1530 Commits (846db9d7b1d03cdce467a75e534e3e5f9aea2425)

Author	SHA1	Message	Date
Changyu Bi	1f410ff95f	Make `rocksdb_options_add_compact_on_deletion_collector_factory` backward compatible (#11593) ... Summary: https://github.com/facebook/rocksdb/issues/11542 added a parameter to the C API `rocksdb_options_add_compact_on_deletion_collector_factory` which causes some internal builds to fail. External users using this API would also require code change. Making the API backward compatible by restoring the old C API and add the parameter to a new C API `rocksdb_options_add_compact_on_deletion_collector_factory_del_ratio`. Also updated change log for 8.4 and will backport this change to 8.4 branch once landed. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11593 Test Plan: `make c_test && ./c_test` Reviewed By: akankshamahajan15 Differential Revision: D47299555 Pulled By: cbi42 fbshipit-source-id: 517dc093ef4cf02cac2fe4af4f1af13754bbda63	1 year ago
akankshamahajan	94c247bff8	Update HISTORY.md for branch cut for 8.4.fb (#11565) ... Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/11565 Reviewed By: jowlyzhang, cbi42 Differential Revision: D47027788 Pulled By: akankshamahajan15 fbshipit-source-id: e5e8db2eb21f8aa68fe072f0e1b63b83ba7beb9f	1 year ago
Peter Dillinger	8848ec92dd	Better management of unreleased HISTORY (#11481) ... Summary: See new NOTE in HISTORY.md and unreleased_history/README.txt Pull Request resolved: https://github.com/facebook/rocksdb/pull/11481 Test Plan: some manual testing on my CentOS 8 system Reviewed By: jaykorean Differential Revision: D46233342 Pulled By: pdillinger fbshipit-source-id: daf59cf3dc907f450b469090dcc481a30a7d7c0d	1 year ago
anand76	fcc358baf2	Integrate CacheReservationManager with compressed secondary cache (#11449) ... Summary: This draft PR implements charging of reserved memory, for write buffers, table readers, and other purposes, proportionally to the block cache and the compressed secondary cache. The basic flow of memory reservation is maintained - clients use ```CacheReservationManager``` to request reservations, and ```CacheReservationManager``` inserts placeholder entries, i.e null value and non-zero charge, into the block cache. The ```CacheWithSecondaryAdapter``` wrapper uses its own instance of ```CacheReservationManager``` to keep track of reservations charged to the secondary cache, while the placeholder entries are inserted into the primary block cache. The design is as follows. When ```CacheWithSecondaryAdapter``` is constructed with the ```distribute_cache_res``` parameter set to true, it manages the entire memory budget across the primary and secondary cache. The secondary cache is assumed to be in memory, such as the ```CompressedSecondaryCache```. When a placeholder entry is inserted by a CacheReservationManager instance to reserve memory, the ```CacheWithSecondaryAdapter```ensures that the reservation is distributed proportionally across the primary/secondary caches. The primary block cache is initially sized to the sum of the primary cache budget + the secondary cache budget, as follows - |--------- Primary Cache Configured Capacity -----------| |---Secondary Cache Budget----|----Primary Cache Budget-----| A ```ConcurrentCacheReservationManager``` member in the ```CacheWithSecondaryAdapter```, ```pri_cache_res_```, is used to help with tracking the distribution of memory reservations. Initially, it accounts for the entire secondary cache budget as a reservation against the primary cache. This shrinks the usable capacity of the primary cache to the budget that the user originally desired. |--Reservation for Sec Cache--|-Pri Cache Usable Capacity---| When a reservation placeholder is inserted into the adapter, it is inserted directly into the primary cache. This means the entire charge of the placeholder is counted against the primary cache. To compensate and count a portion of it against the secondary cache, the secondary cache ```Deflate()``` method is called to shrink it. Since the ```Deflate()``` causes the secondary actual usage to shrink, it is reflected here by releasing an equal amount from the ```pri_cache_res_``` reservation. For example, if the pri/sec ratio is 50/50, this would be the state after placeholder insertion - |-Reservation for Sec Cache-|-Pri Cache Usable Capacity-|-R-| Likewise, when the user inserted placeholder is released, the secondary cache ```Inflate()``` method is called to grow it, and the ```pri_cache_res_``` reservation is increased by an equal amount. Other alternatives - 1. Another way of implementing this would have been to simply split the user reservation in ```CacheWithSecondaryAdapter``` into primary and secondary components. However, this would require allocating a structure to track the associated secondary cache reservation, which adds some complexity and overhead. 2. Yet another option is to implement the splitting directly in ```CacheReservationManager```. However, there are multiple instances of ```CacheReservationManager``` in a DB instance, making it complicated to keep track of them. The PR contains the following changes - 1. A new cache allocator, ```NewTieredVolatileCache()```, is defined for allocating a tiered primary block cache and compressed secondary cache. This internally allocates an instance of ```CacheWithSecondaryAdapter```. 3. New interfaces, ```Deflate()``` and ```Inflate()```, are added to the ```SecondaryCache``` interface. The default implementaion returns ```NotSupported``` with overrides in ```CompressedSecondaryCache```. 4. The ```CompressedSecondaryCache``` uses a ```ConcurrentCacheReservationManager``` instance to manage reservations done using ```Inflate()/Deflate()```. 5. The ```CacheWithSecondaryAdapter``` optionally distributes memory reservations across the primary and secondary caches. The primary cache is sized to the total memory budget (primary + secondary), and the capacity allocated to secondary cache is "reserved" against the primary cache. For any subsequent reservations, the primary cache pre-reserved capacity is adjusted. Benchmarks - Baseline ``` time ~/rocksdb_anand76/db_bench --db=/dev/shm/comp_cache_res/base --use_existing_db=true --benchmarks="readseq,readwhilewriting" --key_size=32 --value_size=1024 --num=20000000 --threads=32 --bloom_bits=10 --cache_size=30000000000 --use_compressed_secondary_cache=true --compressed_secondary_cache_size=5000000000 --duration=300 --cost_write_buffer_to_cache=true ``` ``` readseq : 3.301 micros/op 9694317 ops/sec 66.018 seconds 640000000 operations; 9763.0 MB/s readwhilewriting : 22.921 micros/op 1396058 ops/sec 300.021 seconds 418846968 operations; 1405.9 MB/s (13068999 of 13068999 found) real 6m31.052s user 152m5.660s sys 26m18.738s ``` With TieredVolatileCache ``` time ~/rocksdb_anand76/db_bench --db=/dev/shm/comp_cache_res/base --use_existing_db=true --benchmarks="readseq,readwhilewriting" --key_size=32 --value_size=1024 --num=20000000 --threads=32 --bloom_bits=10 --cache_size=30000000000 --use_compressed_secondary_cache=true --compressed_secondary_cache_size=5000000000 --duration=300 --cost_write_buffer_to_cache=true --use_tiered_volatile_cache=true ``` ``` readseq : 4.064 micros/op 7873915 ops/sec 81.281 seconds 640000000 operations; 7929.7 MB/s readwhilewriting : 20.944 micros/op 1527827 ops/sec 300.020 seconds 458378968 operations; 1538.6 MB/s (14296999 of 14296999 found) real 6m42.743s user 157m58.972s sys 33m16.671 ``` ``` readseq : 3.484 micros/op 9184967 ops/sec 69.679 seconds 640000000 operations; 9250.0 MB/s readwhilewriting : 21.261 micros/op 1505035 ops/sec 300.024 seconds 451545968 operations; 1515.7 MB/s (14101999 of 14101999 found) real 6m31.469s user 155m16.570s sys 27m47.834s ``` ToDo - 1. Add to db_stress Pull Request resolved: https://github.com/facebook/rocksdb/pull/11449 Reviewed By: pdillinger Differential Revision: D46197388 Pulled By: anand1976 fbshipit-source-id: 42d16f0254df683db4929db20d06ff26030e90df	1 year ago
Andrew Kryczka	3e7fc88167	add WriteBatch::Release() (#11482) ... Summary: Together with the existing constructor, `explicit WriteBatch(std::string&& rep)`, this enables transferring `WriteBatch` via its `std::string` representation. Associated info like KV checksums are dropped but the caller can use `WriteBatch::VerifyChecksum()` before taking ownership if needed. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11482 Reviewed By: cbi42 Differential Revision: D46233884 Pulled By: ajkr fbshipit-source-id: 6bc64a6e75fb7bbf61d08c09520fc3705a7b44d8	1 year ago
Jay Huh	23f4e9ad63	Move WaitForCompect() change entry to Unreleased in History file (#11479) ... Summary: Context: Because of the branch cut, History change made it to the previous release. Moving entry to Unreleased Pull Request resolved: https://github.com/facebook/rocksdb/pull/11479 Test Plan: History change. Not needed. Reviewed By: pdillinger Differential Revision: D46226237 Pulled By: jaykorean fbshipit-source-id: 33e7d84a05db254d227f05d76038fc6d225dbabf	1 year ago
Jay Huh	81aeb15988	Add WaitForCompact with WaitForCompactOptions to public API (#11436) ... Summary: Context: This is the first PR for WaitForCompact() Implementation with WaitForCompactOptions. In this PR, we are introducing `Status WaitForCompact(const WaitForCompactOptions& wait_for_compact_options)` in the public API. This currently utilizes the existing internal `WaitForCompact()` implementation (with default abort_on_pause = false). `abort_on_pause` has been moved to `WaitForCompactOptions&`. In the later PRs, we will introduce the following two options in `WaitForCompactOptions` 1. `bool flush = false` by default - If true, flush before waiting for compactions to finish. Must be set to true to ensure no immediate compactions (except perhaps periodic compactions) after closing and re-opening the DB. 2. `bool close_db = false` by default - If true, will also close the DB upon compactions finishing. 1. struct `WaitForCompactOptions` added to options.h and `abort_on_pause` in the internal API moved to the option struct. 2. `Status WaitForCompact(const WaitForCompactOptions& wait_for_compact_options)` introduced in `db.h` 3. Changed the internal WaitForCompact() to `WaitForCompact(const WaitForCompactOptions& wait_for_compact_options)` and checks for the `abort_on_pause` inside the option. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11436 Test Plan: Following tests added - `DBCompactionTest::WaitForCompactWaitsOnCompactionToFinish` - `DBCompactionTest::WaitForCompactAbortOnPauseAborted` - `DBCompactionTest::WaitForCompactContinueAfterPauseNotAborted` - `DBCompactionTest::WaitForCompactShutdownWhileWaiting` - `TransactionTest::WaitForCompactAbortOnPause` NOTE: `TransactionTest::WaitForCompactAbortOnPause` was added to use `StackableDB` to ensure the wrapper function is in place. Reviewed By: pdillinger Differential Revision: D45799659 Pulled By: jaykorean fbshipit-source-id: b5b58f95957f2ab47d1221dee32a61d6cdc4685b	1 year ago
Hui Xiao	dcc6fc99f9	Fix StopWatch bug; Remove setting `record_read_stats` (#11474) ... Summary: **Context/Summary:** - StopWatch enable stats even when `StatsLevel::kExceptTimers` is set. It's a harmless bug though since `reportTimeToHistogram()` will not report it anyway according to https://github.com/facebook/rocksdb/blob/main/include/rocksdb/statistics.h#L705 - https://github.com/facebook/rocksdb/pull/11288 should have removed logics of setting `record_read_stats = !for_compaction` as we don't differentiate `RandomAccessFileReader`'s stats behavior based on compaction or not (instead we now report stats of different IO activities including compaction to different stats). Fixing this should report more compaction related file read micros that aren't reported previously due to `for_compaction==true` Pull Request resolved: https://github.com/facebook/rocksdb/pull/11474 Test Plan: - DB bench pre vs post fix with small max_open_files Setup command `./db_ bench -db=/dev/shm/testdb/ -statistics=true -benchmarks=fillseq -key_size=32 -value_size=512 -num=5000 -write_buffer_size=655 -target_file_size_base=655 -disable_auto_compactions=true -compression_type=none -bloom_bits=3` Run command `./db_bench --open_files=1 -use_existing_db=true -db=/dev/shm/testdb2/ -statistics=true -benchmarks=compactall -key_size=32 -value_size=512 -num=5000 -write_buffer_size=655 -target_file_size_base=655 -disable_auto_compactions=true -compression_type=none -bloom_bits=3` Pre-fix ``` rocksdb.sst.read.micros P50 : 2.056175 P95 : 4.647739 P99 : 8.948475 P100 : 25.000000 COUNT : 4451 SUM : 12827 rocksdb.file.read.flush.micros P50 : 0.000000 P95 : 0.000000 P99 : 0.000000 P100 : 0.000000 COUNT : 0 SUM : 0 rocksdb.file.read.compaction.micros P50 : 2.057397 P95 : 4.625253 P99 : 8.749474 P100 : 25.000000 COUNT : 4382 SUM : 12608 rocksdb.file.read.db.open.micros P50 : 1.985294 P95 : 9.100000 P99 : 13.000000 P100 : 13.000000 COUNT : 69 SUM : 219 ``` Post-fix (with a higher `rocksdb.file.read.compaction.micros` count) ``` rocksdb.sst.read.micros P50 : 1.858968 P95 : 3.653086 P99 : 5.968000 P100 : 21.000000 COUNT : 3548 SUM : 9119 rocksdb.file.read.flush.micros P50 : 0.000000 P95 : 0.000000 P99 : 0.000000 P100 : 0.000000 COUNT : 0 SUM : 0 rocksdb.file.read.compaction.micros P50 : 1.857027 P95 : 3.627614 P99 : 5.738621 P100 : 21.000000 COUNT : 3479 SUM : 8904 rocksdb.file.read.db.open.micros P50 : 2.000000 P95 : 6.733333 P99 : 11.000000 P100 : 11.000000 COUNT : 69 SUM : 215 ``` - CI Reviewed By: ajkr Differential Revision: D46137221 Pulled By: hx235 fbshipit-source-id: e5b4ee7001af26f2ee0377bc6334f43b2a527388	2 years ago
Peter Dillinger	17bc27741f	Improve memory efficiency of many OptimisticTransactionDBs (#11439) ... Summary: Currently it's easy to use a ton of memory with many small OptimisticTransactionDB instances, because each one by default allocates a million mutexes (40 bytes each on my compiler) for validating transactions. It even puts a lot of pressure on the allocator by allocating each one individually! In this change: * Create a new object and option that enables sharing these buckets of mutexes between instances. This is generally good for load balancing potential contention as various DBs become hotter or colder with txn writes. About the only cases where this sharing wouldn't make sense (e.g. each DB usually written by one thread) are cases that would be better off with OccValidationPolicy::kValidateSerial which doesn't use the buckets anyway. * Allocate the mutexes in a contiguous array, for efficiency * Add an option to ensure the mutexes are cache-aligned. In several other places we use cache-aligned mutexes but OptimisticTransactionDB historically does not. It should be a space-time trade-off the user can choose. * Provide some visibility into the memory used by the mutex buckets with an ApproximateMemoryUsage() function (also used in unit testing) * Share code with other users of "striped" mutexes, appropriate refactoring for customization & efficiency (e.g. using FastRange instead of modulus) Pull Request resolved: https://github.com/facebook/rocksdb/pull/11439 Test Plan: unit tests added. Ran sized-up versions of stress test in unit test, including a before-and-after performance test showing no consistent difference. (NOTE: OptimisticTransactionDB not currently covered by db_stress!) Reviewed By: ltamasi Differential Revision: D45796393 Pulled By: pdillinger fbshipit-source-id: ae2b3a26ad91ceeec15debcdc63ff48df6736a54	2 years ago
Yu Zhang	509116c53b	Update HISTORY.md/version.h/format compatiblity test for 8.3 release (#11464) ... Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/11464 Reviewed By: akankshamahajan15 Differential Revision: D46041333 Pulled By: jowlyzhang fbshipit-source-id: 7d83cf9e611451fcc7f7e4a837681ed0d4271df4	2 years ago
Peter Dillinger	39f5846ec7	Much better stats for seeks and prefix filtering (#11460) ... Summary: We want to know more about opportunities for better range filters, and the effectiveness of our own range filters. Currently the stats are very limited, essentially logging just hits and misses against prefix filters for range scans in BLOOM_FILTER_PREFIX_* without tracking the false positive rate. Perhaps confusingly, when prefix filters are used for point queries, the stats are currently going into the non-PREFIX tickers. This change does several things: * Introduce new stat tickers for seeks and related filtering, \*LEVEL_SEEK\* * Most importantly, allows us to see opportunities for range filtering. Specifically, we can count how many times a seek in an SST file accesses at least one data block, and how many times at least one value() is then accessed. If a data block was accessed but no value(), we can generally assume that the key(s) seen was(were) not of interest so could have been filtered with the right kind of filter, avoiding the data block access. * We can get the same level of detail when a filter (for now, prefix Bloom/ribbon) is used, or not. Specifically, we can infer a false positive rate for prefix filters (not available before) from the seek "false positive" rate: when a data block is accessed but no value() is called. (There can be other explanations for a seek false positive, but in typical iterator usage it would indicate a filter false positive.) * For efficiency, I wanted to avoid making additional calls to the prefix extractor (or key comparisons, etc.), which would be required if we wanted to more precisely detect filter false positives. I believe that instrumenting value() is the best balance of efficiency vs. accurately measuring what we are often interested in. * The stats are divided between last level and non-last levels, to help understand potential tiered storage use cases. * The old BLOOM_FILTER_PREFIX_* stats have a different meaning: no longer referring to iterators but to point queries using prefix filters. BLOOM_FILTER_PREFIX_TRUE_POSITIVE is added for computing the prefix false positive rate on point queries, which can be due to filter false positives as well as different keys with the same prefix. * Similarly, the non-PREFIX BLOOM_FILTER stats are now for whole key filtering only. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11460 Test Plan: unit tests updated, including updating many to pop the stat value since last read to improve test readability and maintainability. Performance test shows a consistent small improvement with these changes, both with clang and with gcc. CPU profile indicates that RecordTick is using less CPU, and this makes sense at least for a high filter miss rate. Before, we were recording two ticks per filter miss in iterators (CHECKED & USEFUL) and now recording just one (FILTERED). Create DB with ``` TEST_TMPDIR=/dev/shm ./db_bench -benchmarks=fillrandom -num=10000000 -disable_wal=1 -write_buffer_size=30000000 -bloom_bits=8 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=10000 -fifo_compaction_allow_compaction=0 -prefix_size=8 ``` And run simultaneous before&after with ``` TEST_TMPDIR=/dev/shm ./db_bench -readonly -benchmarks=seekrandom[-X1000] -num=10000000 -bloom_bits=8 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=10000 -fifo_compaction_allow_compaction=0 -prefix_size=8 -seek_nexts=1 -duration=20 -seed=43 -threads=8 -cache_size=1000000000 -statistics ``` Before: seekrandom [AVG 275 runs] : 189680 (± 222) ops/sec; 18.4 (± 0.0) MB/sec After: seekrandom [AVG 275 runs] : 197110 (± 208) ops/sec; 19.1 (± 0.0) MB/sec Reviewed By: ajkr Differential Revision: D46029177 Pulled By: pdillinger fbshipit-source-id: cdace79a2ea548d46c5900b068c5b7c3a02e5822	2 years ago
mayue.fight	8d8eb0e77e	Support Clip DB to KeyRange (#11379) ... Summary: This PR is part of the request https://github.com/facebook/rocksdb/issues/11317. (Another part is https://github.com/facebook/rocksdb/pull/11378) ClipDB() will clip the entries in the CF according to the range [begin_key, end_key). All the entries outside this range will be completely deleted (including tombstones). This feature is mainly used to ensure that there is no overlapping Key when calling CreateColumnFamilyWithImports() to import multiple CFs. When Calling ClipDB [begin, end), there are the following steps 1. Quickly and directly delete files without overlap DeleteFilesInRanges(nullptr, begin) + DeleteFilesInRanges(end, nullptr) 2. Delete the Key outside the range Delete[smallest_key, begin) + Delete[end, largest_key] 3. Delete the tombstone through Manul Compact CompactRange(option, nullptr, nullptr) Pull Request resolved: https://github.com/facebook/rocksdb/pull/11379 Reviewed By: ajkr Differential Revision: D45840358 Pulled By: cbi42 fbshipit-source-id: 54152e8a45fd8ede137f99787eb252f0b51440a4	2 years ago
Hui Xiao	50046869a4	Add `rocksdb.file.read.db.open.micros` (#11455) ... Summary: **Context/Summary:** `rocksdb.file.read.db.open.micros` is left out in https://github.com/facebook/rocksdb/pull/11288 Pull Request resolved: https://github.com/facebook/rocksdb/pull/11455 Test Plan: - db bench Setup: `./db_bench -db=/dev/shm/testdb/ -statistics=true -benchmarks="fillseq" -key_size=32 -value_size=512 -num=5000 -write_buffer_size=655 -target_file_size_base=655 -disable_auto_compactions=false -compression_type=none -bloom_bits=3` Run: `./db_bench --bloom_bits=3 --use_existing_db=1 --seed=1682546046158958 --partition_index_and_filters=1 --statistics=1 -db=/dev/shm/testdb/ -benchmarks=readrandom -key_size=3200 -value_size=512 -num=0 -write_buffer_size=6550000 -disable_auto_compactions=false -target_file_size_base=6550000 -compression_type=none -file_checksum=1 -cache_size=1` ``` rocksdb.sst.read.micros P50 : 3.979798 P95 : 9.738420 P99 : 19.566667 P100 : 39.000000 COUNT : 2360 SUM : 12148 rocksdb.file.read.flush.micros P50 : 0.000000 P95 : 0.000000 P99 : 0.000000 P100 : 0.000000 COUNT : 0 SUM : 0 rocksdb.file.read.compaction.micros P50 : 0.000000 P95 : 0.000000 P99 : 0.000000 P100 : 0.000000 COUNT : 0 SUM : 0 rocksdb.file.read.db.open.micros P50 : 3.979798 P95 : 9.738420 P99 : 19.566667 P100 : 39.000000 COUNT : 2360 SUM : 12148 ``` Reviewed By: ajkr Differential Revision: D45951934 Pulled By: hx235 fbshipit-source-id: 6c88639dc1b10d98ecccc963ce32a8800495f55b	2 years ago
anand76	2084cdf237	Delete temp OPTIONS file on failure to write it (#11423) ... Summary: When the DB is opened, RocksDB creates a temp OPTIONS file, writes the current options to it, and renames it. In case of a failure, the temp file is left behind, and is not deleted by PurgeObsoleteFiles(). Fix this by explicitly deleting the temp file if writing to it or renaming it fails. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11423 Test Plan: Add a unit test Reviewed By: akankshamahajan15 Differential Revision: D45540454 Pulled By: anand1976 fbshipit-source-id: 47facdc30d8cc5667036312d04b21d3fc253c92e	2 years ago
Andrew Kryczka	113f3250f1	Add block checksum mismatch ticker stat (#11438) ... Summary: Added a ticker stat, `BLOCK_CHECKSUM_MISMATCH_COUNT`, to count how many block checksum verifications detected a mismatch. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11438 Test Plan: new unit test Reviewed By: pdillinger Differential Revision: D45788179 Pulled By: ajkr fbshipit-source-id: e2b44eba7c23b3e110ebe69eaa78a710dec2590f	2 years ago
Changyu Bi	8827cd0618	Support compacting files to different temperatures in FIFO compaction (#11428) ... Summary: - Add a new option `CompactionOptionsFIFO::file_temperature_age_thresholds` that allows user to specify age thresholds for compacting files to different temperatures. File temperature can be used to store files in different storage media. The new options allows specifying multiple temperature-age pairs. The option uses struct for a temperature-age pair to use the existing parsing functionality to make the option dynamically settable. - Deprecate the old option `age_for_warm` that was added for a similar purpose. - Compaction score calculation logic is updated to check if a file needs to be compacted to change its temperature. - Some refactoring is done in `FIFOCompactionPicker::PickTemperatureChangeCompaction`. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11428 Test Plan: adapted unit tests that were for `age_for_warm` to this new option. Reviewed By: ajkr Differential Revision: D45611412 Pulled By: cbi42 fbshipit-source-id: 2dc384841f61cc04abb9681e31aa2de0f0b06106	2 years ago
Peter Dillinger	459969e993	Simplify detection of x86 CPU features (#11419) ... Summary: **Background** - runtime detection of certain x86 CPU features was added for optimizing CRC32c checksums, where performance is dramatically affected by the availability of certain CPU instructions and code using intrinsics for those instructions. And Java builds with native library try to be broadly compatible but performant. What has changed is that CRC32c is no longer the most efficient cheecksum on contemporary x86_64 hardware, nor the default checksum. XXH3 is generally faster and not as dramatically impacted by the availability of certain CPU instructions. For example, on my Skylake system using db_bench (similar on an older Skylake system without AVX512): PORTABLE=1 empty USE_SSE : xxh3->8 GB/s crc32c->0.8 GB/s (no SSE4.2 nor AVX2 instructions) PORTABLE=1 USE_SSE=1 : xxh3->19 GB/s crc32c->16 GB/s (with SSE4.2 and AVX2) PORTABLE=0 USE_SSE ignored: xxh3->28 GB/s crc32c->16 GB/s (also some AVX512) Testing a ~10 year old system, with SSE4.2 but without AVX2, crc32c is a similar speed to the new systems but xxh3 is only about half that speed, also 8GB/s like the non-AVX2 compile above. Given that xxh3 has specific optimization for AVX2, I think we can infer that that crc32c is only fastest for that ~2008-2013 period when SSE4.2 was included but not AVX2. And given that xxh3 is only about 2x slower on these systems (not like >10x slower for unoptimized crc32c), I don't think we need to invest too much in optimally adapting to these old cases. x86 hardware that doesn't support fast CRC32c is now extremely rare, so requiring a custom build to support such hardware is fine IMHO. **This change** does two related things: * Remove runtime CPU detection for optimizing CRC32c on x86. Maintaining this code is non-zero work, and compiling special code that doesn't work on the configured target instruction set for code generation is always dubious. (On the one hand we have to ensure the CRC32c code uses SSE4.2 but on the other hand we have to ensure nothing else does.) * Detect CPU features in source code, not in build scripts. Although there are some hypothetical advantages to detectiong in build scripts (compiler generality), RocksDB supports at least three build systems: make, cmake, and buck. It's not practical to support feature detection on all three, and we have suffered from missed optimization opportunities by relying on missing or incomplete detection in cmake and buck. We also depend on some components like xxhash that do source code detection anyway. **In more detail:** * `HAVE_SSE42`, `HAVE_AVX2`, and `HAVE_PCLMUL` replaced by standard macros `__SSE4_2__`, `__AVX2__`, and `__PCLMUL__`. * MSVC does not provide high fidelity defines for SSE, PCLMUL, or POPCNT, but we can infer those from `__AVX__` or `__AVX2__` in a compatibility header. In rare cases of false negative or false positive feature detection, a build engineer should be able to set defines to work around the issue. * `__POPCNT__` is another standard define, but we happen to only need it on MSVC, where it is set by that compatibility header, or can be set by the build engineer. * `PORTABLE` can be set to a CPU type, e.g. "haswell", to compile for that CPU type. * `USE_SSE` is deprecated, now equivalent to PORTABLE=haswell, which roughly approximates its old behavior. Notably, this change should enable more builds to use the AVX2-optimized Bloom filter implementation. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11419 Test Plan: existing tests, CI Manual performance tests after the change match the before above (none expected with make build). We also see AVX2 optimized Bloom filter code enabled when expected, by injecting a compiler error. (Performance difference is not big on my current CPU.) Reviewed By: ajkr Differential Revision: D45489041 Pulled By: pdillinger fbshipit-source-id: 60ceb0dd2aa3b365c99ed08a8b2a087a9abb6a70	2 years ago
Peter Dillinger	f4a02f2c52	Add hash_seed to Caches (#11391) ... Summary: See motivation and description in new ShardedCacheOptions::hash_seed option. Updated db_bench so that its seed param is used for the cache hash seed. Made its code more safe to ensure seed is set before use. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11391 Test Plan: unit tests added / updated **Performance** - no discernible difference seen running cache_bench repeatedly before & after. With lru_cache and hyper_clock_cache. Reviewed By: hx235 Differential Revision: D45557797 Pulled By: pdillinger fbshipit-source-id: 40bf4da6d66f9d41a8a0eb8e5cf4246a4aa07934	2 years ago
Hui Xiao	8f763bdeab	Record and use the tail size to prefetch table tail (#11406) ... Summary: **Context:** We prefetch the tail part of a SST file (i.e, the blocks after data blocks till the end of the file) during each SST file open in hope to prefetch all the stuff at once ahead of time for later read e.g, footer, meta index, filter/index etc. The existing approach to estimate the tail size to prefetch is through `TailPrefetchStats` heuristics introduced in https://github.com/facebook/rocksdb/pull/4156, which has caused small reads in unlucky case (e.g, small read into the tail buffer during table open in thread 1 under the same BlockBasedTableFactory object can make thread 2's tail prefetching use a small size that it shouldn't) and is hard to debug. Therefore we decide to record the exact tail size and use it directly to prefetch tail of the SST instead of relying heuristics. **Summary:** - Obtain and record in manifest the tail size in `BlockBasedTableBuilder::Finish()` - For backward compatibility, we fall back to TailPrefetchStats and last to simple heuristics that the tail size is a linear portion of the file size - see PR conversation for more. - Make`tail_start_offset` part of the table properties and deduct tail size to record in manifest for external files (e.g, file ingestion, import CF) and db repair (with no access to manifest). Pull Request resolved: https://github.com/facebook/rocksdb/pull/11406 Test Plan: 1. New UT 2. db bench Note: db bench on /tmp/ where direct read is supported is too slow to finish and the default pinning setting in db bench is not helpful to profile # sst read of Get. Therefore I hacked the following to obtain the following comparison. ``` diff --git a/table/block_based/block_based_table_reader.cc b/table/block_based/block_based_table_reader.cc index bd5669f0f..791484c1f 100644 --- a/table/block_based/block_based_table_reader.cc +++ b/table/block_based/block_based_table_reader.cc @@ -838,7 +838,7 @@ Status BlockBasedTable::PrefetchTail( &tail_prefetch_size); // Try file system prefetch - if (!file->use_direct_io() && !force_direct_prefetch) { + if (false && !file->use_direct_io() && !force_direct_prefetch) { if (!file->Prefetch(prefetch_off, prefetch_len, ro.rate_limiter_priority) .IsNotSupported()) { prefetch_buffer->reset(new FilePrefetchBuffer( diff --git a/tools/db_bench_tool.cc b/tools/db_bench_tool.cc index ea40f5fa0..39a0ac385 100644 --- a/tools/db_bench_tool.cc +++ b/tools/db_bench_tool.cc @@ -4191,6 +4191,8 @@ class Benchmark { std::shared_ptr<TableFactory>(NewCuckooTableFactory(table_options)); } else { BlockBasedTableOptions block_based_options; + block_based_options.metadata_cache_options.partition_pinning = + PinningTier::kAll; block_based_options.checksum = static_cast<ChecksumType>(FLAGS_checksum_type); if (FLAGS_use_hash_search) { ``` Create DB ``` ./db_bench --bloom_bits=3 --use_existing_db=1 --seed=1682546046158958 --partition_index_and_filters=1 --statistics=1 -db=/dev/shm/testdb/ -benchmarks=readrandom -key_size=3200 -value_size=512 -num=1000000 -write_buffer_size=6550000 -disable_auto_compactions=false -target_file_size_base=6550000 -compression_type=none ``` ReadRandom ``` ./db_bench --bloom_bits=3 --use_existing_db=1 --seed=1682546046158958 --partition_index_and_filters=1 --statistics=1 -db=/dev/shm/testdb/ -benchmarks=readrandom -key_size=3200 -value_size=512 -num=1000000 -write_buffer_size=6550000 -disable_auto_compactions=false -target_file_size_base=6550000 -compression_type=none ``` (a) Existing (Use TailPrefetchStats for tail size + use seperate prefetch buffer in PartitionedFilter/IndexReader::CacheDependencies()) ``` rocksdb.table.open.prefetch.tail.hit COUNT : 3395 rocksdb.sst.read.micros P50 : 5.655570 P95 : 9.931396 P99 : 14.845454 P100 : 585.000000 COUNT : 999905 SUM : 6590614 ``` (b) This PR (Record tail size + use the same tail buffer in PartitionedFilter/IndexReader::CacheDependencies()) ``` rocksdb.table.open.prefetch.tail.hit COUNT : 14257 rocksdb.sst.read.micros P50 : 5.173347 P95 : 9.015017 P99 : 12.912610 P100 : 228.000000 COUNT : 998547 SUM : 5976540 ``` As we can see, we increase the prefetch tail hit count and decrease SST read count with this PR 3. Test backward compatibility by stepping through reading with post-PR code on a db generated pre-PR. Reviewed By: pdillinger Differential Revision: D45413346 Pulled By: hx235 fbshipit-source-id: 7d5e36a60a72477218f79905168d688452a4c064	2 years ago
anand76	03a892a9fb	Delete empty WAL files on reopen (#11409) ... Summary: When a DB is opened, RocksDB creates an empty WAL file. When the DB is reopened and the WAL is empty, the min log number to keep is not advanced until a memtable flush happens. If a process crashes soon after reopening the DB, its likely that no memtable flush would have happened, which means the empty WAL file is not deleted. In a crash loop scenario, this leads to empty WAL files accumulating. Fix this by ensuring the min log number is advanced if the WAL is empty. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11409 Test Plan: Add a unit test Reviewed By: ajkr Differential Revision: D45281685 Pulled By: anand1976 fbshipit-source-id: 0225877c613e65ffb30972a0051db2830105423e	2 years ago
Peter Dillinger	41a7fbf758	Avoid long parameter lists configuring Caches (#11386) ... Summary: For better clarity, encouraging more options explicitly specified using fields rather than positionally via constructor parameter lists. Simplifies code maintenance as new fields are added. Deprecate some cases of the confusing pattern of NewWhatever() functions returning shared_ptr. Net reduction of about 70 source code lines (including comments). Pull Request resolved: https://github.com/facebook/rocksdb/pull/11386 Test Plan: existing tests Reviewed By: ajkr Differential Revision: D45059075 Pulled By: pdillinger fbshipit-source-id: d53fa09b268024f9c55254bb973b6c69feebf41a	2 years ago
Andrew Kryczka	925d8252e5	Shard JemallocNodumpAllocator (#11400) ... Summary: RocksDB's jemalloc no-dump allocator (`NewJemallocNodumpAllocator()`) was using a single manual arena. This arena's lock contention could be very high when thread caching is disabled for RocksDB blocks (e.g., when using `MALLOC_CONF='tcache_max:4096'` and `rocksdb_block_size=16384`). This PR changes the jemalloc no-dump allocator to use a configurable number of manual arenas. That number is required to be a power of two so we can avoid division. The allocator shards allocation requests randomly across those manual arenas. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11400 Test Plan: - mysqld setup - Branch: fb-mysql-8.0.28 (653eba2e56) - Build: `mysqlbuild.sh --clean --release` - Set env var `MALLOC_CONF='tcache_max:$tcache_max'` - Added CLI args `--rocksdb_cache_dump=false --rocksdb_block_cache_size=4294967296 --rocksdb_block_size=16384` - Ran under /usr/bin/time - Large database scenario - Setup command: `mysqlslap -h 127.0.0.1 -P 13020 --auto-generate-sql=1 --auto-generate-sql-load-type=write --auto-generate-sql-guid-primary=1 --number-char-cols=8 --auto-generate-sql-execute-number=262144 --concurrency=32 --no-drop` - Benchmark command: `mysqlslap -h 127.0.0.1 -P 13020 --query='select count(*) from mysqlslap.t1;' --number-of-queries=320 --concurrency=32` - Results: | tcache_max | num_arenas | Peak RSS MB (% change) | Query latency seconds (% change) | |---|---|---|---| | 4096 | **(baseline)** | 4541 | 37.1 | | 4096 | 1 | 4535 (-0.1%) | 36.7 (-1%) | | 4096 | 8 | 4687 (+3%) | 10.2 (-73%) | | 16384 | **(baseline)** | 4514 | 8.4 | | 16384 | 1 | 4526 (+0.3%) | 8.5 (+1%) | | 16384 | 8 | 4580 (+1%) | 8.5 (+1%) | Reviewed By: pdillinger Differential Revision: D45220794 Pulled By: ajkr fbshipit-source-id: 9a50c9872bdef5d299e52b115a65ee8a5557d58d	2 years ago
Changyu Bi	62fc15f009	Block per key-value checksum (#11287) ... Summary: add option `block_protection_bytes_per_key` and implementation for block per key-value checksum. The main changes are 1. checksum construction and verification in block.cc/h 2. pass the option `block_protection_bytes_per_key` around (mainly for methods defined in table_cache.h) 3. unit tests/crash test updates Tests: * Added unit tests * Crash test: `python3 tools/db_crashtest.py blackbox --simple --block_protection_bytes_per_key=1 --write_buffer_size=1048576` Follow up (maybe as a separate PR): make sure corruption status returned from BlockIters are correctly handled. Performance: Turning on block per KV protection has a non-trivial negative impact on read performance and costs additional memory. For memory, each block includes additional 24 bytes for checksum-related states beside checksum itself. For CPU, I set up a DB of size ~1.2GB with 5M keys (32 bytes key and 200 bytes value) which compacts to ~5 SST files (target file size 256 MB) in L6 without compression. I tested readrandom performance with various block cache size (to mimic various cache hit rates): ``` SETUP make OPTIMIZE_LEVEL="-O3" USE_LTO=1 DEBUG_LEVEL=0 -j32 db_bench ./db_bench -benchmarks=fillseq,compact0,waitforcompaction,compact,waitforcompaction -write_buffer_size=33554432 -level_compaction_dynamic_level_bytes=true -max_background_jobs=8 -target_file_size_base=268435456 --num=5000000 --key_size=32 --value_size=200 --compression_type=none BENCHMARK ./db_bench --use_existing_db -benchmarks=readtocache,readrandom[-X10] --num=5000000 --key_size=32 --disable_auto_compactions --reads=1000000 --block_protection_bytes_per_key=[0|1] --cache_size=$CACHESIZE The readrandom ops/sec looks like the following: Block cache size: 2GB 1.2GB * 0.9 1.2GB * 0.8 1.2GB * 0.5 8MB Main 240805 223604 198176 161653 139040 PR prot_bytes=0 238691 226693 200127 161082 141153 PR prot_bytes=1 214983 193199 178532 137013 108211 prot_bytes=1 vs -10% -15% -10.8% -15% -23% prot_bytes=0 ``` The benchmark has a lot of variance, but there was a 5% to 25% regression in this benchmark with different cache hit rates. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11287 Reviewed By: ajkr Differential Revision: D43970708 Pulled By: cbi42 fbshipit-source-id: ef98d898b71779846fa74212b9ec9e08b7183940	2 years ago
Peter Dillinger	46dbcfd799	Start version 8.3 (#11405) ... Summary: Update and clean up history. Update version number. Add to compatibility test. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11405 Reviewed By: ltamasi Differential Revision: D45242779 Pulled By: pdillinger fbshipit-source-id: 860bd047584d051472ba9ccefae7ebc3f37b1d8f	2 years ago
Peter Dillinger	d79be3dca2	Changes and enhancements to compression stats, thresholds (#11388) ... Summary: ## Option API updates * Add new CompressionOptions::max_compressed_bytes_per_kb, which corresponds to 1024.0 / min allowable compression ratio. This avoids the hard-coded minimum ratio of 8/7. * Remove unnecessary constructor for CompressionOptions. * Document undocumented CompressionOptions. Use idiom for default values shown clearly in one place (not precariously repeated). ## Stat API updates * Deprecate the BYTES_COMPRESSED, BYTES_DECOMPRESSED histograms. Histograms incur substantial extra space & time costs compared to tickers, and the distribution of uncompressed data block sizes tends to be uninteresting. If we're interested in that distribution, I don't see why it should be limited to blocks stored as compressed. * Deprecate the NUMBER_BLOCK_NOT_COMPRESSED ticker, because the name is very confusing. * New or existing tickers relevant to compression: * BYTES_COMPRESSED_FROM * BYTES_COMPRESSED_TO * BYTES_COMPRESSION_BYPASSED * BYTES_COMPRESSION_REJECTED * COMPACT_WRITE_BYTES + FLUSH_WRITE_BYTES (both existing) * NUMBER_BLOCK_COMPRESSED (existing) * NUMBER_BLOCK_COMPRESSION_BYPASSED * NUMBER_BLOCK_COMPRESSION_REJECTED * BYTES_DECOMPRESSED_FROM * BYTES_DECOMPRESSED_TO We can compute a number of things with these stats: * "Successful" compression ratio: BYTES_COMPRESSED_FROM / BYTES_COMPRESSED_TO * Compression ratio of data on which compression was attempted: (BYTES_COMPRESSED_FROM + BYTES_COMPRESSION_REJECTED) / (BYTES_COMPRESSED_TO + BYTES_COMPRESSION_REJECTED) * Compression ratio of data that could be eligible for compression: (BYTES_COMPRESSED_FROM + X) / (BYTES_COMPRESSED_TO + X) where X = BYTES_COMPRESSION_REJECTED + NUMBER_BLOCK_COMPRESSION_REJECTED * Overall SST compression ratio (compression disabled vs. actual): (Y - BYTES_COMPRESSED_TO + BYTES_COMPRESSED_FROM) / Y where Y = COMPACT_WRITE_BYTES + FLUSH_WRITE_BYTES Keeping _REJECTED separate from _BYPASSED helps us to understand "wasted" CPU time in compression. ## BlockBasedTableBuilder Various small refactorings, optimizations, and name clean-ups. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11388 Test Plan: unit tests added * `options_settable_test.cc`: use non-deprecated idiom for configuring CompressionOptions from string. The old idiom is tested elsewhere and does not need to be updated to support the new field. Reviewed By: ajkr Differential Revision: D45128202 Pulled By: pdillinger fbshipit-source-id: 5a652bf5c022b7ec340cf79018cccf0686962803	2 years ago
Hui Xiao	151242ce46	Group rocksdb.sst.read.micros stat by IOActivity flush and compaction (#11288) ... Summary: **Context:** The existing stat rocksdb.sst.read.micros does not reflect each of compaction and flush cases but aggregate them, which is not so helpful for us to understand IO read behavior of each of them. **Summary** - Update `StopWatch` and `RandomAccessFileReader` to record `rocksdb.sst.read.micros` and `rocksdb.file.{flush/compaction}.read.micros` - Fixed the default histogram in `RandomAccessFileReader` - New field `ReadOptions/IOOptions::io_activity`; Pass `ReadOptions` through paths under db open, flush and compaction to where we can prepare `IOOptions` and pass it to `RandomAccessFileReader` - Use `thread_status_util` for assertion in `DbStressFSWrapper` for continuous testing on we are passing correct `io_activity` under db open, flush and compaction Pull Request resolved: https://github.com/facebook/rocksdb/pull/11288 Test Plan: - **Stress test** - **Db bench 1: rocksdb.sst.read.micros COUNT ≈ sum of rocksdb.file.read.flush.micros's and rocksdb.file.read.compaction.micros's.** (without blob) - May not be exactly the same due to `HistogramStat::Add` only guarantees atomic not accuracy across threads. ``` ./db_bench -db=/dev/shm/testdb/ -statistics=true -benchmarks="fillseq" -key_size=32 -value_size=512 -num=50000 -write_buffer_size=655 -target_file_size_base=655 -disable_auto_compactions=false -compression_type=none -bloom_bits=3 (-use_plain_table=1 -prefix_size=10) ``` ``` // BlockBasedTable rocksdb.sst.read.micros P50 : 2.009374 P95 : 4.968548 P99 : 8.110362 P100 : 43.000000 COUNT : 40456 SUM : 114805 rocksdb.file.read.flush.micros P50 : 1.871841 P95 : 3.872407 P99 : 5.540541 P100 : 43.000000 COUNT : 2250 SUM : 6116 rocksdb.file.read.compaction.micros P50 : 2.023109 P95 : 5.029149 P99 : 8.196910 P100 : 26.000000 COUNT : 38206 SUM : 108689 // PlainTable Does not apply ``` - **Db bench 2: performance** **Read** SETUP: db with 900 files ``` ./db_bench -db=/dev/shm/testdb/ -benchmarks="fillseq" -key_size=32 -value_size=512 -num=50000 -write_buffer_size=655 -disable_auto_compactions=true -target_file_size_base=655 -compression_type=none ```run till convergence ``` ./db_bench -seed=1678564177044286 -use_existing_db=true -db=/dev/shm/testdb -benchmarks=readrandom[-X60] -statistics=true -num=1000000 -disable_auto_compactions=true -compression_type=none -bloom_bits=3 ``` Pre-change `readrandom [AVG 60 runs] : 21568 (± 248) ops/sec` Post-change (no regression, -0.3%) `readrandom [AVG 60 runs] : 21486 (± 236) ops/sec` **Compaction/Flush**run till convergence ``` ./db_bench -db=/dev/shm/testdb2/ -seed=1678564177044286 -benchmarks="fillseq[-X60]" -key_size=32 -value_size=512 -num=50000 -write_buffer_size=655 -disable_auto_compactions=false -target_file_size_base=655 -compression_type=none rocksdb.sst.read.micros COUNT : 33820 rocksdb.sst.read.flush.micros COUNT : 1800 rocksdb.sst.read.compaction.micros COUNT : 32020 ``` Pre-change `fillseq [AVG 46 runs] : 1391 (± 214) ops/sec; 0.7 (± 0.1) MB/sec` Post-change (no regression, ~-0.4%) `fillseq [AVG 46 runs] : 1385 (± 216) ops/sec; 0.7 (± 0.1) MB/sec` Reviewed By: ajkr Differential Revision: D44007011 Pulled By: hx235 fbshipit-source-id: a54c89e4846dfc9a135389edf3f3eedfea257132	2 years ago
Changyu Bi	43e9a60bb2	Always allow L0->L1 trivial move during manual compaction (#11375) ... Summary: during manual compaction (CompactRange()), L0->L1 trivial move is disabled when only L0 overlaps with compacting key range (introduced in https://github.com/facebook/rocksdb/issues/7368 to enforce kForce* contract). This can cause large memory usage due to compaction readahead when number of L0 files is large. This PR allows L0->L1 trivial move in this case, and will do a L1 -> L1 intra-level compaction when needed (`bottommost_level_compaction` is kForce*). In brief, consider a DB with only L0 file, and user calls CompactRange(kForce, nullptr, nullptr), - before this PR, RocksDB does a L0 -> L1 compaction (disallow trivial move), - after this PR, RocksDB does a L0 -> L1 compaction (allow trivial move), and a L1 -> L1 compaction. Users can use kForceOptimized to avoid this extra L1->L1 compaction overhead when L0s are overlapping and cannot be trivial moved. This PR also fixed a bug (see previous discussion in https://github.com/facebook/rocksdb/issues/11041) where `final_output_level` of a manual compaction can be miscalculated when `level_compaction_dynamic_level_bytes=true`. This bug could cause incorrect level being moved when CompactRangeOptions::change_level is specified. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11375 Test Plan: - Added new unit tests to test that L0 -> L1 compaction allows trivial move and L1 -> L1 compaction is done when needed. Reviewed By: ajkr Differential Revision: D44943518 Pulled By: cbi42 fbshipit-source-id: e9fb770d17b163c18a623e1d1bd6b81159192708	2 years ago
Peter Dillinger	f9db0c6e9c	Refactor block cache tracing w/improved MultiGet (#11339) ... Summary: After https://github.com/facebook/rocksdb/issues/11301, I wasn't sure whether I had regressed block cache tracing with MultiGet. Demo PR https://github.com/facebook/rocksdb/issues/11330 shows the flawed state of tracing MultiGet before my change, and based on the unit test, there was essentially no change in tracing behavior with https://github.com/facebook/rocksdb/issues/11301. This change is to leave that code and behavior better than I found it. This change is not intended to change any production behaviors except when block cache tracing is active, though might improve general read path efficiency by disabling some related tracking when such tracing is disabled. More detail on production code: * Refactoring to consolidate the construction of BlockCacheTraceRecord, and other related functionality, in block-based table reader, though it's somewhat awkward to preserve an optimization to avoid copying Slices into temporary strings in BlockCacheLookupContext. * Accurately track cache hits and misses (etc.) for each data block accessed by a MultiGet(). (Previously reported hits as misses.) * Reduced repeated checking of `block_cache_tracer_` state (by creating lookup_context only when active) for efficiency and to reduce the risk of corner case bugs where tracing is enabled or disabled for different parts of a read op. (See a TODO below) * Improved estimate calculation for num_keys_in_block (see code comment) Possible follow-up: * `XXX:` use_cache=true means double cache query? (possible double-query of block cache when allow_mmap_reads=true) * `TODO:` need more than one lookup_context here to track individual filter and index partition hits and misses * `TODO:` optimize more state checks of `block_cache_tracer_` down to `lookup_context != nullptr` * Pre-existing `XXX:` There appear to be 'break' statements above that bypass this writing of the block cache trace record * Expand test coverage (see below) Pull Request resolved: https://github.com/facebook/rocksdb/pull/11339 Test Plan: * Added a basic unit test for block cache tracing MultiGet, for now just covering one data block with two keys. * Added HitMissCountingCache to independently verify that the actual block cache trace and expected block cache trace also agree with the actual number of cache hits / misses (nothing missing or mislabeled). For now only used with MultiGet test. * Better testing of num_keys_in_block, for now just with MultiGet * Misc improvements to table_test to improve clarity, such as making it clear that certain keys are auto-inserted at the start of every test. Performance test: Testing multireadrandom as in https://github.com/facebook/rocksdb/issues/11301, except averaging over distinct runs rather than [-X30] which doesn't seem to sufficiently reset after each run to work as an independent test run. Base with revert of 11301: 3148926 ops/sec Base: 3019146 ops/sec New: 2999529 ops/sec Possibly a tiny MultiGet CPU regression with this change. We are now always allocating an additional vector for the LookupContexts. I'm still contemplating options to try to correct the regression in https://github.com/facebook/rocksdb/issues/11301. Testing readrandom: Base with revert of 11301: 2311988 Base: 2281726 New: 2299722 Possibly a tiny Get CPU improvement with this change. We are now avoiding some unnecessary LookupContext population. Reviewed By: akankshamahajan15 Differential Revision: D44557845 Pulled By: pdillinger fbshipit-source-id: b841691799d2a48fb59cc8880dc7cbb1e107ae3d	2 years ago
Changyu Bi	b3c43a5b99	Drain unnecessary levels when `level_compaction_dynamic_level_bytes=true` (#11340) ... Summary: When a user migrates to level compaction + `level_compaction_dynamic_level_bytes=true`, or when a DB shrinks, there can be unnecessary levels in the DB. Before this PR, this is no way to remove these levels except a manual compaction. These extra unnecessary levels make it harder to guarantee max_bytes_for_level_multiplier and can cause extra space amp. This PR boosts compaction score for these levels to allow RocksDB to automatically drain these levels. Together with https://github.com/facebook/rocksdb/issues/11321, this makes migration to `level_compaction_dynamic_level_bytes=true` automatic without needing user to do a one time full manual compaction. Credit: this PR is modified from https://github.com/facebook/rocksdb/issues/3921. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11340 Test Plan: - New unit tests - `python3 tools/db_crashtest.py whitebox --simple` which randomly sets level_compaction_dynamic_level_bytes in each run. Reviewed By: ajkr Differential Revision: D44563884 Pulled By: cbi42 fbshipit-source-id: e20d3620bd73dff22be18c5a91a07f340740bcc8	2 years ago
anand76	0623c5b903	Ensure VerifyFileChecksums reads don't exceed readahead_size (#11328) ... Summary: VerifyFileChecksums currently interprets the readahead_size as a payload of readahead_size for calculating the checksum, plus a prefetch of an additional readahead_size. Hence each read is readahead_size * 2. This change treats it as chunks of readahead_size for checksum calculation. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11328 Test Plan: Add a unit test Reviewed By: pdillinger Differential Revision: D44718781 Pulled By: anand1976 fbshipit-source-id: 79bae1ebaa27de2a13bc86f5910bf09356936e63	2 years ago
Andrew Kryczka	b45738622a	Use user-provided ReadOptions for metadata block reads more often (#11208) ... Summary: This is mostly taken from https://github.com/facebook/rocksdb/issues/10427 with my own comments addressed. This PR plumbs the user’s `ReadOptions` down to `GetOrReadIndexBlock()`, `GetOrReadFilterBlock()`, and `GetFilterPartitionBlock()`. Now those functions no longer have to make up a `ReadOptions` with incomplete information. I also let `PartitionIndexReader::NewIterator()` pass through its caller's `ReadOptions::verify_checksums`, which was inexplicably dropped previously. Fixes https://github.com/facebook/rocksdb/issues/10463 Pull Request resolved: https://github.com/facebook/rocksdb/pull/11208 Test Plan: Functional: - Measured `-verify_checksum=false` applies to metadata blocks read outside of table open - setup command: `TEST_TMPDIR=/tmp/100M-DB/ ./db_bench -benchmarks=filluniquerandom,waitforcompaction -write_buffer_size=1048576 -target_file_size_base=1048576 -max_bytes_for_level_base=4194304 -compression_type=none -num=1638400 -key_size=8 -value_size=56` - run command: `TEST_TMPDIR=/tmp/100M-DB/ ./db_bench -benchmarks=readrandom -use_existing_db=true -write_buffer_size=1048576 -target_file_size_base=1048576 -max_bytes_for_level_base=4194304 -compression_type=none -num=1638400 -key_size=8 -value_size=56 -duration=10 -threads=32 -cache_size=131072 -statistics=true -verify_checksum=false -open_files=20 -cache_index_and_filter_blocks=true` - before: `rocksdb.block.checksum.compute.count COUNT : 384353` - after: `rocksdb.block.checksum.compute.count COUNT : 22` Performance: - Setup command (tmpfs, 128MB logical data size, cache indexes/filters without pinning so index/filter lookups go through table reader): `TEST_TMPDIR=/dev/shm/128M-DB/ ./db_bench -benchmarks=filluniquerandom,waitforcompaction -write_buffer_size=131072 -target_file_size_base=131072 -max_bytes_for_level_base=524288 -compression_type=none -num=4194304 -key_size=8 -value_size=24 -bloom_bits=8 -whole_key_filtering=1` - Measured point lookup performance. Database is fully cached to emphasize any new callstack overheads - Command: `TEST_TMPDIR=/dev/shm/128M-DB/ ./db_bench -benchmarks=readrandom[-W1][-X20] -use_existing_db=true -cache_index_and_filter_blocks=true -disable_auto_compactions=true -num=4194304 -key_size=8 -value_size=24 -bloom_bits=8 -whole_key_filtering=1 -duration=10 -cache_size=1048576000` - Before: `readrandom [AVG 20 runs] : 274848 (± 3717) ops/sec; 8.4 (± 0.1) MB/sec` - After: `readrandom [AVG 20 runs] : 277904 (± 4474) ops/sec; 8.5 (± 0.1) MB/sec` Reviewed By: hx235 Differential Revision: D43145366 Pulled By: ajkr fbshipit-source-id: 75ec062ece86a82cd788783de9de2c72df57f994	2 years ago
Peter Dillinger	3c17930ede	Change default block cache from 8MB to 32MB (#11350) ... Summary: ... which increases default number of shards from 16 to 64. Although the default block cache size is only recommended for applications where RocksDB is not performance-critical, under stress conditions, block cache mutex contention could become a performance bottleneck. This change of default should alleviate that. Note that reducing the size of cache shards (recommended minimum 512MB) could cause thrashing, e.g. on filter blocks, so capacity needs to increase to safely increase number of shards. The 8MB default dates back to 2011 or earlier (f779e7a5), when the most simultaneous threads you could get from a single CPU socket was 20 (e.g. Intel Xeon E7-8870). Now more than 100 is available. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11350 Test Plan: unit tests updated Reviewed By: cbi42 Differential Revision: D44674873 Pulled By: pdillinger fbshipit-source-id: 91ed3070789b42679283c7e6dc97c41a6a97bdf4	2 years ago
Hui Xiao	39c29372bf	Add `SetAllowStall()` (#11335) ... Summary: **Context/Summary:** - Allow runtime changes to whether `WriteBufferManager` allows stall or not by calling `SetAllowStall()` - Misc: some clean up - see PR conversation Pull Request resolved: https://github.com/facebook/rocksdb/pull/11335 Test Plan: - New UT Reviewed By: akankshamahajan15 Differential Revision: D44502555 Pulled By: hx235 fbshipit-source-id: 24b5cc57df7734b11d42e4870c06c87b95312b5e	2 years ago
Hui Xiao	c14eb134ed	Add experimental PerfContext counters for db iterator Prev/Next/Seek* APIs (#11320) ... Summary: **Context/Summary:** Motived by user need of investigating db iterator behavior during an interval of any time length of a certain thread, we decide to collect and expose related counters in `PerfContext` as an experimental feature, in addition to the existing db-scope ones (i.e, tickers) Pull Request resolved: https://github.com/facebook/rocksdb/pull/11320 Test Plan: - new UT - db bench Setup ``` ./db_bench -db=/dev/shm/testdb/ -benchmarks="fillseq" -key_size=32 -value_size=512 -num=1000000 -compression_type=none -bloom_bits=3 ``` Test till converges ``` ./db_bench -seed=1679526311157283 -use_existing_db=1 -perf_level=2 -db=/dev/shm/testdb/ -benchmarks="seekrandom[-X60]" ``` pre-change `seekrandom [AVG 33 runs] : 7545 (± 100) ops/sec` post-change (no regression) `seekrandom [AVG 33 runs] : 7688 (± 67) ops/sec` Reviewed By: cbi42 Differential Revision: D44321931 Pulled By: hx235 fbshipit-source-id: f98a254ba3e3ced95eb5928884e33f1b99dca401	2 years ago
Changyu Bi	601320164b	Trivially move files down when opening db with level_compaction_dynamic_l… (#11321) ... Summary: …evel_bytes During DB open, if a column family uses level compaction with level_compaction_dynamic_level_bytes=true, trivially move its files down in the LSM such that the bottommost files are in Lmax, the second from bottommost level files are in Lmax-1 and so on. This is aimed to make it easier to migrate level_compaction_dynamic_level_bytes from false to true. Before this change, a full manual compaction is suggested for such migration. After this change, user can just restart DB to turn on this option. db_crashtest.py is updated to randomly choose value for level_compaction_dynamic_level_bytes. Note that there may still be too many unnecessary levels if a user is migrating from universal compaction or level compaction with a smaller level multiplier. A full manual compaction may still be needed in that case before some PR that automatically drain unnecessary levels like https://github.com/facebook/rocksdb/issues/3921 lands. Eventually we may want to change the default value of option level_compaction_dynamic_level_bytes to true. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11321 Test Plan: 1. Added unit tests. 2. Crash test: ran a variation of db_crashtest.py (like 32516507e77521ae887e45091b69139e32e8efb7) that turns level_compaction_dynamic_level_bytes on and off and switches between LC and UC for the same DB. TODO: Update `OptionChangeMigration`, either after this PR or https://github.com/facebook/rocksdb/issues/3921. Reviewed By: ajkr Differential Revision: D44341930 Pulled By: cbi42 fbshipit-source-id: 013de19a915c6a0502be569f07c4cc8f1c3c6be2	2 years ago
karemta-orday	40c2ec6d08	Add in-transaction multi-get-for-update to the C interface (#11107) ... Summary: Hi, this is basically a part of https://github.com/facebook/rocksdb/pull/6488 that only adds `multi_get_for_update` functionality to C API (I'd like to call it from Rust), since `multi_get` was already added here https://github.com/facebook/rocksdb/pull/9252 https://github.com/facebook/rocksdb/pull/6488 has conflicts, so I guess it might be easier to get this one in Pull Request resolved: https://github.com/facebook/rocksdb/pull/11107 Reviewed By: pdillinger Differential Revision: D42680764 Pulled By: ajkr fbshipit-source-id: a50f96e1c7f3d470b4ab07e9ff5a283e5cf44865	2 years ago
Andrew Kryczka	9f8cdc8ad6	validate SstFileWriter range tombstones cover positive ranges (#11322) ... Summary: As titled. This is the same as https://github.com/facebook/rocksdb/issues/6788 but for range tombstones written through `SstFileWriter` rather than through `DB`. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11322 Reviewed By: cbi42 Differential Revision: D44317733 Pulled By: ajkr fbshipit-source-id: f6eb8791ae2c09c169b6bfe0d047449d924b377e	2 years ago
Levi Tamasi	87de4fee6b	Updates for the 8.1 release (HISTORY, version.h, compatibility tests) (#11307) ... Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/11307 Reviewed By: hx235 Differential Revision: D44196571 Pulled By: ltamasi fbshipit-source-id: 52489d6f8bd3c79cd33c87e9e1f719ea5e8bd382	2 years ago
Hui Xiao	cb58477185	New stat rocksdb.{cf|db}-write-stall-stats exposed in a structural way (#11300) ... Summary: **Context/Summary:** Users are interested in figuring out what has caused write stall. - Refactor write stall related stats from property `kCFStats` into its own db property `rocksdb.cf-write-stall-stats` as a map or string. For now, this only contains count of different combination of (CF-scope `WriteStallCause`) + (`WriteStallCondition`) - Add new `WriteStallCause::kWriteBufferManagerLimit` to reflect write stall caused by write buffer manager - Add new `rocksdb.db-write-stall-stats`. For now, this only contains `WriteStallCause::kWriteBufferManagerLimit` + `WriteStallCondition::kStopped` - Expose functions in new class `WriteStallStatsMapKeys` for examining the above two properties returned as map - Misc: rename/comment some write stall InternalStats for clarity Pull Request resolved: https://github.com/facebook/rocksdb/pull/11300 Test Plan: - New UT - Stress test `python3 tools/db_crashtest.py blackbox --simple --get_property_one_in=1` - Perf test: Both converge very slowly at similar rates but post-change has higher average ops/sec than pre-change even though they are run at the same time. ``` ./db_bench -seed=1679014417652004 -db=/dev/shm/testdb/ -statistics=false -benchmarks="fillseq[-X60]" -key_size=32 -value_size=512 -num=100000 -db_write_buffer_size=655 -target_file_size_base=655 -disable_auto_compactions=false -compression_type=none -bloom_bits=3 ``` pre-change: ``` fillseq [AVG 15 runs] : 1176 (± 732) ops/sec; 0.6 (± 0.4) MB/sec fillseq : 1052.671 micros/op 949 ops/sec 105.267 seconds 100000 operations; 0.5 MB/s fillseq [AVG 16 runs] : 1162 (± 685) ops/sec; 0.6 (± 0.4) MB/sec fillseq : 1387.330 micros/op 720 ops/sec 138.733 seconds 100000 operations; 0.4 MB/s fillseq [AVG 17 runs] : 1136 (± 646) ops/sec; 0.6 (± 0.3) MB/sec fillseq : 1232.011 micros/op 811 ops/sec 123.201 seconds 100000 operations; 0.4 MB/s fillseq [AVG 18 runs] : 1118 (± 610) ops/sec; 0.6 (± 0.3) MB/sec fillseq : 1282.567 micros/op 779 ops/sec 128.257 seconds 100000 operations; 0.4 MB/s fillseq [AVG 19 runs] : 1100 (± 578) ops/sec; 0.6 (± 0.3) MB/sec fillseq : 1914.336 micros/op 522 ops/sec 191.434 seconds 100000 operations; 0.3 MB/s fillseq [AVG 20 runs] : 1071 (± 551) ops/sec; 0.6 (± 0.3) MB/sec fillseq : 1227.510 micros/op 814 ops/sec 122.751 seconds 100000 operations; 0.4 MB/s fillseq [AVG 21 runs] : 1059 (± 525) ops/sec; 0.5 (± 0.3) MB/sec ``` post-change: ``` fillseq [AVG 15 runs] : 1226 (± 732) ops/sec; 0.6 (± 0.4) MB/sec fillseq : 1323.825 micros/op 755 ops/sec 132.383 seconds 100000 operations; 0.4 MB/s fillseq [AVG 16 runs] : 1196 (± 687) ops/sec; 0.6 (± 0.4) MB/sec fillseq : 1223.905 micros/op 817 ops/sec 122.391 seconds 100000 operations; 0.4 MB/s fillseq [AVG 17 runs] : 1174 (± 647) ops/sec; 0.6 (± 0.3) MB/sec fillseq : 1168.996 micros/op 855 ops/sec 116.900 seconds 100000 operations; 0.4 MB/s fillseq [AVG 18 runs] : 1156 (± 611) ops/sec; 0.6 (± 0.3) MB/sec fillseq : 1348.729 micros/op 741 ops/sec 134.873 seconds 100000 operations; 0.4 MB/s fillseq [AVG 19 runs] : 1134 (± 579) ops/sec; 0.6 (± 0.3) MB/sec fillseq : 1196.887 micros/op 835 ops/sec 119.689 seconds 100000 operations; 0.4 MB/s fillseq [AVG 20 runs] : 1119 (± 550) ops/sec; 0.6 (± 0.3) MB/sec fillseq : 1193.697 micros/op 837 ops/sec 119.370 seconds 100000 operations; 0.4 MB/s fillseq [AVG 21 runs] : 1106 (± 524) ops/sec; 0.6 (± 0.3) MB/sec ``` Reviewed By: ajkr Differential Revision: D44159541 Pulled By: hx235 fbshipit-source-id: 8d29efb70001fdc52d34535eeb3364fc3e71e40b	2 years ago
Peter Dillinger	204fcff751	HyperClockCache support for SecondaryCache, with refactoring (#11301) ... Summary: Internally refactors SecondaryCache integration out of LRUCache specifically and into a wrapper/adapter class that works with various Cache implementations. Notably, this relies on separating the notion of async lookup handles from other cache handles, so that HyperClockCache doesn't have to deal with the problem of allocating handles from the hash table for lookups that might fail anyway, and might be on the same key without support for coalescing. (LRUCache's hash table can incorporate previously allocated handles thanks to its pointer indirection.) Specifically, I'm worried about the case in which hundreds of threads try to access the same block and probing in the hash table degrades to linear search on the pile of entries with the same key. This change is a big step in the direction of supporting stacked SecondaryCaches, but there are obstacles to completing that. Especially, there is no SecondaryCache hook for evictions to pass from one to the next. It has been proposed that evictions be transmitted simply as the persisted data (as in SaveToCallback), but given the current structure provided by the CacheItemHelpers, that would require an extra copy of the block data, because there's intentionally no way to ask for a contiguous Slice of the data (to allow for flexibility in storage). `AsyncLookupHandle` and the re-worked `WaitAll()` should be essentially prepared for stacked SecondaryCaches, but several "TODO with stacked secondaries" issues remain in various places. It could be argued that the stacking instead be done as a SecondaryCache adapter that wraps two (or more) SecondaryCaches, but at least with the current API that would require an extra heap allocation on SecondaryCache Lookup for a wrapper SecondaryCacheResultHandle that can transfer a Lookup between secondaries. We could also consider trying to unify the Cache and SecondaryCache APIs, though that might be difficult if `AsyncLookupHandle` is kept a fixed struct. ## cache.h (public API) Moves `secondary_cache` option from LRUCacheOptions to ShardedCacheOptions so that it is applicable to HyperClockCache. ## advanced_cache.h (advanced public API) * Add `Cache::CreateStandalone()` so that the SecondaryCache support wrapper can use it. * Add `SetEvictionCallback()` / `eviction_callback_` so that the SecondaryCache support wrapper can use it. Only a single callback is supported for efficiency. If there is ever a need for more than one, hopefully that can be handled with a broadcast callback wrapper. These are essentially the two "extra" pieces of `Cache` for pulling out specific SecondaryCache support from the `Cache` implementation. I think it's a good trade-off as these are reasonable, limited, and reusable "cut points" into the `Cache` implementations. * Remove async capability from standard `Lookup()` (getting rid of awkward restrictions on pending Handles) and add `AsyncLookupHandle` and `StartAsyncLookup()`. As noted in the comments, the full struct of `AsyncLookupHandle` is exposed so that it can be stack allocated, for efficiency, though more data is being copied around than before, which could impact performance. (Lookup info -> AsyncLookupHandle -> Handle vs. Lookup info -> Handle) I could foresee a future in which a Cache internally saves a pointer to the AsyncLookupHandle, which means it's dangerous to allow it to be copyable or even movable. It also means it's not compatible with std::vector (which I don't like requiring as an API parameter anyway), so `WaitAll()` expects any contiguous array of AsyncLookupHandles. I believe this is best for common case efficiency, while behaving well in other cases also. For example, `WaitAll()` has no effect on default-constructed AsyncLookupHandles, which look like a completed cache miss. ## cacheable_entry.h A couple of functions are obsolete because Cache::Handle can no longer be pending. ## cache.cc Provides default implementations for new or revamped Cache functions, especially appropriate for non-blocking caches. ## secondary_cache_adapter.{h,cc} The full details of the Cache wrapper adding SecondaryCache support. Essentially replicates the SecondaryCache handling that was in LRUCache, but obviously refactored. There is a bit of logic duplication, where Lookup() is essentially a manually optimized version of StartAsyncLookup() and Wait(), but it's roughly a dozen lines of code. ## sharded_cache.h, typed_cache.h, charged_cache.{h,cc}, sim_cache.cc Simply updated for Cache API changes. ## lru_cache.{h,cc} Carefully remove SecondaryCache logic, implement `CreateStandalone` and eviction handler functionality. ## clock_cache.{h,cc} Expose existing `CreateStandalone` functionality, add eviction handler functionality. Light refactoring. ## block_based_table_reader* Mostly re-worked the only usage of async Lookup, which is in BlockBasedTable::MultiGet. Used arrays in place of autovector in some places for efficiency. Simplified some logic by not trying to process some cache results before they're all ready. Created new function `BlockBasedTable::GetCachePriority()` to reduce some pre-existing code duplication (and avoid making it worse). Fixed at least one small bug from the prior confusing mixture of async and sync Lookups. In MaybeReadBlockAndLoadToCache(), called by RetrieveBlock(), called by MultiGet() with wait=false, is_cache_hit for the block_cache_tracer entry would not be set to true if the handle was pending after Lookup and before Wait. ## Intended follow-up work * Figure out if there are any missing stats or block_cache_tracer work in refactored BlockBasedTable::MultiGet * Stacked secondary caches (see above discussion) * See if we can make up for the small MultiGet performance regression. * Study more performance with SecondaryCache * Items evicted from over-full LRUCache in Release were not being demoted to SecondaryCache, and still aren't to minimize unit test churn. Ideally they would be demoted, but it's an exceptional case so not a big deal. * Use CreateStandalone for cache reservations (save unnecessary hash table operations). Not a big deal, but worthy cleanup. * Somehow I got the contract for SecondaryCache::Insert wrong in #10945. (Doesn't take ownership!) That API comment needs to be fixed, but didn't want to mingle that in here. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11301 Test Plan: ## Unit tests Generally updated to include HCC in SecondaryCache tests, though HyperClockCache has some different, less strict behaviors that leads to some tests not really being set up to work with it. Some of the tests remain disabled with it, but I think we have good coverage without them. ## Crash/stress test Updated to use the new combination. ## Performance First, let's check for regression on caches without secondary cache configured. Adding support for the eviction callback is likely to have a tiny effect, but it shouldn't be worrisome. LRUCache could benefit slightly from less logic around SecondaryCache handling. We can test with cache_bench default settings, built with DEBUG_LEVEL=0 and PORTABLE=0. ``` (while :; do base/cache_bench --cache_type=hyper_clock_cache | grep Rough; done) | awk '{ sum += $9; count++; print $0; print "Average: " int(sum / count) }' ``` **Before** this and #11299 (which could also have a small effect), running for about an hour, before & after running concurrently for each cache type: HyperClockCache: 3168662 (average parallel ops/sec) LRUCache: 2940127 **After** this and #11299, running for about an hour: HyperClockCache: 3164862 (average parallel ops/sec) (0.12% slower) LRUCache: 2940928 (0.03% faster) This is an acceptable difference IMHO. Next, let's consider essentially the worst case of new CPU overhead affecting overall performance. MultiGet uses the async lookup interface regardless of whether SecondaryCache or folly are used. We can configure a benchmark where all block cache queries are for data blocks, and all are hits. Create DB and test (before and after tests running simultaneously): ``` TEST_TMPDIR=/dev/shm ./db_bench -benchmarks=fillrandom -num=30000000 -disable_wal=1 -bloom_bits=16 TEST_TMPDIR=/dev/shm base/db_bench -benchmarks=multireadrandom[-X30] -readonly -multiread_batched -batch_size=32 -num=30000000 -bloom_bits=16 -cache_size=6789000000 -duration 20 -threads=16 ``` **Before**: multireadrandom [AVG 30 runs] : 3444202 (± 57049) ops/sec; 240.9 (± 4.0) MB/sec multireadrandom [MEDIAN 30 runs] : 3514443 ops/sec; 245.8 MB/sec **After**: multireadrandom [AVG 30 runs] : 3291022 (± 58851) ops/sec; 230.2 (± 4.1) MB/sec multireadrandom [MEDIAN 30 runs] : 3366179 ops/sec; 235.4 MB/sec So that's roughly a 3% regression, on kind of a *worst case* test of MultiGet CPU. Similar story with HyperClockCache: **Before**: multireadrandom [AVG 30 runs] : 3933777 (± 41840) ops/sec; 275.1 (± 2.9) MB/sec multireadrandom [MEDIAN 30 runs] : 3970667 ops/sec; 277.7 MB/sec **After**: multireadrandom [AVG 30 runs] : 3755338 (± 30391) ops/sec; 262.6 (± 2.1) MB/sec multireadrandom [MEDIAN 30 runs] : 3785696 ops/sec; 264.8 MB/sec Roughly a 4-5% regression. Not ideal, but not the whole story, fortunately. Let's also look at Get() in db_bench: ``` TEST_TMPDIR=/dev/shm ./db_bench -benchmarks=readrandom[-X30] -readonly -num=30000000 -bloom_bits=16 -cache_size=6789000000 -duration 20 -threads=16 ``` **Before**: readrandom [AVG 30 runs] : 2198685 (± 13412) ops/sec; 153.8 (± 0.9) MB/sec readrandom [MEDIAN 30 runs] : 2209498 ops/sec; 154.5 MB/sec **After**: readrandom [AVG 30 runs] : 2292814 (± 43508) ops/sec; 160.3 (± 3.0) MB/sec readrandom [MEDIAN 30 runs] : 2365181 ops/sec; 165.4 MB/sec That's showing roughly a 4% improvement, perhaps because of the secondary cache code that is no longer part of LRUCache. But weirdly, HyperClockCache is also showing 2-3% improvement: **Before**: readrandom [AVG 30 runs] : 2272333 (± 9992) ops/sec; 158.9 (± 0.7) MB/sec readrandom [MEDIAN 30 runs] : 2273239 ops/sec; 159.0 MB/sec **After**: readrandom [AVG 30 runs] : 2332407 (± 11252) ops/sec; 163.1 (± 0.8) MB/sec readrandom [MEDIAN 30 runs] : 2335329 ops/sec; 163.3 MB/sec Reviewed By: ltamasi Differential Revision: D44177044 Pulled By: pdillinger fbshipit-source-id: e808e48ff3fe2f792a79841ba617be98e48689f5	2 years ago
anand76	eac6b6d0cd	Ignore async_io ReadOption if FileSystem doesn't support it (#11296) ... Summary: In PosixFileSystem, IO uring support is opt-in. If the support is not enabled by the user, then ignore the async_io ReadOption in MultiGet and iteration at the top, rather than follow the async_io codepath and transparently switch to sync IO at the FileSystem layer. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11296 Test Plan: Add new unit tests Reviewed By: akankshamahajan15 Differential Revision: D44045776 Pulled By: anand1976 fbshipit-source-id: a0881bf763ca2fde50b84063d0068bb521edd8b9	2 years ago
Hui Xiao	bab5f9a6f2	Add new stat rocksdb.table.open.prefetch.tail.read.bytes, rocksdb.table.open.prefetch.tail.{miss|hit} (#11265) ... Summary: **Context/Summary:** We are adding new stats to measure behavior of prefetched tail size and look up into this buffer The stat collection is done in FilePrefetchBuffer but only for prefetched tail buffer during table open for now using FilePrefetchBuffer enum. It's cleaner than the alternative of implementing in upper-level call places of FilePrefetchBuffer for table open. It also has the benefit of extensible to other types of FilePrefetchBuffer if needed. See db bench for perf regression concern. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11265 Test Plan: **- Piggyback on existing test** **- rocksdb.table.open.prefetch.tail.miss is harder to UT so I manually set prefetch tail read bytes to be small and run db bench.** ``` ./db_bench -db=/tmp/testdb -statistics=true -benchmarks="fillseq" -key_size=32 -value_size=512 -num=5000 -write_buffer_size=655 -target_file_size_base=655 -disable_auto_compactions=false -compression_type=none -bloom_bits=3 -use_direct_reads=true ``` ``` rocksdb.table.open.prefetch.tail.read.bytes P50 : 4096.000000 P95 : 4096.000000 P99 : 4096.000000 P100 : 4096.000000 COUNT : 225 SUM : 921600 rocksdb.table.open.prefetch.tail.miss COUNT : 91 rocksdb.table.open.prefetch.tail.hit COUNT : 1034 ``` **- No perf regression observed in db_bench** SETUP command: create same db with ~900 files for pre-change/post-change. ``` ./db_bench -db=/tmp/testdb -benchmarks="fillseq" -key_size=32 -value_size=512 -num=500000 -write_buffer_size=655360 -disable_auto_compactions=true -target_file_size_base=16777216 -compression_type=none ``` TEST command 60 runs or til convergence: as suggested by anand1976 and akankshamahajan15, vary `seek_nexts` and `async_io` in testing. ``` ./db_bench -use_existing_db=true -db=/tmp/testdb -statistics=false -cache_size=0 -cache_index_and_filter_blocks=false -benchmarks=seekrandom[-X60] -num=50000 -seek_nexts={10, 500, 1000} -async_io={0|1} -use_direct_reads=true ``` async io = 0, direct io read = true | seek_nexts = 10, 30 runs | seek_nexts = 500, 12 runs | seek_nexts = 1000, 6 runs -- | -- | -- | -- pre-post change | 4776 (± 28) ops/sec; 24.8 (± 0.1) MB/sec | 288 (± 1) ops/sec; 74.8 (± 0.4) MB/sec | 145 (± 4) ops/sec; 75.6 (± 2.2) MB/sec post-change | 4790 (± 32) ops/sec; 24.9 (± 0.2) MB/sec | 288 (± 3) ops/sec; 74.7 (± 0.8) MB/sec | 143 (± 3) ops/sec; 74.5 (± 1.6) MB/sec async io = 1, direct io read = true | seek_nexts = 10, 54 runs | seek_nexts = 500, 6 runs | seek_nexts = 1000, 4 runs -- | -- | -- | -- pre-post change | 3350 (± 36) ops/sec; 17.4 (± 0.2) MB/sec | 264 (± 0) ops/sec; 68.7 (± 0.2) MB/sec | 138 (± 1) ops/sec; 71.8 (± 1.0) MB/sec post-change | 3358 (± 27) ops/sec; 17.4 (± 0.1) MB/sec | 263 (± 2) ops/sec; 68.3 (± 0.8) MB/sec | 139 (± 1) ops/sec; 72.6 (± 0.6) MB/sec Reviewed By: ajkr Differential Revision: D43781467 Pulled By: hx235 fbshipit-source-id: a706a18472a8edb2b952bac3af40eec803537f2a	2 years ago
Hui Xiao	11cb6af6e5	Fix bug of prematurely excluded CF in atomic flush contains unflushed data that should've been included in the atomic flush (#11148) ... Summary: **Context:** Atomic flush should guarantee recoverability of all data of seqno up to the max seqno of the flush. It achieves this by ensuring all such data are flushed by the time this atomic flush finishes through `SelectColumnFamiliesForAtomicFlush()`. However, our crash test exposed the following case where an excluded CF from an atomic flush contains unflushed data of seqno less than the max seqno of that atomic flush and loses its data with `WriteOptions::DisableWAL=true` in face of a crash right after the atomic flush finishes . ``` ./db_stress --preserve_unverified_changes=1 --reopen=0 --acquire_snapshot_one_in=0 --adaptive_readahead=1 --allow_data_in_errors=True --async_io=1 --atomic_flush=1 --avoid_flush_during_recovery=0 --avoid_unnecessary_blocking_io=0 --backup_max_size=104857600 --backup_one_in=0 --batch_protection_bytes_per_key=0 --block_size=16384 --bloom_bits=15 --bottommost_compression_type=none --bytes_per_sync=262144 --cache_index_and_filter_blocks=0 --cache_size=8388608 --cache_type=lru_cache --charge_compression_dictionary_building_buffer=0 --charge_file_metadata=1 --charge_filter_construction=0 --charge_table_reader=0 --checkpoint_one_in=0 --checksum_type=kXXH3 --clear_column_family_one_in=0 --compact_files_one_in=0 --compact_range_one_in=0 --compaction_pri=1 --compaction_ttl=100 --compression_max_dict_buffer_bytes=134217727 --compression_max_dict_bytes=16384 --compression_parallel_threads=1 --compression_type=lz4hc --compression_use_zstd_dict_trainer=0 --compression_zstd_max_train_bytes=0 --continuous_verification_interval=0 --data_block_index_type=0 --db=$db --db_write_buffer_size=1048576 --delpercent=4 --delrangepercent=1 --destroy_db_initially=0 --detect_filter_construct_corruption=0 --disable_wal=1 --enable_compaction_filter=0 --enable_pipelined_write=0 --expected_values_dir=$exp --fail_if_options_file_error=0 --fifo_allow_compaction=0 --file_checksum_impl=none --flush_one_in=0 --format_version=5 --get_current_wal_file_one_in=0 --get_live_files_one_in=100 --get_property_one_in=0 --get_sorted_wal_files_one_in=0 --index_block_restart_interval=2 --index_type=0 --ingest_external_file_one_in=0 --initial_auto_readahead_size=524288 --iterpercent=10 --key_len_percent_dist=1,30,69 --level_compaction_dynamic_level_bytes=True --long_running_snapshots=1 --manual_wal_flush_one_in=100 --mark_for_compaction_one_file_in=0 --max_auto_readahead_size=0 --max_background_compactions=20 --max_bytes_for_level_base=10485760 --max_key=10000 --max_key_len=3 --max_manifest_file_size=1073741824 --max_write_batch_group_size_bytes=64 --max_write_buffer_number=3 --max_write_buffer_size_to_maintain=0 --memtable_prefix_bloom_size_ratio=0.01 --memtable_protection_bytes_per_key=4 --memtable_whole_key_filtering=0 --memtablerep=skip_list --min_write_buffer_number_to_merge=2 --mmap_read=1 --mock_direct_io=False --nooverwritepercent=1 --num_file_reads_for_auto_readahead=0 --open_files=-1 --open_metadata_write_fault_one_in=0 --open_read_fault_one_in=0 --open_write_fault_one_in=0 --ops_per_thread=100000000 --optimize_filters_for_memory=1 --paranoid_file_checks=1 --partition_filters=0 --partition_pinning=3 --pause_background_one_in=0 --periodic_compaction_seconds=100 --prefix_size=8 --prefixpercent=5 --prepopulate_block_cache=0 --preserve_internal_time_seconds=3600 --progress_reports=0 --read_fault_one_in=32 --readahead_size=16384 --readpercent=50 --recycle_log_file_num=0 --ribbon_starting_level=6 --secondary_cache_fault_one_in=0 --set_options_one_in=10000 --snapshot_hold_ops=100000 --sst_file_manager_bytes_per_sec=104857600 --sst_file_manager_bytes_per_truncate=1048576 --stats_dump_period_sec=10 --subcompactions=1 --sync=0 --sync_fault_injection=0 --target_file_size_base=524288 --target_file_size_multiplier=2 --test_batches_snapshots=0 --top_level_index_pinning=0 --unpartitioned_pinning=1 --use_direct_io_for_flush_and_compaction=0 --use_direct_reads=0 --use_full_merge_v1=0 --use_merge=0 --use_multiget=1 --use_put_entity_one_in=0 --user_timestamp_size=0 --value_size_mult=32 --verify_checksum=1 --verify_checksum_one_in=0 --verify_db_one_in=1000 --verify_sst_unique_id_in_manifest=1 --wal_bytes_per_sync=524288 --wal_compression=none --write_buffer_size=524288 --write_dbid_to_manifest=1 --write_fault_one_in=0 --writepercent=30 & pid=$! sleep 0.2 sleep 10 kill $pid sleep 0.2 ./db_stress --ops_per_thread=1 --preserve_unverified_changes=1 --reopen=0 --acquire_snapshot_one_in=0 --adaptive_readahead=1 --allow_data_in_errors=True --async_io=1 --atomic_flush=1 --avoid_flush_during_recovery=0 --avoid_unnecessary_blocking_io=0 --backup_max_size=104857600 --backup_one_in=0 --batch_protection_bytes_per_key=0 --block_size=16384 --bloom_bits=15 --bottommost_compression_type=none --bytes_per_sync=262144 --cache_index_and_filter_blocks=0 --cache_size=8388608 --cache_type=lru_cache --charge_compression_dictionary_building_buffer=0 --charge_file_metadata=1 --charge_filter_construction=0 --charge_table_reader=0 --checkpoint_one_in=0 --checksum_type=kXXH3 --clear_column_family_one_in=0 --compact_files_one_in=0 --compact_range_one_in=0 --compaction_pri=1 --compaction_ttl=100 --compression_max_dict_buffer_bytes=134217727 --compression_max_dict_bytes=16384 --compression_parallel_threads=1 --compression_type=lz4hc --compression_use_zstd_dict_trainer=0 --compression_zstd_max_train_bytes=0 --continuous_verification_interval=0 --data_block_index_type=0 --db=$db --db_write_buffer_size=1048576 --delpercent=4 --delrangepercent=1 --destroy_db_initially=0 --detect_filter_construct_corruption=0 --disable_wal=1 --enable_compaction_filter=0 --enable_pipelined_write=0 --expected_values_dir=$exp --fail_if_options_file_error=0 --fifo_allow_compaction=0 --file_checksum_impl=none --flush_one_in=0 --format_version=5 --get_current_wal_file_one_in=0 --get_live_files_one_in=100 --get_property_one_in=0 --get_sorted_wal_files_one_in=0 --index_block_restart_interval=2 --index_type=0 --ingest_external_file_one_in=0 --initial_auto_readahead_size=524288 --iterpercent=10 --key_len_percent_dist=1,30,69 --level_compaction_dynamic_level_bytes=True --long_running_snapshots=1 --manual_wal_flush_one_in=100 --mark_for_compaction_one_file_in=0 --max_auto_readahead_size=0 --max_background_compactions=20 --max_bytes_for_level_base=10485760 --max_key=10000 --max_key_len=3 --max_manifest_file_size=1073741824 --max_write_batch_group_size_bytes=64 --max_write_buffer_number=3 --max_write_buffer_size_to_maintain=0 --memtable_prefix_bloom_size_ratio=0.01 --memtable_protection_bytes_per_key=4 --memtable_whole_key_filtering=0 --memtablerep=skip_list --min_write_buffer_number_to_merge=2 --mmap_read=1 --mock_direct_io=False --nooverwritepercent=1 --num_file_reads_for_auto_readahead=0 --open_files=-1 --open_metadata_write_fault_one_in=0 --open_read_fault_one_in=0 --open_write_fault_one_in=0 --ops_per_thread=100000000 --optimize_filters_for_memory=1 --paranoid_file_checks=1 --partition_filters=0 --partition_pinning=3 --pause_background_one_in=0 --periodic_compaction_seconds=100 --prefix_size=8 --prefixpercent=5 --prepopulate_block_cache=0 --preserve_internal_time_seconds=3600 --progress_reports=0 --read_fault_one_in=32 --readahead_size=16384 --readpercent=50 --recycle_log_file_num=0 --ribbon_starting_level=6 --secondary_cache_fault_one_in=0 --set_options_one_in=10000 --snapshot_hold_ops=100000 --sst_file_manager_bytes_per_sec=104857600 --sst_file_manager_bytes_per_truncate=1048576 --stats_dump_period_sec=10 --subcompactions=1 --sync=0 --sync_fault_injection=0 --target_file_size_base=524288 --target_file_size_multiplier=2 --test_batches_snapshots=0 --top_level_index_pinning=0 --unpartitioned_pinning=1 --use_direct_io_for_flush_and_compaction=0 --use_direct_reads=0 --use_full_merge_v1=0 --use_merge=0 --use_multiget=1 --use_put_entity_one_in=0 --user_timestamp_size=0 --value_size_mult=32 --verify_checksum=1 --verify_checksum_one_in=0 --verify_db_one_in=1000 --verify_sst_unique_id_in_manifest=1 --wal_bytes_per_sync=524288 --wal_compression=none --write_buffer_size=524288 --write_dbid_to_manifest=1 --write_fault_one_in=0 --writepercent=30 & pid=$! sleep 0.2 sleep 40 kill $pid sleep 0.2 Verification failed for column family 6 key 0000000000000239000000000000012B0000000000000138 (56622): value_from_db: , value_from_expected: 4A6331754E4F4C4D42434041464744455A5B58595E5F5C5D5253505156575455, msg: Value not found: NotFound: Crash-recovery verification failed :( No writes or ops? Verification failed :( ``` The bug is due to the following: - When atomic flush is used, an empty CF is legally [excluded](https://github.com/facebook/rocksdb/blob/7.10.fb/db/db_filesnapshot.cc#L39) in `SelectColumnFamiliesForAtomicFlush` as the first step of `DBImpl::FlushForGetLiveFiles` before [passing](https://github.com/facebook/rocksdb/blob/7.10.fb/db/db_filesnapshot.cc#L42) the included CFDs to `AtomicFlushMemTables`. - But [later](https://github.com/facebook/rocksdb/blob/7.10.fb/db/db_impl/db_impl_compaction_flush.cc#L2133) in `AtomicFlushMemTables`, `WaitUntilFlushWouldNotStallWrites` will [release the db mutex](https://github.com/facebook/rocksdb/blob/7.10.fb/db/db_impl/db_impl_compaction_flush.cc#L2403), during which data@seqno N can be inserted into the excluded CF and data@seqno M can be inserted into one of the included CFs, where M > N. - However, data@seqno N in an already-excluded CF is thus excluded from this atomic flush while we seqno N is less than seqno M. **Summary:** - Replace `SelectColumnFamiliesForAtomicFlush()`-before-`AtomicFlushMemTables()` with `SelectColumnFamiliesForAtomicFlush()`-after-wait-within-`AtomicFlushMemTables()` so we ensure no write affecting the recoverability of this atomic job (i.e, change to max seqno of this atomic flush or insertion of data with less seqno than the max seqno of the atomic flush to excluded CF) can happen after calling `SelectColumnFamiliesForAtomicFlush()`. - For above, refactored and clarified comments on `SelectColumnFamiliesForAtomicFlush()` and `AtomicFlushMemTables()` for clearer semantics of passed-in CFDs to atomic-flush Pull Request resolved: https://github.com/facebook/rocksdb/pull/11148 Test Plan: - New unit test failed before the fix and passes after - Make check - Rehearsal stress test Reviewed By: ajkr Differential Revision: D42799871 Pulled By: hx235 fbshipit-source-id: 13636b63e9c25c5895857afc36ea580d57f6d644	2 years ago
Levi Tamasi	49881921cd	Rename a recently added PerfContext counter (#11294) ... Summary: The patch renames the counter added in https://github.com/facebook/rocksdb/issues/11284 for better consistency with the existing naming scheme. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11294 Test Plan: `make check` Reviewed By: jowlyzhang Differential Revision: D44035964 Pulled By: ltamasi fbshipit-source-id: 8b1a2a03ee728148365367e0ecc1fcf462f62191	2 years ago
Changyu Bi	9aa3b6f9ae	Support range deletion tombstones in `CreateColumnFamilyWithImport` (#11252) ... Summary: CreateColumnFamilyWithImport() did not support range tombstones for two reasons: 1. it uses point keys of a input file to determine its boundary (smallest and largest internal key), which means range tombstones outside of the point key range will be effectively dropped. 2. it does not handle files with no point keys. Also included a fix in external_sst_file_ingestion_job.cc where the blocks read in `GetIngestedFileInfo()` can be added to block cache now (issue fixed in https://github.com/facebook/rocksdb/pull/6429). This PR adds support for exporting and importing column family with range tombstones. The main change is to add smallest internal key and largest internal key to `SstFileMetaData` that will be part of the output of `ExportColumnFamily()`. Then during `CreateColumnFamilyWithImport(...,const ExportImportFilesMetaData& metadata,...)`, file boundaries can be set from `metadata` directly. This is needed since when file boundaries are extended by range tombstones, sometimes they cannot be deduced from a file's content alone. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11252 Test Plan: - added unit tests that fails before this change Closes https://github.com/facebook/rocksdb/issues/11245 Reviewed By: ajkr Differential Revision: D43577443 Pulled By: cbi42 fbshipit-source-id: 6bff78e583cc50c44854994dea0a8dd519398f2f	2 years ago
Levi Tamasi	1d52438504	Add a PerfContext counter for merge operands applied in point lookups (#11284) ... Summary: The existing PerfContext counter `internal_merge_count` only tracks the Merge operands applied during range scans. The patch adds a new counter called `internal_merge_count_point_lookups` to track the same metric for point lookups (`Get` / `MultiGet` / `GetEntity` / `MultiGetEntity`), and also fixes a couple of cases in the iterator where the existing counter wasn't updated. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11284 Test Plan: `make check` Reviewed By: jowlyzhang Differential Revision: D43926082 Pulled By: ltamasi fbshipit-source-id: 321566d8b4cf0a3b6c9b73b7a5c984fb9bb492e9	2 years ago
Yu Zhang	8dfcfd4e90	Fix backward iteration issue when user defined timestamp is enabled in BlobDB (#11258) ... Summary: During backward iteration, blob verification would fail because the user key (ts included) in `saved_key_` doesn't match the blob. This happens because during`FindValueForCurrentKey`, `saved_key_` is not updated when the user key(ts not included) is the same for all cases except when `timestamp_lb_` is specified. This breaks the blob verification logic when user defined timestamp is enabled and `timestamp_lb_` is not specified. Fix this by always updating `saved_key_` when a smaller user key (ts included) is seen. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11258 Test Plan: `make check` `./db_blob_basic_test --gtest_filter=DBBlobWithTimestampTest.IterateBlobs` Run db_bench (built with DEBUG_LEVEL=0) to demonstrate that no overhead is introduced with: `./db_bench -user_timestamp_size=8 -db=/dev/shm/rocksdb -disable_wal=1 -benchmarks=fillseq,seekrandom[-W1-X6] -reverse_iterator=1 -seek_nexts=5` Baseline: - seekrandom [AVG 6 runs] : 72188 (± 1481) ops/sec; 37.2 (± 0.8) MB/sec With this PR: - seekrandom [AVG 6 runs] : 74171 (± 1427) ops/sec; 38.2 (± 0.7) MB/sec Reviewed By: ltamasi Differential Revision: D43675642 Pulled By: jowlyzhang fbshipit-source-id: 8022ae8522d1f66548821855e6eed63640c14e04	2 years ago
anand76	cf09917c18	Add filter/index/data secondary cache hits stats (#11246) ... Summary: Add more stats for better visibility into the usefulness of the secondary cache. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11246 Test Plan: Add a new unit test Reviewed By: akankshamahajan15 Differential Revision: D43521364 Pulled By: anand1976 fbshipit-source-id: a92f04884e738a9bf40ad4047acaaaea343838a7	2 years ago
Yu Zhang	f007b8fdea	Support iter_start_ts in integrated BlobDB (#11244) ... Summary: Fixed an issue during backward iteration when `iter_start_ts` is set in an integrated BlobDB. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11244 Test Plan: ```make check ./db_blob_basic_test --gtest_filter="DBBlobWithTimestampTest.IterateBlobs" tools/db_crashtest.py --stress_cmd=./db_stress --cleanup_cmd='' --enable_ts whitebox --random_kill_odd 888887 --enable_blob_files=1``` Reviewed By: ltamasi Differential Revision: D43506726 Pulled By: jowlyzhang fbshipit-source-id: 2cdc19ebf8da909d8d43d621353905784949a9f0	2 years ago
Changyu Bi	229297d1b8	Refactor AddRangeDels() + consider range tombstone during compaction file cutting (#11113) ... Summary: A second attempt after https://github.com/facebook/rocksdb/issues/10802, with bug fixes and refactoring. This PR updates compaction logic to take range tombstones into account when determining whether to cut the current compaction output file (https://github.com/facebook/rocksdb/issues/4811). Before this change, only point keys were considered, and range tombstones could cause large compactions. For example, if the current compaction outputs is a range tombstone [a, b) and 2 point keys y, z, they would be added to the same file, and may overlap with too many files in the next level and cause a large compaction in the future. This PR also includes ajkr's effort to simplify the logic to add range tombstones to compaction output files in `AddRangeDels()` ([https://github.com/facebook/rocksdb/issues/11078](https://github.com/facebook/rocksdb/pull/11078#issuecomment-1386078861)). The main change is for `CompactionIterator` to emit range tombstone start keys to be processed by `CompactionOutputs`. A new class `CompactionMergingIterator` is introduced to replace `MergingIterator` under `CompactionIterator` to enable emitting of range tombstone start keys. Further improvement after this PR include cutting compaction output at some grandparent boundary key (instead of the next output key) when cutting within a range tombstone to reduce overlap with grandparents. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11113 Test Plan: * added unit test in db_range_del_test * crash test with a small key range: `python3 tools/db_crashtest.py blackbox --simple --max_key=100 --interval=600 --write_buffer_size=262144 --target_file_size_base=256 --max_bytes_for_level_base=262144 --block_size=128 --value_size_mult=33 --subcompactions=10 --use_multiget=1 --delpercent=3 --delrangepercent=2 --verify_iterator_with_expected_state_one_in=2 --num_iterations=10` Reviewed By: ajkr Differential Revision: D42655709 Pulled By: cbi42 fbshipit-source-id: 8367e36ef5640e8f21c14a3855d4a8d6e360a34c	2 years ago