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35 Commits
| Author | SHA1 | Message | Date | |
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Peter Dillinger
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d8b1893c9d |
DROP support for block-based SST format_version < 2 (#14315)
Summary: ... and remove some old code and tech debt in the process. This is arguably a great milestone and precendent in RocksDB history as for the first time we are explicitly dropping support for the ability to read source-of-truth data in old formats. (We previously dropped support for reading some old bloom filters, but those are performance optimizers not source-of-truth. https://github.com/facebook/rocksdb/issues/10184) However, DBs written with default settings since release 4.6.0, which is very nearly 10 years ago, can still be read. And by using compaction with intermediate versions, there's an upgrade path going back to (AFAIK) early releases of LevelDB (from which RocksDB was forked). Some detail: * The magic number for LevelDB SST files (0xdb4775248b80fb57, most recently called kLegacyBlockBasedTableMagicNumber) now only exists in the code to provide a good error message and to test that good error message. * There is some notable refactoring and renaming around format_version handling. This is a bit of a messy area of code because the footer code being shared between different table formats (block-based, plain, cuckoo) means format_version in the footer is in ways tied to all of them, but in other ways is just tied to block-based table where we have been making updates. Hopefully code comments keep this clear. * Now that there are old format_versions we can't read (and can't write authoritatively in tests), I've needed to split out kMinSupportedFormatVersion into a constant for reads and for writes, currently the same at format_version=2. Comments describe how to update these in the future. * The idea of versioning the compression format is basically going away, though we're keeping BuiltinV2 in places just because it's already there. There's lots of room in the BuiltinV2 schema to expand to new built-in compression types, or new ways of handling existing compression algorithms. CompressionManager with CompatibilityName gives users the power to customize compression without the need for versions tied to format_version. Immediate follow-up: * Clean up compression loose ends like OLD_Compress, OLD_Uncompress Suggested follow-up: * Update plain table builder to migrate to new footer version so that we can drop support for legacy footer. We have to be careful that the (likely untested) forward compatibility path I put in place a while back works (or fix it and wait a while) before dropping support for plain table with legacy footer. Pull Request resolved: https://github.com/facebook/rocksdb/pull/14315 Test Plan: * Some tests updated / added * A couple tests are obsolete: removed * Also updated format compatible test, which now doesn't need to dig as far back into history building RocksDB. Reviewed By: hx235 Differential Revision: D92577766 Pulled By: pdillinger fbshipit-source-id: a23be846189d901ce087af4ca9a99cef18445cb7 |
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Peter Dillinger
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48ec45d7bb |
Remove useless option CompressedSecondaryCacheOptions::compress_format_version (#14302)
Summary: I don't think this option was ever useful. There was no compressed secondary cache compatibility issue that needed to accommodate compression format version 1. It was needlessly imported from legacy SST file formats. Version 1 is simply an inefficient format because it requires guessing the uncompressed size on decompression. And as far as I know, we don't have any plans to make compressed secondary cache entries persistable across RocksDB versions. I.e. if persisting, we would simply tag the persistence layer with the version (perhaps major and minor) and throw out the cache whenever that changes. Then we don't have to deal with explicit schema versioning in persistenct caches. This is a workable approach because unlike SSTs, caches are not source-of-truth that need to survive version rollback. Pull Request resolved: https://github.com/facebook/rocksdb/pull/14302 Test Plan: existing tests Reviewed By: anand1976 Differential Revision: D92315003 Pulled By: pdillinger fbshipit-source-id: 0b82cfdbd92bcd2b8fbddd6586824f53c88069c4 |
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Peter Dillinger
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0a169cea0e |
Compressor::CompressBlock API change and refactoring/improvement (#13805)
Summary: The main motivation for this change is to more flexibly and efficiently support compressing data without extra copies when we do not want to support saving compressed data that is LARGER than the uncompressed. We believe pretty strongly that for the various workloads served by RocksDB, it is well worth a single byte compression marker so that we have the flexibility to save compressed or uncompressed data when compression is attempted. Why? Compression algorithms can add tens of bytes in fixed overheads and percents of bytes in relative overheads. It is also an advantage for the reader when they can bypass decompression, including at least a buffer copy in most cases, after reading just one byte. The block-based table format in RocksDB follows this model with a single-byte compression marker, and at least after https://github.com/facebook/rocksdb/pull/13797 so does CompressedSecondaryCache. (Notably, the blob file format DOES NOT. This is left to follow-up work.) In particular, Compressor::CompressBlock now takes in a fixed size buffer for output rather than a `std::string*`. CompressBlock itself rejects the compression if the output would not fit in the provided buffer. This also works well with `max_compressed_bytes_per_kb` option to reject compression even sooner if its ratio is insufficient (implemented in this change). In the future we might use this functionality to reduce a buffer copy (in many cases) into the WritableFileWriter buffer of the block based table builder. This is a large change because we needed to (or were compelled to) * Update all the existing callers of CompressBlock, sometimes with substantial changes. This includes introducing GrowableBuffer to reuse between calls rather than std::string, which (at least in C++17) requires zeroing out data when allocating/growing a buffer. * Re-implement built-in Compressors (V2; V1 is obsolete) to efficiently implement the new version of the API, no longer wrapping the `OLD_CompressData()` function. The new compressors appropriately leverage the CompressBlock virtual call required for the customization interface and no rely on `switch` on compression type for each block. The implementations are largely adaptations of the old implementations, except * LZ4 and LZ4HC are notably upgraded to take advantage of WorkingArea (see performance tests). And for simplicity in the new implementation, we are dropping support for some super old versions of the library. * Getting snappy to work with limited-size output buffer required using the Sink/Source interfaces, which appear to be well supported for a long time and efficient (see performance tests). * Replace awkward old CompressionManager::GetDecompressorForCompressor with Compressor::GetOptimizedDecompressor (which is optional to implement) * Small behavior change where we treat lack of support for compression closer to not configuring compression, such as incompatibility with block_align. This is motivated by giving CompressionManager the freedom of determining when compression can be excluded for an entire file despite the configured "compression" type, and thus only surfacing actual incompatibilities not hypothetical ones that might be irrelevant to the CompressionManager (or build configuration). Unit tests in `table_test` and `compact_files_test` required update. * Some lingering clean up of CompressedSecondaryCache and a re-optimization made possible by compressing into an existing buffer. Pull Request resolved: https://github.com/facebook/rocksdb/pull/13805 Test Plan: for correctness, existing tests ## Performance Test As I generally only modified compression paths, I'm using a db_bench write benchmark, with before & after configurations running at the same time. vc=1 means verify_compression=1 ``` USE_CLANG=1 DEBUG_LEVEL=0 LIB_MODE=static make -j100 db_bench SUFFIX=`tty | sed 's|/|_|g'`; for CT in zlib bzip2 none snappy zstd lz4 lz4hc none snappy zstd lz4 bzip2; do for VC in 0 1; do echo "$CT vc=$VC"; (for I in `seq 1 20`; do BIN=/dev/shm/dbbench${SUFFIX}.bin; rm -f $BIN; cp db_bench $BIN; $BIN -db=/dev/shm/dbbench$SUFFIX --benchmarks=fillseq -num=10000000 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=1000 -fifo_compaction_allow_compaction=0 -disable_wal -write_buffer_size=12000000 -format_version=7 -compression_type=$CT -verify_compression=$VC 2>&1 | grep micros/op; done) | awk '{n++; sum += $5;} END { print int(sum / n); }'; done; done ``` zlib vc=0 524198 -> 524904 (+0.1%) zlib vc=1 430521 -> 430699 (+0.0%) bzip2 vc=0 61841 -> 60835 (-1.6%) bzip2 vc=1 49232 -> 48734 (-1.0%) none vc=0 1802375 -> 1906227 (+5.8%) none vc=1 1837181 -> 1950308 (+6.2%) snappy vc=0 1783266 -> 1901461 (+6.6%) snappy vc=1 1799703 -> 1879660 (+4.4%) zstd vc=0 1216779 -> 1230507 (+1.1%) zstd vc=1 996370 -> 1015415 (+1.9%) lz4 vc=0 1801473 -> 1943095 (+7.9%) lz4 vc=1 1799155 -> 1935242 (+7.6%) lz4hc vc=0 349719 -> 1126909 (+222.2%) lz4hc vc=1 348099 -> 1108933 (+218.6%) (Repeating the most important ones) none vc=0 1816878 -> 1952221 (+7.4%) none vc=1 1813736 -> 1904622 (+5.0%) snappy vc=0 1794816 -> 1875062 (+4.5%) snappy vc=1 1789363 -> 1873771 (+4.7%) zstd vc=0 1202592 -> 1225164 (+1.9%) zstd vc=1 994322 -> 1016688 (+2.2%) lz4 vc=0 1786959 -> 1971518 (+10.3%) lz4 vc=1 1829483 -> 1935871 (+5.8%) I confirmed manually that the new WorkingArea for LZ4HC makes the huge difference on that one, but not as much difference for LZ4, presumably because LZ4HC uses much larger buffers/structures/whatever for better compression ratios. Reviewed By: hx235 Differential Revision: D79111736 Pulled By: pdillinger fbshipit-source-id: 1ce1b14af9f15365f1b6da49906b5073a8cecc14 |
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Peter Dillinger
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ee6b0def55 |
Refactor, improve CompressedSecondaryCache (#13797)
Summary: To be compatible with some upcoming compression change/refactoring where we supply a fixed size buffer to CompressBlock, we need to support CompressedSecondaryCache storing uncompressed values when the compression ratio is not suitable. It seems crazy that CompressedSecondaryCache currently stores compressed values that are *larger* than the uncompressed value, and even explicitly exercises that case (almost exclusively) in the existing unit tests. But it's true. This change fixes that with some other nearby refactoring/improvement: * Update the in-memory representation of these cache entries to support uncompressed entries even when compression is enabled. AFAIK this also allows us to safely get rid of "don't support custom split/merge for the tiered case". * Use more efficient in-memory representation for non-split entries * For CompressionType and CacheTier, which are defined as single-byte data types, use a single byte instead of varint32. (I don't know if varint32 was an attempt at future-proofing for a memory-only schema or what.) Now using lossless_cast will raise a compiler error if either of these types is made too large for a single byte. * Don't wrap entries in a CacheAllocationPtr object; it's not necessary. We can rely on the same allocator being provided at delete time. * Restructure serialization/deserialization logic, hopefully simpler or easier to read/understand. * Use a RelaxedAtomic for disable_cache_ to avoid race. Suggested follow-up on CompressedSecondaryCache: * Refine the exact strategy for rejecting compressions * Still have a lot of buffer copies; try to reduce * Revisit the split-merge logic and try to make it more efficient overall, more unified with non-split case Pull Request resolved: https://github.com/facebook/rocksdb/pull/13797 Test Plan: Unit tests updated to use actually compressible strings in many places and more testing around non-compressible string. ## Performance Test There was some pre-existing issue causing decompression failures in compressed secondary cache with cache_bench that is somehow fixed in this change. This decompression failures were present before the new compression API, but since then cause assertion failures rather than being quietly ignored. For the "before" test here, they are back to quietly ignored. And the cache_bench changes here were back-ported to the "before" configuration. ### No compressed secondary (setting expectations) ``` ./cache_bench --cache_type=auto_hyper_clock_cache -cache_size=8000000000 -populate_cache ``` Max key : 3906250 Before: Complete in 12.784 s; Rough parallel ops/sec = 2503123 Thread ops/sec = 160329; Lookup hit ratio: 0.686771 After: Complete in 12.745 s; Rough parallel ops/sec = 2510717 (in the noise) Thread ops/sec = 159498; Lookup hit ratio: 0.68686 ### Compressed secondary, no split/merge Same max key and approximate total memory size ``` /usr/bin/time ./cache_bench --cache_type=auto_hyper_clock_cache -cache_size=4000000000 -populate_cache -resident_ratio=0.125 -compressible_to_ratio=0.4 --secondary_cache_uri=compressed_secondary_cache://capacity=4000000000 ``` Before: Complete in 18.690 s; Rough parallel ops/sec = 1712144 Thread ops/sec = 108683; Lookup hit ratio: 0.776683 Latency: P50: 4205.19 P75: 15281.76 P99: 43810.98 P99.9: 71487.41 P99.99: 165453.32 max RSS (according to /usr/bin/time): 9341856 After: Complete in 17.878 s; Rough parallel ops/sec = 1789951 (+4.5%) Thread ops/sec = 114957; Lookup hit ratio: 0.792998 (+0.016) Latency: P50: 4012.70 P75: 14477.63 P99: 40039.70 P99.9: 62521.04 P99.99: 167049.18 max RSS (according to /usr/bin/time): 9235688 The improved hit ratio is probably from fixing the failed decompressions (somehow). And my modifications could have improved CPU efficiency, or it could be the small penalty the benchmark naturally imposes on most misses (generate another value and insert it). ### Compressed secondary, with split/merge ``` /usr/bin/time ./cache_bench --cache_type=auto_hyper_clock_cache -cache_size=4000000000 -populate_cache -resident_ratio=0.125 -compressible_to_ratio=0.4 --secondary_cache_uri='compressed_secondary_cache://capacity=4000000000;enable_custom_split_merge=true' ``` Before: Complete in 20.062 s; Rough parallel ops/sec = 1595075 Thread ops/sec = 101759; Lookup hit ratio: 0.787129 Latency: P50: 5338.53 P75: 16073.46 P99: 46752.65 P99.9: 73459.11 P99.99: 201318.75 max RSS (according to /usr/bin/time): 9049852 After: Complete in 18.564 s; Rough parallel ops/sec = 1723771 (+8.1%) Thread ops/sec = 110724; Lookup hit ratio: 0.813414 (+0.026) Latency: P50: 5234.75 P75: 14590.43 P99: 41401.03 P99.9: 65606.50 P99.99: 157248.04 max RSS (according to /usr/bin/time): 8917592 Looks like an improvement Reviewed By: anand1976 Differential Revision: D78842120 Pulled By: pdillinger fbshipit-source-id: 5f754b160c37ebee789279178ebb5e862071bdb2 |
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Peter Dillinger
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78c83ac1ec |
Publish/support format_version=7, related enhancements (#13713)
Summary: * Make new format_version=7 a supported setting. * Fix a bug in compressed_secondary_cache.cc that is newly exercised by custom compression types and showing up in crash test with tiered secondary cache * Small change to handling of disabled compression in fv=7: use empty compression manager compatibility name. * Get rid of GetDefaultBuiltinCompressionManager() in public API because it could cause unexpected+unsafe schema change on a user's CompressionManager if built upon the default built-in manager and we add a new built-in schema. Now must be referenced by explicit compression schema version in the public API. (That notion was already exposed in compressed secondary cache API, for better or worse.) * Improve some error messages for compression misconfiguration * Improve testing with ObjectLibrary and CompressionManagers * Improve testing of compression_name table property in BlockBasedTableTest.BlockBasedTableProperties2 * Improve some comments Pull Request resolved: https://github.com/facebook/rocksdb/pull/13713 Test Plan: existing and updated tests. Notably, the crash test has already been running with (unpublished) format_version=7 Reviewed By: mszeszko-meta, hx235 Differential Revision: D77035482 Pulled By: pdillinger fbshipit-source-id: 95278de8734a79706a22361bff2184b1edb230ca |
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Peter Dillinger
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7c9b580681 |
Big refactor for preliminary custom compression API (#13540)
Summary: Adds new classes etc. in internal compression.h that are intended to become public APIs for supporting custom/pluggable compression. Some steps remain to allow for pluggable compression and to remove a lot of legacy code (e.g. now called `OLD_CompressData` and `OLD_UncompressData`), but this change refactors the key integration points of SST building and reading and compressed secondary cache over to the new APIs. Compared with the proposed https://github.com/facebook/rocksdb/issues/7650, this fixes a number of issues including * Making a clean divide between public and internal APIs (currently just indicated with comments) * Enough generality that built-in compressions generally fit into the framework rather than needing special treatment * Avoid exposing obnoxious idioms like `compress_format_version` to the user. * Enough generality that a compressor mixing algorithms/strategies from other compressors is pretty well supported without an extra schema layer * Explicit thread-safety contracts (carefully considered) * Contract details around schema compatibility and extension with code changes (more detail in next PR) * Customizable "working areas" (e.g. for ZSTD "context") * Decompression into an arbitrary memory location (rather than involving the decompressor in memory allocation; should facilitate reducing number of objects in block cache) Pull Request resolved: https://github.com/facebook/rocksdb/pull/13540 Test Plan: This is currently an internal refactor. More testing will come when the new API is migrated to the public API. A test in db_block_cache_test is updated to meaningfully cover a case (cache warming compression dictionary block) that was previously only covered in the crash test. SST write performance test, like https://github.com/facebook/rocksdb/issues/13583. Compile with CLANG, run before & after simultaneously: ``` SUFFIX=`tty | sed 's|/|_|g'`; for ARGS in "-compression_parallel_threads=1 -compression_type=none" "-compression_parallel_threads=1 -compression_type=snappy" "-compression_parallel_threads=1 -compression_type=zstd" "-compression_parallel_threads=1 -compression_type=zstd -verify_compression=1" "-compression_parallel_threads=1 -compression_type=zstd -compression_max_dict_bytes=8180" "-compression_parallel_threads=4 -compression_type=snappy"; do echo $ARGS; (for I in `seq 1 20`; do ./db_bench -db=/dev/shm/dbbench$SUFFIX --benchmarks=fillseq -num=10000000 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=1000 -fifo_compaction_allow_compaction=0 -disable_wal -write_buffer_size=12000000 $ARGS 2>&1 | grep micros/op; done) | awk '{n++; sum += $5;} END { print int(sum / n); }'; done ``` Before (this PR and with https://github.com/facebook/rocksdb/issues/13583 reverted): -compression_parallel_threads=1 -compression_type=none 1908372 -compression_parallel_threads=1 -compression_type=snappy 1926093 -compression_parallel_threads=1 -compression_type=zstd 1208259 -compression_parallel_threads=1 -compression_type=zstd -verify_compression=1 997583 -compression_parallel_threads=1 -compression_type=zstd -compression_max_dict_bytes=8180 934246 -compression_parallel_threads=4 -compression_type=snappy 1644849 After: -compression_parallel_threads=1 -compression_type=none 1956054 (+2.5%) -compression_parallel_threads=1 -compression_type=snappy 1911433 (-0.8%) -compression_parallel_threads=1 -compression_type=zstd 1205668 (-0.3%) -compression_parallel_threads=1 -compression_type=zstd -verify_compression=1 999263 (+0.2%) -compression_parallel_threads=1 -compression_type=zstd -compression_max_dict_bytes=8180 934322 (+0.0%) -compression_parallel_threads=4 -compression_type=snappy 1642519 (-0.2%) Pretty neutral change(s) overall. SST read performance test (related to https://github.com/facebook/rocksdb/issues/13583). Set up: ``` for COMP in none snappy zstd; do echo $ARGS; ./db_bench -db=/dev/shm/dbbench-$COMP --benchmarks=fillseq,flush -num=10000000 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=1000 -fifo_compaction_allow_compaction=0 -disable_wal -write_buffer_size=12000000 -compression_type=$COMP; done ``` Test (compile with CLANG, run before & after simultaneously): ``` for COMP in none snappy zstd; do echo $COMP; (for I in `seq 1 5`; do ./db_bench -readonly -db=/dev/shm/dbbench-$COMP --benchmarks=readrandom -num=10000000 -duration=20 -threads=8 2>&1 | grep micros/op; done) | awk '{n++; sum += $5;} END { print int(sum / n); }'; done ``` Before (this PR and with https://github.com/facebook/rocksdb/issues/13583 reverted): none 1495646 snappy 1172443 zstd 706036 zstd (after constructing with -compression_max_dict_bytes=8180) 656182 After: none 1494981 (-0.0%) snappy 1171846 (-0.1%) zstd 696363 (-1.4%) zstd (after constructing with -compression_max_dict_bytes=8180) 667585 (+1.7%) Pretty neutral. Reviewed By: hx235 Differential Revision: D74626863 Pulled By: pdillinger fbshipit-source-id: dc8ff3178da9b4eaa7c16aa1bb910c872afaf14a |
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Peter Dillinger
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c368c6afe8 |
Minor compression refactoring (#13539)
Summary: * Mostly, remove `sample_for_compression` from CompressionInfo because it's not used by the core function it serves, `CompressData()`. Confusing (and inefficient), especially in db_bench where it appears to use `FLAGS_sample_for_compression` in places where it is actually ignored. * Various clarifying comments, clean-ups, and tiny optimizations * Prepare some structures like `CompressionDict` for more usage * Some TODOs and FIXMEs about some things I've noticed are amiss, confusing, or excessive * A notable optimization opportunity that might become a "pay as you go" improvement for the potential indirection costs of customizable compression: use C++23's resize_and_overwrite() in compress functions to avoid zeroing the string buffer contents before populating it. Pull Request resolved: https://github.com/facebook/rocksdb/pull/13539 Test Plan: existing tests / CI Reviewed By: hx235 Differential Revision: D73451273 Pulled By: pdillinger fbshipit-source-id: 0373627466d695043d21146ce34d52f189ae9432 |
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anand76
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22105366d9 |
More accurate accounting of compressed cache memory (#13032)
Summary: When an item is inserted into the compressed secondary cache, this PR calculates the charge using the malloc_usable_size of the allocated memory, as well as the unique pointer allocation. Pull Request resolved: https://github.com/facebook/rocksdb/pull/13032 Test Plan: New unit test Reviewed By: pdillinger Differential Revision: D63418493 Pulled By: anand1976 fbshipit-source-id: 1db2835af6867442bb8cf6d9bf412e120ddd3824 |
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yuzhangyu@fb.com
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1cfdece85d |
Run internal cpp modernizer on RocksDB repo (#12398)
Summary: When internal cpp modernizer attempts to format rocksdb code, it will replace macro `ROCKSDB_NAMESPACE` with its default definition `rocksdb` when collapsing nested namespace. We filed a feedback for the tool T180254030 and the team filed a bug for this: https://github.com/llvm/llvm-project/issues/83452. At the same time, they suggested us to run the modernizer tool ourselves so future auto codemod attempts will be smaller. This diff contains: Running `xplat/scripts/codemod_service/cpp_modernizer.sh` in fbcode/internal_repo_rocksdb/repo (excluding some directories in utilities/transactions/lock/range/range_tree/lib that has a non meta copyright comment) without swapping out the namespace macro `ROCKSDB_NAMESPACE` Followed by RocksDB's own `make format` Pull Request resolved: https://github.com/facebook/rocksdb/pull/12398 Test Plan: Auto tests Reviewed By: hx235 Differential Revision: D54382532 Pulled By: jowlyzhang fbshipit-source-id: e7d5b40f9b113b60e5a503558c181f080b9d02fa |
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Richard Barnes
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ced333ee45 |
Remove extra semi colon from instagram/ranking/mezql/shots/parser/fast/Token.cpp
Summary: `-Wextra-semi` or `-Wextra-semi-stmt` If the code compiles, this is safe to land. Reviewed By: palmje Differential Revision: D54362213 fbshipit-source-id: 0bbc9e5fce917fc4f72423f0a4c8cb2c2b1759dd |
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anand76
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b49f9cdd3c |
Add CompressionOptions to the compressed secondary cache (#12234)
Summary: Add ```CompressionOptions``` to ```CompressedSecondaryCacheOptions``` to allow users to set options such as compression level. It allows performance to be fine tuned. Tests - Run db_bench and verify compression options in the LOG file Pull Request resolved: https://github.com/facebook/rocksdb/pull/12234 Reviewed By: ajkr Differential Revision: D52758133 Pulled By: anand1976 fbshipit-source-id: af849fbffce6f84704387c195d8edba40d9548f6 |
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anand76
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cc069f25b3 |
Add some compressed and tiered secondary cache stats (#12150)
Summary: Add statistics for more visibility. Pull Request resolved: https://github.com/facebook/rocksdb/pull/12150 Reviewed By: akankshamahajan15 Differential Revision: D52184633 Pulled By: anand1976 fbshipit-source-id: 9969e05d65223811cd12627102b020bb6d229352 |
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anand76
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d367b34cc9 |
Fix TSAN crash test false positive (#11941)
Summary: Fix the TSAN false positive caused by reading a bool flag without synchronization. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11941 Test Plan: Run tsan crash test locally Reviewed By: akankshamahajan15 Differential Revision: D50181799 Pulled By: anand1976 fbshipit-source-id: 889e7237e9f3c9452a9df94a0d949db5fe13bb57 |
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anand76
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48589b961f |
Fix updating the capacity of a tiered cache (#11873)
Summary: Updating the tiered cache (cache allocated using ```NewTieredCache()```) by calling ```SetCapacity()``` on it was not working properly. The initial creation would set the primary cache capacity to the combined primary and compressed secondary cache capacity. But ```SetCapacity()``` would just set the primary cache capacity, with no way to change the secondary cache capacity. Additionally, the API was confusing, since the primary and compressed secondary capacities would be specified separately during creation, but ```SetCapacity``` took the combined capacity. With this fix, the user always specifies the total budget and compressed secondary cache ratio on creation. Subsequently, `SetCapacity` will distribute the new capacity across the two caches by the same ratio. The `NewTieredCache` API has been changed to take the total cache capacity (inclusive of both the primary and the compressed secondary cache) and the ratio of total capacity to allocate to the compressed cache. These are specified in `TieredCacheOptions`. Any capacity specified in `LRUCacheOptions`, `HyperClockCacheOptions` and `CompressedSecondaryCacheOptions` is ignored. A new API, `UpdateTieredCache` is provided to dynamically update the total capacity, ratio of compressed cache, and admission policy. Tests: New unit tests Pull Request resolved: https://github.com/facebook/rocksdb/pull/11873 Reviewed By: akankshamahajan15 Differential Revision: D49562250 Pulled By: anand1976 fbshipit-source-id: 57033bc713b68d5da6292207765a6b3dbe539ddf |
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anand76
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269478ee46 |
Support compressed and local flash secondary cache stacking (#11812)
Summary: This PR implements support for a three tier cache - primary block cache, compressed secondary cache, and a nvm (local flash) secondary cache. This allows more effective utilization of the nvm cache, and minimizes the number of reads from local flash by caching compressed blocks in the compressed secondary cache. The basic design is as follows - 1. A new secondary cache implementation, ```TieredSecondaryCache```, is introduced. It keeps the compressed and nvm secondary caches and manages the movement of blocks between them and the primary block cache. To setup a three tier cache, we allocate a ```CacheWithSecondaryAdapter```, with a ```TieredSecondaryCache``` instance as the secondary cache. 2. The table reader passes both the uncompressed and compressed block to ```FullTypedCacheInterface::InsertFull```, allowing the block cache to optionally store the compressed block. 3. When there's a miss, the block object is constructed and inserted in the primary cache, and the compressed block is inserted into the nvm cache by calling ```InsertSaved```. This avoids the overhead of recompressing the block, as well as avoiding putting more memory pressure on the compressed secondary cache. 4. When there's a hit in the nvm cache, we attempt to insert the block in the compressed secondary cache and the primary cache, subject to the admission policy of those caches (i.e admit on second access). Blocks/items evicted from any tier are simply discarded. We can easily implement additional admission policies if desired. Todo (In a subsequent PR): 1. Add to db_bench and run benchmarks 2. Add to db_stress Pull Request resolved: https://github.com/facebook/rocksdb/pull/11812 Reviewed By: pdillinger Differential Revision: D49461842 Pulled By: anand1976 fbshipit-source-id: b40ac1330ef7cd8c12efa0a3ca75128e602e3a0b |
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anand76
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548aabfe5f |
Disable compressed secondary cache if capacity is 0 (#11863)
Summary: This PR makes disabling the compressed secondary cache by setting capacity to 0 a bit more efficient. Previously, inserts/lookups would go to the backing LRUCache before getting rejected due to 0 capacity. With this change, insert/lookup would return from ```CompressedSecondaryCache``` itself. Tests: Existing tests Pull Request resolved: https://github.com/facebook/rocksdb/pull/11863 Reviewed By: akankshamahajan15 Differential Revision: D49476248 Pulled By: anand1976 fbshipit-source-id: f0f17a5e3df7d8bfc06709f8f23c1302056ba590 |
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Changyu Bi
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c2aad555c3 |
Add CompressionOptions::checksum for enabling ZSTD checksum (#11666)
Summary:
Optionally enable zstd checksum flag (
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anand76
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a1743e85be |
Implement a allow cache hits admission policy for the compressed secondary cache (#11713)
Summary: This PR implements a new admission policy for the compressed secondary cache, which includes the functionality of the existing policy, and also admits items evicted from the primary block cache with the hit bit set. Effectively, the new policy works as follows - 1. When an item is demoted from the primary cache without a hit, a placeholder is inserted in the compressed cache. A second demotion will insert the full entry. 2. When an item is promoted from the compressed cache to the primary cache for the first time, a placeholder is inserted in the primary. The second promotion inserts the full entry, while erasing it form the compressed cache. 3. If an item is demoted from the primary cache with the hit bit set, it is immediately inserted in the compressed secondary cache. The ```TieredVolatileCacheOptions``` has been updated with a new option, ```adm_policy```, which allows the policy to be selected. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11713 Reviewed By: pdillinger Differential Revision: D48444512 Pulled By: anand1976 fbshipit-source-id: b4cbf8c169a88097dff08e36e8bc4b3088de1492 |
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anand76
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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 |
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Peter Dillinger
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206fdea3d9 |
Change internal headers with duplicate names (#11408)
Summary: In IDE navigation I find it annoying that there are two statistics.h files (etc.) and often land on the wrong one. Here I migrate several headers to use the blah.h <- blah_impl.h <- blah.cc idiom. Although clang-format wants "blah.h" to be the top include for "blah.cc", I think overall this is an improvement. No public API changes. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11408 Test Plan: existing tests Reviewed By: ltamasi Differential Revision: D45456696 Pulled By: pdillinger fbshipit-source-id: 809d931253f3272c908cf5facf7e1d32fc507373 |
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Peter Dillinger
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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 |
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Peter Dillinger
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601efe3cf2 |
Misc cleanup of block cache code (#11291)
Summary: ... ahead of a larger change. * Rename confusingly named `is_in_sec_cache` to `kept_in_sec_cache` * Unify naming of "standalone" block cache entries (was "detached" in clock_cache) * Remove some unused definitions in clock_cache.h (leftover from a previous revision) Pull Request resolved: https://github.com/facebook/rocksdb/pull/11291 Test Plan: usual tests and CI, no behavior changes Reviewed By: anand1976 Differential Revision: D43984642 Pulled By: pdillinger fbshipit-source-id: b8bf0c5b90a932a88bcbdb413b2f256834aedf97 |
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Peter Dillinger
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64a1f7670f |
Customize CompressedSecondaryCache by block kind (#11204)
Summary: Added `do_not_compress_roles` to `CompressedSecondaryCacheOptions` to disable compression on certain kinds of block. Filter blocks are now not compressed by CompressedSecondaryCache by default. Pull Request resolved: https://github.com/facebook/rocksdb/pull/11204 Test Plan: unit test added Reviewed By: anand1976 Differential Revision: D43147698 Pulled By: pdillinger fbshipit-source-id: db496975ae975fa18f157f93fe131a16315ac875 |
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Peter Dillinger
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9f7801c5f1 |
Major Cache refactoring, CPU efficiency improvement (#10975)
Summary: This is several refactorings bundled into one to avoid having to incrementally re-modify uses of Cache several times. Overall, there are breaking changes to Cache class, and it becomes more of low-level interface for implementing caches, especially block cache. New internal APIs make using Cache cleaner than before, and more insulated from block cache evolution. Hopefully, this is the last really big block cache refactoring, because of rather effectively decoupling the implementations from the uses. This change also removes the EXPERIMENTAL designation on the SecondaryCache support in Cache. It seems reasonably mature at this point but still subject to change/evolution (as I warn in the API docs for Cache). The high-level motivation for this refactoring is to minimize code duplication / compounding complexity in adding SecondaryCache support to HyperClockCache (in a later PR). Other benefits listed below. * static_cast lines of code +29 -35 (net removed 6) * reinterpret_cast lines of code +6 -32 (net removed 26) ## cache.h and secondary_cache.h * Always use CacheItemHelper with entries instead of just a Deleter. There are several motivations / justifications: * Simpler for implementations to deal with just one Insert and one Lookup. * Simpler and more efficient implementation because we don't have to track which entries are using helpers and which are using deleters * Gets rid of hack to classify cache entries by their deleter. Instead, the CacheItemHelper includes a CacheEntryRole. This simplifies a lot of code (cache_entry_roles.h almost eliminated). Fixes https://github.com/facebook/rocksdb/issues/9428. * Makes it trivial to adjust SecondaryCache behavior based on kind of block (e.g. don't re-compress filter blocks). * It is arguably less convenient for many direct users of Cache, but direct users of Cache are now rare with introduction of typed_cache.h (below). * I considered and rejected an alternative approach in which we reduce customizability by assuming each secondary cache compatible value starts with a Slice referencing the uncompressed block contents (already true or mostly true), but we apparently intend to stack secondary caches. Saving an entry from a compressed secondary to a lower tier requires custom handling offered by SaveToCallback, etc. * Make CreateCallback part of the helper and introduce CreateContext to work with it (alternative to https://github.com/facebook/rocksdb/issues/10562). This cleans up the interface while still allowing context to be provided for loading/parsing values into primary cache. This model works for async lookup in BlockBasedTable reader (reader owns a CreateContext) under the assumption that it always waits on secondary cache operations to finish. (Otherwise, the CreateContext could be destroyed while async operation depending on it continues.) This likely contributes most to the observed performance improvement because it saves an std::function backed by a heap allocation. * Use char* for serialized data, e.g. in SaveToCallback, where void* was confusingly used. (We use `char*` for serialized byte data all over RocksDB, with many advantages over `void*`. `memcpy` etc. are legacy APIs that should not be mimicked.) * Add a type alias Cache::ObjectPtr = void*, so that we can better indicate the intent of the void* when it is to be the object associated with a Cache entry. Related: started (but did not complete) a refactoring to move away from "value" of a cache entry toward "object" or "obj". (It is confusing to call Cache a key-value store (like DB) when it is really storing arbitrary in-memory objects, not byte strings.) * Remove unnecessary key param from DeleterFn. This is good for efficiency in HyperClockCache, which does not directly store the cache key in memory. (Alternative to https://github.com/facebook/rocksdb/issues/10774) * Add allocator to Cache DeleterFn. This is a kind of future-proofing change in case we get more serious about using the Cache allocator for memory tracked by the Cache. Right now, only the uncompressed block contents are allocated using the allocator, and a pointer to that allocator is saved as part of the cached object so that the deleter can use it. (See CacheAllocationPtr.) If in the future we are able to "flatten out" our Cache objects some more, it would be good not to have to track the allocator as part of each object. * Removes legacy `ApplyToAllCacheEntries` and changes `ApplyToAllEntries` signature for Deleter->CacheItemHelper change. ## typed_cache.h Adds various "typed" interfaces to the Cache as internal APIs, so that most uses of Cache can use simple type safe code without casting and without explicit deleters, etc. Almost all of the non-test, non-glue code uses of Cache have been migrated. (Follow-up work: CompressedSecondaryCache deserves deeper attention to migrate.) This change expands RocksDB's internal usage of metaprogramming and SFINAE (https://en.cppreference.com/w/cpp/language/sfinae). The existing usages of Cache are divided up at a high level into these new interfaces. See updated existing uses of Cache for examples of how these are used. * PlaceholderCacheInterface - Used for making cache reservations, with entries that have a charge but no value. * BasicTypedCacheInterface<TValue> - Used for primary cache storage of objects of type TValue, which can be cleaned up with std::default_delete<TValue>. The role is provided by TValue::kCacheEntryRole or given in an optional template parameter. * FullTypedCacheInterface<TValue, TCreateContext> - Used for secondary cache compatible storage of objects of type TValue. In addition to BasicTypedCacheInterface constraints, we require TValue::ContentSlice() to return persistable data. This simplifies usage for the normal case of simple secondary cache compatibility (can give you a Slice to the data already in memory). In addition to TCreateContext performing the role of Cache::CreateContext, it is also expected to provide a factory function for creating TValue. * For each of these, there's a "Shared" version (e.g. FullTypedSharedCacheInterface) that holds a shared_ptr to the Cache, rather than assuming external ownership by holding only a raw `Cache*`. These interfaces introduce specific handle types for each interface instantiation, so that it's easy to see what kind of object is controlled by a handle. (Ultimately, this might not be worth the extra complexity, but it seems OK so far.) Note: I attempted to make the cache 'charge' automatically inferred from the cache object type, such as by expecting an ApproximateMemoryUsage() function, but this is not so clean because there are cases where we need to compute the charge ahead of time and don't want to re-compute it. ## block_cache.h This header is essentially the replacement for the old block_like_traits.h. It includes various things to support block cache access with typed_cache.h for block-based table. ## block_based_table_reader.cc Before this change, accessing the block cache here was an awkward mix of static polymorphism (template TBlocklike) and switch-case on a dynamic BlockType value. This change mostly unifies on static polymorphism, relying on minor hacks in block_cache.h to distinguish variants of Block. We still check BlockType in some places (especially for stats, which could be improved in follow-up work) but at least the BlockType is a static constant from the template parameter. (No more awkward partial redundancy between static and dynamic info.) This likely contributes to the overall performance improvement, but hasn't been tested in isolation. The other key source of simplification here is a more unified system of creating block cache objects: for directly populating from primary cache and for promotion from secondary cache. Both use BlockCreateContext, for context and for factory functions. ## block_based_table_builder.cc, cache_dump_load_impl.cc Before this change, warming caches was super ugly code. Both of these source files had switch statements to basically transition from the dynamic BlockType world to the static TBlocklike world. None of that mess is needed anymore as there's a new, untyped WarmInCache function that handles all the details just as promotion from SecondaryCache would. (Fixes `TODO akanksha: Dedup below code` in block_based_table_builder.cc.) ## Everything else Mostly just updating Cache users to use new typed APIs when reasonably possible, or changed Cache APIs when not. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10975 Test Plan: tests updated Performance test setup similar to https://github.com/facebook/rocksdb/issues/10626 (by cache size, LRUCache when not "hyper" for HyperClockCache): 34MB 1thread base.hyper -> kops/s: 0.745 io_bytes/op: 2.52504e+06 miss_ratio: 0.140906 max_rss_mb: 76.4844 34MB 1thread new.hyper -> kops/s: 0.751 io_bytes/op: 2.5123e+06 miss_ratio: 0.140161 max_rss_mb: 79.3594 34MB 1thread base -> kops/s: 0.254 io_bytes/op: 1.36073e+07 miss_ratio: 0.918818 max_rss_mb: 45.9297 34MB 1thread new -> kops/s: 0.252 io_bytes/op: 1.36157e+07 miss_ratio: 0.918999 max_rss_mb: 44.1523 34MB 32thread base.hyper -> kops/s: 7.272 io_bytes/op: 2.88323e+06 miss_ratio: 0.162532 max_rss_mb: 516.602 34MB 32thread new.hyper -> kops/s: 7.214 io_bytes/op: 2.99046e+06 miss_ratio: 0.168818 max_rss_mb: 518.293 34MB 32thread base -> kops/s: 3.528 io_bytes/op: 1.35722e+07 miss_ratio: 0.914691 max_rss_mb: 264.926 34MB 32thread new -> kops/s: 3.604 io_bytes/op: 1.35744e+07 miss_ratio: 0.915054 max_rss_mb: 264.488 233MB 1thread base.hyper -> kops/s: 53.909 io_bytes/op: 2552.35 miss_ratio: 0.0440566 max_rss_mb: 241.984 233MB 1thread new.hyper -> kops/s: 62.792 io_bytes/op: 2549.79 miss_ratio: 0.044043 max_rss_mb: 241.922 233MB 1thread base -> kops/s: 1.197 io_bytes/op: 2.75173e+06 miss_ratio: 0.103093 max_rss_mb: 241.559 233MB 1thread new -> kops/s: 1.199 io_bytes/op: 2.73723e+06 miss_ratio: 0.10305 max_rss_mb: 240.93 233MB 32thread base.hyper -> kops/s: 1298.69 io_bytes/op: 2539.12 miss_ratio: 0.0440307 max_rss_mb: 371.418 233MB 32thread new.hyper -> kops/s: 1421.35 io_bytes/op: 2538.75 miss_ratio: 0.0440307 max_rss_mb: 347.273 233MB 32thread base -> kops/s: 9.693 io_bytes/op: 2.77304e+06 miss_ratio: 0.103745 max_rss_mb: 569.691 233MB 32thread new -> kops/s: 9.75 io_bytes/op: 2.77559e+06 miss_ratio: 0.103798 max_rss_mb: 552.82 1597MB 1thread base.hyper -> kops/s: 58.607 io_bytes/op: 1449.14 miss_ratio: 0.0249324 max_rss_mb: 1583.55 1597MB 1thread new.hyper -> kops/s: 69.6 io_bytes/op: 1434.89 miss_ratio: 0.0247167 max_rss_mb: 1584.02 1597MB 1thread base -> kops/s: 60.478 io_bytes/op: 1421.28 miss_ratio: 0.024452 max_rss_mb: 1589.45 1597MB 1thread new -> kops/s: 63.973 io_bytes/op: 1416.07 miss_ratio: 0.0243766 max_rss_mb: 1589.24 1597MB 32thread base.hyper -> kops/s: 1436.2 io_bytes/op: 1357.93 miss_ratio: 0.0235353 max_rss_mb: 1692.92 1597MB 32thread new.hyper -> kops/s: 1605.03 io_bytes/op: 1358.04 miss_ratio: 0.023538 max_rss_mb: 1702.78 1597MB 32thread base -> kops/s: 280.059 io_bytes/op: 1350.34 miss_ratio: 0.023289 max_rss_mb: 1675.36 1597MB 32thread new -> kops/s: 283.125 io_bytes/op: 1351.05 miss_ratio: 0.0232797 max_rss_mb: 1703.83 Almost uniformly improving over base revision, especially for hot paths with HyperClockCache, up to 12% higher throughput seen (1597MB, 32thread, hyper). The improvement for that is likely coming from much simplified code for providing context for secondary cache promotion (CreateCallback/CreateContext), and possibly from less branching in block_based_table_reader. And likely a small improvement from not reconstituting key for DeleterFn. Reviewed By: anand1976 Differential Revision: D42417818 Pulled By: pdillinger fbshipit-source-id: f86bfdd584dce27c028b151ba56818ad14f7a432 |
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gitbw95
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47b57a3731 |
add SetCapacity and GetCapacity for secondary cache (#10712)
Summary: To support tuning secondary cache dynamically, add `SetCapacity()` and `GetCapacity()` for CompressedSecondaryCache. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10712 Test Plan: Unit Tests Reviewed By: anand1976 Differential Revision: D39685212 Pulled By: gitbw95 fbshipit-source-id: 19573c67237011927320207732b5de083cb87240 |
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gitbw95
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2cc5b39560 |
Add enable_split_merge option for CompressedSecondaryCache (#10690)
Summary: `enable_custom_split_merge` is added for enabling the custom split and merge feature, which split the compressed value into chunks so that they may better fit jemalloc bins. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10690 Test Plan: Unit Tests Stress Tests Reviewed By: anand1976 Differential Revision: D39567604 Pulled By: gitbw95 fbshipit-source-id: f6d1d46200f365220055f793514601dcb0edc4b7 |
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gitbw95
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0148c4934d |
Add PerfContext counters for CompressedSecondaryCache (#10650)
Summary: Add PerfContext counters for CompressedSecondaryCache. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10650 Test Plan: Unit Tests. Reviewed By: anand1976 Differential Revision: D39354712 Pulled By: gitbw95 fbshipit-source-id: 1b90d3df99d08ddecd351edfd48d1e3723fdbc15 |
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Bo Wang
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d490bfcdb6 |
Avoid recompressing cold block in CompressedSecondaryCache (#10527)
Summary:
**Summary:**
When a block is firstly `Lookup` from the secondary cache, we just insert a dummy block in the primary cache (charging the actual size of the block) and don’t erase the block from the secondary cache. A standalone handle is returned from `Lookup`. Only if the block is hit again, we erase it from the secondary cache and add it into the primary cache.
When a block is firstly evicted from the primary cache to the secondary cache, we just insert a dummy block (size 0) in the secondary cache. When the block is evicted again, it is treated as a hot block and is inserted into the secondary cache.
**Implementation Details**
Add a new state of LRUHandle: The handle is never inserted into the LRUCache (both hash table and LRU list) and it doesn't experience the above three states. The entry can be freed when refs becomes 0. (refs >= 1 && in_cache == false && IS_STANDALONE == true)
The behaviors of `LRUCacheShard::Lookup()` are updated if the secondary_cache is CompressedSecondaryCache:
1. If a handle is found in primary cache:
1.1. If the handle's value is not nullptr, it is returned immediately.
1.2. If the handle's value is nullptr, this means the handle is a dummy one. For a dummy handle, if it was retrieved from secondary cache, it may still exist in secondary cache.
- 1.2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr.
- 1.2.2. If the handle from secondary cache is valid, erase it from the secondary cache and add it into the primary cache.
2. If a handle is not found in primary cache:
2.1. If no valid handle can be `Lookup` from secondary cache, return nullptr.
2.2. If the handle from secondary cache is valid, insert a dummy block in the primary cache (charging the actual size of the block) and return a standalone handle.
The behaviors of `LRUCacheShard::Promote()` are updated as follows:
1. If `e->sec_handle` has value, one of the following steps can happen:
1.1. Insert a dummy handle and return a standalone handle to caller when `secondary_cache_` is `CompressedSecondaryCache` and e is a standalone handle.
1.2. Insert the item into the primary cache and return the handle to caller.
1.3. Exception handling.
3. If `e->sec_handle` has no value, mark the item as not in cache and charge the cache as its only metadata that'll shortly be released.
The behavior of `CompressedSecondaryCache::Insert()` is updated:
1. If a block is evicted from the primary cache for the first time, a dummy item is inserted.
4. If a dummy item is found for a block, the block is inserted into the secondary cache.
The behavior of `CompressedSecondaryCache:::Lookup()` is updated:
1. If a handle is not found or it is a dummy item, a nullptr is returned.
2. If `erase_handle` is true, the handle is erased.
The behaviors of `LRUCacheShard::Release()` are adjusted for the standalone handles.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10527
Test Plan:
1. stress tests.
5. unit tests.
6. CPU profiling for db_bench.
Reviewed By: siying
Differential Revision: D38747613
Pulled By: gitbw95
fbshipit-source-id: 74a1eba7e1957c9affb2bd2ae3e0194584fa6eca
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Gang Liao
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275cd80cdb |
Add a blob-specific cache priority (#10461)
Summary: RocksDB's `Cache` abstraction currently supports two priority levels for items: high (used for frequently accessed/highly valuable SST metablocks like index/filter blocks) and low (used for SST data blocks). Blobs are typically lower-value targets for caching than data blocks, since 1) with BlobDB, data blocks containing blob references conceptually form an index structure which has to be consulted before we can read the blob value, and 2) cached blobs represent only a single key-value, while cached data blocks generally contain multiple KVs. Since we would like to make it possible to use the same backing cache for the block cache and the blob cache, it would make sense to add a new, lower-than-low cache priority level (bottom level) for blobs so data blocks are prioritized over them. This task is a part of https://github.com/facebook/rocksdb/issues/10156 Pull Request resolved: https://github.com/facebook/rocksdb/pull/10461 Reviewed By: siying Differential Revision: D38672823 Pulled By: ltamasi fbshipit-source-id: 90cf7362036563d79891f47be2cc24b827482743 |
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gitbw95
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f060b47ee8 |
Fix the segdefault bug in CompressedSecondaryCache and its tests (#10507)
Summary: This fix is to replace `AllocateBlock()` with `new`. Once I figure out why `AllocateBlock()` might cause the segfault, I will update the implementation. Fix the bug that causes ./compressed_secondary_cache_test output following test failures: ``` Note: Google Test filter = CompressedSecondaryCacheTest.MergeChunksIntoValueTest [==========] Running 1 test from 1 test case. [----------] Global test environment set-up. [----------] 1 test from CompressedSecondaryCacheTest [ RUN ] CompressedSecondaryCacheTest.MergeChunksIntoValueTest [ OK ] CompressedSecondaryCacheTest.MergeChunksIntoValueTest (1 ms) [----------] 1 test from CompressedSecondaryCacheTest (1 ms total) [----------] Global test environment tear-down [==========] 1 test from 1 test case ran. (9 ms total) [ PASSED ] 1 test. t/run-compressed_secondary_cache_test-CompressedSecondaryCacheTest.MergeChunksIntoValueTest: line 4: 1091086 Segmentation fault (core dumped) TEST_TMPDIR=$d ./compressed_secondary_cache_test --gtest_filter=CompressedSecondaryCacheTest.MergeChunksIntoValueTest Note: Google Test filter = CompressedSecondaryCacheTest.BasicTestWithMemoryAllocatorAndCompression [==========] Running 1 test from 1 test case. [----------] Global test environment set-up. [----------] 1 test from CompressedSecondaryCacheTest [ RUN ] CompressedSecondaryCacheTest.BasicTestWithMemoryAllocatorAndCompression [ OK ] CompressedSecondaryCacheTest.BasicTestWithMemoryAllocatorAndCompression (1 ms) [----------] 1 test from CompressedSecondaryCacheTest (1 ms total) [----------] Global test environment tear-down [==========] 1 test from 1 test case ran. (2 ms total) [ PASSED ] 1 test. t/run-compressed_secondary_cache_test-CompressedSecondaryCacheTest.BasicTestWithMemoryAllocatorAndCompression: line 4: 1090883 Segmentation fault (core dumped) TEST_TMPDIR=$d ./compressed_secondary_cache_test --gtest_filter=CompressedSecondaryCacheTest.BasicTestWithMemoryAllocatorAndCompression ``` Pull Request resolved: https://github.com/facebook/rocksdb/pull/10507 Test Plan: Test 1: ``` $make -j 24 $./compressed_secondary_cache_test ``` Test 2: ``` $COMPILE_WITH_ASAN=1 make -j 24 $./compressed_secondary_cache_test ``` Test 3: ``` $COMPILE_WITH_TSAN=1 make -j 24 $./compressed_secondary_cache_test ``` Reviewed By: anand1976 Differential Revision: D38529885 Pulled By: gitbw95 fbshipit-source-id: d903fa3fadbd4d29f9528728c63a4f61c4396890 |
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Bo Wang
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87b82f28a1 |
Split cache to minimize internal fragmentation (#10287)
Summary: ### **Summary:** To minimize the internal fragmentation caused by the variable size of the compressed blocks, the original block is split according to the jemalloc bin size in `Insert()` and then merged back in `Lookup()`. Based on the analysis of the results of the following tests, from the overall internal fragmentation perspective, this PR does mitigate the internal fragmentation issue. _Do more myshadow tests with the latest commit. I finished several myshadow AB Testing and the results are promising. For the config of 4GB primary cache and 3GB secondary cache, Jemalloc resident stats shows consistently ~0.15GB memory saving; the allocated and active stats show similar memory savings. The CPU usage is almost the same before and after this PR._ To evaluate the issue of memory fragmentations and the benefits of this PR, I conducted two sets of local tests as follows. **T1** Keys: 16 bytes each (+ 0 bytes user-defined timestamp) Values: 100 bytes each (50 bytes after compression) Entries: 90000000 RawSize: 9956.4 MB (estimated) FileSize: 5664.8 MB (estimated) | Test Name | Primary Cache Size (MB) | Compressed Secondary Cache Size (MB) | | - | - | - | | T1_3 | 4000 | 4000 | | T1_4 | 2000 | 3000 | Populate the DB: ./db_bench --benchmarks=fillrandom --num=90000000 -db=/mem_fragmentation/db_bench_1 Overwrite it to a stable state: ./db_bench --benchmarks=overwrite --num=90000000 -use_existing_db -db=/mem_fragmentation/db_bench_1 Run read tests with differnt cache setting: T1_3: MALLOC_CONF="prof:true,prof_stats:true" ../rocksdb/db_bench --benchmarks=seekrandom --threads=16 --num=90000000 -use_existing_db --benchmark_write_rate_limit=52000000 -use_direct_reads --cache_size=4000000000 -compressed_secondary_cache_size=4000000000 -use_compressed_secondary_cache -db=/mem_fragmentation/db_bench_1 --print_malloc_stats=true > ~/temp/mem_frag/20220710/jemalloc_stats_json_T1_3_20220710 -duration=1800 & T1_4: MALLOC_CONF="prof:true,prof_stats:true" ../rocksdb/db_bench --benchmarks=seekrandom --threads=16 --num=90000000 -use_existing_db --benchmark_write_rate_limit=52000000 -use_direct_reads --cache_size=2000000000 -compressed_secondary_cache_size=3000000000 -use_compressed_secondary_cache -db=/mem_fragmentation/db_bench_1 --print_malloc_stats=true > ~/temp/mem_frag/20220710/jemalloc_stats_json_T1_4_20220710 -duration=1800 & For T1_3 and T1_4, I also conducted the tests before and after this PR. The following table show the important jemalloc stats. | Test Name | T1_3 | T1_3 after mem defrag | T1_4 | T1_4 after mem defrag | | - | - | - | - | - | | allocated (MB) | 8728 | 8076 | 5518 | 5043 | | available (MB) | 8753 | 8092 | 5536 | 5051 | | external fragmentation rate | 0.003 | 0.002 | 0.003 | 0.0016 | | resident (MB) | 8956 | 8365 | 5655 | 5235 | **T2** Keys: 32 bytes each (+ 0 bytes user-defined timestamp) Values: 256 bytes each (128 bytes after compression) Entries: 40000000 RawSize: 10986.3 MB (estimated) FileSize: 6103.5 MB (estimated) | Test Name | Primary Cache Size (MB) | Compressed Secondary Cache Size (MB) | | - | - | - | | T2_3 | 4000 | 4000 | | T2_4 | 2000 | 3000 | Create DB (10GB): ./db_bench -benchmarks=fillrandom -use_direct_reads=true -num=40000000 -key_size=32 -value_size=256 -db=/mem_fragmentation/db_bench_2 Overwrite it to a stable state: ./db_bench --benchmarks=overwrite --num=40000000 -use_existing_db -key_size=32 -value_size=256 -db=/mem_fragmentation/db_bench_2 Run read tests with differnt cache setting: T2_3: MALLOC_CONF="prof:true,prof_stats:true" ./db_bench --benchmarks="mixgraph" -use_direct_io_for_flush_and_compaction=true -use_direct_reads=true -cache_size=4000000000 -compressed_secondary_cache_size=4000000000 -use_compressed_secondary_cache -keyrange_dist_a=14.18 -keyrange_dist_b=-2.917 -keyrange_dist_c=0.0164 -keyrange_dist_d=-0.08082 -keyrange_num=30 -value_k=0.2615 -value_sigma=25.45 -iter_k=2.517 -iter_sigma=14.236 -mix_get_ratio=0.85 -mix_put_ratio=0.14 -mix_seek_ratio=0.01 -sine_mix_rate_interval_milliseconds=5000 -sine_a=1000 -sine_b=0.000073 -sine_d=400000 -reads=80000000 -num=40000000 -key_size=32 -value_size=256 -use_existing_db=true -db=/mem_fragmentation/db_bench_2 --print_malloc_stats=true > ~/temp/mem_frag/jemalloc_stats_T2_3 -duration=1800 & T2_4: MALLOC_CONF="prof:true,prof_stats:true" ./db_bench --benchmarks="mixgraph" -use_direct_io_for_flush_and_compaction=true -use_direct_reads=true -cache_size=2000000000 -compressed_secondary_cache_size=3000000000 -use_compressed_secondary_cache -keyrange_dist_a=14.18 -keyrange_dist_b=-2.917 -keyrange_dist_c=0.0164 -keyrange_dist_d=-0.08082 -keyrange_num=30 -value_k=0.2615 -value_sigma=25.45 -iter_k=2.517 -iter_sigma=14.236 -mix_get_ratio=0.85 -mix_put_ratio=0.14 -mix_seek_ratio=0.01 -sine_mix_rate_interval_milliseconds=5000 -sine_a=1000 -sine_b=0.000073 -sine_d=400000 -reads=80000000 -num=40000000 -key_size=32 -value_size=256 -use_existing_db=true -db=/mem_fragmentation/db_bench_2 --print_malloc_stats=true > ~/temp/mem_frag/jemalloc_stats_T2_4 -duration=1800 & For T2_3 and T2_4, I also conducted the tests before and after this PR. The following table show the important jemalloc stats. | Test Name | T2_3 | T2_3 after mem defrag | T2_4 | T2_4 after mem defrag | | - | - | - | - | - | | allocated (MB) | 8425 | 8093 | 5426 | 5149 | | available (MB) | 8489 | 8138 | 5435 | 5158 | | external fragmentation rate | 0.008 | 0.0055 | 0.0017 | 0.0017 | | resident (MB) | 8676 | 8392 | 5541 | 5321 | Pull Request resolved: https://github.com/facebook/rocksdb/pull/10287 Test Plan: Unit tests. Reviewed By: anand1976 Differential Revision: D37743362 Pulled By: gitbw95 fbshipit-source-id: 0010c5af08addeacc5ebbc4ffe5be882fb1d38ad |
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Peter Dillinger
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65036e4217 |
Revert "Add a blob-specific cache priority (#10309)" (#10434)
Summary:
This reverts commit
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Gang Liao
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8d178090be |
Add a blob-specific cache priority (#10309)
Summary: RocksDB's `Cache` abstraction currently supports two priority levels for items: high (used for frequently accessed/highly valuable SST metablocks like index/filter blocks) and low (used for SST data blocks). Blobs are typically lower-value targets for caching than data blocks, since 1) with BlobDB, data blocks containing blob references conceptually form an index structure which has to be consulted before we can read the blob value, and 2) cached blobs represent only a single key-value, while cached data blocks generally contain multiple KVs. Since we would like to make it possible to use the same backing cache for the block cache and the blob cache, it would make sense to add a new, lower-than-low cache priority level (bottom level) for blobs so data blocks are prioritized over them. This task is a part of https://github.com/facebook/rocksdb/issues/10156 Pull Request resolved: https://github.com/facebook/rocksdb/pull/10309 Reviewed By: ltamasi Differential Revision: D38211655 Pulled By: gangliao fbshipit-source-id: 65ef33337db4d85277cc6f9782d67c421ad71dd5 |
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Bo Wang
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86c2d0a95d |
Add the secondary cache information into LRUCache:: GetPrintableOptions (#10346)
Summary: If the primary cache is LRU cache and there is a secondary cache, add Secondary Cache printable options into LRUCache::GetPrintableOptions. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10346 Test Plan: 1. Current Unit Tests should pass. 2. Use db_bench (with compressed_secondary_cache ) and the LOG should includes the new printable options from Seoncdary Cache. Reviewed By: jay-zhuang Differential Revision: D37779310 Pulled By: gitbw95 fbshipit-source-id: 88ce1f7df6b5f25740e598d9e7fa91e4c414cb8f |
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gitbw95
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f241d082b6 |
Prevent double caching in the compressed secondary cache (#9747)
Summary: ### **Summary:** When both LRU Cache and CompressedSecondaryCache are configured together, there possibly are some data blocks double cached. **Changes include:** 1. Update IS_PROMOTED to IS_IN_SECONDARY_CACHE to prevent confusions. 2. This PR updates SecondaryCacheResultHandle and use IsErasedFromSecondaryCache to determine whether the handle is erased in the secondary cache. Then, the caller can determine whether to SetIsInSecondaryCache(). 3. Rename LRUSecondaryCache to CompressedSecondaryCache. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9747 Test Plan: **Test Scripts:** 1. Populate a DB. The on disk footprint is 482 MB. The data is set to be 50% compressible, so the total decompressed size is expected to be 964 MB. ./db_bench --benchmarks=fillrandom --num=10000000 -db=/db_bench_1 2. overwrite it to a stable state: ./db_bench --benchmarks=overwrite,stats --num=10000000 -use_existing_db -duration=10 --benchmark_write_rate_limit=2000000 -db=/db_bench_1 4. Run read tests with diffeernt cache setting: T1: ./db_bench --benchmarks=seekrandom,stats --threads=16 --num=10000000 -use_existing_db -duration=120 --benchmark_write_rate_limit=52000000 -use_direct_reads --cache_size=520000000 --statistics -db=/db_bench_1 T2: ./db_bench --benchmarks=seekrandom,stats --threads=16 --num=10000000 -use_existing_db -duration=120 --benchmark_write_rate_limit=52000000 -use_direct_reads --cache_size=320000000 -compressed_secondary_cache_size=400000000 --statistics -use_compressed_secondary_cache -db=/db_bench_1 T3: ./db_bench --benchmarks=seekrandom,stats --threads=16 --num=10000000 -use_existing_db -duration=120 --benchmark_write_rate_limit=52000000 -use_direct_reads --cache_size=520000000 -compressed_secondary_cache_size=400000000 --statistics -use_compressed_secondary_cache -db=/db_bench_1 T4: ./db_bench --benchmarks=seekrandom,stats --threads=16 --num=10000000 -use_existing_db -duration=120 --benchmark_write_rate_limit=52000000 -use_direct_reads --cache_size=20000000 -compressed_secondary_cache_size=500000000 --statistics -use_compressed_secondary_cache -db=/db_bench_1 **Before this PR** | Cache Size | Compressed Secondary Cache Size | Cache Hit Rate | |------------|-------------------------------------|----------------| |520 MB | 0 MB | 85.5% | |320 MB | 400 MB | 96.2% | |520 MB | 400 MB | 98.3% | |20 MB | 500 MB | 98.8% | **Before this PR** | Cache Size | Compressed Secondary Cache Size | Cache Hit Rate | |------------|-------------------------------------|----------------| |520 MB | 0 MB | 85.5% | |320 MB | 400 MB | 99.9% | |520 MB | 400 MB | 99.9% | |20 MB | 500 MB | 99.2% | Reviewed By: anand1976 Differential Revision: D35117499 Pulled By: gitbw95 fbshipit-source-id: ea2657749fc13efebe91a8a1b56bc61d6a224a12 |