11 Commits (b6ad0d958f3a9765f4c970b574e18afe44fa62da)

Author	SHA1	Message	Date
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
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
Akanksha Mahajan	04b2c16f9b	Fix bug in rocksdb internal automatic prefetching (#9234) ... Summary: After introducing adaptive_readahead, the original flow got broken. Readahead size was set to 0 because of which rocksdb wasn't be able to do automatic prefetching which it enables after seeing sequential reads. This PR fixes it. ---------------------------------------------------------------------------------------------------- Before this patch: b_bench -use_existing_db=true -db=/tmp/prefix_scan -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 6.27 Date: Tue Nov 30 11:56:50 2021 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 WARNING: Assertions are enabled; benchmarks unnecessarily slow ------------------------------------------------ DB path: [/tmp/prefix_scan] seekrandom : 5356367.174 micros/op 0 ops/sec; 29.4 MB/s (23 of 23 found) ---------------------------------------------------------------------------------------------------- After the patch: ./db_bench -use_existing_db=true -db=/tmp/prefix_scan -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 6.27 Date: Tue Nov 30 14:38:33 2021 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 WARNING: Assertions are enabled; benchmarks unnecessarily slow ------------------------------------------------ DB path: [/tmp/prefix_scan] seekrandom : 456504.277 micros/op 2 ops/sec; 359.8 MB/s (264 of 264 found) Pull Request resolved: https://github.com/facebook/rocksdb/pull/9234 Test Plan: Ran ./db_bench -db=/data/mysql/rocksdb/prefix_scan -benchmarks="fillseq" -key_size=32 -value_size=512 -num=5000000 -use_d irect_io_for_flush_and_compaction=true -target_file_size_base=16777216 and then ./db_bench -use_existing_db=true -db=/data/mysql/rocksdb/prefix_scan -benchmarks="seekrandom" -key_size=32 -value_siz e=512 -num=5000000 -use_direct_reads=true -seek_nexts=327680 -duration=120 -ops_between_duration_checks=1 and compared the results. Reviewed By: anand1976 Differential Revision: D32743965 Pulled By: akankshamahajan15 fbshipit-source-id: b950fba68c91963b7deb5c20acdf471bc60251f5	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
Akanksha Mahajan	17ce1ca48b	Reuse internal auto readhead_size at each Level (expect L0) for Iterations (#9056) ... Summary: RocksDB does auto-readahead for iterators on noticing more than two sequential reads for a table file if user doesn't provide readahead_size. The readahead starts at 8KB and doubles on every additional read up to max_auto_readahead_size. However at each level, if iterator moves over next file, readahead_size starts again from 8KB. This PR introduces a new ReadOption "adaptive_readahead" which when set true will maintain readahead_size at each level. So when iterator moves from one file to another, new file's readahead_size will continue from previous file's readahead_size instead of scratch. However if reads are not sequential it will fall back to 8KB (default) with no prefetching for that block. 1. If block is found in cache but it was eligible for prefetch (block wasn't in Rocksdb's prefetch buffer), readahead_size will decrease by 8KB. 2. It maintains readahead_size for L1 - Ln levels. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9056 Test Plan: Added new unit tests Ran db_bench for "readseq, seekrandom, seekrandomwhilewriting, readrandom" with --adaptive_readahead=true and there was no regression if new feature is enabled. Reviewed By: anand1976 Differential Revision: D31773640 Pulled By: akankshamahajan15 fbshipit-source-id: 7332d16258b846ae5cea773009195a5af58f8f98	3 years ago
Akanksha Mahajan	a0e0feca62	Improve BlockPrefetcher to prefetch only for sequential scans (#7394) ... Summary: BlockPrefetcher is used by iterators to prefetch data if they anticipate more data to be used in future and this is valid for forward sequential scans. But BlockPrefetcher tracks only num_file_reads_ and not if reads are sequential. This presents problem for MultiGet with large number of keys when it reseeks index iterator and data block. FilePrefetchBuffer can end up doing large readahead for reseeks as readahead size increases exponentially once readahead is enabled. Same issue is with BlockBasedTableIterator. Add previous length and offset read as well in BlockPrefetcher (creates FilePrefetchBuffer) and FilePrefetchBuffer (does prefetching of data) to determine if reads are sequential and then prefetch. Update the last block read after cache hit to take reads from cache also in account. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7394 Test Plan: Add new unit test case Reviewed By: anand1976 Differential Revision: D23737617 Pulled By: akankshamahajan15 fbshipit-source-id: 8e6917c25ed87b285ee495d1b68dc623d71205a3	4 years ago
Ziyue Yang	0c2d71edba	Fix typo: replace readadhead with readahead (#7953) ... Summary: This PR replaces several "readadhead" typos with "readahead". Pull Request resolved: https://github.com/facebook/rocksdb/pull/7953 Reviewed By: ajkr Differential Revision: D26518903 Pulled By: jay-zhuang fbshipit-source-id: 6f7dece0e39ec4f71c4a936399bcb2e02574f42a	4 years ago
anand76	01298c8ff7	Return Status from FilePrefetchBuffer::TryReadFromCache() (#7816) ... Summary: Return the Status from TryReadFromCache() in an argument to make it easier to report prefetch errors to the user. Tests: make crash_test make check Pull Request resolved: https://github.com/facebook/rocksdb/pull/7816 Reviewed By: akankshamahajan15 Differential Revision: D25717222 Pulled By: anand1976 fbshipit-source-id: c320d3c12d4146bda16df78ff6927eee584c1810	4 years ago
Anand Ananthabhotla	9a5886bd8c	Extend Get/MultiGet deadline support to table open (#6982) ... Summary: Current implementation of the ```read_options.deadline``` option only checks the deadline for random file reads during point lookups. This PR extends the checks to file opens, prefetches and preloads as part of table open. The main changes are in the ```BlockBasedTable```, partitioned index and filter readers, and ```TableCache``` to take ReadOptions as an additional parameter. In ```BlockBasedTable::Open```, in order to retain existing behavior w.r.t checksum verification and block cache usage, we filter out most of the options in ```ReadOptions``` except ```deadline```. However, having the ```ReadOptions``` gives us more flexibility to honor other options like verify_checksums, fill_cache etc. in the future. Additional changes in callsites due to function signature changes in ```NewTableReader()``` and ```FilePrefetchBuffer```. Pull Request resolved: https://github.com/facebook/rocksdb/pull/6982 Test Plan: Add new unit tests in db_basic_test Reviewed By: riversand963 Differential Revision: D22219515 Pulled By: anand1976 fbshipit-source-id: 8a3b92f4a889808013838603aa3ca35229cd501b	4 years ago
sdong	fdf882ded2	Replace namespace name "rocksdb" with ROCKSDB_NAMESPACE (#6433) ... Summary: When dynamically linking two binaries together, different builds of RocksDB from two sources might cause errors. To provide a tool for user to solve the problem, the RocksDB namespace is changed to a flag which can be overridden in build time. Pull Request resolved: https://github.com/facebook/rocksdb/pull/6433 Test Plan: Build release, all and jtest. Try to build with ROCKSDB_NAMESPACE with another flag. Differential Revision: D19977691 fbshipit-source-id: aa7f2d0972e1c31d75339ac48478f34f6cfcfb3e	5 years ago
sdong	b931f84e56	Divide file_reader_writer.h and .cc (#5803) ... Summary: file_reader_writer.h and .cc contain several files and helper function, and it's hard to navigate. Separate it to multiple files and put them under file/ Pull Request resolved: https://github.com/facebook/rocksdb/pull/5803 Test Plan: Build whole project using make and cmake. Differential Revision: D17374550 fbshipit-source-id: 10efca907721e7a78ed25bbf74dc5410dea05987	5 years ago