91 Commits (692d6be3586fd03ba955f8afe8cdccadf742cc58)

Author	SHA1	Message	Date
Peter Dillinger	3182beeffc	Observe and warn about misconfigured HyperClockCache (#10965) ... Summary: Background. One of the core risks of chosing HyperClockCache is ending up with degraded performance if estimated_entry_charge is very significantly wrong. Too low leads to under-utilized hash table, which wastes a bit of (tracked) memory and likely increases access times due to larger working set size (more TLB misses). Too high leads to fully populated hash table (at some limit with reasonable lookup performance) and not being able to cache as many objects as the memory limit would allow. In either case, performance degradation is graceful/continuous but can be quite significant. For example, cutting block size in half without updating estimated_entry_charge could lead to a large portion of configured block cache memory (up to roughly 1/3) going unused. Fix. This change adds a mechanism through which the DB periodically probes the block cache(s) for "problems" to report, and adds diagnostics to the HyperClockCache for bad estimated_entry_charge. The periodic probing is currently done with DumpStats / stats_dump_period_sec, and diagnostics reported to info_log (normally LOG file). Pull Request resolved: https://github.com/facebook/rocksdb/pull/10965 Test Plan: unit test included. Doesn't cover all the implemented subtleties of reporting, but ensures basics of when to report or not. Also manual testing with db_bench. Create db with ``` ./db_bench --benchmarks=fillrandom,flush --num=3000000 --disable_wal=1 ``` Use and check LOG file for HyperClockCache for various block sizes (used as estimated_entry_charge) ``` ./db_bench --use_existing_db --benchmarks=readrandom --num=3000000 --duration=20 --stats_dump_period_sec=8 --cache_type=hyper_clock_cache -block_size=XXXX ``` Seeing warnings / errors or not as expected. Reviewed By: anand1976 Differential Revision: D41406932 Pulled By: pdillinger fbshipit-source-id: 4ca56162b73017e4b9cec2cad74466f49c27a0a7	2 years ago
Peter Dillinger	32520df1d9	Remove prototype FastLRUCache (#10954) ... Summary: This was just a stepping stone to what eventually became HyperClockCache, and is now just more code to maintain. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10954 Test Plan: tests updated Reviewed By: akankshamahajan15 Differential Revision: D41310123 Pulled By: pdillinger fbshipit-source-id: 618ee148a1a0a29ee756ba8fe28359617b7cd67c	2 years ago
Andrew Kryczka	5cf6ab6f31	Ran clang-format on db/ directory (#10910) ... Summary: Ran `find ./db/ -type f | xargs clang-format -i`. Excluded minor changes it tried to make on db/db_impl/. Everything else it changed was directly under db/ directory. Included minor manual touchups mentioned in PR commit history. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10910 Reviewed By: riversand963 Differential Revision: D40880683 Pulled By: ajkr fbshipit-source-id: cfe26cda05b3fb9a72e3cb82c286e21d8c5c4174	2 years ago
Andrew Kryczka	33ceea9b76	Add DB property for fast block cache stats collection (#10832) ... Summary: This new property allows users to trigger the background block cache stats collection mode through the `GetProperty()` and `GetMapProperty()` APIs. The background mode has much lower overhead at the expense of returning stale values in more cases. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10832 Test Plan: updated unit test Reviewed By: pdillinger Differential Revision: D40497883 Pulled By: ajkr fbshipit-source-id: bdcc93402f426463abb2153756aad9e295447343	2 years ago
Peter Dillinger	0f91c72adc	Call experimental new clock cache HyperClockCache (#10684) ... Summary: This change establishes a distinctive name for the experimental new lock-free clock cache (originally developed by guidotag and revamped in PR https://github.com/facebook/rocksdb/issues/10626). A few reasons: * We want to make it clear that this is a fundamentally different implementation vs. the old clock cache, to avoid people saying "I already tried clock cache." * We want to highlight the key feature: it's fast (especially under parallel load) * Because it requires an estimated charge per entry, it is not drop-in API compatible with old clock cache. This estimate might always be required for highest performance, and giving it a distinct name should reduce confusion about the distinct API requirements. * We might develop a variant requiring the same estimate parameter but with LRU eviction. In that case, using the name HyperLRUCache should make things more clear. (FastLRUCache is just a prototype that might soon be removed.) Some API detail: * To reduce copy-pasting parameter lists, etc. as in LRUCache construction, I have a `MakeSharedCache()` function on `HyperClockCacheOptions` instead of `NewHyperClockCache()`. * Changes -cache_type=clock_cache to -cache_type=hyper_clock_cache for applicable tools. I think this is more consistent / sustainable for reasons already stated. For performance tests see https://github.com/facebook/rocksdb/pull/10626 Pull Request resolved: https://github.com/facebook/rocksdb/pull/10684 Test Plan: no interesting functional changes; tests updated Reviewed By: anand1976 Differential Revision: D39547800 Pulled By: pdillinger fbshipit-source-id: 5c0fe1b5cf3cb680ab369b928c8569682b9795bf	2 years ago
Peter Dillinger	5724348689	Revamp, optimize new experimental clock cache (#10626) ... Summary: * Consolidates most metadata into a single word per slot so that more can be accomplished with a single atomic update. In the common case, Lookup was previously about 4 atomic updates, now just 1 atomic update. Common case Release was previously 1 atomic read + 1 atomic update, now just 1 atomic update. * Eliminate spins / waits / yields, which likely threaten some "lock free" benefits. Compare-exchange loops are only used in explicit Erase, and strict_capacity_limit=true Insert. Eviction uses opportunistic compare- exchange. * Relaxes some aggressiveness and guarantees. For example, * Duplicate Inserts will sometimes go undetected and the shadow duplicate will age out with eviction. * In many cases, the older Inserted value for a given cache key will be kept (i.e. Insert does not support overwrite). * Entries explicitly erased (rather than evicted) might not be freed immediately in some rare cases. * With strict_capacity_limit=false, capacity limit is not tracked/enforced as precisely as LRUCache, but is self-correcting and should only deviate by a very small number of extra or fewer entries. * Use smaller "computed default" number of cache shards in many cases, because benefits to larger usage tracking / eviction pools outweigh the small cost of more lock-free atomic contention. The improvement in CPU and I/O is dramatic in some limit-memory cases. * Even without the sharding change, the eviction algorithm is likely more effective than LRU overall because it's more stateful, even though the "hot path" state tracking for it is essentially free with ref counting. It is like a generalized CLOCK with aging (see code comments). I don't have performance numbers showing a specific improvement, but in theory, for a Poisson access pattern to each block, keeping some state allows better estimation of time to next access (Poisson interval) than strict LRU. The bounded randomness in CLOCK can also reduce "cliff" effect for repeated range scans approaching and exceeding cache size. ## Hot path algorithm comparison Rough descriptions, focusing on number and kind of atomic operations: * Old `Lookup()` (2-5 atomic updates per probe): ``` Loop: Increment internal ref count at slot If possible hit: Check flags atomic (and non-atomic fields) If cache hit: Three distinct updates to 'flags' atomic Increment refs for internal-to-external Return Decrement internal ref count while atomic read 'displacements' > 0 ``` * New `Lookup()` (1-2 atomic updates per probe): ``` Loop: Increment acquire counter in meta word (optimistic) If visible entry (already read meta word): If match (read non-atomic fields): Return Else: Decrement acquire counter in meta word Else if invisible entry (rare, already read meta word): Decrement acquire counter in meta word while atomic read 'displacements' > 0 ``` * Old `Release()` (1 atomic update, conditional on atomic read, rarely more): ``` Read atomic ref count If last reference and invisible (rare): Use CAS etc. to remove Return Else: Decrement ref count ``` * New `Release()` (1 unconditional atomic update, rarely more): ``` Increment release counter in meta word If last reference and invisible (rare): Use CAS etc. to remove Return ``` ## Performance test setup Build DB with ``` TEST_TMPDIR=/dev/shm ./db_bench -benchmarks=fillrandom -num=30000000 -disable_wal=1 -bloom_bits=16 ``` Test with ``` TEST_TMPDIR=/dev/shm ./db_bench -benchmarks=readrandom -readonly -num=30000000 -bloom_bits=16 -cache_index_and_filter_blocks=1 -cache_size=${CACHE_MB}000000 -duration 60 -threads=$THREADS -statistics ``` Numbers on a single socket Skylake Xeon system with 48 hardware threads, DEBUG_LEVEL=0 PORTABLE=0. Very similar story on a dual socket system with 80 hardware threads. Using (every 2nd) Fibonacci MB cache sizes to sample the territory between powers of two. Configurations: base: LRUCache before this change, but with db_bench change to default cache_numshardbits=-1 (instead of fixed at 6) folly: LRUCache before this change, with folly enabled (distributed mutex) but on an old compiler (sorry) gt_clock: experimental ClockCache before this change new_clock: experimental ClockCache with this change ## Performance test results First test "hot path" read performance, with block cache large enough for whole DB: 4181MB 1thread base -> kops/s: 47.761 4181MB 1thread folly -> kops/s: 45.877 4181MB 1thread gt_clock -> kops/s: 51.092 4181MB 1thread new_clock -> kops/s: 53.944 4181MB 16thread base -> kops/s: 284.567 4181MB 16thread folly -> kops/s: 249.015 4181MB 16thread gt_clock -> kops/s: 743.762 4181MB 16thread new_clock -> kops/s: 861.821 4181MB 24thread base -> kops/s: 303.415 4181MB 24thread folly -> kops/s: 266.548 4181MB 24thread gt_clock -> kops/s: 975.706 4181MB 24thread new_clock -> kops/s: 1205.64 (~= 24 * 53.944) 4181MB 32thread base -> kops/s: 311.251 4181MB 32thread folly -> kops/s: 274.952 4181MB 32thread gt_clock -> kops/s: 1045.98 4181MB 32thread new_clock -> kops/s: 1370.38 4181MB 48thread base -> kops/s: 310.504 4181MB 48thread folly -> kops/s: 268.322 4181MB 48thread gt_clock -> kops/s: 1195.65 4181MB 48thread new_clock -> kops/s: 1604.85 (~= 24 * 1.25 * 53.944) 4181MB 64thread base -> kops/s: 307.839 4181MB 64thread folly -> kops/s: 272.172 4181MB 64thread gt_clock -> kops/s: 1204.47 4181MB 64thread new_clock -> kops/s: 1615.37 4181MB 128thread base -> kops/s: 310.934 4181MB 128thread folly -> kops/s: 267.468 4181MB 128thread gt_clock -> kops/s: 1188.75 4181MB 128thread new_clock -> kops/s: 1595.46 Whether we have just one thread on a quiet system or an overload of threads, the new version wins every time in thousand-ops per second, sometimes dramatically so. Mutex-based implementation quickly becomes contention-limited. New clock cache shows essentially perfect scaling up to number of physical cores (24), and then each hyperthreaded core adding about 1/4 the throughput of an additional physical core (see 48 thread case). Block cache miss rates (omitted above) are negligible across the board. With partitioned instead of full filters, the maximum speed-up vs. base is more like 2.5x rather than 5x. Now test a large block cache with low miss ratio, but some eviction is required: 1597MB 1thread base -> kops/s: 46.603 io_bytes/op: 1584.63 miss_ratio: 0.0201066 max_rss_mb: 1589.23 1597MB 1thread folly -> kops/s: 45.079 io_bytes/op: 1530.03 miss_ratio: 0.019872 max_rss_mb: 1550.43 1597MB 1thread gt_clock -> kops/s: 48.711 io_bytes/op: 1566.63 miss_ratio: 0.0198923 max_rss_mb: 1691.4 1597MB 1thread new_clock -> kops/s: 51.531 io_bytes/op: 1589.07 miss_ratio: 0.0201969 max_rss_mb: 1583.56 1597MB 32thread base -> kops/s: 301.174 io_bytes/op: 1439.52 miss_ratio: 0.0184218 max_rss_mb: 1656.59 1597MB 32thread folly -> kops/s: 273.09 io_bytes/op: 1375.12 miss_ratio: 0.0180002 max_rss_mb: 1586.8 1597MB 32thread gt_clock -> kops/s: 904.497 io_bytes/op: 1411.29 miss_ratio: 0.0179934 max_rss_mb: 1775.89 1597MB 32thread new_clock -> kops/s: 1182.59 io_bytes/op: 1440.77 miss_ratio: 0.0185449 max_rss_mb: 1636.45 1597MB 128thread base -> kops/s: 309.91 io_bytes/op: 1438.25 miss_ratio: 0.018399 max_rss_mb: 1689.98 1597MB 128thread folly -> kops/s: 267.605 io_bytes/op: 1394.16 miss_ratio: 0.0180286 max_rss_mb: 1631.91 1597MB 128thread gt_clock -> kops/s: 691.518 io_bytes/op: 9056.73 miss_ratio: 0.0186572 max_rss_mb: 1982.26 1597MB 128thread new_clock -> kops/s: 1406.12 io_bytes/op: 1440.82 miss_ratio: 0.0185463 max_rss_mb: 1685.63 610MB 1thread base -> kops/s: 45.511 io_bytes/op: 2279.61 miss_ratio: 0.0290528 max_rss_mb: 615.137 610MB 1thread folly -> kops/s: 43.386 io_bytes/op: 2217.29 miss_ratio: 0.0289282 max_rss_mb: 600.996 610MB 1thread gt_clock -> kops/s: 46.207 io_bytes/op: 2275.51 miss_ratio: 0.0290057 max_rss_mb: 637.934 610MB 1thread new_clock -> kops/s: 48.879 io_bytes/op: 2283.1 miss_ratio: 0.0291253 max_rss_mb: 613.5 610MB 32thread base -> kops/s: 306.59 io_bytes/op: 2250 miss_ratio: 0.0288721 max_rss_mb: 683.402 610MB 32thread folly -> kops/s: 269.176 io_bytes/op: 2187.86 miss_ratio: 0.0286938 max_rss_mb: 628.742 610MB 32thread gt_clock -> kops/s: 855.097 io_bytes/op: 2279.26 miss_ratio: 0.0288009 max_rss_mb: 733.062 610MB 32thread new_clock -> kops/s: 1121.47 io_bytes/op: 2244.29 miss_ratio: 0.0289046 max_rss_mb: 666.453 610MB 128thread base -> kops/s: 305.079 io_bytes/op: 2252.43 miss_ratio: 0.0288884 max_rss_mb: 723.457 610MB 128thread folly -> kops/s: 269.583 io_bytes/op: 2204.58 miss_ratio: 0.0287001 max_rss_mb: 676.426 610MB 128thread gt_clock -> kops/s: 53.298 io_bytes/op: 8128.98 miss_ratio: 0.0292452 max_rss_mb: 956.273 610MB 128thread new_clock -> kops/s: 1301.09 io_bytes/op: 2246.04 miss_ratio: 0.0289171 max_rss_mb: 788.812 The new version is still winning every time, sometimes dramatically so, and we can tell from the maximum resident memory numbers (which contain some noise, by the way) that the new cache is not cheating on memory usage. IMPORTANT: The previous generation experimental clock cache appears to hit a serious bottleneck in the higher thread count configurations, presumably due to some of its waiting functionality. (The same bottleneck is not seen with partitioned index+filters.) Now we consider even smaller cache sizes, with higher miss ratios, eviction work, etc. 233MB 1thread base -> kops/s: 10.557 io_bytes/op: 227040 miss_ratio: 0.0403105 max_rss_mb: 247.371 233MB 1thread folly -> kops/s: 15.348 io_bytes/op: 112007 miss_ratio: 0.0372238 max_rss_mb: 245.293 233MB 1thread gt_clock -> kops/s: 6.365 io_bytes/op: 244854 miss_ratio: 0.0413873 max_rss_mb: 259.844 233MB 1thread new_clock -> kops/s: 47.501 io_bytes/op: 2591.93 miss_ratio: 0.0330989 max_rss_mb: 242.461 233MB 32thread base -> kops/s: 96.498 io_bytes/op: 363379 miss_ratio: 0.0459966 max_rss_mb: 479.227 233MB 32thread folly -> kops/s: 109.95 io_bytes/op: 314799 miss_ratio: 0.0450032 max_rss_mb: 400.738 233MB 32thread gt_clock -> kops/s: 2.353 io_bytes/op: 385397 miss_ratio: 0.048445 max_rss_mb: 500.688 233MB 32thread new_clock -> kops/s: 1088.95 io_bytes/op: 2567.02 miss_ratio: 0.0330593 max_rss_mb: 303.402 233MB 128thread base -> kops/s: 84.302 io_bytes/op: 378020 miss_ratio: 0.0466558 max_rss_mb: 1051.84 233MB 128thread folly -> kops/s: 89.921 io_bytes/op: 338242 miss_ratio: 0.0460309 max_rss_mb: 812.785 233MB 128thread gt_clock -> kops/s: 2.588 io_bytes/op: 462833 miss_ratio: 0.0509158 max_rss_mb: 1109.94 233MB 128thread new_clock -> kops/s: 1299.26 io_bytes/op: 2565.94 miss_ratio: 0.0330531 max_rss_mb: 361.016 89MB 1thread base -> kops/s: 0.574 io_bytes/op: 5.35977e+06 miss_ratio: 0.274427 max_rss_mb: 91.3086 89MB 1thread folly -> kops/s: 0.578 io_bytes/op: 5.16549e+06 miss_ratio: 0.27276 max_rss_mb: 96.8984 89MB 1thread gt_clock -> kops/s: 0.512 io_bytes/op: 4.13111e+06 miss_ratio: 0.242817 max_rss_mb: 119.441 89MB 1thread new_clock -> kops/s: 48.172 io_bytes/op: 2709.76 miss_ratio: 0.0346162 max_rss_mb: 100.754 89MB 32thread base -> kops/s: 5.779 io_bytes/op: 6.14192e+06 miss_ratio: 0.320399 max_rss_mb: 311.812 89MB 32thread folly -> kops/s: 5.601 io_bytes/op: 5.83838e+06 miss_ratio: 0.313123 max_rss_mb: 252.418 89MB 32thread gt_clock -> kops/s: 0.77 io_bytes/op: 3.99236e+06 miss_ratio: 0.236296 max_rss_mb: 396.422 89MB 32thread new_clock -> kops/s: 1064.97 io_bytes/op: 2687.23 miss_ratio: 0.0346134 max_rss_mb: 155.293 89MB 128thread base -> kops/s: 4.959 io_bytes/op: 6.20297e+06 miss_ratio: 0.323945 max_rss_mb: 823.43 89MB 128thread folly -> kops/s: 4.962 io_bytes/op: 5.9601e+06 miss_ratio: 0.319857 max_rss_mb: 626.824 89MB 128thread gt_clock -> kops/s: 1.009 io_bytes/op: 4.1083e+06 miss_ratio: 0.242512 max_rss_mb: 1095.32 89MB 128thread new_clock -> kops/s: 1224.39 io_bytes/op: 2688.2 miss_ratio: 0.0346207 max_rss_mb: 218.223 ^ Now something interesting has happened: the new clock cache has gained a dramatic lead in the single-threaded case, and this is because the cache is so small, and full filters are so big, that dividing the cache into 64 shards leads to significant (random) imbalances in cache shards and excessive churn in imbalanced shards. This new clock cache only uses two shards for this configuration, and that helps to ensure that entries are part of a sufficiently big pool that their eviction order resembles the single-shard order. (This effect is not seen with partitioned index+filters.) Even smaller cache size: 34MB 1thread base -> kops/s: 0.198 io_bytes/op: 1.65342e+07 miss_ratio: 0.939466 max_rss_mb: 48.6914 34MB 1thread folly -> kops/s: 0.201 io_bytes/op: 1.63416e+07 miss_ratio: 0.939081 max_rss_mb: 45.3281 34MB 1thread gt_clock -> kops/s: 0.448 io_bytes/op: 4.43957e+06 miss_ratio: 0.266749 max_rss_mb: 100.523 34MB 1thread new_clock -> kops/s: 1.055 io_bytes/op: 1.85439e+06 miss_ratio: 0.107512 max_rss_mb: 75.3125 34MB 32thread base -> kops/s: 3.346 io_bytes/op: 1.64852e+07 miss_ratio: 0.93596 max_rss_mb: 180.48 34MB 32thread folly -> kops/s: 3.431 io_bytes/op: 1.62857e+07 miss_ratio: 0.935693 max_rss_mb: 137.531 34MB 32thread gt_clock -> kops/s: 1.47 io_bytes/op: 4.89704e+06 miss_ratio: 0.295081 max_rss_mb: 392.465 34MB 32thread new_clock -> kops/s: 8.19 io_bytes/op: 3.70456e+06 miss_ratio: 0.20826 max_rss_mb: 519.793 34MB 128thread base -> kops/s: 2.293 io_bytes/op: 1.64351e+07 miss_ratio: 0.931866 max_rss_mb: 449.484 34MB 128thread folly -> kops/s: 2.34 io_bytes/op: 1.6219e+07 miss_ratio: 0.932023 max_rss_mb: 396.457 34MB 128thread gt_clock -> kops/s: 1.798 io_bytes/op: 5.4241e+06 miss_ratio: 0.324881 max_rss_mb: 1104.41 34MB 128thread new_clock -> kops/s: 10.519 io_bytes/op: 2.39354e+06 miss_ratio: 0.136147 max_rss_mb: 1050.52 As the miss ratio gets higher (say, above 10%), the CPU time spent in eviction starts to erode the advantage of using fewer shards (13% miss rate much lower than 94%). LRU's O(1) eviction time can eventually pay off when there's enough block cache churn: 13MB 1thread base -> kops/s: 0.195 io_bytes/op: 1.65732e+07 miss_ratio: 0.946604 max_rss_mb: 45.6328 13MB 1thread folly -> kops/s: 0.197 io_bytes/op: 1.63793e+07 miss_ratio: 0.94661 max_rss_mb: 33.8633 13MB 1thread gt_clock -> kops/s: 0.519 io_bytes/op: 4.43316e+06 miss_ratio: 0.269379 max_rss_mb: 100.684 13MB 1thread new_clock -> kops/s: 0.176 io_bytes/op: 1.54148e+07 miss_ratio: 0.91545 max_rss_mb: 66.2383 13MB 32thread base -> kops/s: 3.266 io_bytes/op: 1.65544e+07 miss_ratio: 0.943386 max_rss_mb: 132.492 13MB 32thread folly -> kops/s: 3.396 io_bytes/op: 1.63142e+07 miss_ratio: 0.943243 max_rss_mb: 101.863 13MB 32thread gt_clock -> kops/s: 2.758 io_bytes/op: 5.13714e+06 miss_ratio: 0.310652 max_rss_mb: 396.121 13MB 32thread new_clock -> kops/s: 3.11 io_bytes/op: 1.23419e+07 miss_ratio: 0.708425 max_rss_mb: 321.758 13MB 128thread base -> kops/s: 2.31 io_bytes/op: 1.64823e+07 miss_ratio: 0.939543 max_rss_mb: 425.539 13MB 128thread folly -> kops/s: 2.339 io_bytes/op: 1.6242e+07 miss_ratio: 0.939966 max_rss_mb: 346.098 13MB 128thread gt_clock -> kops/s: 3.223 io_bytes/op: 5.76928e+06 miss_ratio: 0.345899 max_rss_mb: 1087.77 13MB 128thread new_clock -> kops/s: 2.984 io_bytes/op: 1.05341e+07 miss_ratio: 0.606198 max_rss_mb: 898.27 gt_clock is clearly blowing way past its memory budget for lower miss rates and best throughput. new_clock also seems to be exceeding budgets, and this warrants more investigation but is not the use case we are targeting with the new cache. With partitioned index+filter, the miss ratio is much better, and although still high enough that the eviction CPU time is definitely offsetting mutex contention: 13MB 1thread base -> kops/s: 16.326 io_bytes/op: 23743.9 miss_ratio: 0.205362 max_rss_mb: 65.2852 13MB 1thread folly -> kops/s: 15.574 io_bytes/op: 19415 miss_ratio: 0.184157 max_rss_mb: 56.3516 13MB 1thread gt_clock -> kops/s: 14.459 io_bytes/op: 22873 miss_ratio: 0.198355 max_rss_mb: 63.9688 13MB 1thread new_clock -> kops/s: 16.34 io_bytes/op: 24386.5 miss_ratio: 0.210512 max_rss_mb: 61.707 13MB 128thread base -> kops/s: 289.786 io_bytes/op: 23710.9 miss_ratio: 0.205056 max_rss_mb: 103.57 13MB 128thread folly -> kops/s: 185.282 io_bytes/op: 19433.1 miss_ratio: 0.184275 max_rss_mb: 116.219 13MB 128thread gt_clock -> kops/s: 354.451 io_bytes/op: 23150.6 miss_ratio: 0.200495 max_rss_mb: 102.871 13MB 128thread new_clock -> kops/s: 295.359 io_bytes/op: 24626.4 miss_ratio: 0.212452 max_rss_mb: 121.109 Pull Request resolved: https://github.com/facebook/rocksdb/pull/10626 Test Plan: updated unit tests, stress/crash test runs including with TSAN, ASAN, UBSAN Reviewed By: anand1976 Differential Revision: D39368406 Pulled By: pdillinger fbshipit-source-id: 5afc44da4c656f8f751b44552bbf27bd3ca6fef9	2 years ago
Peter Dillinger	6de7081cf3	Always verify SST unique IDs on SST file open (#10532) ... Summary: Although we've been tracking SST unique IDs in the DB manifest unconditionally, checking has been opt-in and with an extra pass at DB::Open time. This changes the behavior of `verify_sst_unique_id_in_manifest` to check unique ID against manifest every time an SST file is opened through table cache (normal DB operations), replacing the explicit pass over files at DB::Open time. This change also enables the option by default and removes the "EXPERIMENTAL" designation. One possible criticism is that the option no longer ensures the integrity of a DB at Open time. This is far from an all-or-nothing issue. Verifying the IDs of all SST files hardly ensures all the data in the DB is readable. (VerifyChecksum is supposed to do that.) Also, with max_open_files=-1 (default, extremely common), all SST files are opened at DB::Open time anyway. Implementation details: * `VerifySstUniqueIdInManifest()` functions are the extra/explicit pass that is now removed. * Unit tests that manipulate/corrupt table properties have to opt out of this check, because that corrupts the "actual" unique id. (And even for testing we don't currently have a mechanism to set "no unique id" in the in-memory file metadata for new files.) * A lot of other unit test churn relates to (a) default checking on, and (b) checking on SST open even without DB::Open (e.g. on flush) * Use `FileMetaData` for more `TableCache` operations (in place of `FileDescriptor`) so that we have access to the unique_id whenever we might need to open an SST file. **There is the possibility of performance impact because we can no longer use the more localized `fd` part of an `FdWithKeyRange` but instead follow the `file_metadata` pointer. However, this change (possible regression) is only done for `GetMemoryUsageByTableReaders`.** * Removed a completely unnecessary constructor overload of `TableReaderOptions` Possible follow-up: * Verification only happens when opening through table cache. Are there more places where this should happen? * Improve error message when there is a file size mismatch vs. manifest (FIXME added in the appropriate place). * I'm not sure there's a justification for `FileDescriptor` to be distinct from `FileMetaData`. * I'm skeptical that `FdWithKeyRange` really still makes sense for optimizing some data locality by duplicating some data in memory, but I could be wrong. * An unnecessary overload of NewTableReader was recently added, in the public API nonetheless (though unusable there). It should be cleaned up to put most things under `TableReaderOptions`. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10532 Test Plan: updated unit tests Performance test showing no significant difference (just noise I think): `./db_bench -benchmarks=readwhilewriting[-X10] -num=3000000 -disable_wal=1 -bloom_bits=8 -write_buffer_size=1000000 -target_file_size_base=1000000` Before: readwhilewriting [AVG 10 runs] : 68702 (± 6932) ops/sec After: readwhilewriting [AVG 10 runs] : 68239 (± 7198) ops/sec Reviewed By: jay-zhuang Differential Revision: D38765551 Pulled By: pdillinger fbshipit-source-id: a827a708155f12344ab2a5c16e7701c7636da4c2	2 years ago
Andrew Kryczka	fe5fbe32cb	Deflake DBBlockCacheTest1.WarmCacheWithBlocksDuringFlush (#10635) ... Summary: Previously, automatic compaction could be triggered prior to the test invoking CompactRange(). It could lead to the following flaky failure: ``` /root/project/db/db_block_cache_test.cc:753: Failure Expected equality of these values: 1 + kNumBlocks Which is: 11 options.statistics->getTickerCount(BLOCK_CACHE_INDEX_ADD) Which is: 10 ``` A sequence leading to this failure was: * Automatic compaction * files [1] [2] trivially moved * files [3] [4] [5] [6] trivially moved * CompactRange() * files [7] [8] [9] trivially moved * file [10] trivially moved In such a case, the index/filter block adds that the test expected did not happen since there were no new files. This PR just tweaks settings to ensure the `CompactRange()` produces one new file. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10635 Reviewed By: cbi42 Differential Revision: D39250869 Pulled By: ajkr fbshipit-source-id: a3c94c49069e28c49c40b4b80dae0059739d19fd	2 years ago
Gang Liao	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	2 years ago
Peter Dillinger	86a1e3e0e7	Derive cache keys from SST unique IDs (#10394) ... Summary: ... so that cache keys can be derived from DB manifest data before reading the file from storage--so that every part of the file can potentially go in a persistent cache. See updated comments in cache_key.cc for technical details. Importantly, the new cache key encoding uses some fancy but efficient math to pack data into the cache key without depending on the sizes of the various pieces. This simplifies some existing code creating cache keys, like cache warming before the file size is known. This should provide us an essentially permanent mapping between SST unique IDs and base cache keys, with the ability to "upgrade" SST unique IDs (and thus cache keys) with new SST format_versions. These cache keys are of similar, perhaps indistinguishable quality to the previous generation. Before this change (see "corrected" days between collision): ``` ./cache_bench -stress_cache_key -sck_keep_bits=43 18 collisions after 2 x 90 days, est 10 days between (1.15292e+19 corrected) ``` After this change (keep 43 bits, up through 50, to validate "trajectory" is ok on "corrected" days between collision): ``` 19 collisions after 3 x 90 days, est 14.2105 days between (1.63836e+19 corrected) 16 collisions after 5 x 90 days, est 28.125 days between (1.6213e+19 corrected) 15 collisions after 7 x 90 days, est 42 days between (1.21057e+19 corrected) 15 collisions after 17 x 90 days, est 102 days between (1.46997e+19 corrected) 15 collisions after 49 x 90 days, est 294 days between (2.11849e+19 corrected) 15 collisions after 62 x 90 days, est 372 days between (1.34027e+19 corrected) 15 collisions after 53 x 90 days, est 318 days between (5.72858e+18 corrected) 15 collisions after 309 x 90 days, est 1854 days between (1.66994e+19 corrected) ``` However, the change does modify (probably weaken) the "guaranteed unique" promise from this > SST files generated in a single process are guaranteed to have unique cache keys, unless/until number session ids * max file number = 2**86 to this (see https://github.com/facebook/rocksdb/issues/10388) > With the DB id limitation, we only have nice guaranteed unique cache keys for files generated in a single process until biggest session_id_counter and offset_in_file reach combined 64 bits I don't think this is a practical concern, though. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10394 Test Plan: unit tests updated, see simulation results above Reviewed By: jay-zhuang Differential Revision: D38667529 Pulled By: pdillinger fbshipit-source-id: 49af3fe7f47e5b61162809a78b76c769fd519fba	2 years ago
Jay Zhuang	5d3aefb682	Migrate to docker for CI run (#10496) ... Summary: Moved linux builds to using docker to avoid CI instability caused by dependency installation site down. Added the `Dockerfile` which is used to build the image. The build time is also significantly reduced, because no dependencies installation and with using 2xlarge+ instance for slow build (like tsan test). Also fixed a few issues detected while building this: * `DestoryDB()` Status not checked for a few tests * nullptr might be used in `inlineskiplist.cc` Pull Request resolved: https://github.com/facebook/rocksdb/pull/10496 Test Plan: CI Reviewed By: ajkr Differential Revision: D38554200 Pulled By: jay-zhuang fbshipit-source-id: 16e8fb2bf07b9c84bb27fb18421c4d54f2f248fd	2 years ago
Guido Tagliavini Ponce	a0798f6f92	Enable ClockCache in DB block cache test (#10482) ... Summary: A test in db_block_cache_test.cc was skipping ClockCache due to the 16-byte key length requirement. We fixed this. Along the way, we fixed a bug in ApplyToSomeEntries, which assumed the function being applied could modify handle metadata, and thus took an exclusive reference. This is incompatible with calls that need to inspect every element (including externally referenced ones) to gather stats. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10482 Test Plan: ``make -j24 check`` Reviewed By: anand1976 Differential Revision: D38553073 Pulled By: guidotag fbshipit-source-id: 0ed63fed4d3b89e5056b35b7091fce579f5647ae	2 years ago
Peter Dillinger	65036e4217	Revert "Add a blob-specific cache priority (#10309)" (#10434) ... Summary: This reverts commit 8d178090be because of a clear performance regression seen in internal dashboard https://fburl.com/unidash/tpz75iee Pull Request resolved: https://github.com/facebook/rocksdb/pull/10434 Reviewed By: ltamasi Differential Revision: D38256373 Pulled By: pdillinger fbshipit-source-id: 134aa00f50dd7b1bbe037c227884a351342ec44b	2 years ago
Gang Liao	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	2 years ago
Guido Tagliavini Ponce	9645e66fc9	Temporarily return a LRUCache from NewClockCache (#10351) ... Summary: ClockCache is still in experimental stage, and currently fails some pre-release fbcode tests. See https://www.internalfb.com/diff/D37772011. API calls to construct ClockCache are done via the function NewClockCache. For now, NewClockCache calls will return an LRUCache (with appropriate arguments), which is stable. The idea that NewClockCache returns nullptr was also floated, but this would be interpreted as unsupported cache, and a default LRUCache would be constructed instead, potentially causing a performance regression that is harder to identify. A new version of the NewClockCache function was created for our internal tests. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10351 Test Plan: ``make -j24 check`` and re-run the pre-release tests. Reviewed By: pdillinger Differential Revision: D37802685 Pulled By: guidotag fbshipit-source-id: 0a8d10612ff21e576f7360cb13e20bc36e244972	2 years ago
Peter Dillinger	e6c5e0ab9a	Have Cache use Status::MemoryLimit (#10262) ... Summary: I noticed it would clean up some things to have Cache::Insert() return our MemoryLimit Status instead of Incomplete for the case in which the capacity limit is reached. I suspect this fixes some existing but unknown bugs where this Incomplete could be confused with other uses of Incomplete, especially no_io cases. This is the most suspicious case I noticed, but was not able to reproduce a bug, in part because the existing code is not covered by unit tests (FIXME added): 57adbf0e91/table/get_context.cc (L397) I audited all the existing uses of IsIncomplete and updated those that seemed relevant. HISTORY updated with a clear warning to users of strict_capacity_limit=true to update uses of `IsIncomplete()` Pull Request resolved: https://github.com/facebook/rocksdb/pull/10262 Test Plan: updated unit tests Reviewed By: hx235 Differential Revision: D37473155 Pulled By: pdillinger fbshipit-source-id: 4bd9d9353ccddfe286b03ebd0652df8ce20f99cb	2 years ago
sdong	a9565ccb26	Try to trivial move more than one files (#10190) ... Summary: In leveled compaction, try to trivial move more than one files if possible, up to 4 files or max_compaction_bytes. This is to allow higher write throughput for some use cases where data is loaded in sequential order, where appying compaction results is the bottleneck. When pick up a file to compact and it doesn't have overlapping files in the next level, try to expand to the next file if there is still no overlapping. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10190 Test Plan: Add some unit tests. For performance, Try to run ./db_bench_multi_move --benchmarks=fillseq --compression_type=lz4 --write_buffer_size=5000000 --num=100000000 --value_size=1000 -level_compaction_dynamic_level_bytes Together with https://github.com/facebook/rocksdb/pull/10188 , stalling will be eliminated in this benchmark. Reviewed By: jay-zhuang Differential Revision: D37230647 fbshipit-source-id: 42b260f545c46abc5d90335ac2bbfcd09602b549	3 years ago
Guido Tagliavini Ponce	57a0e2f304	Clock cache (#10273) ... Summary: This is the initial step in the development of a lock-free clock cache. This PR includes the base hash table design (which we mostly ported over from FastLRUCache) and the clock eviction algorithm. Importantly, it's still _not_ lock-free---all operations use a shard lock. Besides the locking, there are other features left as future work: - Remove keys from the handles. Instead, use 128-bit bijective hashes of them for handle comparisons, probing (we need two 32-bit hashes of the key for double hashing) and sharding (we need one 6-bit hash). - Remove the clock_usage_ field, which is updated on every lookup. Even if it were atomically updated, it could cause memory invalidations across cores. - Middle insertions into the clock list. - A test that exercises the clock eviction policy. - Update the Java API of ClockCache and Java calls to C++. Along the way, we improved the code and comments quality of FastLRUCache. These changes are relatively minor. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10273 Test Plan: ``make -j24 check`` Reviewed By: pdillinger Differential Revision: D37522461 Pulled By: guidotag fbshipit-source-id: 3d70b737dbb70dcf662f00cef8c609750f083943	3 years ago
Peter Dillinger	126c223714	Remove deprecated block-based filter (#10184) ... Summary: In https://github.com/facebook/rocksdb/issues/9535, release 7.0, we hid the old block-based filter from being created using the public API, because of its inefficiency. Although we normally maintain read compatibility on old DBs forever, filters are not required for reading a DB, only for optimizing read performance. Thus, it should be acceptable to remove this code and the substantial maintenance burden it carries as useful features are developed and validated (such as user timestamp). This change completely removes the code for reading and writing the old block-based filters, net removing about 1370 lines of code no longer needed. Options removed from testing / benchmarking tools. The prior existence is only evident in a couple of places: * `CacheEntryRole::kDeprecatedFilterBlock` - We can update this public API enum in a major release to minimize source code incompatibilities. * A warning is logged when an old table file is opened that used the old block-based filter. This is provided as a courtesy, and would be a pain to unit test, so manual testing should suffice. Unfortunately, sst_dump does not tell you whether a file uses block-based filter, and the structure of the code makes it very difficult to fix. * To detect that case, `kObsoleteFilterBlockPrefix` (renamed from `kFilterBlockPrefix`) for metaindex is maintained (for now). Other notes: * In some cases where numbers are associated with filter configurations, we have had to update the assigned numbers so that they all correspond to something that exists. * Fixed potential stat counting bug by assuming `filter_checked = false` for cases like `filter == nullptr` rather than assuming `filter_checked = true` * Removed obsolete `block_offset` and `prefix_extractor` parameters from several functions. * Removed some unnecessary checks `if (!table_prefix_extractor() && !prefix_extractor)` because the caller guarantees the prefix extractor exists and is compatible Pull Request resolved: https://github.com/facebook/rocksdb/pull/10184 Test Plan: tests updated, manually test new warning in LOG using base version to generate a DB Reviewed By: riversand963 Differential Revision: D37212647 Pulled By: pdillinger fbshipit-source-id: 06ee020d8de3b81260ffc36ad0c1202cbf463a80	3 years ago
Guido Tagliavini Ponce	f105e1a501	Make the per-shard hash table fixed-size. (#10154) ... Summary: We make the size of the per-shard hash table fixed. The base level of the hash table is now preallocated with the required capacity. The user must provide an estimate of the size of the values. Notice that even though the base level becomes fixed, the chains are still dynamic. Overall, the shard capacity mechanisms haven't changed, so we don't need to test this. Pull Request resolved: https://github.com/facebook/rocksdb/pull/10154 Test Plan: `make -j24 check` Reviewed By: pdillinger Differential Revision: D37124451 Pulled By: guidotag fbshipit-source-id: cba6ac76052fe0ec60b8ff4211b3de7650e80d0c	3 years ago
Guido Tagliavini Ponce	415200d792	Assume fixed size key (#10137) ... Summary: FastLRUCache now only supports 16B keys. The tests have changed to reflect this. Because the unit tests were designed for caches that accept any string as keys, some tests are no longer compatible with FastLRUCache. We have disabled those for runs with FastLRUCache. (We could potentially change all tests to use 16B keys, but we don't because the cache public API does not require this.) Pull Request resolved: https://github.com/facebook/rocksdb/pull/10137 Test Plan: make -j24 check Reviewed By: gitbw95 Differential Revision: D37083934 Pulled By: guidotag fbshipit-source-id: be1719cf5f8364a9a32bc4555bce1a0de3833b0d	3 years ago
sdong	736a7b5433	Remove own ToString() (#9955) ... Summary: ToString() is created as some platform doesn't support std::to_string(). However, we've already used std::to_string() by mistake for 16 months (in db/db_info_dumper.cc). This commit just remove ToString(). Pull Request resolved: https://github.com/facebook/rocksdb/pull/9955 Test Plan: Watch CI tests Reviewed By: riversand963 Differential Revision: D36176799 fbshipit-source-id: bdb6dcd0e3a3ab96a1ac810f5d0188f684064471	3 years ago
Peter Dillinger	bb87164db3	Fork and simplify LRUCache for developing enhancements (#9917) ... Summary: To support a project to prototype and evaluate algorithmic enhancments and alternatives to LRUCache, here I have separated out LRUCache into internal-only "FastLRUCache" and cut it down to essentials, so that details like secondary cache handling and priorities do not interfere with prototyping. These can be re-integrated later as needed, along with refactoring to minimize code duplication (which would slow down prototyping for now). Pull Request resolved: https://github.com/facebook/rocksdb/pull/9917 Test Plan: unit tests updated to ensure basic functionality has (likely) been preserved Reviewed By: anand1976 Differential Revision: D35995554 Pulled By: pdillinger fbshipit-source-id: d67b20b7ada3b5d3bfe56d897a73885894a1d9db	3 years ago
Andrew Kryczka	d6e016be6d	Expose `CacheEntryRole` and map keys for block cache stat collections (#9838) ... Summary: This gives users the ability to examine the map populated by `GetMapProperty()` with property `kBlockCacheEntryStats`. It also sets us up for a possible future where cache reservations are configured according to `CacheEntryRole`s rather than flags coupled to roles. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9838 Test Plan: - migrated test DBBlockCacheTest.CacheEntryRoleStats to use this API. That test verifies some of the contents are as expected - added a DBPropertiesTest to verify the public map keys are present, and nothing else Reviewed By: hx235 Differential Revision: D35629493 Pulled By: ajkr fbshipit-source-id: 5c4356b8560e85d1f881fd32c44c15960b02fc68	3 years ago
Peter Dillinger	afc280fdfd	Enhance new cache key testing & comments (#9329) ... Summary: Follow-up to https://github.com/facebook/rocksdb/issues/9126 Added new unit tests to validate some of the claims of guaranteed uniqueness within certain large bounds. Also cleaned up the cache_bench -stress-cache-key tool with better comments and description. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9329 Test Plan: no changes to production code Reviewed By: mrambacher Differential Revision: D33269328 Pulled By: pdillinger fbshipit-source-id: 3a2b684a6b2b15f79dc872e563e3d16563be26de	3 years ago
Peter Dillinger	0050a73a4f	New stable, fixed-length cache keys (#9126) ... Summary: This change standardizes on a new 16-byte cache key format for block cache (incl compressed and secondary) and persistent cache (but not table cache and row cache). The goal is a really fast cache key with practically ideal stability and uniqueness properties without external dependencies (e.g. from FileSystem). A fixed key size of 16 bytes should enable future optimizations to the concurrent hash table for block cache, which is a heavy CPU user / bottleneck, but there appears to be measurable performance improvement even with no changes to LRUCache. This change replaces a lot of disjointed and ugly code handling cache keys with calls to a simple, clean new internal API (cache_key.h). (Preserving the old cache key logic under an option would be very ugly and likely negate the performance gain of the new approach. Complete replacement carries some inherent risk, but I think that's acceptable with sufficient analysis and testing.) The scheme for encoding new cache keys is complicated but explained in cache_key.cc. Also: EndianSwapValue is moved to math.h to be next to other bit operations. (Explains some new include "math.h".) ReverseBits operation added and unit tests added to hash_test for both. Fixes https://github.com/facebook/rocksdb/issues/7405 (presuming a root cause) Pull Request resolved: https://github.com/facebook/rocksdb/pull/9126 Test Plan: ### Basic correctness Several tests needed updates to work with the new functionality, mostly because we are no longer relying on filesystem for stable cache keys so table builders & readers need more context info to agree on cache keys. This functionality is so core, a huge number of existing tests exercise the cache key functionality. ### Performance Create db with `TEST_TMPDIR=/dev/shm ./db_bench -bloom_bits=10 -benchmarks=fillrandom -num=3000000 -partition_index_and_filters` And test performance with `TEST_TMPDIR=/dev/shm ./db_bench -readonly -use_existing_db -bloom_bits=10 -benchmarks=readrandom -num=3000000 -duration=30 -cache_index_and_filter_blocks -cache_size=250000 -threads=4` using DEBUG_LEVEL=0 and simultaneous before & after runs. Before ops/sec, avg over 100 runs: 121924 After ops/sec, avg over 100 runs: 125385 (+2.8%) ### Collision probability I have built a tool, ./cache_bench -stress_cache_key to broadly simulate host-wide cache activity over many months, by making some pessimistic simplifying assumptions: * Every generated file has a cache entry for every byte offset in the file (contiguous range of cache keys) * All of every file is cached for its entire lifetime We use a simple table with skewed address assignment and replacement on address collision to simulate files coming & going, with quite a variance (super-Poisson) in ages. Some output with `./cache_bench -stress_cache_key -sck_keep_bits=40`: ``` Total cache or DBs size: 32TiB Writing 925.926 MiB/s or 76.2939TiB/day Multiply by 9.22337e+18 to correct for simulation losses (but still assume whole file cached) ``` These come from default settings of 2.5M files per day of 32 MB each, and `-sck_keep_bits=40` means that to represent a single file, we are only keeping 40 bits of the 128-bit cache key. With file size of 2\*\*25 contiguous keys (pessimistic), our simulation is about 2\*\*(128-40-25) or about 9 billion billion times more prone to collision than reality. More default assumptions, relatively pessimistic: * 100 DBs in same process (doesn't matter much) * Re-open DB in same process (new session ID related to old session ID) on average every 100 files generated * Restart process (all new session IDs unrelated to old) 24 times per day After enough data, we get a result at the end: ``` (keep 40 bits) 17 collisions after 2 x 90 days, est 10.5882 days between (9.76592e+19 corrected) ``` If we believe the (pessimistic) simulation and the mathematical generalization, we would need to run a billion machines all for 97 billion days to expect a cache key collision. To help verify that our generalization ("corrected") is robust, we can make our simulation more precise with `-sck_keep_bits=41` and `42`, which takes more running time to get enough data: ``` (keep 41 bits) 16 collisions after 4 x 90 days, est 22.5 days between (1.03763e+20 corrected) (keep 42 bits) 19 collisions after 10 x 90 days, est 47.3684 days between (1.09224e+20 corrected) ``` The generalized prediction still holds. With the `-sck_randomize` option, we can see that we are beating "random" cache keys (except offsets still non-randomized) by a modest amount (roughly 20x less collision prone than random), which should make us reasonably comfortable even in "degenerate" cases: ``` 197 collisions after 1 x 90 days, est 0.456853 days between (4.21372e+18 corrected) ``` I've run other tests to validate other conditions behave as expected, never behaving "worse than random" unless we start chopping off structured data. Reviewed By: zhichao-cao Differential Revision: D33171746 Pulled By: pdillinger fbshipit-source-id: f16a57e369ed37be5e7e33525ace848d0537c88f	3 years ago
Akanksha Mahajan	96d0773a11	Update prepopulate_block_cache logic to support block-based filter (#9300) ... Summary: Update prepopulate_block_cache logic to support block-based filter during insertion in block cache Pull Request resolved: https://github.com/facebook/rocksdb/pull/9300 Test Plan: CircleCI tests, make crash_test -j64 Reviewed By: pdillinger Differential Revision: D33132018 Pulled By: akankshamahajan15 fbshipit-source-id: 241deabab8645bda704728e572d6de6354df18b2	3 years ago
Peter Dillinger	653c392e47	More refactoring ahead of footer & meta changes (#9240) ... Summary: I'm working on a new format_version=6 to support context checksum (https://github.com/facebook/rocksdb/issues/9058) and this includes much of the refactoring and test updates to support that change. Test coverage data and manual inspection agree on dead code in block_based_table_reader.cc (removed). Pull Request resolved: https://github.com/facebook/rocksdb/pull/9240 Test Plan: tests enhanced to cover more cases etc. Extreme case performance testing indicates small % regression in fillseq (w/ compaction), though CPU profile etc. doesn't suggest any explanation. There is enhanced correctness checking in Footer::DecodeFrom, but this should be negligible. TEST_TMPDIR=/dev/shm/ ./db_bench -benchmarks=fillseq -memtablerep=vector -allow_concurrent_memtable_write=false -num=30000000 -checksum_type=1 --disable_wal={false,true} (Each is ops/s averaged over 50 runs, run simultaneously with competing configuration for load fairness) Before w/ wal: 454512 After w/ wal: 444820 (-2.1%) Before w/o wal: 1004560 After w/o wal: 998897 (-0.6%) Since this doesn't modify WAL code, one would expect real effects to be larger in w/o wal case. This regression will be corrected in a follow-up PR. Reviewed By: ajkr Differential Revision: D32813769 Pulled By: pdillinger fbshipit-source-id: 444a244eabf3825cd329b7d1b150cddce320862f	3 years ago
Akanksha Mahajan	9e4d56f2c9	Fix segmentation fault in table_options.prepopulate_block_cache when used with partition_filters (#9263) ... Summary: When table_options.prepopulate_block_cache is set to BlockBasedTableOptions::PrepopulateBlockCache::kFlushOnly and table_options.partition_filters is also set true, then there is segmentation failure when top level filter is fetched because its entered with wrong type in cache. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9263 Test Plan: Updated unit tests; Ran db_stress: make crash_test -j32 Reviewed By: pdillinger Differential Revision: D32936566 Pulled By: akankshamahajan15 fbshipit-source-id: 8bd79e53830d3e3c1bb79787e1ffbc3cb46d4426	3 years ago
Peter Dillinger	f8c685c4fc	Check for and disallow shared key space in block caches (#9172) ... Summary: We have three layers of block cache that often use the same key but map to different physical data: * BlockBasedTableOptions::block_cache * BlockBasedTableOptions::block_cache_compressed * BlockBasedTableOptions::persistent_cache If any two of these happen to share an underlying implementation and key space (insertion into one shows up in another), then memory safety is broken. The simplest case is block_cache == block_cache_compressed. (Credit mrambacher for asking about this case in a review.) With this change, we explicitly check for overlap and preemptively and safely fail with a Status code. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9172 Test Plan: test added. Crashes without new check Reviewed By: anand1976 Differential Revision: D32465659 Pulled By: pdillinger fbshipit-source-id: 3876b45b6dce6167e5a7a642725ddc86b96f8e40	3 years ago
Peter Dillinger	2819c7840e	Fix PrepopulateBlockCache::kFlushOnly (#8750) ... Summary: kFlushOnly currently means "always" except in the case of remote compaction. This makes it flushes only. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8750 Test Plan: test updated Reviewed By: akankshamahajan15 Differential Revision: D30968034 Pulled By: pdillinger fbshipit-source-id: 5dbd24dde18852a0e937a540995fba9bfbe89037	3 years ago
Peter Dillinger	04db764831	Embed original file number in SST table properties (#8686) ... Summary: I very recently realized that with https://github.com/facebook/rocksdb/issues/8669 we cannot later add file numbers to external SST files (so that more can share db session ids for better uniqueness properties), because of forward compatibility. We would have a version of RocksDB that assumes session IDs are unique on external SST files and therefore can't really break that invariant in future files. This change adds a table property for "orig_file_number" which is populated by normal SST files and also external SST files generated by SstFileWriter. SstFileWriter now keeps a db_session_id for life of the object and increments its own file numbers for embedding in table properties. (They are arguably "fake" file numbers because these numbers and not embedded in the file name.) While updating block_based_table_builder, I removed several unnecessary fields from Rep, because following the pattern would have created another unnecessary field. This change also updates block_based_table_reader to use this new property when available, which means that for newer SST files, we can determine the stable/original <db_session_id,file_number> unique identifier using just the file contents, not the file name. (It's a bit complicated; detailed comments in block_based_table_reader.) Also added DB host id to properties listing by sst_dump, which could be useful in debugging. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8686 Test Plan: majorly overhauled StableCacheKeys test for this change Reviewed By: zhichao-cao Differential Revision: D30457742 Pulled By: pdillinger fbshipit-source-id: 2e5ae7dddeb94fb9d8eac8a928486aed8b8cd445	3 years ago
Peter Dillinger	b6269b078a	Stable cache keys on ingested SST files (#8669) ... Summary: Extends https://github.com/facebook/rocksdb/issues/8659 to work for ingested external SST files, even the same file ingested into different DBs sharing a block cache. Note: These new cache keys are currently only enabled when FileSystem does not provide GetUniqueId. For now, they are typically larger, so slightly less efficient. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8669 Test Plan: Extended unit test Reviewed By: zhichao-cao Differential Revision: D30398532 Pulled By: pdillinger fbshipit-source-id: 1f13e2af4b8bfff5741953a69466e9589fbc23c7	3 years ago
Peter Dillinger	a207c27809	Stable cache keys using DB session ids in SSTs (#8659) ... Summary: Use DB session ids in SST table properties to make cache keys stable across DB re-open and copy / move / restore / etc. These new cache keys are currently only enabled when FileSystem does not provide GetUniqueId. For now, they are typically larger, so slightly less efficient. Relevant to https://github.com/facebook/rocksdb/issues/7405 This change has a minor regression in PersistentCache functionality: metaindex blocks are no longer cached in PersistentCache. Table properties blocks already were not but ideally should be. I didn't spent effort to fix & test these issues because we don't believe PersistentCache is used much if at all and expect SecondaryCache to replace it. (Though PRs are welcome.) FIXME: there is more to be fixed for stable cache keys on external SST files Pull Request resolved: https://github.com/facebook/rocksdb/pull/8659 Test Plan: new unit test added, which fails when disabling new functionality Reviewed By: zhichao-cao Differential Revision: D30297705 Pulled By: pdillinger fbshipit-source-id: e8539a5c8802a79340405629870f2e3fb3822d3a	3 years ago
Akanksha Mahajan	fd2079938d	Dynamically configure BlockBasedTableOptions.prepopulate_block_cache (#8620) ... Summary: Dynamically configure BlockBasedTableOptions.prepopulate_block_cache using DB::SetOptions. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8620 Test Plan: Added new unit test Reviewed By: anand1976 Differential Revision: D30091319 Pulled By: akankshamahajan15 fbshipit-source-id: fb586d1848a8dd525bba7b2f9eeac34f2fc6d82c	3 years ago
Akanksha Mahajan	8b2f60b668	Cache warming blocks during flush (#8561) ... Summary: Insert warm blocks (data, uncompressed dict, index and filter blocks) during flush in Block cache which is enabled under option BlockBasedTableOptions.prepopulate_block_cache. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8561 Test Plan: Added unit test Reviewed By: anand1976 Differential Revision: D29773411 Pulled By: akankshamahajan15 fbshipit-source-id: 6631123c10134340ef0bd7e90baafaa6deba0e66	3 years ago
Drewryz	3b27725245	Fix a minor issue with initializing the test path (#8555) ... Summary: The PerThreadDBPath has already specified a slash. It does not need to be specified when initializing the test path. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8555 Reviewed By: ajkr Differential Revision: D29758399 Pulled By: jay-zhuang fbshipit-source-id: 6d2b878523e3e8580536e2829cb25489844d9011	3 years ago
Peter Dillinger	df5dc73bec	Don't hold DB mutex for block cache entry stat scans (#8538) ... Summary: I previously didn't notice the DB mutex was being held during block cache entry stat scans, probably because I primarily checked for read performance regressions, because they require the block cache and are traditionally latency-sensitive. This change does some refactoring to avoid holding DB mutex and to avoid triggering and waiting for a scan in GetProperty("rocksdb.cfstats"). Some tests have to be updated because now the stats collector is populated in the Cache aggressively on DB startup rather than lazily. (I hope to clean up some of this added complexity in the future.) This change also ensures proper treatment of need_out_of_mutex for non-int DB properties. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8538 Test Plan: Added unit test logic that uses sync points to fail if the DB mutex is held during a scan, covering the various ways that a scan might be triggered. Performance test - the known impact to holding the DB mutex is on TransactionDB, and the easiest way to see the impact is to hack the scan code to almost always miss and take an artificially long time scanning. Here I've injected an unconditional 5s sleep at the call to ApplyToAllEntries. Before (hacked): $ TEST_TMPDIR=/dev/shm ./db_bench.base_xxx -benchmarks=randomtransaction,stats -cache_index_and_filter_blocks=1 -bloom_bits=10 -partition_index_and_filters=1 -duration=30 -stats_dump_period_sec=12 -cache_size=100000000 -statistics -transaction_db 2>&1 | egrep 'db.db.write.micros|micros/op' randomtransaction : 433.219 micros/op 2308 ops/sec; 0.1 MB/s ( transactions:78999 aborts:0) rocksdb.db.write.micros P50 : 16.135883 P95 : 36.622503 P99 : 66.036115 P100 : 5000614.000000 COUNT : 149677 SUM : 8364856 $ TEST_TMPDIR=/dev/shm ./db_bench.base_xxx -benchmarks=randomtransaction,stats -cache_index_and_filter_blocks=1 -bloom_bits=10 -partition_index_and_filters=1 -duration=30 -stats_dump_period_sec=12 -cache_size=100000000 -statistics -transaction_db 2>&1 | egrep 'db.db.write.micros|micros/op' randomtransaction : 448.802 micros/op 2228 ops/sec; 0.1 MB/s ( transactions:75999 aborts:0) rocksdb.db.write.micros P50 : 16.629221 P95 : 37.320607 P99 : 72.144341 P100 : 5000871.000000 COUNT : 143995 SUM : 13472323 Notice the 5s P100 write time. After (hacked): $ TEST_TMPDIR=/dev/shm ./db_bench.new_xxx -benchmarks=randomtransaction,stats -cache_index_and_filter_blocks=1 -bloom_bits=10 -partition_index_and_filters=1 -duration=30 -stats_dump_period_sec=12 -cache_size=100000000 -statistics -transaction_db 2>&1 | egrep 'db.db.write.micros|micros/op' randomtransaction : 303.645 micros/op 3293 ops/sec; 0.1 MB/s ( transactions:98999 aborts:0) rocksdb.db.write.micros P50 : 16.061871 P95 : 33.978834 P99 : 60.018017 P100 : 616315.000000 COUNT : 187619 SUM : 4097407 $ TEST_TMPDIR=/dev/shm ./db_bench.new_xxx -benchmarks=randomtransaction,stats -cache_index_and_filter_blocks=1 -bloom_bits=10 -partition_index_and_filters=1 -duration=30 -stats_dump_period_sec=12 -cache_size=100000000 -statistics -transaction_db 2>&1 | egrep 'db.db.write.micros|micros/op' randomtransaction : 310.383 micros/op 3221 ops/sec; 0.1 MB/s ( transactions:96999 aborts:0) rocksdb.db.write.micros P50 : 16.270026 P95 : 35.786844 P99 : 64.302878 P100 : 603088.000000 COUNT : 183819 SUM : 4095918 P100 write is now ~0.6s. Not good, but it's the same even if I completely bypass all the scanning code: $ TEST_TMPDIR=/dev/shm ./db_bench.new_skip -benchmarks=randomtransaction,stats -cache_index_and_filter_blocks=1 -bloom_bits=10 -partition_index_and_filters=1 -duration=30 -stats_dump_period_sec=12 -cache_size=100000000 -statistics -transaction_db 2>&1 | egrep 'db.db.write.micros|micros/op' randomtransaction : 311.365 micros/op 3211 ops/sec; 0.1 MB/s ( transactions:96999 aborts:0) rocksdb.db.write.micros P50 : 16.274362 P95 : 36.221184 P99 : 68.809783 P100 : 649808.000000 COUNT : 183819 SUM : 4156767 $ TEST_TMPDIR=/dev/shm ./db_bench.new_skip -benchmarks=randomtransaction,stats -cache_index_and_filter_blocks=1 -bloom_bits=10 -partition_index_and_filters=1 -duration=30 -stats_dump_period_sec=12 -cache_size=100000000 -statistics -transaction_db 2>&1 | egrep 'db.db.write.micros|micros/op' randomtransaction : 308.395 micros/op 3242 ops/sec; 0.1 MB/s ( transactions:97999 aborts:0) rocksdb.db.write.micros P50 : 16.106222 P95 : 37.202403 P99 : 67.081875 P100 : 598091.000000 COUNT : 185714 SUM : 4098832 No substantial difference. Reviewed By: siying Differential Revision: D29738847 Pulled By: pdillinger fbshipit-source-id: 1c5c155f5a1b62e4fea0fd4eeb515a8b7474027b	3 years ago
hongrubb	870033291a	Fix Get() return status when block cache is disabled (#8485) ... Summary: This PR is for https://github.com/facebook/rocksdb/issues/8453 We need to update `s = biter.status();` when `biter.status().IsIncomplete()` is true. By doing this, can fix the problem in issue. Besides, we still need to update `db_statistics` in `get_context.ReportCounters()` before return back. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8485 Reviewed By: jay-zhuang Differential Revision: D29604835 Pulled By: ajkr fbshipit-source-id: c7f2f1cd058223ce1b507ec05d57cf264b9c9710	3 years ago
Akanksha Mahajan	5ba1b6e549	Cache warming data blocks during flush (#8242) ... Summary: This PR prepopulates warm/hot data blocks which are already in memory into block cache at the time of flush. On a flush, the data block that is in memory (in memtables) get flushed to the device. If using Direct IO, additional IO is incurred to read this data back into memory again, which is avoided by enabling newly added option. Right now, this is enabled only for flush for data blocks. We plan to expand this option to cover compactions in the future and for other types of blocks. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8242 Test Plan: Add new unit test Reviewed By: anand1976 Differential Revision: D28521703 Pulled By: akankshamahajan15 fbshipit-source-id: 7219d6958821cedce689a219c3963a6f1a9d5f05	4 years ago
Peter Dillinger	d5a46c40e5	Pin CacheEntryStatsCollector to fix performance bug (#8385) ... Summary: If the block Cache is full with strict_capacity_limit=false, then our CacheEntryStatsCollector could be immediately evicted on release, so iterating through column families with shared block cache could trigger re-scan for each CF. This change fixes that problem by pinning the CacheEntryStatsCollector from InternalStats so that it's not evicted. I had originally thought that this object could participate in LRU like everything else, but even though a re-load+re-scan only touches memory, it can be orders of magnitude more expensive than other cache misses. One service in Facebook has scans that take ~20s over 100GB block cache that is mostly 4KB entries. (The up-side of this bug and https://github.com/facebook/rocksdb/issues/8369 is that we had a natural experiment on the effect on some service metrics even with block cache scans running continuously in the background--a kind of worst case scenario. Metrics like latency were not affected enough to trigger warnings.) Other smaller fixes: 20s is already a sizable portion of 600s stats dump period, or 180s default max age to force re-scan, so added logic to ensure that (for each block cache) we don't spend more than 0.2% of our background thread time scanning it. Nevertheless, "foreground" requests for cache entry stats (calls to `db->GetMapProperty(DB::Properties::kBlockCacheEntryStats)`) are permitted to consume more CPU. Renamed field to cache_entry_stats_ to match code style. This change is intended for patching in 6.21 release. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8385 Test Plan: unit test expanded to cover new logic (detect regression), some manual testing with db_bench Reviewed By: ajkr Differential Revision: D29042759 Pulled By: pdillinger fbshipit-source-id: 236faa902397f50038c618f50fbc8cf3f277308c	4 years ago
Peter Dillinger	2f93a3b809	Fix a major performance bug in 6.21 for cache entry stats (#8369) ... Summary: In final polishing of https://github.com/facebook/rocksdb/issues/8297 (after most manual testing), I broke my own caching layer by sanitizing an input parameter with std::min(0, x) instead of std::max(0, x). I resisted unit testing the timing part of the result caching because historically, these test are either flaky or difficult to write, and this was not a correctness issue. This bug is essentially unnoticeable with a small number of column families but can explode background work with a large number of column families. This change fixes the logical error, removes some unnecessary related optimization, and adds mock time/sleeps to the unit test to ensure we can cache hit within the age limit. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8369 Test Plan: added time testing logic to existing unit test Reviewed By: ajkr Differential Revision: D28950892 Pulled By: pdillinger fbshipit-source-id: e79cd4ff3eec68fd0119d994f1ed468c38026c3b	4 years ago
Zhichao Cao	7303d02bdf	Use new Insert and Lookup APIs in table reader to support secondary cache (#8315) ... Summary: Secondary cache is implemented to achieve the secondary cache tier for block cache. New Insert and Lookup APIs are introduced in https://github.com/facebook/rocksdb/issues/8271 . To support and use the secondary cache in block based table reader, this PR introduces the corresponding callback functions that will be used in secondary cache, and update the Insert and Lookup APIs accordingly. benchmarking: ./db_bench --benchmarks="fillrandom" -num=1000000 -key_size=32 -value_size=256 -use_direct_io_for_flush_and_compaction=true -db=/tmp/rocks_t/db -partition_index_and_filters=true ./db_bench -db=/tmp/rocks_t/db -use_existing_db=true -benchmarks=readrandom -num=1000000 -key_size=32 -value_size=256 -use_direct_reads=true -cache_size=1073741824 -cache_numshardbits=5 -cache_index_and_filter_blocks=true -read_random_exp_range=17 -statistics -partition_index_and_filters=true -stats_dump_period_sec=30 -reads=50000000 master benchmarking results: readrandom : 3.923 micros/op 254881 ops/sec; 33.4 MB/s (23849796 of 50000000 found) rocksdb.db.get.micros P50 : 2.820992 P95 : 5.636716 P99 : 16.450553 P100 : 8396.000000 COUNT : 50000000 SUM : 179947064 Current PR benchmarking results readrandom : 4.083 micros/op 244925 ops/sec; 32.1 MB/s (23849796 of 50000000 found) rocksdb.db.get.micros P50 : 2.967687 P95 : 5.754916 P99 : 15.665912 P100 : 8213.000000 COUNT : 50000000 SUM : 187250053 About 3.8% throughput reduction. P50: 5.2% increasing, P95, 2.09% increasing, P99 4.77% improvement Pull Request resolved: https://github.com/facebook/rocksdb/pull/8315 Test Plan: added the testing case Reviewed By: anand1976 Differential Revision: D28599774 Pulled By: zhichao-cao fbshipit-source-id: 098c4df0d7327d3a546df7604b2f1602f13044ed	4 years ago
Peter Dillinger	311a544c2a	Use deleters to label cache entries and collect stats (#8297) ... Summary: This change gathers and publishes statistics about the kinds of items in block cache. This is especially important for profiling relative usage of cache by index vs. filter vs. data blocks. It works by iterating over the cache during periodic stats dump (InternalStats, stats_dump_period_sec) or on demand when DB::Get(Map)Property(kBlockCacheEntryStats), except that for efficiency and sharing among column families, saved data from the last scan is used when the data is not considered too old. The new information can be seen in info LOG, for example: Block cache LRUCache@0x7fca62229330 capacity: 95.37 MB collections: 8 last_copies: 0 last_secs: 0.00178 secs_since: 0 Block cache entry stats(count,size,portion): DataBlock(7092,28.24 MB,29.6136%) FilterBlock(215,867.90 KB,0.888728%) FilterMetaBlock(2,5.31 KB,0.00544%) IndexBlock(217,180.11 KB,0.184432%) WriteBuffer(1,256.00 KB,0.262144%) Misc(1,0.00 KB,0%) And also through DB::GetProperty and GetMapProperty (here using ldb just for demonstration): $ ./ldb --db=/dev/shm/dbbench/ get_property rocksdb.block-cache-entry-stats rocksdb.block-cache-entry-stats.bytes.data-block: 0 rocksdb.block-cache-entry-stats.bytes.deprecated-filter-block: 0 rocksdb.block-cache-entry-stats.bytes.filter-block: 0 rocksdb.block-cache-entry-stats.bytes.filter-meta-block: 0 rocksdb.block-cache-entry-stats.bytes.index-block: 178992 rocksdb.block-cache-entry-stats.bytes.misc: 0 rocksdb.block-cache-entry-stats.bytes.other-block: 0 rocksdb.block-cache-entry-stats.bytes.write-buffer: 0 rocksdb.block-cache-entry-stats.capacity: 8388608 rocksdb.block-cache-entry-stats.count.data-block: 0 rocksdb.block-cache-entry-stats.count.deprecated-filter-block: 0 rocksdb.block-cache-entry-stats.count.filter-block: 0 rocksdb.block-cache-entry-stats.count.filter-meta-block: 0 rocksdb.block-cache-entry-stats.count.index-block: 215 rocksdb.block-cache-entry-stats.count.misc: 1 rocksdb.block-cache-entry-stats.count.other-block: 0 rocksdb.block-cache-entry-stats.count.write-buffer: 0 rocksdb.block-cache-entry-stats.id: LRUCache@0x7f3636661290 rocksdb.block-cache-entry-stats.percent.data-block: 0.000000 rocksdb.block-cache-entry-stats.percent.deprecated-filter-block: 0.000000 rocksdb.block-cache-entry-stats.percent.filter-block: 0.000000 rocksdb.block-cache-entry-stats.percent.filter-meta-block: 0.000000 rocksdb.block-cache-entry-stats.percent.index-block: 2.133751 rocksdb.block-cache-entry-stats.percent.misc: 0.000000 rocksdb.block-cache-entry-stats.percent.other-block: 0.000000 rocksdb.block-cache-entry-stats.percent.write-buffer: 0.000000 rocksdb.block-cache-entry-stats.secs_for_last_collection: 0.000052 rocksdb.block-cache-entry-stats.secs_since_last_collection: 0 Solution detail - We need some way to flag what kind of blocks each entry belongs to, preferably without changing the Cache API. One of the complications is that Cache is a general interface that could have other users that don't adhere to whichever convention we decide on for keys and values. Or we would pay for an extra field in the Handle that would only be used for this purpose. This change uses a back-door approach, the deleter, to indicate the "role" of a Cache entry (in addition to the value type, implicitly). This has the added benefit of ensuring proper code origin whenever we recognize a particular role for a cache entry; if the entry came from some other part of the code, it will use an unrecognized deleter, which we simply attribute to the "Misc" role. An internal API makes for simple instantiation and automatic registration of Cache deleters for a given value type and "role". Another internal API, CacheEntryStatsCollector, solves the problem of caching the results of a scan and sharing them, to ensure scans are neither excessive nor redundant so as not to harm Cache performance. Because code is added to BlocklikeTraits, it is pulled out of block_based_table_reader.cc into its own file. This is a reformulation of https://github.com/facebook/rocksdb/issues/8276, without the type checking option (could still be added), and with actual stat gathering. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8297 Test Plan: manual testing with db_bench, and a couple of basic unit tests Reviewed By: ltamasi Differential Revision: D28488721 Pulled By: pdillinger fbshipit-source-id: 472f524a9691b5afb107934be2d41d84f2b129fb	4 years ago
anand76	feb06e83b2	Initial support for secondary cache in LRUCache (#8271) ... Summary: Defined the abstract interface for a secondary cache in include/rocksdb/secondary_cache.h, and updated LRUCacheOptions to take a std::shared_ptr<SecondaryCache>. An item is initially inserted into the LRU (primary) cache. When it ages out and evicted from memory, its inserted into the secondary cache. On a LRU cache miss and successful lookup in the secondary cache, the item is promoted to the LRU cache. Only support synchronous lookup currently. The secondary cache would be used to implement a persistent (flash cache) or compressed cache. Tests: Results from cache_bench and db_bench don't show any regression due to these changes. cache_bench results before and after this change - Command ```./cache_bench -ops_per_thread=10000000 -threads=1``` Before ```Complete in 40.688 s; QPS = 245774``` ```Complete in 40.486 s; QPS = 246996``` ```Complete in 42.019 s; QPS = 237989``` After ```Complete in 40.672 s; QPS = 245869``` ```Complete in 44.622 s; QPS = 224107``` ```Complete in 42.445 s; QPS = 235599``` db_bench results before this change, and with this change + https://github.com/facebook/rocksdb/issues/8213 and https://github.com/facebook/rocksdb/issues/8191 - Commands ```./db_bench --benchmarks="fillseq,compact" -num=30000000 -key_size=32 -value_size=256 -use_direct_io_for_flush_and_compaction=true -db=/home/anand76/nvm_cache/db -partition_index_and_filters=true``` ```./db_bench -db=/home/anand76/nvm_cache/db -use_existing_db=true -benchmarks=readrandom -num=30000000 -key_size=32 -value_size=256 -use_direct_reads=true -cache_size=1073741824 -cache_numshardbits=6 -cache_index_and_filter_blocks=true -read_random_exp_range=17 -statistics -partition_index_and_filters=true -threads=16 -duration=300``` Before ``` DB path: [/home/anand76/nvm_cache/db] readrandom : 80.702 micros/op 198104 ops/sec; 54.4 MB/s (3708999 of 3708999 found) ``` ``` DB path: [/home/anand76/nvm_cache/db] readrandom : 87.124 micros/op 183625 ops/sec; 50.4 MB/s (3439999 of 3439999 found) ``` After ``` DB path: [/home/anand76/nvm_cache/db] readrandom : 77.653 micros/op 206025 ops/sec; 56.6 MB/s (3866999 of 3866999 found) ``` ``` DB path: [/home/anand76/nvm_cache/db] readrandom : 84.962 micros/op 188299 ops/sec; 51.7 MB/s (3535999 of 3535999 found) ``` Pull Request resolved: https://github.com/facebook/rocksdb/pull/8271 Reviewed By: zhichao-cao Differential Revision: D28357511 Pulled By: anand1976 fbshipit-source-id: d1cfa236f00e649a18c53328be10a8062a4b6da2	4 years ago
Adam Retter	8ff6557e7f	Add further tests to ASSERT_STATUS_CHECKED (2) (#7698) ... Summary: Second batch of adding more tests to ASSERT_STATUS_CHECKED. * external_sst_file_basic_test * checkpoint_test * db_wal_test * db_block_cache_test * db_logical_block_size_cache_test * db_blob_index_test * optimistic_transaction_test * transaction_test * point_lock_manager_test * write_prepared_transaction_test * write_unprepared_transaction_test Pull Request resolved: https://github.com/facebook/rocksdb/pull/7698 Reviewed By: cheng-chang Differential Revision: D25441664 Pulled By: pdillinger fbshipit-source-id: 9e78867f32321db5d4833e95eb96c5734526ef00	4 years ago
Andrew Kryczka	1adbceb581	Expand effect of dictionary settings in `ColumnFamilyOptions::compression_opts` (#7619) ... Summary: In dictionary compression's initial implementation, in order to save CPU overhead, we only enabled it for bottom level under the assumption that the vast majority of data is stored there. At that time, there was no such thing as `ColumnFamilyOptions::bottommost_compression_opts`, so we just hardcoded disabling dictionary compression in flush and compactions to non-bottommost level. Now, we have users who generate all their files through flush and are considering using dictionary compression. To support such a use case, this PR expands the scope of `ColumnFamilyOptions::compression_opts` to additionally include flushed files and files generated by compaction to a non-bottommost level. Users can still get the old behavior by moving their dictionary settings to `ColumnFamilyOptions::bottommost_compression_opts` and explicitly enabling both that and `ColumnFamilyOptions::bottommost_compression`. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7619 Reviewed By: ltamasi Differential Revision: D24665610 Pulled By: ajkr fbshipit-source-id: 656b90bce1033fe21c71e09af931ef5bde3e464c	4 years ago
Andrew Kryczka	75d3b6fdf0	Redesign block cache pinning API (#7520) ... Summary: The old flag-based APIs (`BlockBasedTableOptions::pin_l0_filter_and_index_blocks_in_cache` and `BlockBasedTableOptions::pin_top_level_index_and_filter`) were insufficient for our needs. For example, it was impossible to pin only unpartitioned meta-blocks, which could prevent block cache contention when turning on dictionary compression or during a migration to partitioned indexes/filters. It was also impossible to pin all meta-blocks in memory while having predictable memory usage via block cache. If we had continued adding flags to address these scenarios, they would have had significant overlap causing confusion. Instead, this PR deprecates the flags and starts a new API with non-overlapping options. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7520 Test Plan: - new unit test - added new options to stress/crash test and ran for a while: `$ python tools/db_crashtest.py blackbox --simple --max_key=1000000 -write_buffer_size=1048576 -target_file_size_base=1048576 -max_bytes_for_level_base=4194304 --interval=10 -value_size_mult=33 -column_families=1 -reopen=0` Reviewed By: pdillinger Differential Revision: D24200034 Pulled By: ajkr fbshipit-source-id: 3fa7cfc71e7960f7a867511dd6ae5834dd73b13e	4 years ago
mrambacher	7d472accdc	Bring the Configurable options together (#5753) ... Summary: This PR merges the functionality of making the ColumnFamilyOptions, TableFactory, and DBOptions into Configurable into a single PR, resolving any merge conflicts Pull Request resolved: https://github.com/facebook/rocksdb/pull/5753 Reviewed By: ajkr Differential Revision: D23385030 Pulled By: zhichao-cao fbshipit-source-id: 8b977a7731556230b9b8c5a081b98e49ee4f160a	4 years ago
sdong	b194c21bba	Whole DBTest to skip fsync (#7274) ... Summary: After https://github.com/facebook/rocksdb/pull/7036, we still see extra DBTest that can timeout when running 10 or 20 in parallel. Expand skip-fsync mode in whole DBTest. Still preserve other tests from doing this mode to be conservative. This commit reinstates https://github.com/facebook/rocksdb/issues/7049, whose un-revert was lost in an automatic infrastructure mis-merge. Pull Request resolved: https://github.com/facebook/rocksdb/pull/7274 Test Plan: Run all existing files. Reviewed By: pdillinger Differential Revision: D23177444 fbshipit-source-id: 1f61690b2ac6333c3b2c87176fef6b2cba086b33	4 years ago