Commit graph

7764 commits

Author SHA1 Message Date
Siying Dong f48758e939 Deprecate CompactionFilter::IgnoreSnapshots() = false (#4954)
Summary:
We found that the behavior of CompactionFilter::IgnoreSnapshots() = false isn't
what we have expected. We thought that snapshot will always be preserved.
However, we just realized that, if no snapshot is created while compaction
starts, and a snapshot is created after that, the data seen from the snapshot
can successfully be dropped by the compaction. This creates a strange behavior
to the feature, which is hard to explain. Like what is documented in code
comment, this feature is not very useful with snapshot anyway. The decision
is to deprecate the feature.

We keep the function to avoid to break users code. However, we will fail
compactions if false is returned.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4954

Differential Revision: D13981900

Pulled By: siying

fbshipit-source-id: 2db8c2c3865acd86a28dca625945d1481b1d1e36
2019-02-07 16:57:33 -08:00
Siying Dong cf3a671733 Remove cuckoo hash memtable (#4953)
Summary:
Cuckoo Hash is less useful than we initially expected. Remove it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4953

Differential Revision: D13979264

Pulled By: siying

fbshipit-source-id: 2a60afdaa989f045357398b43a1cc5d46f4492ed
2019-02-07 16:15:27 -08:00
Maysam Yabandeh 199fabc197 WritePrepared: non-atomic commit of delayed prepared (#4947)
Summary:
Commit of delayed prepared has two non-atomic steps: add to commit cache, remove from delayed_prepared_. Similarly in ::IsInSnapshot we read from commit cache first and then look into delayed_prepared_. Due to non-atomicity thus the reader might not find the
prep_seq that is just committed neither in commit cache nor in delayed_prepared_. To fix that i)
we check if there was any delayed prepared BEFORE looking into commit
cache, ii) if there was, we complete the search steps to be these: i)
commit cache, ii) delayed prepared, commit cache again. In this way if
the first query to commit cache missed the commit, the 2nd will catch it. The cost of the redundant read from commit cache is paid only if delayed_prepared_ is nonempty which should be a very rare scenario.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4947

Differential Revision: D13952754

Pulled By: maysamyabandeh

fbshipit-source-id: 8f47826b13f8ce154398d842028342423f4ca2b2
2019-02-06 08:48:06 -08:00
Siying Dong d9c9f3c809 db_bench: fix "micros/op" reporting (#4949)
Summary:
4985a9f73b (diff-e5276985b26a0551957144f4420a594bR511)
changes the meaning of latency reporting from running time per query, to elapse_time / #ops, without providing a reason why.
Considering that this is a counter-intuitive reporting, Reverting the change.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4949

Differential Revision: D13964684

Pulled By: siying

fbshipit-source-id: d6304d3d4b5a802daa292302623c7dbca9a680bc
2019-02-05 17:20:02 -08:00
Zhongyi Xie 71cae59a99 exclude test CompactFilesShouldTriggerAutoCompaction from ROCKSDB_LITE (#4950)
Summary:
This will fix the following build error:

> db/db_test.cc: In member function ‘virtual void rocksdb::DBTest_CompactFilesShouldTriggerAutoCompaction_Test::TestBody()’:
> db/db_test.cc:5462:8: error: ‘class rocksdb::DB’ has no member named ‘GetColumnFamilyMetaData’
>    db_->GetColumnFamilyMetaData(db_->DefaultColumnFamily(), &cf_meta_data);
> db/db_test.cc:5490:8: error: ‘class rocksdb::DB’ has no member named ‘GetColumnFamilyMetaData’
>    db_->GetColumnFamilyMetaData(db_->DefaultColumnFamily(), &cf_meta_data);
> db/db_test.cc:5499:8: error: ‘class rocksdb::DB’ has no member named ‘GetColumnFamilyMetaData’
>    db_->GetColumnFamilyMetaData(db_->DefaultColumnFamily(), &cf_meta_data);
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4950

Differential Revision: D13965378

Pulled By: miasantreble

fbshipit-source-id: a975435476fe555b1cd9d5da263ee3da3acdea56
2019-02-05 17:01:11 -08:00
Zhongyi Xie 00ed41daee Allow copy for PerfContext objects (#4919)
Summary:
Existing implementation of PerfContext does not define copy constructor or assignment operator, which could potentially cause problems when user create copies and resets the builtin one. This PR address the issue by providing these two constructors with deep copy semantics.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4919

Differential Revision: D13960406

Pulled By: miasantreble

fbshipit-source-id: 36aab5aaee65d4480f537e4e22148faa45e8e334
2019-02-05 14:29:08 -08:00
Jay Zhuang c9a52cbdc8 Fix potential DB hang while using CompactFiles (#4940)
Summary:
CompactFiles() may block auto compaction which could cuase DB hang when it
reachs level0_stop_writes_trigger.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4940

Differential Revision: D13929648

Pulled By: cooldoger

fbshipit-source-id: 10842df38df3bebf862cd1a120a88ce961fdd381
2019-02-05 11:23:38 -08:00
Siying Dong 8fe073324f BYTES_READ stats miscount for NotFound cases (#4938)
Summary:
In NotFound cases, stats BYTES_READ and perf_context.get_read_bytes is still be increased. The amount increased will be
whatever size of the string or PinnableSlice that users passed in as the output data structure. This is wrong. Fix this by not
increasing these two counters.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4938

Differential Revision: D13908963

Pulled By: siying

fbshipit-source-id: 60bce42e4fbb9862bba3da36dbc27b2963ea6162
2019-02-05 10:53:35 -08:00
yangzhijia 31221bb7e8 Properly set upper bound of subcompaction output (#4879) (#4898)
Summary:
Fix the ouput overlap bug when using subcompactions, the upper bound of output
file was extended incorrectly.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4898

Differential Revision: D13736107

Pulled By: ajkr

fbshipit-source-id: 21dca09f81d5f07bf2766bf566f9b50dcab7d8e3
2019-02-05 10:20:16 -08:00
Maysam Yabandeh dcb73e7735 WritePrepared: release snapshot equal to max (#4944)
Summary:
WritePrepared maintains a list of snapshots that are <= max_evicted_seq_. Based on this list, old_commit_map_ is updated if an evicted commit entry overlaps with such snapshot. Such lists are garbage collected when the release of snapshot is reported to WritePreparedTxnDB, which is the next time max_evicted_seq_ is updated and yet the snapshot is not found is the list returned from DB. This logic was broken since ReleaseSnapshotInternal was using "< max_evicted_seq_" to cleanup old_commit_map_, which would leave a snapshot uncleaned if it "= max_evicted_seq_". The patch fixes that and adds a unit test to check for the bug.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4944

Differential Revision: D13945000

Pulled By: maysamyabandeh

fbshipit-source-id: 0c904294f735911f52348a148bf1f945282fc17c
2019-02-04 12:57:23 -08:00
Maysam Yabandeh 30468d8eb4 Fix analyze error on possible un-initialized value (#4937)
Summary:
The patch fixes the following analyze error by checking the return status of ParseInternalKey.
```
db/merge_helper.cc:306:23: warning: The right operand of '==' is a garbage value
    assert(kTypeMerge == orig_ikey.type);
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4937

Differential Revision: D13908506

Pulled By: maysamyabandeh

fbshipit-source-id: 68d7771e75519da3d4bd807fd231675ec12093f6
2019-02-01 09:41:27 -08:00
Ming Zhao 59244447e3 Zero seqnum of final key / drop final tombstone when compacting to bottommost level
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/4927

Differential Revision: D13889458

Pulled By: mzhaom

fbshipit-source-id: d6b66db85901a9eb90748fba6a9dc4e7457b9c5e
2019-02-01 09:21:57 -08:00
Young Tack Jin 4091597c67 fix for nvme device path (#4866)
Summary:
nvme device path doesn't have "block" as like "nvme/nvme0/nvme0n1"
or "nvme/nvme0/nvme0n1/nvme0n1p1". the last directory such as
"nvme0n1p1" should be removed if nvme drive is partitioned.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4866

Differential Revision: D13627824

Pulled By: riversand963

fbshipit-source-id: 09ab968f349f3dbb890beea20193f1359b17d317
2019-01-31 19:08:37 -08:00
Yanqin Jin 842cdc11dd Use correct FileMeta for atomic flush result install (#4932)
Summary:
1. this commit fixes our handling of a combination of two separate edge
cases. If a flush job does not pick any memtable to flush (because another
flush job has already picked the same memtables), and the column family
assigned to the flush job is dropped right before RocksDB calls
rocksdb::InstallMemtableAtomicFlushResults, our original code passes
a FileMetaData object whose file number is 0, failing the assertion in
rocksdb::InstallMemtableAtomicFlushResults (assert(m->GetFileNumber() > 0)).
2. Also piggyback a small change: since we already create a local copy of column family's mutable CF options to eliminate potential race condition with `SetOptions` call, we might as well use the local copy in other function calls in the same scope.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4932

Differential Revision: D13901322

Pulled By: riversand963

fbshipit-source-id: b936580af7c127ea0c6c19ea10cd5fcede9fb0f9
2019-01-31 14:49:51 -08:00
Andrew Kryczka 0ea57115a3 Fix WriteBatchBase::DeleteRange API comment (#4935)
Summary:
The `DeleteRange` end key is exclusive, not inclusive. Updated API comment accordingly.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4935

Differential Revision: D13905406

Pulled By: ajkr

fbshipit-source-id: f577db841a279427991ecf9005cd56b30c8eb3c7
2019-01-31 14:43:40 -08:00
Maysam Yabandeh 35e5689e11 Take snapshots once for all cf flushes (#4934)
Summary:
FlushMemTablesToOutputFiles calls FlushMemTableToOutputFile for each column family. The patch moves the take-snapshot logic to outside FlushMemTableToOutputFile so that it does it once for all the flushes. This also addresses a deadlock issue for resetting the managed snapshot of job_snapshot in the 2nd call to FlushMemTableToOutputFile.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4934

Differential Revision: D13900747

Pulled By: maysamyabandeh

fbshipit-source-id: f3cd650c5fff24cf95c1aaf8a10c149d42bf042c
2019-01-31 12:21:59 -08:00
Alexander Zinoviev 32a6dd9a41 Add a new CPU time counter to compaction report (#4889)
Summary:
Measure CPU time consumed for a compaction and report it in the stats report
Enable NowCPUNanos() to work for MacOS
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4889

Differential Revision: D13701276

Pulled By: zinoale

fbshipit-source-id: 5024e5bbccd4dd10fd90d947870237f436445055
2019-01-29 17:24:00 -08:00
Yanqin Jin 158da7a6ee Verify checksum before ingestion (#4916)
Summary:
before file ingestion (in preparation phase), verify the checksums of
the blocks of the external SST file, including properties block with global
seqno.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4916

Differential Revision: D13863501

Pulled By: riversand963

fbshipit-source-id: dc54697f970e3807832e2460f7228fcc7efe81ee
2019-01-29 17:17:29 -08:00
anand76 d0d484b132 Always delete Blob DB files in the background (#4928)
Summary:
Blob DB files are not tracked by the SFM, so they currently don't get
deleted in the background. Force them to be deleted in background so
rate limiting can be applied
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4928

Differential Revision: D13854649

Pulled By: anand1976

fbshipit-source-id: 8031ce66842ff0af440c715d886b377983dad7d8
2019-01-29 15:50:03 -08:00
Yanqin Jin 95604d13e9 Change the command to invoke parallel tests (#4922)
Summary:
We used to call `printf $(t_run)` and later feed the result to GNU parallel in the recipe of target `check_0`. However, this approach is problematic when the length of $(t_run) exceeds the
maximum length of a command and the `printf` command cannot be executed. Instead we use 'find -print' to avoid generating an overly long command.

**This PR is actually the last commit of #4916. Prefer to merge this PR separately.**
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4922

Differential Revision: D13845883

Pulled By: riversand963

fbshipit-source-id: b56de7f7af43337c6ec89b931de843c9667cb679
2019-01-28 15:02:26 -08:00
Sagar Vemuri 4978caaa6f Remove a redundant call to TableFileName in CompactionJob::FinishCompactionOutputFile (#4925)
Summary:
While stepping through the code I noticed that there is a redundant call to TableFileName.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4925

Differential Revision: D13845749

Pulled By: sagar0

fbshipit-source-id: 31db45716b4d720e0e0350dd457b49d6f1848e7d
2019-01-28 13:33:23 -08:00
Siying Dong ee1818081f Remove PlainTable's feature store_index_in_file (#4914)
Summary:
Store_index_in_file is a less useful feature. To simplify the code to maintain, we are dropping the feature.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4914

Differential Revision: D13791883

Pulled By: siying

fbshipit-source-id: d187c5d662584866103e4b77d09dfb925509ae2e
2019-01-28 12:50:22 -08:00
zhichao-cao e2547103fd Fix the build error caused by the dynamic array (#4918)
Summary:
In the MixGraph benchmark of db_bench #4788 , the char array is initialized with an argument from user's input, which can cause build error on some platforms. Also, the msg char array size can be potentially smaller than the printed data, which should be extended from 100 to 256.

Tested with make check.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4918

Differential Revision: D13844298

Pulled By: sagar0

fbshipit-source-id: 33c4809c5c4438f0a9f7b289d3f42e20c545bbab
2019-01-28 12:39:57 -08:00
Andrew Kryczka e242fa4664 Add latest toolchain (gcc-8, etc.) build support for fbcode users (#4923)
Summary:
- When building with internal dependencies, specify this toolchain by setting `ROCKSDB_FBCODE_BUILD_WITH_PLATFORM007=1`
- It is not enabled by default. However, it is enabled for TSAN builds in CI since there is a known problem with TSAN in gcc-5: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71090
- I did not add support for Lua since (1) we agreed to deprecate it, and (2) we only have an internal build for v5.3 with this toolchain while that has breaking changes compared to our current version (v5.2).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4923

Differential Revision: D13827226

Pulled By: ajkr

fbshipit-source-id: 9aa3388ed3679777cfb15ef8cbcb83c07f62f947
2019-01-28 11:26:32 -08:00
Siying Dong bc7d1661a8 Fix test name typo in PlainTableDBTest
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/4926

Differential Revision: D13830196

Pulled By: siying

fbshipit-source-id: e06bf2a6cd273b5eb18dfd82bdd35ffce197d021
2019-01-25 18:14:26 -08:00
Siying Dong f184bee77b PlainTable should avoid copying Get() results from immortal source. (#4924)
Summary:
https://github.com/facebook/rocksdb/pull/4053 avoids memcopy for Get() results if files are immortable
(read-only DB, max_open_files=-1) and the file is ammaped. The same optimization is being applied to PlainTable
here.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4924

Differential Revision: D13827749

Pulled By: siying

fbshipit-source-id: 1f2cbfc530b40ce08ccd53f95f6e78de4d1c2f96
2019-01-25 17:12:19 -08:00
Yanqin Jin e1de88c8c7 Escape '.' by adding a '\' to avoid matching any char
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/4912

Differential Revision: D13789449

Pulled By: riversand963

fbshipit-source-id: 0639dae82049b7ac977c8f81851f1c9fdc346705
2019-01-24 11:25:27 -08:00
Siying Dong fc53839bfa Disallow customized hash function in DynamicBloom (#4915)
Summary:
I didn't find where customized hash function is used in DynamicBloom. This can only reduce performance. Remove it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4915

Differential Revision: D13794452

Pulled By: siying

fbshipit-source-id: e38669b11e01444d2d782da11c7decabbd851819
2019-01-24 10:34:30 -08:00
Dmitry Fink e07aa8669d Allow full merge when root of history for a key is reached (#4909)
Summary:
Previously compaction was not collapsing operands for a first
key on a layer, even in cases when it was its root of history. Some
tests (CompactionJobTest.NonAssocMerge) was actually accounting
for that bug,
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4909

Differential Revision: D13781169

Pulled By: finik

fbshipit-source-id: d2de353ecf05bec39b942cd8d5b97a8dc445f336
2019-01-23 21:46:10 -08:00
Andrew Kryczka 8ec3e72551 Cache dictionary used for decompressing data blocks (#4881)
Summary:
- If block cache disabled or not used for meta-blocks, `BlockBasedTableReader::Rep::uncompression_dict` owns the `UncompressionDict`. It is preloaded during `PrefetchIndexAndFilterBlocks`.
- If block cache is enabled and used for meta-blocks, block cache owns the `UncompressionDict`, which holds dictionary and digested dictionary when needed. It is never prefetched though there is a TODO for this in the code. The cache key is simply the compression dictionary block handle.
- New stats for compression dictionary accesses in block cache: "BLOCK_CACHE_COMPRESSION_DICT_*" and "compression_dict_block_read_count"
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4881

Differential Revision: D13663801

Pulled By: ajkr

fbshipit-source-id: bdcc54044e180855cdcc57639b493b0e016c9a3f
2019-01-23 18:15:47 -08:00
PeifengSi 43defe9872 Correct the code comment in Compaction::KeyNotExistsBeyondOutputLevel (#4902)
Summary:
Even one key falls in a file's range, we can not infer it definitely exists in this file.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4902

Differential Revision: D13795018

Pulled By: siying

fbshipit-source-id: 590956f727e9440fcdee55ad9541ace934c64914
2019-01-23 18:00:56 -08:00
Siying Dong d94aa2f7db Make compaction_pri = kMinOverlappingRatio to be default (#4911)
Summary:
compaction_pri = kMinOverlappingRatio usually provides much better write amplification than the default.
https://github.com/facebook/rocksdb/pull/4907 fixes one shortcome of this option. Make it default.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4911

Differential Revision: D13789262

Pulled By: siying

fbshipit-source-id: d90acf8c4dede44f00d183ca4c7a210259378269
2019-01-23 16:47:38 -08:00
Andrew Kryczka 27054d837b Call NewDataBlockIterator with correct arguments in DB::Get (#4913)
Summary:
The pointer `get_context` was passed as the value for the boolean argument `index_key_is_full`. Luckily the pointer was always non-null so evaluated to true which is the correct value for the boolean argument. But we were missing out on batch updates to stats since we were not passing anything for the `GetContext*` argument and it defaults to `nullptr`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4913

Differential Revision: D13791449

Pulled By: ajkr

fbshipit-source-id: dbe40bf406c64d34cb5298604145d18b9e0ca9be
2019-01-23 15:39:05 -08:00
Sagar Vemuri 0cead31d10 Fix Clang static analyzer warning in db_bench (#4910)
Summary:
Fixed clang static analyzer warning about division by 0.
```
ar: creating librocksdb_debug.a
tools/db_bench_tool.cc:4650:43: warning: Division by zero
      int pos = static_cast<int>(rand_num % range_);
                                 ~~~~~~~~~^~~~~~~~
1 warning generated.
make: *** [analyze] Error 1
```

This is from the new code I recently merged in ce8e88d2d7.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4910

Differential Revision: D13788037

Pulled By: sagar0

fbshipit-source-id: f48851dca85047c19fbb1a361e25ce643aa4c7ea
2019-01-23 13:33:02 -08:00
Siying Dong 5bf941966b CompactionPri = kMinOverlappingRatio also uses compensated file size (#4907)
Summary:
Right now, CompactionPri = kMinOverlappingRatio provides best write amplification, but it doesn't
prioritize files with more tombstones. We combine the two good features: make kMinOverlappingRatio
to boost files with lots of tombstones too.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4907

Differential Revision: D13788774

Pulled By: siying

fbshipit-source-id: 1991cbb495fb76c8b529de69896e38d81ed9d9b3
2019-01-23 13:21:01 -08:00
Remington Brasga 1eded07f00 Bug in Regular Expression in Makefile (#4682)
Summary:
False-negative about path not existing. The regex is ignoring the "." in front of a path.
Example: "./path/to/file"
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4682

Differential Revision: D13777110

Pulled By: sagar0

fbshipit-source-id: 9f8173b7581407555fdc055580732aeab37d4ade
2019-01-23 10:24:10 -08:00
Zhongyi Xie cbe0239270 add cast to avoid loss of precision error (#4906)
Summary:
this PR address the following error:
> tools/db_bench_tool.cc:4776:68: error: implicit conversion loses integer precision: 'int64_t' (aka 'long') to 'unsigned int' [-Werror,-Wshorten-64-to-32]
        s = db_with_cfh->db->Put(write_options_, key, gen.Generate(value_size));
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4906

Differential Revision: D13780185

Pulled By: miasantreble

fbshipit-source-id: 1c83a77d341099518c72f0f4a63e97ab9c4784b3
2019-01-22 22:44:17 -08:00
Siying Dong 08b8cea69f Deleting Blob files also goes through SstFileManager (#4904)
Summary:
Right now, deleting blob files is not rate limited, even if SstFileManger is specified.
On the other hand, rate limiting blob deletion is not supported. With this change, Blob file
deletion will go through SstFileManager too.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4904

Differential Revision: D13772545

Pulled By: siying

fbshipit-source-id: bd1b1d0beb26d5167385e00b7ecb8b94b879de84
2019-01-22 17:00:29 -08:00
Philip Jameson b2ba06856a Add load() statements to TARGETS files
Reviewed By: luciang

Differential Revision: D13733578

fbshipit-source-id: 556c115935aa42c1da85ec0e91199b9f198fc467
2019-01-22 15:24:51 -08:00
Sagar Vemuri 8189c184ec Remove unused Blob WAL filter (#4896)
Summary:
Remove unused blob WAL filter so that users are not confused.
I was initially under the impression that we have WAL Filter support in BlobDB.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4896

Differential Revision: D13725709

Pulled By: sagar0

fbshipit-source-id: f997d7546e138a474036e88b957907cc714327f1
2019-01-22 11:13:49 -08:00
Zhichao Cao ce8e88d2d7 Generate mixed workload with Get, Put, Seek in db_bench (#4788)
Summary:
Based on the specific workload models (key access distribution, value size distribution, and iterator scan length distribution, the QPS variation), the MixGraph benchmark generate the synthetic workload according to these distributions which can reflect the real-world workload characteristics.

After user enable the tracing function, they will get the trace file. By analyzing the trace file with the trace_analyzer tool, user can generate a set of statistic data files including. The *_accessed_key_stats.txt,  *-accessed_value_size_distribution.txt, *-iterator_length_distribution.txt, and *-qps_stats.txt are mainly used to fit the Matlab model fitting. After that, user can get the parameters of the workload distributions (the modeling details are described: [here](https://github.com/facebook/rocksdb/wiki/RocksDB-Trace%2C-Replay%2C-and-Analyzer))

The key access distribution follows the The two-term power model. The probability density function is: `f(x) = ax^{b}+c`. The corresponding parameters are key_dist_a, key_dist_b, and key_dist_c in db_bench

For the value size distribution and iterator scan length distribution, they both follow the Generalized Pareto Distribution. The probability density function is `f(x) = (1/sigma)(1+k*(x-theta)/sigma))^{-1-1/k)`. The parameters are: value_k, value_theta, value_sigma and iter_k, iter_theta, iter_sigma. For more information about the Generalized Pareto Distribution, users can find the [wiki](https://en.wikipedia.org/wiki/Generalized_Pareto_distribution) and [Matalb page](https://www.mathworks.com/help/stats/generalized-pareto-distribution.html)

As for the QPS, it follows the diurnal pattern. So Sine is a good model to fit it. `F(x) = sine_a*sin(sine_b*x + sine_c) + sine_d`. The trace_will tell you the average QPS in the print out resutls, which is sine_d. After user fit the "*-qps_stats.txt" to the Matlab model, user can get the sine_a, sine_b, and sine_c. By using the 4 parameters, user can control the QPS variation including the period, average, changes.

To use the bench mark, user can indicate the following parameters as examples:
```
-benchmarks="mixgraph" -key_dist_a=0.002312 -key_dist_b=0.3467 -value_k=0.9233 -value_sigma=226.4092 -iter_k=2.517 -iter_sigma=14.236 -mix_get_ratio=0.7 -mix_put_ratio=0.25 -mix_seek_ratio=0.05 -sine_mix_rate_interval_milliseconds=500 -sine_a=15000 -sine_b=1 -sine_d=20000
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4788

Differential Revision: D13573940

Pulled By: sagar0

fbshipit-source-id: e184c27e07b4f1bc0b436c2be36c5090c1fb0222
2019-01-22 10:44:26 -08:00
Andrew Kryczka 16a5ac5b69 Update HISTORY.md with new use of ZSTD_CDict (#4901)
Summary:
Mention feature introduced by #4849 in HISTORY.md.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4901

Differential Revision: D13746430

Pulled By: ajkr

fbshipit-source-id: f7bdea6f0522ed55428cbc521f8a9f3cd0002d4e
2019-01-19 19:17:50 -08:00
Andrew Kryczka 01013ae766 Digest ZSTD compression dictionary once when writing SST file (#4849)
Summary:
This is essentially a re-submission of #4251 with a few improvements:

- Split `CompressionDict` into two separate classes: `CompressionDict` and `UncompressionDict`
- Eliminated `Init` functions. Instead do all initialization work in constructors.
- Added test case for parallel DB open, which is the scenario where #4251 failed under TSAN.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4849

Differential Revision: D13606039

Pulled By: ajkr

fbshipit-source-id: 08c236059798c710db9cbf545fce0f371232d447
2019-01-18 19:12:57 -08:00
Yi Wu b1ad6ebba8 WritePrepared: fix two versions in compaction see different status for released snapshots (#4890)
Summary:
Fix how CompactionIterator::findEarliestVisibleSnapshots handles released snapshot. It fixing the two scenarios:

Scenario 1:
key1 has two values v1 and v2. There're two snapshots s1 and s2 taken after v1 and v2 are committed. Right after compaction output v2, s1 is released. Now findEarliestVisibleSnapshot may see s1 being released, and return the next snapshot, which is s2. That's larger than v2's earliest visible snapshot, which was s1.
The fix: the only place we check against last snapshot and current key snapshot is when we decide whether to compact out a value if it is hidden by a later value. In the check if we see current snapshot is even larger than last snapshot, we know last snapshot is released, and we are safe to compact out current key.

Scenario 2:
key1 has two values v1 and v2. there are two snapshots s1 and s2 taken after v1 and v2 are committed. During compaction before we process the key, s1 is released. When compaction process v2, snapshot checker may return kSnapshotReleased, and the earliest visible snapshot for v2 become s2. When compaction process v1, snapshot checker may return kIsInSnapshot (for WritePrepared transaction, it could be because v1 is still in commit cache). The result will become inconsistent here.
The fix: remember the set of released snapshots ever reported by snapshot checker, and ignore them when finding result for findEarliestVisibleSnapshot.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4890

Differential Revision: D13705538

Pulled By: maysamyabandeh

fbshipit-source-id: e577f0d9ee1ff5a6035f26859e56902ecc85a5a4
2019-01-18 17:24:06 -08:00
Maysam Yabandeh 7fd9813b9f WritePrepared: commit of delayed prepared entries (#4894)
Summary:
Here is the order of ops in a commit: 1) update commit cache 2) publish seq, 3) RemovePrepared. In case of a delayed prepared, there will be a gap between when the commit is visible to snapshots until delayed_prepared_ is cleaned up. To tell apart this case from a delayed uncommitted txn from, the commit entry of a delayed prepared is also stored in delayed_prepared_commits_, which is updated before publishing the commit.
Also logic in GetSnapshotInternal that ensures that each new snapshot is always larger than max_evicted_seq_ is updated to check against the upcoming value of max_evicted_seq_ rather than its current one. This is because AdvanceMaxEvictedSeq gets the list of snapshots lower than the new max, before updating max_evicted_seq_.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4894

Differential Revision: D13726988

Pulled By: maysamyabandeh

fbshipit-source-id: 1e70d78061b50c944c9816bf4b6dac405ab4ccd3
2019-01-18 11:36:36 -08:00
tom wang 73ff15c07b WritePrepared: fix typo in comments
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/4891

Differential Revision: D13718016

Pulled By: miasantreble

fbshipit-source-id: 90bd372cff453a1c2d104c1cf49731d5dd770c14
2019-01-17 12:36:36 -08:00
Yanqin Jin dd9eca1c58 Remove unused variable to fix clang compilation err (#4893)
Summary:
as title.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4893

Differential Revision: D13716733

Pulled By: riversand963

fbshipit-source-id: 6811d6a99fe2094d5344f854e8939f01238b2adb
2019-01-17 11:57:31 -08:00
Sagar Vemuri 3cfc7515fc Remove an unused option (#4888)
Summary:
Remove `garbage_collection_deletion_size_threshold` as it is not used anywhere.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4888

Differential Revision: D13685982

Pulled By: sagar0

fbshipit-source-id: e08d3017b9a0c8fa99bc332b595ee4ed9db70c87
2019-01-16 11:48:43 -08:00
Yi Wu 128f532858 WritePrepared: fix issue with snapshot released during compaction (#4858)
Summary:
Compaction iterator keep a copy of list of live snapshots at the beginning of compaction, and then query snapshot checker to verify if values of a sequence number is visible to these snapshots. However when the snapshot is released in the middle of compaction, the snapshot checker implementation (i.e. WritePreparedSnapshotChecker) may remove info with the snapshot and may report incorrect result, which lead to values being compacted out when it shouldn't. This patch conservatively keep the values if snapshot checker determines that the snapshots is released.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4858

Differential Revision: D13617146

Pulled By: maysamyabandeh

fbshipit-source-id: cf18a94f6f61a94bcff73c280f117b224af5fbc3
2019-01-16 09:55:32 -08:00
Yanqin Jin e79df377c5 Use chrono::time_point instead of time_t (#4868)
Summary:
By convention, time_t almost always stores the integral number of seconds since
00:00 hours, Jan 1, 1970 UTC, according to http://www.cplusplus.com/reference/ctime/time_t/.
We surely want more precision than seconds.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4868

Differential Revision: D13633046

Pulled By: riversand963

fbshipit-source-id: 4e01e23a22e8838023c51a91247a286dbf3a5396
2019-01-16 09:51:05 -08:00