() table/block_fetcher.cc:325 https://github.com/facebook/rocksdb/issues/5 0x11b1f45 in rocksdb::Status rocksdb::BlockBasedTable::MaybeReadBlockAndLoadToCache<rocksdb::Block>(rocksdb::FilePrefetchBuffer*, rocksdb::ReadOptions const&, rocksdb::BlockHandle const&, rocksdb::UncompressionDict const&, bool, rocksdb::CachableEntry<rocksdb::Block>*, rocksdb::BlockType, rocksdb::GetContext*, rocksdb::BlockCacheLookupContext*, rocksdb::BlockContents*) const table/block_based/block_based_table_reader.cc:1503 ``` Here is the analysis: - We have [PinnedIteratorsManager](https://github.com/facebook/rocksdb/blob/6.28.fb/db/version_set.cc#L1980) with `Cleanable` capability in our `Version::Get()` path. It's responsible for managing the life-time of pinned iterator and invoking registered cleanup functions during its own destruction. - For example in case above, the merge operands's clean-up gets associated with this manger in [GetContext::push_operand](https://github.com/facebook/rocksdb/blob/6.28.fb/table/get_context.cc#L405). During PinnedIteratorsManager's [destruction](https://github.com/facebook/rocksdb/blob/6.28.fb/db/pinned_iterators_manager.h#L67), the release function associated with those merge operand data is invoked. **And that's what we see in "freed by thread T955 here" in ASAN.** - Bug 🐛: `PinnedIteratorsManager` is local to `Version::Get()` while the data of merge operands need to outlive `Version::Get` and stay till they get [PinSelf()](https://github.com/facebook/rocksdb/blob/6.28.fb/db/db_impl/db_impl.cc#L1905), **which is the read-after-free in ASAN.** - This bug is likely to be an overlook of `PinnedIteratorsManager` when developing the API `DB::GetMergeOperands` cuz the current logic works fine with the existing case of getting the *merged value* where the operands do not need to live that long. - This bug was not surfaced much (even in its unit test) due to the release function associated with the merge operands (which are actually blocks put in cache as you can see in `BlockBasedTable::MaybeReadBlockAndLoadToCache` **in "previously allocated by" in ASAN report**) is a cache entry deleter. The deleter will call `Cache::Release()` which, for LRU cache, won't immediately deallocate the block based on LRU policy [unless the cache is full or being instructed to force erase](https://github.com/facebook/rocksdb/blob/6.28.fb/cache/lru_cache.cc#L521-L531) - `DBMergeOperandTest.MergeOperandReadAfterFreeBug` makes the cache extremely small to force cache full. **Summary:** - Fix the bug by align `PinnedIteratorsManager`'s lifetime with the merge operands Pull Request resolved: https://github.com/facebook/rocksdb/pull/9507 Test Plan: - New test `DBMergeOperandTest.MergeOperandReadAfterFreeBug` - db bench on read path - Setup (LSM tree with several levels, cache the whole db to avoid read IO, warm cache with readseq to avoid read IO): `TEST_TMPDIR=/dev/shm/rocksdb ./db_bench -benchmarks="fillrandom,readseq -num=1000000 -cache_size=100000000 -write_buffer_size=10000 -statistics=1 -max_bytes_for_level_base=10000 -level0_file_num_compaction_trigger=1``TEST_TMPDIR=/dev/shm/rocksdb ./db_bench -benchmarks="readrandom" -num=1000000 -cache_size=100000000 ` - Actual command run (run 20-run for 20 times and then average the 20-run's average micros/op) - `for j in {1..20}; do (for i in {1..20}; do rm -rf /dev/shm/rocksdb/ && TEST_TMPDIR=/dev/shm/rocksdb ./db_bench -benchmarks="fillrandom,readseq,readrandom" -num=1000000 -cache_size=100000000 -write_buffer_size=10000 -statistics=1 -max_bytes_for_level_base=10000 -level0_file_num_compaction_trigger=1 | egrep 'readrandom'; done > rr_output_pre.txt && (awk '{sum+=$3; sum_sqrt+=$3^2}END{print sum/20, sqrt(sum_sqrt/20-(sum/20)^2)}' rr_output_pre.txt) >> rr_output_pre_2.txt); done` - **Result: Pre-change: 3.79193 micros/op; Post-change: 3.79528 micros/op (+0.09%)** (pre-change)sorted avg micros/op of each 20-run | std of micros/op of each 20-run | (post-change) sorted avg micros/op of each 20-run | std of micros/op of each 20-run -- | -- | -- | -- 3.58355 | 0.265209 | 3.48715 | 0.382076 3.58845 | 0.519927 | 3.5832 | 0.382726 3.66415 | 0.452097 | 3.677 | 0.563831 3.68495 | 0.430897 | 3.68405 | 0.495355 3.70295 | 0.482893 | 3.68465 | 0.431438 3.719 | 0.463806 | 3.71945 | 0.457157 3.7393 | 0.453423 | 3.72795 | 0.538604 3.7806 | 0.527613 | 3.75075 | 0.444509 3.7817 | 0.426704 | 3.7683 | 0.468065 3.809 | 0.381033 | 3.8086 | 0.557378 3.80985 | 0.466011 | 3.81805 | 0.524833 3.8165 | 0.500351 | 3.83405 | 0.529339 3.8479 | 0.430326 | 3.86285 | 0.44831 3.85125 | 0.434108 | 3.8717 | 0.544098 3.8556 | 0.524602 | 3.895 | 0.411679 3.8656 | 0.476383 | 3.90965 | 0.566636 3.8911 | 0.488477 | 3.92735 | 0.608038 3.898 | 0.493978 | 3.9439 | 0.524511 3.97235 | 0.515008 | 3.9623 | 0.477416 3.9768 | 0.519993 | 3.98965 | 0.521481 - CI Reviewed By: ajkr Differential Revision: D34030519 Pulled By: hx235 fbshipit-source-id: a99ac585c11704c5ed93af033cb29ba0a7b16ae8	3 years ago
Levi Tamasi	073ac54739	Log blob file space amp and expose it via the rocksdb.blob-stats DB property (#9538) ... Summary: Extend the periodic statistics in the info log with the total amount of garbage in blob files and the space amplification pertaining to blob files, where the latter is defined as `total_blob_file_size / (total_blob_file_size - total_blob_garbage_size)`. Also expose the space amp via the `rocksdb.blob-stats` DB property. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9538 Test Plan: `make check` Reviewed By: riversand963 Differential Revision: D34126855 Pulled By: ltamasi fbshipit-source-id: 3153e7a0fe0eca440322db273f4deaabaccc51b2	3 years ago
Levi Tamasi	320d9a8e8a	Use a sorted vector instead of a map to store blob file metadata (#9526) ... Summary: The patch replaces `std::map` with a sorted `std::vector` for `VersionStorageInfo::blob_files_` and preallocates the space for the `vector` before saving the `BlobFileMetaData` into the new `VersionStorageInfo` in `VersionBuilder::Rep::SaveBlobFilesTo`. These changes reduce the time the DB mutex is held while saving new `Version`s, and using a sorted `vector` also makes lookups faster thanks to better memory locality. In addition, the patch introduces helper methods `VersionStorageInfo::GetBlobFileMetaData` and `VersionStorageInfo::GetBlobFileMetaDataLB` that can be used by clients to perform lookups in the `vector`, and does some general cleanup in the parts of code where blob file metadata are used. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9526 Test Plan: Ran `make check` and the crash test script for a while. Performance was tested using a load-optimized benchmark (`fillseq` with vector memtable, no WAL) and small file sizes so that a significant number of files are produced: ``` numactl --interleave=all ./db_bench --benchmarks=fillseq --allow_concurrent_memtable_write=false --level0_file_num_compaction_trigger=4 --level0_slowdown_writes_trigger=20 --level0_stop_writes_trigger=30 --max_background_jobs=8 --max_write_buffer_number=8 --db=/data/ltamasi-dbbench --wal_dir=/data/ltamasi-dbbench --num=800000000 --num_levels=8 --key_size=20 --value_size=400 --block_size=8192 --cache_size=51539607552 --cache_numshardbits=6 --compression_max_dict_bytes=0 --compression_ratio=0.5 --compression_type=lz4 --bytes_per_sync=8388608 --cache_index_and_filter_blocks=1 --cache_high_pri_pool_ratio=0.5 --benchmark_write_rate_limit=0 --write_buffer_size=16777216 --target_file_size_base=16777216 --max_bytes_for_level_base=67108864 --verify_checksum=1 --delete_obsolete_files_period_micros=62914560 --max_bytes_for_level_multiplier=8 --statistics=0 --stats_per_interval=1 --stats_interval_seconds=20 --histogram=1 --memtablerep=skip_list --bloom_bits=10 --open_files=-1 --subcompactions=1 --compaction_style=0 --min_level_to_compress=3 --level_compaction_dynamic_level_bytes=true --pin_l0_filter_and_index_blocks_in_cache=1 --soft_pending_compaction_bytes_limit=167503724544 --hard_pending_compaction_bytes_limit=335007449088 --min_level_to_compress=0 --use_existing_db=0 --sync=0 --threads=1 --memtablerep=vector --allow_concurrent_memtable_write=false --disable_wal=1 --enable_blob_files=1 --blob_file_size=16777216 --min_blob_size=0 --blob_compression_type=lz4 --enable_blob_garbage_collection=1 --seed=<some value> ``` Final statistics before the patch: ``` Cumulative writes: 0 writes, 700M keys, 0 commit groups, 0.0 writes per commit group, ingest: 284.62 GB, 121.27 MB/s Interval writes: 0 writes, 334K keys, 0 commit groups, 0.0 writes per commit group, ingest: 139.28 MB, 72.46 MB/s ``` With the patch: ``` Cumulative writes: 0 writes, 760M keys, 0 commit groups, 0.0 writes per commit group, ingest: 308.66 GB, 131.52 MB/s Interval writes: 0 writes, 445K keys, 0 commit groups, 0.0 writes per commit group, ingest: 185.35 MB, 93.15 MB/s ``` Total time to complete the benchmark is 2611 seconds with the patch, down from 2986 secs. Reviewed By: riversand963 Differential Revision: D34082728 Pulled By: ltamasi fbshipit-source-id: fc598abf676dce436734d06bb9d2d99a26a004fc	3 years ago
Levi Tamasi	0cc0543893	Mitigate the overhead of building the hash of file locations (#9504) ... Summary: The patch builds on the refactoring done in https://github.com/facebook/rocksdb/issues/9494 and improves the performance of building the hash of file locations in `VersionStorageInfo` in two ways. First, the hash building is moved from `AddFile` (which is called under the DB mutex) to a separate post-processing step done as part of `PrepareForVersionAppend` (during which the mutex is *not* held). Second, the space necessary for the hash is preallocated to prevent costly reallocation/rehashing operations. These changes mitigate the overhead of the file location hash, which can be significant with certain workloads where the baseline CPU usage is low (see https://github.com/facebook/rocksdb/issues/9351, which is a workload where keys are sorted, WAL is turned off, the vector memtable implementation is used, and there are lots of small SST files). Fixes https://github.com/facebook/rocksdb/issues/9351 Pull Request resolved: https://github.com/facebook/rocksdb/pull/9504 Test Plan: `make check` ``` numactl --interleave=all ./db_bench --benchmarks=fillseq --allow_concurrent_memtable_write=false --level0_file_num_compaction_trigger=4 --level0_slowdown_writes_trigger=20 --level0_stop_writes_trigger=30 --max_background_jobs=8 --max_write_buffer_number=8 --db=/data/ltamasi-dbbench --wal_dir=/data/ltamasi-dbbench --num=800000000 --num_levels=8 --key_size=20 --value_size=400 --block_size=8192 --cache_size=51539607552 --cache_numshardbits=6 --compression_max_dict_bytes=0 --compression_ratio=0.5 --compression_type=lz4 --bytes_per_sync=8388608 --cache_index_and_filter_blocks=1 --cache_high_pri_pool_ratio=0.5 --benchmark_write_rate_limit=0 --write_buffer_size=16777216 --target_file_size_base=16777216 --max_bytes_for_level_base=67108864 --verify_checksum=1 --delete_obsolete_files_period_micros=62914560 --max_bytes_for_level_multiplier=8 --statistics=0 --stats_per_interval=1 --stats_interval_seconds=20 --histogram=1 --bloom_bits=10 --open_files=-1 --subcompactions=1 --compaction_style=0 --level_compaction_dynamic_level_bytes=true --pin_l0_filter_and_index_blocks_in_cache=1 --soft_pending_compaction_bytes_limit=167503724544 --hard_pending_compaction_bytes_limit=335007449088 --min_level_to_compress=0 --use_existing_db=0 --sync=0 --threads=1 --memtablerep=vector --disable_wal=1 --seed=<some_seed> ``` Final statistics before this patch: ``` Cumulative writes: 0 writes, 697M keys, 0 commit groups, 0.0 writes per commit group, ingest: 283.25 GB, 241.08 MB/s Interval writes: 0 writes, 1264K keys, 0 commit groups, 0.0 writes per commit group, ingest: 525.69 MB, 176.67 MB/s ``` With the patch: ``` Cumulative writes: 0 writes, 759M keys, 0 commit groups, 0.0 writes per commit group, ingest: 308.57 GB, 262.63 MB/s Interval writes: 0 writes, 1555K keys, 0 commit groups, 0.0 writes per commit group, ingest: 646.61 MB, 215.11 MB/s ``` Reviewed By: riversand963 Differential Revision: D34014734 Pulled By: ltamasi fbshipit-source-id: acb2703677451d5ccaa7e9d950844b33d240695b	3 years ago
Levi Tamasi	42e0751b3a	Clean up VersionStorageInfo a bit (#9494) ... Summary: The patch does some cleanup in and around `VersionStorageInfo`: * Renames the method `PrepareApply` to `PrepareAppend` in `Version` to make it clear that it is to be called before appending the `Version` to `VersionSet` (via `AppendVersion`), not before applying any `VersionEdit`s. * Introduces a helper method `VersionStorageInfo::PrepareForVersionAppend` (called by `Version::PrepareAppend`) that encapsulates the population of the various derived data structures in `VersionStorageInfo`, and turns the methods computing the derived structures (`UpdateNumNonEmptyLevels`, `CalculateBaseBytes` etc.) into private helpers. * Changes `Version::PrepareAppend` so it only calls `UpdateAccumulatedStats` if the `update_stats` flag is set. (Earlier, this was checked by the callee.) Related to this, it also moves the call to `ComputeCompensatedSizes` to `VersionStorageInfo::PrepareForVersionAppend`. * Updates and cleans up `version_builder_test`, `version_set_test`, and `compaction_picker_test` so `PrepareForVersionAppend` is called anytime a new `VersionStorageInfo` is set up or saved. This cleanup also involves splitting `VersionStorageInfoTest.MaxBytesForLevelDynamic` into multiple smaller test cases. * Fixes up a bunch of comments that were outdated or just plain incorrect. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9494 Test Plan: Ran `make check` and the crash test script for a while. Reviewed By: riversand963 Differential Revision: D33971666 Pulled By: ltamasi fbshipit-source-id: fda52faac7783041126e4f8dec0fe01bdcadf65a	3 years ago
Youngjae Lee	3dfee770c6	Remove obsolete function declaration (#8724) ... Summary: Function `Version::UpdateFilesByCompactionPri()` is never called and not implemented. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8724 Reviewed By: ajkr Differential Revision: D30643943 Pulled By: riversand963 fbshipit-source-id: 174b2d9a2a42e286222909a035cc74a7b5602335	3 years ago
Andrew Kryczka	b860a42158	Recover to exact latest seqno of data committed to MANIFEST (#9305) ... Summary: The LastSequence field in the MANIFEST file is the baseline seqno for a recovered DB. Recovering WAL entries might cause the recovered DB's seqno to advance above this baseline, but the recovered DB will never use a smaller seqno. Before this PR, we were writing the DB's seqno at the time of LogAndApply() as the LastSequence value. This works in the sense that it is a large enough baseline for the recovered DB that it'll never overwrite any records in existing SST files. At the same time, it's arbitrarily larger than what's needed. This behavior comes from LevelDB, where there was no tracking of largest seqno in an SST file. Now we know the largest seqno of newly written SST files, so we can write an exact value in LastSequence that actually reflects the largest seqno in any file referred to by the MANIFEST. This is primarily useful for correctness testing with unsynced data loss, where the recovered DB's seqno needs to indicate what records were recovered. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9305 Test Plan: - https://github.com/facebook/rocksdb/issues/9338 adds crash-recovery correctness testing coverage for WAL disabled use cases - https://github.com/facebook/rocksdb/issues/9357 will extend that testing to cover file ingestion - Added assertion at end of LogAndApply() for `VersionSet::descriptor_last_sequence_` consistency with files - Manually tested upgrade/downgrade compatibility with a custom crash test that randomly picks between a `db_stress` built with and without this PR (for old code it must run with `-disable_wal=0`) Reviewed By: riversand963 Differential Revision: D33182770 Pulled By: ajkr fbshipit-source-id: 0bfafaf685f347cc8cb0e1d62e0186340a738f7d	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
Levi Tamasi	dc5de45af8	Support readahead during compaction for blob files (#9187) ... Summary: The patch adds a new BlobDB configuration option `blob_compaction_readahead_size` that can be used to enable prefetching data from blob files during compaction. This is important when using storage with higher latencies like HDDs or remote filesystems. If enabled, prefetching is used for all cases when blobs are read during compaction, namely garbage collection, compaction filters (when the existing value has to be read from a blob file), and `Merge` (when the value of the base `Put` is stored in a blob file). Pull Request resolved: https://github.com/facebook/rocksdb/pull/9187 Test Plan: Ran `make check` and the stress/crash test. Reviewed By: riversand963 Differential Revision: D32565512 Pulled By: ltamasi fbshipit-source-id: 87be9cebc3aa01cc227bec6b5f64d827b8164f5d	3 years ago
Levi Tamasi	081722780b	Refactor the detailed consistency checks and the SST saving logic in VersionBuilder (#9099) ... Summary: The patch refactors the parts of `VersionBuilder` that deal with SST file comparisons. Specifically, it makes the following changes: * Turns `NewestFirstBySeqNo` and `BySmallestKey` from free-standing functions into function objects. Note: `BySmallestKey` has a pointer to the `InternalKeyComparator`, while `NewestFirstBySeqNo` is completely stateless. * Eliminates the wrapper `FileComparator`, which was essentially an unnecessary DIY virtual function call mechanism. * Refactors `CheckConsistencyDetails` and `SaveSSTFilesTo` using helper function templates that take comparator/checker function objects. Using static polymorphism eliminates the need to make runtime decisions about which comparator to use. * Extends some error messages returned by the consistency checks and makes them more uniform. * Removes some incomplete/redundant consistency checks from `VersionBuilder` and `FilePicker`. * Improves const correctness in several places. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9099 Test Plan: `make check` Reviewed By: riversand963 Differential Revision: D32027503 Pulled By: ltamasi fbshipit-source-id: 621326ae41f4f55f7ad6a91abbd6e666d5c7857c	3 years ago
sdong	a2b9be42b6	Try to start TTL earlier with kMinOverlappingRatio is used (#8749) ... Summary: Right now, when options.ttl is set, compactions are triggered around the time when TTL is reached. This might cause extra compactions which are often bursty. This commit tries to mitigate it by picking those files earlier in normal compaction picking process. This is only implemented using kMinOverlappingRatio with Leveled compaction as it is the default value and it is more complicated to change other styles. When a file is aged more than ttl/2, RocksDB starts to boost the compaction priority of files in normal compaction picking process, and hope by the time TTL is reached, very few extra compaction is needed. In order for this to work, another change is made: during a compaction, if an output level file is older than ttl/2, cut output files based on original boundary (if it is not in the last level). This is to make sure that after an old file is moved to the next level, and new data is merged from the upper level, the new data falling into this range isn't reset with old timestamp. Without this change, in many cases, most files from one level will keep having old timestamp, even if they have newer data and we stuck in it. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8749 Test Plan: Add a unit test to test the boosting logic. Will add a unit test to test it end-to-end. Reviewed By: jay-zhuang Differential Revision: D30735261 fbshipit-source-id: 503c2d89250b22911eb99e72b379be154de3428e	3 years ago
Peter Dillinger	3ffb3baa0b	Add (Live)FileStorageInfo API (#8968) ... Summary: New classes FileStorageInfo and LiveFileStorageInfo and 'experimental' function DB::GetLiveFilesStorageInfo, which is intended to largely replace several fragmented DB functions needed to create checkpoints and backups. This function is now used to create checkpoints and backups, because it fixes many (probably not all) of the prior complexities of checkpoint not having atomic access to DB metadata. This also ensures strong functional test coverage of the new API. Specifically, much of the old CheckpointImpl::CreateCustomCheckpoint has been migrated to and updated in DBImpl::GetLiveFilesStorageInfo, with the former now calling the latter. Also, the class FileStorageInfo in metadata.h compatibly replaces BackupFileInfo and serves as a new base class for SstFileMetaData. Some old fields of SstFileMetaData are still provided (for now) but deprecated. Although FileStorageInfo::directory is accurate when using db_paths and/or cf_paths, these have never been supported by Checkpoint nor BackupEngine and still are not. This change does now detect these cases and return NotSupported when appropriate. (More work needed for support.) Somehow this change broke ProgressCallbackDuringBackup, but the progress_callback logic was dubious to begin with because it would call the callback based on copy buffer size, not size actually copied. Logic and test updated to track size actually copied per-thread. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8968 Test Plan: tests updated. DB::GetLiveFilesStorageInfo mostly tested by use in CheckpointImpl. DBTest.SnapshotFiles updated to also test GetLiveFilesStorageInfo, including reading the data after DB close. Added CheckpointTest.CheckpointWithDbPath (NotSupported). Reviewed By: siying Differential Revision: D31242045 Pulled By: pdillinger fbshipit-source-id: b183d1ce9799e220daaefd6b3b5365d98de676c0	3 years ago
Levi Tamasi	3e1bf771a3	Make it possible to force the garbage collection of the oldest blob files (#8994) ... Summary: The current BlobDB garbage collection logic works by relocating the valid blobs from the oldest blob files as they are encountered during compaction, and cleaning up blob files once they contain nothing but garbage. However, with sufficiently skewed workloads, it is theoretically possible to end up in a situation when few or no compactions get scheduled for the SST files that contain references to the oldest blob files, which can lead to increased space amp due to the lack of GC. In order to efficiently handle such workloads, the patch adds a new BlobDB configuration option called `blob_garbage_collection_force_threshold`, which signals to BlobDB to schedule targeted compactions for the SST files that keep alive the oldest batch of blob files if the overall ratio of garbage in the given blob files meets the threshold *and* all the given blob files are eligible for GC based on `blob_garbage_collection_age_cutoff`. (For example, if the new option is set to 0.9, targeted compactions will get scheduled if the sum of garbage bytes meets or exceeds 90% of the sum of total bytes in the oldest blob files, assuming all affected blob files are below the age-based cutoff.) The net result of these targeted compactions is that the valid blobs in the oldest blob files are relocated and the oldest blob files themselves cleaned up (since *all* SST files that rely on them get compacted away). These targeted compactions are similar to periodic compactions in the sense that they force certain SST files that otherwise would not get picked up to undergo compaction and also in the sense that instead of merging files from multiple levels, they target a single file. (Note: such compactions might still include neighboring files from the same level due to the need of having a "clean cut" boundary but they never include any files from any other level.) This functionality is currently only supported with the leveled compaction style and is inactive by default (since the default value is set to 1.0, i.e. 100%). Pull Request resolved: https://github.com/facebook/rocksdb/pull/8994 Test Plan: Ran `make check` and tested using `db_bench` and the stress/crash tests. Reviewed By: riversand963 Differential Revision: D31489850 Pulled By: ltamasi fbshipit-source-id: 44057d511726a0e2a03c5d9313d7511b3f0c4eab	3 years ago
Yanqin Jin	b92cef2d1d	Sort per-file blob read requests by offset (#8953) ... Summary: `RandomAccessFileReader::MultiRead()` tries to merge requests in direct IO, assuming input IO requests are sorted by offsets. Add a test in direct IO mode. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8953 Test Plan: make check Reviewed By: ltamasi Differential Revision: D31183546 Pulled By: riversand963 fbshipit-source-id: 5d043ec68e2daa47a3149066150afd41ee3d73e6	3 years ago
Yanqin Jin	b512f4bc76	Batch blob read IO for MultiGet (#8699) ... Summary: In batched `MultiGet()`, RocksDB batches blob read IO and uses `RandomAccessFileReader::MultiRead()` to read the blobs instead of issuing multiple `Read()`. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8699 Test Plan: ``` make check ``` Reviewed By: ltamasi Differential Revision: D31030861 Pulled By: riversand963 fbshipit-source-id: a0df6060cbfd54cff9515a4eee08807b1dbcb0c8	3 years ago
Levi Tamasi	306b779957	Use GetBlobFileSize instead of GetTotalBlobBytes in DB properties (#8902) ... Summary: The patch adjusts the definition of BlobDB's DB properties a bit by switching to `GetBlobFileSize` from `GetTotalBlobBytes`. The difference is that the value returned by `GetBlobFileSize` includes the blob file header and footer as well, and thus matches the on-disk size of blob files. In addition, the patch removes the `Version` number from the `blob_stats` property, and updates/extends the unit tests a little. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8902 Test Plan: `make check` Reviewed By: riversand963 Differential Revision: D30859542 Pulled By: ltamasi fbshipit-source-id: e3426d2d567bd1bd8c8636abdafaafa0743c854c	3 years ago
Zhiyi Zhang	0cb0fc6fd3	Add DB properties for BlobDB (#8734) ... Summary: RocksDB exposes certain internal statistics via the DB property interface. However, there are currently no properties related to BlobDB. For starters, we would like to add the following BlobDB properties: `rocksdb.num-blob-files`: number of blob files in the current Version (kind of like `num-files-at-level` but note this is not per level, since blob files are not part of the LSM tree). `rocksdb.blob-stats`: this could return the total number and size of all blob files, and potentially also the total amount of garbage (in bytes) in the blob files in the current Version. `rocksdb.total-blob-file-size`: the total size of all blob files (as a blob counterpart for `total-sst-file-size`) of all Versions. `rocksdb.live-blob-file-size`: the total size of all blob files in the current Version. `rocksdb.estimate-live-data-size`: this is actually an existing property that we can extend so it considers blob files as well. When it comes to blobs, we actually have an exact value for live bytes. Namely, live bytes can be computed simply as total bytes minus garbage bytes, summed over the entire set of blob files in the Version. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8734 Test Plan: ``` ➜ rocksdb git:(new_feature_blobDB_properties) ./db_blob_basic_test [==========] Running 16 tests from 2 test cases. [----------] Global test environment set-up. [----------] 10 tests from DBBlobBasicTest [ RUN ] DBBlobBasicTest.GetBlob [ OK ] DBBlobBasicTest.GetBlob (12 ms) [ RUN ] DBBlobBasicTest.MultiGetBlobs [ OK ] DBBlobBasicTest.MultiGetBlobs (11 ms) [ RUN ] DBBlobBasicTest.GetBlob_CorruptIndex [ OK ] DBBlobBasicTest.GetBlob_CorruptIndex (10 ms) [ RUN ] DBBlobBasicTest.GetBlob_InlinedTTLIndex [ OK ] DBBlobBasicTest.GetBlob_InlinedTTLIndex (12 ms) [ RUN ] DBBlobBasicTest.GetBlob_IndexWithInvalidFileNumber [ OK ] DBBlobBasicTest.GetBlob_IndexWithInvalidFileNumber (9 ms) [ RUN ] DBBlobBasicTest.GenerateIOTracing [ OK ] DBBlobBasicTest.GenerateIOTracing (11 ms) [ RUN ] DBBlobBasicTest.BestEffortsRecovery_MissingNewestBlobFile [ OK ] DBBlobBasicTest.BestEffortsRecovery_MissingNewestBlobFile (13 ms) [ RUN ] DBBlobBasicTest.GetMergeBlobWithPut [ OK ] DBBlobBasicTest.GetMergeBlobWithPut (11 ms) [ RUN ] DBBlobBasicTest.MultiGetMergeBlobWithPut [ OK ] DBBlobBasicTest.MultiGetMergeBlobWithPut (14 ms) [ RUN ] DBBlobBasicTest.BlobDBProperties [ OK ] DBBlobBasicTest.BlobDBProperties (21 ms) [----------] 10 tests from DBBlobBasicTest (124 ms total) [----------] 6 tests from DBBlobBasicTest/DBBlobBasicIOErrorTest [ RUN ] DBBlobBasicTest/DBBlobBasicIOErrorTest.GetBlob_IOError/0 [ OK ] DBBlobBasicTest/DBBlobBasicIOErrorTest.GetBlob_IOError/0 (12 ms) [ RUN ] DBBlobBasicTest/DBBlobBasicIOErrorTest.GetBlob_IOError/1 [ OK ] DBBlobBasicTest/DBBlobBasicIOErrorTest.GetBlob_IOError/1 (10 ms) [ RUN ] DBBlobBasicTest/DBBlobBasicIOErrorTest.MultiGetBlobs_IOError/0 [ OK ] DBBlobBasicTest/DBBlobBasicIOErrorTest.MultiGetBlobs_IOError/0 (10 ms) [ RUN ] DBBlobBasicTest/DBBlobBasicIOErrorTest.MultiGetBlobs_IOError/1 [ OK ] DBBlobBasicTest/DBBlobBasicIOErrorTest.MultiGetBlobs_IOError/1 (10 ms) [ RUN ] DBBlobBasicTest/DBBlobBasicIOErrorTest.CompactionFilterReadBlob_IOError/0 [ OK ] DBBlobBasicTest/DBBlobBasicIOErrorTest.CompactionFilterReadBlob_IOError/0 (1011 ms) [ RUN ] DBBlobBasicTest/DBBlobBasicIOErrorTest.CompactionFilterReadBlob_IOError/1 [ OK ] DBBlobBasicTest/DBBlobBasicIOErrorTest.CompactionFilterReadBlob_IOError/1 (1013 ms) [----------] 6 tests from DBBlobBasicTest/DBBlobBasicIOErrorTest (2066 ms total) [----------] Global test environment tear-down [==========] 16 tests from 2 test cases ran. (2190 ms total) [ PASSED ] 16 tests. ``` Reviewed By: ltamasi Differential Revision: D30690849 Pulled By: Zhiyi-Zhang fbshipit-source-id: a7567319487ad76bd1a2e24bf143afdbbd9e4346	3 years ago
Baptiste Lemaire	c521a9ab2b	Retire superfluous functions introduced in earlier mempurge PRs. (#8558) ... Summary: The main challenge to make the memtable garbage collection prototype (nicknamed `mempurge`) was to not get rid of WAL files that contain unflushed (but mempurged) data. That was successfully guaranteed by not writing the VersionEdit to the MANIFEST file after a successful mempurge. By not writing VersionEdits to the `MANIFEST` file after a succesful mempurge operation, we do not change the earliest log file number that contains unflushed data: `cfd->GetLogNumber()` (`cfd->SetLogNumber()` is only called in `VersionSet::ProcessManifestWrites`). As a result, a number of functions introduced earlier just for the mempurge operation are not obscolete/redundant. (e.g.: `FlushJob::ExtractEarliestLogFileNumber`), and this PR aims at cleaning up all these now-unnecessary functions. In particular, we no longer need to store the earliest log file number in the `MemTable` struct itself. This PR therefore also reverts the `MemTable` struct to its original form. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8558 Test Plan: Already included in `db_flush_test.cc`. Reviewed By: anand1976 Differential Revision: D29764351 Pulled By: bjlemaire fbshipit-source-id: 0f43b260fa270251862512f397d3f24ee62e8437	3 years ago
Baptiste Lemaire	206845c057	Mempurge support for wal (#8528) ... Summary: In this PR, `mempurge` is made compatible with the Write Ahead Log: in case of recovery, the DB is now capable of recovering the data that was "mempurged" and kept in the `imm()` list of immutable memtables. The twist was to add a uint64_t to the `memtable` struct to store the number of the earliest log file containing entries from the `memtable`. When a `Flush` operation is replaced with a `MemPurge`, the `VersionEdit` (which usually contains the new min log file number to pick up for recovery and the level 0 file path of the newly created SST file) is no longer appended to the manifest log, and every time the `deleteWal` method is called, a check is made on the list of immutable memtables. This PR also includes a unit test that verifies that no data is lost upon Reopening of the database when the mempurge feature is activated. This extensive unit test includes two column families, with valid data contained in the imm() at time of "crash"/reopening (recovery). Pull Request resolved: https://github.com/facebook/rocksdb/pull/8528 Reviewed By: pdillinger Differential Revision: D29701097 Pulled By: bjlemaire fbshipit-source-id: 072a900fb6ccc1edcf5eef6caf88f3060238edf9	3 years ago
longlijian	ac3f3f3719	Eliminate compiler complaining, which the return type of the function… (#8498) ... Summary: … should be uint64_t. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8498 Reviewed By: jay-zhuang Differential Revision: D29605064 Pulled By: ajkr fbshipit-source-id: e431448ac9d8a37ae83679c4cc5732e29fe49de4	3 years ago
Levi Tamasi	d44ef2ed4d	Remove obsolete method VersionSet::VerifyCompactionFileConsistency (#8449) ... Summary: `VersionSet::VerifyCompactionFileConsistency` was superseded by the LSM tree consistency checks introduced in https://github.com/facebook/rocksdb/pull/6901, which are more comprehensive, more efficient, and are performed unconditionally even in release builds. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8449 Test Plan: `make check` Reviewed By: ajkr Differential Revision: D29337441 Pulled By: ltamasi fbshipit-source-id: a05324f88e3400e27e6a00406c878a6276e0c9cc	3 years ago
mrambacher	d5bd0039b9	Rename ImmutableOptions variables (#8409) ... Summary: This is the next part of the ImmutableOptions cleanup. After changing the use of ImmutableCFOptions to ImmutableOptions, there were places in the code that had did something like "ImmutableOptions* immutable_cf_options", where "cf" referred to the "old" type. This change simply renames the variables to match the current type. No new functionality is introduced. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8409 Reviewed By: pdillinger Differential Revision: D29166248 Pulled By: mrambacher fbshipit-source-id: 96de97f8e743f5c5160f02246e3ed8269556dc6f	3 years ago
Zhichao Cao	f44e69c64a	Use DbSessionId as cache key prefix when secondary cache is enabled (#8360) ... Summary: Currently, we either use the file system inode or a monotonically incrementing runtime ID as the block cache key prefix. However, if we use a monotonically incrementing runtime ID (in the case that the file system does not support inode id generation), in some cases, it cannot ensure uniqueness (e.g., we have secondary cache migrated from host to host). We use DbSessionID (20 bytes) + current file number (at most 10 bytes) as the new cache block key prefix when the secondary cache is enabled. So can accommodate scenarios such as transfer of cache state across hosts. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8360 Test Plan: add the test to lru_cache_test Reviewed By: pdillinger Differential Revision: D29006215 Pulled By: zhichao-cao fbshipit-source-id: 6cff686b38d83904667a2bd39923cd030df16814	3 years ago
mrambacher	8948dc8524	Make ImmutableOptions struct that inherits from ImmutableCFOptions and ImmutableDBOptions (#8262) ... Summary: The ImmutableCFOptions contained a bunch of fields that belonged to the ImmutableDBOptions. This change cleans that up by introducing an ImmutableOptions struct. Following the pattern of Options struct, this class inherits from the DB and CFOption structs (of the Immutable form). Only one structural change (the ImmutableCFOptions::fs was changed to a shared_ptr from a raw one) is in this PR. All of the other changes involve moving the member variables from the ImmutableCFOptions into the ImmutableOptions and changing member variables or function parameters as required for compilation purposes. Follow-on PRs may do a further clean-up of the code, such as renaming variables (such as "ImmutableOptions cf_options") and potentially eliminating un-needed function parameters (there is no longer a need to pass both an ImmutableDBOptions and an ImmutableOptions to a function). Pull Request resolved: https://github.com/facebook/rocksdb/pull/8262 Reviewed By: pdillinger Differential Revision: D28226540 Pulled By: mrambacher fbshipit-source-id: 18ae71eadc879dedbe38b1eb8e6f9ff5c7147dbf	4 years ago
Yanqin Jin	b0e20194ea	Handle blob files when options.best_efforts_recovery is true (#8180) ... Summary: If `options.best_efforts_recovery == true`, RocksDB currently tolerates missing table files and recovers to the latest version without missing table files (not considering WAL). It is necessary to handle blob files as well to make the feature more complete. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8180 Test Plan: make check Reviewed By: ltamasi Differential Revision: D27840556 Pulled By: riversand963 fbshipit-source-id: 041685d0dc2e7779ac4f0374c07a8a327704aa5e	4 years ago
mrambacher	3dff28cf9b	Use SystemClock* instead of std::shared_ptr<SystemClock> in lower level routines (#8033) ... Summary: For performance purposes, the lower level routines were changed to use a SystemClock* instead of a std::shared_ptr<SystemClock>. The shared ptr has some performance degradation on certain hardware classes. For most of the system, there is no risk of the pointer being deleted/invalid because the shared_ptr will be stored elsewhere. For example, the ImmutableDBOptions stores the Env which has a std::shared_ptr<SystemClock> in it. The SystemClock* within the ImmutableDBOptions is essentially a "short cut" to gain access to this constant resource. There were a few classes (PeriodicWorkScheduler?) where the "short cut" property did not hold. In those cases, the shared pointer was preserved. Using db_bench readrandom perf_level=3 on my EC2 box, this change performed as well or better than 6.17: 6.17: readrandom : 28.046 micros/op 854902 ops/sec; 61.3 MB/s (355999 of 355999 found) 6.18: readrandom : 32.615 micros/op 735306 ops/sec; 52.7 MB/s (290999 of 290999 found) PR: readrandom : 27.500 micros/op 871909 ops/sec; 62.5 MB/s (367999 of 367999 found) (Note that the times for 6.18 are prior to revert of the SystemClock). Pull Request resolved: https://github.com/facebook/rocksdb/pull/8033 Reviewed By: pdillinger Differential Revision: D27014563 Pulled By: mrambacher fbshipit-source-id: ad0459eba03182e454391b5926bf5cdd45657b67	4 years ago
Yanqin Jin	64517d184a	Make secondary instance use ManifestTailer (#7998) ... Summary: This PR - adds a class `ManifestTailer` that inherits from `VersionEditHandlerPointInTime`. `ManifestTailer::Iterate()` can be called multiple times to tail the primary instance's MANIFEST and apply the changes to the secondary, - updates the implementation of `ReactiveVersionSet::ReadAndApply` to use this class, - removes unused code in version_set.cc, - updates existing tests, e.g. removing deleted sync points from unit tests, - adds a new test to address the bug in https://github.com/facebook/rocksdb/issues/7815. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7998 Test Plan: make check Existing and newly-added tests in version_set_test.cc and db_secondary_test.cc Reviewed By: jay-zhuang Differential Revision: D26926641 Pulled By: riversand963 fbshipit-source-id: 8d4dd15db0ba863c213f743e33b5a207e948c980	4 years ago
Levi Tamasi	cb25bc1128	Update compaction statistics to include the amount of data read from blob files (#8022) ... Summary: The patch does the following: 1) Exposes the amount of data (number of bytes) read from blob files from `BlobFileReader::GetBlob` / `Version::GetBlob`. 2) Tracks the total number and size of blobs read from blob files during a compaction (due to garbage collection or compaction filter usage) in `CompactionIterationStats` and propagates this data to `InternalStats::CompactionStats` / `CompactionJobStats`. 3) Updates the formulae for write amplification calculations to include the amount of data read from blob files. 4) Extends the compaction stats dump with a new column `Rblob(GB)` and a new line containing the total number and size of blob files in the current `Version` to complement the information about the shape and size of the LSM tree that's already there. 5) Updates `CompactionJobStats` so that the number of files and amount of data written by a compaction are broken down per file type (i.e. table/blob file). Pull Request resolved: https://github.com/facebook/rocksdb/pull/8022 Test Plan: Ran `make check` and `db_bench`. Reviewed By: riversand963 Differential Revision: D26801199 Pulled By: ltamasi fbshipit-source-id: 28a5f072048a702643b28cb5971b4099acabbfb2	4 years ago
mrambacher	12f1137355	Add a SystemClock class to capture the time functions of an Env (#7858) ... Summary: Introduces and uses a SystemClock class to RocksDB. This class contains the time-related functions of an Env and these functions can be redirected from the Env to the SystemClock. Many of the places that used an Env (Timer, PerfStepTimer, RepeatableThread, RateLimiter, WriteController) for time-related functions have been changed to use SystemClock instead. There are likely more places that can be changed, but this is a start to show what can/should be done. Over time it would be nice to migrate most (if not all) of the uses of the time functions from the Env to the SystemClock. There are several Env classes that implement these functions. Most of these have not been converted yet to SystemClock implementations; that will come in a subsequent PR. It would be good to unify many of the Mock Timer implementations, so that they behave similarly and be tested similarly (some override Sleep, some use a MockSleep, etc). Additionally, this change will allow new methods to be introduced to the SystemClock (like https://github.com/facebook/rocksdb/issues/7101 WaitFor) in a consistent manner across a smaller number of classes. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7858 Reviewed By: pdillinger Differential Revision: D26006406 Pulled By: mrambacher fbshipit-source-id: ed10a8abbdab7ff2e23d69d85bd25b3e7e899e90	4 years ago
Cheng Chang	fbce7a3808	Track WAL obsoletion when updating empty CF's log number (#7781) ... Summary: In the write path, there is an optimization: when a new WAL is created during SwitchMemtable, we update the internal log number of the empty column families to the new WAL. `FindObsoleteFiles` marks a WAL as obsolete if the WAL's log number is less than `VersionSet::MinLogNumberWithUnflushedData`. After updating the empty column families' internal log number, `VersionSet::MinLogNumberWithUnflushedData` might change, so some WALs might become obsolete to be purged from disk. For example, consider there are 3 column families: 0, 1, 2: 1. initially, all the column families' log number is 1; 2. write some data to cf0, and flush cf0, but the flush is pending; 3. now a new WAL 2 is created; 4. write data to cf1 and WAL 2, now cf0's log number is 1, cf1's log number is 2, cf2's log number is 2 (because cf1 and cf2 are empty, so their log numbers will be set to the highest log number); 5. now cf0's flush hasn't finished, flush cf1, a new WAL 3 is created, and cf1's flush finishes, now cf0's log number is 1, cf1's log number is 3, cf2's log number is 3, since WAL 1 still contains data for the unflushed cf0, no WAL can be deleted from disk; 6. now cf0's flush finishes, cf0's log number is 2 (because when cf0 was switching memtable, WAL 3 does not exist yet), cf1's log number is 3, cf2's log number is 3, so WAL 1 can be purged from disk now, but WAL 2 still cannot because `MinLogNumberToKeep()` is 2; 7. write data to cf2 and WAL 3, because cf0 is empty, its log number is updated to 3, so now cf0's log number is 3, cf1's log number is 3, cf2's log number is 3; 8. now if the background threads want to purge obsolete files from disk, WAL 2 can be purged because `MinLogNumberToKeep()` is 3. But there are only two flush results written to MANIFEST: the first is for flushing cf1, and the `MinLogNumberToKeep` is 1, the second is for flushing cf0, and the `MinLogNumberToKeep` is 2. So without this PR, if the DB crashes at this point and try to recover, `WalSet` will still expect WAL 2 to exist. When WAL tracking is enabled, we assume WALs will only become obsolete after a flush result is written to MANIFEST in `MemtableList::TryInstallMemtableFlushResults` (or its atomic flush counterpart). The above situation breaks this assumption. This PR tracks WAL obsoletion if necessary before updating the empty column families' log numbers. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7781 Test Plan: watch existing tests and stress tests to pass. `make -j48 blackbox_crash_test` on devserver Reviewed By: ltamasi Differential Revision: D25631695 Pulled By: cheng-chang fbshipit-source-id: ca7fff967bdb42204b84226063d909893bc0a4ec	4 years ago
Levi Tamasi	1afbd1948c	Add initial blob support to batched MultiGet (#7766) ... Summary: The patch adds initial support for reading blobs to the batched `MultiGet` API. The current implementation simply retrieves the blob values as the blob indexes are encountered; that is, reads from blob files are currently not batched. (This will be optimized in a separate phase.) In addition, the patch removes some dead code related to BlobDB from the batched `MultiGet` implementation, namely the `is_blob` / `is_blob_index` flags that are passed around in `DBImpl` and `MemTable` / `MemTableListVersion`. These were never hooked up to anything and wouldn't work anyways, since a single flag is not sufficient to communicate the "blobness" of multiple key-values. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7766 Test Plan: `make check` Reviewed By: jay-zhuang Differential Revision: D25479290 Pulled By: ltamasi fbshipit-source-id: 7aba2d290e31876ee592bcf1adfd1018713a8000	4 years ago
Cheng Chang	80159f6e0b	Carry over min_log_number_to_keep_2pc in new MANIFEST (#7747) ... Summary: When two phase commit is enabled, `VersionSet::min_log_number_to_keep_2pc` is set during flush. But when a new MANIFEST is created, the `min_log_number_to_keep_2pc` is not carried over to the new MANIFEST. So if a new MANIFEST is created and then DB is reopened, the `min_log_number_to_keep_2pc` will be lost. This may cause DB recovery errors. The bug is reproduced in a new unit test in `version_set_test.cc`. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7747 Test Plan: The new unit test in `version_set_test.cc` should pass. Reviewed By: jay-zhuang Differential Revision: D25350661 Pulled By: cheng-chang fbshipit-source-id: eee890d5b19f15769069670692e270ae31044ece	4 years ago
Cheng Chang	efe827baf0	Always track WAL obsoletion (#7759) ... Summary: Currently, when a WAL becomes obsolete after flushing, if VersionSet::WalSet does not contain the WAL, we do not track the WAL obsoletion event in MANIFEST. But consider this case: * WAL 10 is synced, a VersionEdit is LogAndApplied to MANIFEST to log this WAL addition event, but the VersionEdit is not applied to WalSet yet since its corresponding ManifestWriter is still pending in the write queue; * Since the above ManifestWriter is blocking, the LogAndApply will block on a conditional variable and release the db mutex, so another LogAndApply can proceed to enqueue other VersionEdits concurrently; * Now flush happens, and WAL 10 becomes obsolete, although WalSet does not contain WAL 10 yet, we should call LogAndApply to enqueue a VersionEdit to indicate the obsoletion of WAL 10; * otherwise, when the queued edit indicating WAL 10 addition is logged to MANIFEST, and DB crashes and reopens, the WAL 10 might have been removed from disk, but it still exists in MANIFEST. This PR changes the behavior to: always `LogAndApply` any WAL addition or obsoletion event, without considering the order issues caused by concurrency, but when applying the edits to `WalSet`, do not add the WALs if they are already obsolete. In this approach, the logical events of WAL addition and obsoletion are always tracked in MANIFEST, so we can inspect the MANIFEST and know all the previous WAL events, but we choose to ignore certain events due to the concurrency issues such as the case above, or the case in https://github.com/facebook/rocksdb/pull/7725. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7759 Test Plan: make check Reviewed By: pdillinger Differential Revision: D25423089 Pulled By: cheng-chang fbshipit-source-id: 9cb9a7fbc1875bf954f2a42f9b6cfd6d49a7b21c	4 years ago
Cheng Chang	07030c6f4a	Do not track obsolete WALs in MANIFEST even if they are synced (#7725) ... Summary: Consider the case: 1. All column families are flushed, so all WALs become obsolete, but no WAL is removed from disk yet because the removal is asynchronous, a VersionEdit is written to MANIFEST indicating that WALs before a certain WAL number are obsolete, let's say this number is 3; 2. `SyncWAL` is called, so all the on-disk WALs are synced, and if track_and_verify_wal_in_manifest=true, the WALs will be tracked in MANIFEST, let's say the WAL numbers are 1 and 2; 3. DB crashes; 4. During DB recovery, when replaying MANIFEST, we first see that WAL with number < 3 are obsolete, then we see that WAL 1 and 2 are synced, so according to current implementation of `WalSet`, the `WalSet` will be recovered to include WAL 1 and 2; 5. WAL 1 and 2 are asynchronously deleted from disk, then the WAL verification algorithm fails with `Corruption: missing WAL`. The above case is reproduced in a new unit test `DBBasicTestTrackWal::DoNotTrackObsoleteWal`. The fix is to maintain the upper bound of the obsolete WAL numbers, any WAL with number less than the maintained number is considered to be obsolete, so shouldn't be tracked even if they are later synced. The number is maintained in `WalSet`. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7725 Test Plan: 1. a new unit test `DBBasicTestTrackWal::DoNotTrackObsoleteWal` is added. 2. run `make crash_test` on devserver. Reviewed By: riversand963 Differential Revision: D25238914 Pulled By: cheng-chang fbshipit-source-id: f5dccd57c3d89f19565ec5731f2d42f06d272b72	4 years ago
Yanqin Jin	eee0af9af1	Add full_history_ts_low to column family (#7740) ... Summary: Following https://github.com/facebook/rocksdb/issues/7655 and https://github.com/facebook/rocksdb/issues/7657, this PR adds `full_history_ts_low_` to `ColumnFamilyData`. `ColumnFamilyData::full_history_ts_low_` will be used to create `FlushJob` and `CompactionJob`. `ColumnFamilyData::full_history_ts_low` is persisted to the MANIFEST file. An application can only increase its value. Consider the following case: > > The database has a key at ts=950. `full_history_ts_low` is first set to 1000, and then a GC is triggered > and cleans up all data older than 1000. If the application sets `full_history_ts_low` to 900 afterwards, > and tries to read at ts=960, the key at 950 is not seen. From the perspective of the read, the result > is hard to reason. For simplicity, we just do now allow decreasing full_history_ts_low for now. > During recovery, the value of `full_history_ts_low` is restored for each column family if applicable. Note that version edits in the MANIFEST file for the same column family may have `full_history_ts_low` unsorted due to the potential interleaving of `LogAndApply` calls. Only the max will be used to restore the state of the column family. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7740 Test Plan: make check Reviewed By: ltamasi Differential Revision: D25296217 Pulled By: riversand963 fbshipit-source-id: 24acda1df8262cd7cfdc6ce7b0ec56438abe242a	4 years ago
Levi Tamasi	61932cdf1d	Add blob support to DBIter (#7731) ... Summary: The patch adds iterator support to the integrated BlobDB implementation. Whenever a blob reference is encountered during iteration, the corresponding blob is retrieved by calling `Version::GetBlob`, assuming the `expose_blob_index` (formerly `allow_blob`) flag is *not* set. (Note: the flag is set by the old stacked BlobDB implementation, which has its own blob file handling/blob retrieval logic.) In addition, `DBIter` now uniformly returns `Status::NotSupported` with the error message `"BlobDB does not support merge operator."` when encountering a blob reference while performing a merge (instead of potentially returning a message that implies the database should be opened using the stacked BlobDB's `Open`.) TODO: We can implement support for lazily retrieving the blob value (or in other words, bypassing the retrieval of blob values based on key) by extending the `Iterator` API with a new `PrepareValue` method (similarly to `InternalIterator`, which already supports lazy values). Pull Request resolved: https://github.com/facebook/rocksdb/pull/7731 Test Plan: `make check` Reviewed By: riversand963 Differential Revision: D25256293 Pulled By: ltamasi fbshipit-source-id: c39cd782011495a526cdff99c16f5fca400c4811	4 years ago
Levi Tamasi	51a8dc6d14	Integrated blob garbage collection: relocate blobs (#7694) ... Summary: The patch adds basic garbage collection support to the integrated BlobDB implementation. Valid blobs residing in the oldest blob files are relocated as they are encountered during compaction. The threshold that determines which blob files qualify is computed based on the configuration option `blob_garbage_collection_age_cutoff`, which was introduced in https://github.com/facebook/rocksdb/issues/7661 . Once a blob is retrieved for the purposes of relocation, it passes through the same logic that extracts large values to blob files in general. This means that if, for instance, the size threshold for key-value separation (`min_blob_size`) got changed or writing blob files got disabled altogether, it is possible for the value to be moved back into the LSM tree. In particular, one way to re-inline all blob values if needed would be to perform a full manual compaction with `enable_blob_files` set to `false`, `enable_blob_garbage_collection` set to `true`, and `blob_file_garbage_collection_age_cutoff` set to `1.0`. Some TODOs that I plan to address in separate PRs: 1) We'll have to measure the amount of new garbage in each blob file and log `BlobFileGarbage` entries as part of the compaction job's `VersionEdit`. (For the time being, blob files are cleaned up solely based on the `oldest_blob_file_number` relationships.) 2) When compression is used for blobs, the compression type hasn't changed, and the blob still qualifies for being written to a blob file, we can simply copy the compressed blob to the new file instead of going through decompression and compression. 3) We need to update the formula for computing write amplification to account for the amount of data read from blob files as part of GC. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7694 Test Plan: `make check` Reviewed By: riversand963 Differential Revision: D25069663 Pulled By: ltamasi fbshipit-source-id: bdfa8feb09afcf5bca3b4eba2ba72ce2f15cd06a	4 years ago
Cheng Chang	8c93b16f02	Track WAL in MANIFEST: Update logic for computing min_log_number_to_keep in atomic flush (#7660) ... Summary: The logic for computing min_log_number_to_keep in atomic flush was incorrect. For example, when all column families are flushed, the min_log_number_to_keep should be the latest new log. But the incorrect logic calls `PrecomputeMinLogNumberToKeepNon2PC` for each column family, and returns the minimum of them. However, `PrecomputeMinLogNumberToKeepNon2PC(cf)` assumes column families other than `cf` are flushed, but in case all column families are flushed, this assumption is incorrect. Without this fix, the WAL referenced by the computed min_log_number_to_keep may actually contain no unflushed data, so the WAL might have actually been deleted from disk on recovery, then an incorrect error `Corruption: missing WAL` will be reported. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7660 Test Plan: run `make crash_test_with_atomic_flush` on devserver added a unit test in `db_flush_test` Reviewed By: riversand963 Differential Revision: D24906265 Pulled By: cheng-chang fbshipit-source-id: 08deda62e71f67f59e3b7925cdd86dd09bd4f430	4 years ago
Yanqin Jin	8b6b6aeb1a	Refactor with VersionEditHandler (#6581) ... Summary: Added a few classes in the same class hierarchy to remove code duplication and refactor the logic of reading and processing MANIFEST files. New classes are as follows. ``` class VersionEditHandlerBase; class ListColumnFamiliesHandler : VersionEditHandlerBase; class FileChecksumRetriever : VersionEditHandlerBase; class DumpManifestHandler : VersionEditHandler; ``` Classes that already existed before this PR are as follows. ``` class VersionEditHandler : VersionEditHandlerBase; ``` With these classes, refactored functions: `VersionSet::Recover()`, `VersionSet::ListColumnFamilies()`, `VersionSet::DumpManifest()`, `GetFileChecksumFromManifest()`. Test Plan (devserver): ``` make check COMPILE_WITH_ASAN=1 make check ``` These refactored code, especially recovery-related logic, will be tested intensively by all existing unit tests and stress tests. For example, run ``` make crash_test ``` Verified 3 successful runs on devserver. Pull Request resolved: https://github.com/facebook/rocksdb/pull/6581 Reviewed By: ajkr Differential Revision: D20616217 Pulled By: riversand963 fbshipit-source-id: 048c7743aa4be2623ccd0cc3e61c0027e604e78b	4 years ago
Yanqin Jin	6134ce6444	Perform post-flush updates of memtable list in a callback (#6069) ... Summary: Currently, the following interleaving of events can lead to SuperVersion containing both immutable memtables as well as the resulting L0. This can cause Get to return incorrect result if there are merge operands. This may also affect other operations such as single deletes. ``` time main_thr bg_flush_thr bg_compact_thr compact_thr set_opts_thr 0 | WriteManifest:0 1 | issue compact 2 | wait 3 | Merge(counter) 4 | issue flush 5 | wait 6 | WriteManifest:1 7 | wake up 8 | write manifest 9 | wake up 10 | Get(counter) 11 | remove imm V ``` The reason behind is that: one bg flush thread's installing new `Version` can be batched and performed by another thread that is the "leader" MANIFEST writer. This bg thread removes the memtables from current super version only after `LogAndApply` returns. After the leader MANIFEST writer signals (releasing mutex) this bg flush thread, it is possible that another thread sees this cf with both memtables (whose data have been flushed to the newest L0) and the L0 before this bg flush thread removes the memtables. To address this issue, each bg flush thread can pass a callback function to `LogAndApply`. The callback is responsible for removing the memtables. Therefore, the leader MANIFEST writer can call this callback and remove the memtables before releasing the mutex. Test plan (devserver) ``` $make merge_test $./merge_test --gtest_filter=MergeTest.MergeWithCompactionAndFlush $make check ``` Pull Request resolved: https://github.com/facebook/rocksdb/pull/6069 Reviewed By: cheng-chang Differential Revision: D18790894 Pulled By: riversand963 fbshipit-source-id: e41bd600c0448b4f4b2deb3f7677f95e3076b4ed	4 years ago
Cheng Chang	1b224324b5	Track WAL in MANIFEST: persist WALs to and recover WALs from MANIFEST (#7256) ... Summary: This PR makes it able to `LogAndApply` `VersionEdit`s related to WALs, and also be able to `Recover` from MANIFEST with WAL related `VersionEdit`s. The `VersionEdit`s related to WAL are treated similarly as those related to column family operations, they are not applied to versions, but can be in a commit group. Mixing WAL related `VersionEdit`s with other types of edits will make logic in `ProcessManifestWrite` more complicated, so `VersionEdit`s related to WAL can either be WAL additions or deletions, like column family add and drop. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7256 Test Plan: a set of unit tests are added in `version_set_test.cc` Reviewed By: riversand963 Differential Revision: D23123238 Pulled By: cheng-chang fbshipit-source-id: 246be2ed4744fd03fa2738aba408aaa611d0379c	4 years ago
Levi Tamasi	e8cb32ed67	Introduce BlobFileCache and add support for blob files to Get() (#7540) ... Summary: The patch adds blob file support to the `Get` API by extending `Version` so that whenever a blob reference is read from a file, the blob is retrieved from the corresponding blob file and passed back to the caller. (This is assuming the blob reference is valid and the blob file is actually part of the given `Version`.) It also introduces a cache of `BlobFileReader`s called `BlobFileCache` that enables sharing `BlobFileReader`s between callers. `BlobFileCache` uses the same backing cache as `TableCache`, so `max_open_files` (if specified) limits the total number of open (table + blob) files. TODO: proactively open/cache blob files and pin the cache handles of the readers in the metadata objects similarly to what `VersionBuilder::LoadTableHandlers` does for table files. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7540 Test Plan: `make check` Reviewed By: riversand963 Differential Revision: D24260219 Pulled By: ltamasi fbshipit-source-id: a8a2a4f11d3d04d6082201b52184bc4d7b0857ba	4 years ago