Commit Graph

82 Commits

Author SHA1 Message Date
Burton Li
a8b9891f95 Concurrent task limiter for compaction thread control (#4332)
Summary:
The PR is targeting to resolve the issue of:
https://github.com/facebook/rocksdb/issues/3972#issue-330771918

We have a rocksdb created with leveled-compaction with multiple column families (CFs), some of CFs are using HDD to store big and less frequently accessed data and others are using SSD.
When there are continuously write traffics going on to all CFs, the compaction thread pool is mostly occupied by those slow HDD compactions, which blocks fully utilize SSD bandwidth.
Since atomic write and transaction is needed across CFs, so splitting it to multiple rocksdb instance is not an option for us.

With the compaction thread control, we got 30%+ HDD write throughput gain, and also a lot smooth SSD write since less write stall happening.

ConcurrentTaskLimiter can be shared with multi-CFs across rocksdb instances, so the feature does not only work for multi-CFs scenarios, but also for multi-rocksdbs scenarios, who need disk IO resource control per tenant.

The usage is straight forward:
e.g.:

//
// Enable compaction thread limiter thru ColumnFamilyOptions
//
std::shared_ptr<ConcurrentTaskLimiter> ctl(NewConcurrentTaskLimiter("foo_limiter", 4));
Options options;
ColumnFamilyOptions cf_opt(options);
cf_opt.compaction_thread_limiter = ctl;
...

//
// Compaction thread limiter can be tuned or disabled on-the-fly
//
ctl->SetMaxOutstandingTask(12); // enlarge to 12 tasks
...
ctl->ResetMaxOutstandingTask(); // disable (bypass) thread limiter
ctl->SetMaxOutstandingTask(-1); // Same as above
...
ctl->SetMaxOutstandingTask(0);  // full throttle (0 task)

//
// Sharing compaction thread limiter among CFs (to resolve multiple storage perf issue)
//
std::shared_ptr<ConcurrentTaskLimiter> ctl_ssd(NewConcurrentTaskLimiter("ssd_limiter", 8));
std::shared_ptr<ConcurrentTaskLimiter> ctl_hdd(NewConcurrentTaskLimiter("hdd_limiter", 4));
Options options;
ColumnFamilyOptions cf_opt_ssd1(options);
ColumnFamilyOptions cf_opt_ssd2(options);
ColumnFamilyOptions cf_opt_hdd1(options);
ColumnFamilyOptions cf_opt_hdd2(options);
ColumnFamilyOptions cf_opt_hdd3(options);

// SSD CFs
cf_opt_ssd1.compaction_thread_limiter = ctl_ssd;
cf_opt_ssd2.compaction_thread_limiter = ctl_ssd;

// HDD CFs
cf_opt_hdd1.compaction_thread_limiter = ctl_hdd;
cf_opt_hdd2.compaction_thread_limiter = ctl_hdd;
cf_opt_hdd3.compaction_thread_limiter = ctl_hdd;

...

//
// The limiter is disabled by default (or set to nullptr explicitly)
//
Options options;
ColumnFamilyOptions cf_opt(options);
cf_opt.compaction_thread_limiter = nullptr;
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4332

Differential Revision: D13226590

Pulled By: siying

fbshipit-source-id: 14307aec55b8bd59c8223d04aa6db3c03d1b0c1d
2018-12-13 13:18:28 -08:00
anand76
e58d76955a Fix buck dev mode fbcode builds (#4747)
Summary:
Don't enable ROCKSDB_JEMALLOC unless the build mode is opt and default
allocator is jemalloc. In dev mode, this is causing compile/link errors such as -
```
stderr: buck-out/dev/gen/rocksdb/src/rocksdb_lib#compile-pic-malloc_stats.cc.o4768b59e,gcc-5-glibc-2.23-clang/db/malloc_stats.cc.o:malloc_stats.cc:function rocksdb::DumpMallocStats(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*): error: undefined reference to 'malloc_stats_print'
clang-7.0: error: linker command failed with exit code 1
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4747

Differential Revision: D13324840

Pulled By: anand1976

fbshipit-source-id: 45ffbd4f63fe4d9e8a0473d8f066155e4ef64a14
2018-12-05 10:40:31 -08:00
Sagar Vemuri
70645355ad Move FIFOCompactionPicker to a separate file (#4724)
Summary:
**Summary:**
Simplified the code layout by moving FIFOCompactionPicker to a separate file.
**Why?:**
While trying to add ttl functionality to universal compaction, I found that `FIFOCompactionPicker` class and its impl methods to be interspersed between `LevelCompactionPicker` methods which kind-of made the code a little hard to traverse. So I moved `FIFOCompactionPicker` to a separate compaction_picker_fifo.h/cc file, similar to `UniversalCompactionPicker`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4724

Differential Revision: D13227914

Pulled By: sagar0

fbshipit-source-id: 89471766ea67fa4d87664a41c057dd7df4b3d4e3
2018-11-29 16:04:52 -08:00
Huachao Huang
5e72bc113a Add SstFileReader to read sst files (#4717)
Summary:
A user friendly sst file reader is useful when we want to access sst
files outside of RocksDB. For example, we can generate an sst file
with SstFileWriter and send it to other places, then use SstFileReader
to read the file and process the entries in other ways.

Also rename the original SstFileReader to SstFileDumper because of
name conflict, and seems SstFileDumper is more appropriate for tools.

TODO: there is only a very simple test now, because I want to get some feedback first.
If the changes look good, I will add more tests soon.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4717

Differential Revision: D13212686

Pulled By: ajkr

fbshipit-source-id: 737593383264c954b79e63edaf44aaae0d947e56
2018-11-27 13:02:23 -08:00
Abhishek Madan
457f77b9ff Introduce RangeDelAggregatorV2 (#4649)
Summary:
The old RangeDelAggregator did expensive pre-processing work
to create a collapsed, binary-searchable representation of range
tombstones. With FragmentedRangeTombstoneIterator, much of this work is
now unnecessary. RangeDelAggregatorV2 takes advantage of this by seeking
in each iterator to find a covering tombstone in ShouldDelete, while
doing minimal work in AddTombstones. The old RangeDelAggregator is still
used during flush/compaction for now, though RangeDelAggregatorV2 will
support those uses in a future PR.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4649

Differential Revision: D13146964

Pulled By: abhimadan

fbshipit-source-id: be29a4c020fc440500c137216fcc1cf529571eb3
2018-11-21 10:56:45 -08:00
Yi Wu
5f5fddabc7 port folly::JemallocNodumpAllocator (#4534)
Summary:
Introduce `JemallocNodumpAllocator`, which allow exclusion of block cache usage from core dump. It utilize custom hook of jemalloc arena, and when jemalloc arena request memory from system, the allocator use the hook to set `MADV_DONTDUMP ` to the memory. The implementation is basically the same as `folly::JemallocNodumpAllocator`, except for some minor difference:
1. It only support jemalloc >= 5.0
2. When the allocator destruct, it explicitly destruct the corresponding arena via `arena.<i>.destroy` via `mallctl`.

Depending on #4502.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4534

Differential Revision: D10435474

Pulled By: yiwu-arbug

fbshipit-source-id: e80edea755d3853182485d2be710376384ce0bb4
2018-10-26 17:29:18 -07:00
Abhishek Madan
8c78348c77 Use only "local" range tombstones during Get (#4449)
Summary:
Previously, range tombstones were accumulated from every level, which
was necessary if a range tombstone in a higher level covered a key in a lower
level. However, RangeDelAggregator::AddTombstones's complexity is based on
the number of tombstones that are currently stored in it, which is wasteful in
the Get case, where we only need to know the highest sequence number of range
tombstones that cover the key from higher levels, and compute the highest covering
sequence number at the current level. This change introduces this optimization, and
removes the use of RangeDelAggregator from the Get path.

In the benchmark results, the following command was used to initialize the database:
```
./db_bench -db=/dev/shm/5k-rts -use_existing_db=false -benchmarks=filluniquerandom -write_buffer_size=1048576 -compression_type=lz4 -target_file_size_base=1048576 -max_bytes_for_level_base=4194304 -value_size=112 -key_size=16 -block_size=4096 -level_compaction_dynamic_level_bytes=true -num=5000000 -max_background_jobs=12 -benchmark_write_rate_limit=20971520 -range_tombstone_width=100 -writes_per_range_tombstone=100 -max_num_range_tombstones=50000 -bloom_bits=8
```

...and the following command was used to measure read throughput:
```
./db_bench -db=/dev/shm/5k-rts/ -use_existing_db=true -benchmarks=readrandom -disable_auto_compactions=true -num=5000000 -reads=100000 -threads=32
```

The filluniquerandom command was only run once, and the resulting database was used
to measure read performance before and after the PR. Both binaries were compiled with
`DEBUG_LEVEL=0`.

Readrandom results before PR:
```
readrandom   :       4.544 micros/op 220090 ops/sec;   16.9 MB/s (63103 of 100000 found)
```

Readrandom results after PR:
```
readrandom   :      11.147 micros/op 89707 ops/sec;    6.9 MB/s (63103 of 100000 found)
```

So it's actually slower right now, but this PR paves the way for future optimizations (see #4493).

----
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4449

Differential Revision: D10370575

Pulled By: abhimadan

fbshipit-source-id: 9a2e152be1ef36969055c0e9eb4beb0d96c11f4d
2018-10-24 12:31:12 -07:00
Philip Jameson
56e129da01 Remove usages of headers attribute as a string
Reviewed By: andrewjcg

Differential Revision: D10409082

fbshipit-source-id: a1432270f79c2baf2e52e3351b5f481c7398c58d
2018-10-18 13:59:08 -07:00
Yi Wu
f60c4e5a58 Set -DROCKSDB_JEMALLOC for buck build if jemalloc presents (#4489)
Summary:
Set the macro if default allocator is jemalloc. It doesn't handle the case when allocator is specified, e.g.
```
cpp_binary(
    name="xxx"
    allocator="jemalloc", # or "malloc" or something else
    deps=["//rocksdb:rocksdb"],
)
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4489

Differential Revision: D10363683

Pulled By: yiwu-arbug

fbshipit-source-id: 5da490336a8e78e0feb0900c29e8036e7ec6f12b
2018-10-15 11:41:47 -07:00
Yi Wu
d6f2ecf49c Utility to run task periodically in a thread (#4423)
Summary:
Introduce `RepeatableThread` utility to run task periodically in a separate thread. It is basically the same as the the same class in fbcode, and in addition provide a helper method to let tests mock time and trigger execution one at a time.

We can use this class to replace `TimerQueue` in #4382 and `BlobDB`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4423

Differential Revision: D10020932

Pulled By: yiwu-arbug

fbshipit-source-id: 3616bef108c39a33c92eedb1256de424b7c04087
2018-09-27 15:28:00 -07:00
Yi Wu
31d46993cc Update TARGETS file template (#4426)
Summary:
Update template of TARGETS file according to recent changes in #4371 , #4363 and dbf44c314b.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4426

Differential Revision: D10025053

Pulled By: yiwu-arbug

fbshipit-source-id: e6a0a702bfd401fc1af240ee446f5690f0bcd85d
2018-09-25 14:14:01 -07:00
Abhishek Madan
1626f6ab6b Add RangeDelAggregator microbenchmarks (#4363)
Summary:
To measure the results of upcoming DeleteRange v2 work, this commit adds
simple benchmarks for RangeDelAggregator. It measures the average time
for AddTombstones and ShouldDelete calls.

Using this to compare the results before #4014 and on the latest master (using the default arguments) produces the following results:

Before #4014:
```
=======================
Results:
=======================
AddTombstones:          1356.28 us
ShouldDelete:           0.401732 us
```

Latest master:
```
=======================
Results:
=======================
AddTombstones:          740.82 us
ShouldDelete:           0.383271 us
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4363

Differential Revision: D9881676

Pulled By: abhimadan

fbshipit-source-id: 793e7d61aa4b9d47eb917bbcc03f08695b5e5442
2018-09-17 14:58:31 -07:00
Anand Ananthabhotla
dfda91027b Remove trace_analyzer_tool.cc from rocksdb_lib buck target (#4371)
Summary:
Including tools/trace_analyzer_tool.cc in rocksdb_lib was causing conflicts in dependent binaries due to duplicate gflag (other_prefix).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4371

Differential Revision: D9846953

Pulled By: anand1976

fbshipit-source-id: 80b4aa36ab8428b8f6dceb896c45532684102709
2018-09-15 19:58:13 -07:00
Philip Jameson
dbf44c314b Lint TARGETS files with buildifier
Summary: Build file formatting

Reviewed By: mzlee

Differential Revision: D9728238

fbshipit-source-id: 99a266d5d2260eabfd63a200b2994c6850b59cf4
2018-09-11 14:58:19 -07:00
Philip Jameson
a876995ed4 Grab straggler files to explicitly import AutoHeaders
Summary: There were a few files that were missed when AutoHeaders were moved to their own file. Add explicit loads

Reviewed By: yfeldblum

Differential Revision: D9499942

fbshipit-source-id: 942bf3a683b8961e1b6244136f6337477dcc45af
2018-08-28 21:28:55 -07:00
Yi Wu
a6d3de4e7a BlobDB: Implement DisableFileDeletions (#4314)
Summary:
`DB::DiableFileDeletions` and `DB::EnableFileDeletions` are used for applications to stop RocksDB background jobs to delete files while they are doing replication. Implement these methods for BlobDB. `DeleteObsolteFiles` now needs to check `disable_file_deletions_` before starting, and will hold `delete_file_mutex_` the whole time while it is running. `DisableFileDeletions` needs to wait on `delete_file_mutex_` for running `DeleteObsolteFiles` job and set `disable_file_deletions_` flag.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4314

Differential Revision: D9501373

Pulled By: yiwu-arbug

fbshipit-source-id: 81064c1228f1724eff46da22b50ff765b16292cd
2018-08-27 10:58:29 -07:00
Fenggang Wu
19ec44fd39 Improve point-lookup performance using a data block hash index (#4174)
Summary:
Add hash index support to data blocks, which helps to reduce the CPU utilization of point-lookup operations. This feature is backward compatible with the data block created without the hash index. It is disabled by default unless `BlockBasedTableOptions::data_block_index_type` is set to `data_block_index_type = kDataBlockBinaryAndHash.`

The DB size would be bigger with the hash index option as a hash table is added at the end of each data block. If the hash utilization ratio is 1:1, the space overhead is one byte per key. The hash table utilization ratio is adjustable using `BlockBasedTableOptions::data_block_hash_table_util_ratio`. A lower utilization ratio will improve more on the point-lookup efficiency, but take more space too.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4174

Differential Revision: D8965914

Pulled By: fgwu

fbshipit-source-id: 1c6bae5d1fc39c80282d8890a72e9e67bc247198
2018-08-15 14:30:03 -07:00
Zhichao Cao
999d955e4f RocksDB Trace Analyzer (#4091)
Summary:
A framework of trace analyzing for RocksDB

After collecting the trace by using the tool of [PR #3837](https://github.com/facebook/rocksdb/pull/3837). User can use the Trace Analyzer to interpret, analyze, and characterize the collected workload.
**Input:**
1. trace file
2. Whole keys space file

**Statistics:**
1. Access count of each operation (Get, Put, Delete, SingleDelete, DeleteRange, Merge) in each column family.
2. Key hotness (access count) of each one
3. Key space separation based on given prefix
4. Key size distribution
5. Value size distribution if appliable
6. Top K accessed keys
7. QPS statistics including the average QPS and peak QPS
8. Top K accessed prefix
9. The query correlation analyzing, output the number of X after Y and the corresponding average time
    intervals

**Output:**
1. key access heat map (either in the accessed key space or whole key space)
2. trace sequence file (interpret the raw trace file to line base text file for future use)
3. Time serial (The key space ID and its access time)
4. Key access count distritbution
5. Key size distribution
6. Value size distribution (in each intervals)
7. whole key space separation by the prefix
8. Accessed key space separation by the prefix
9. QPS of each operation and each column family
10. Top K QPS and their accessed prefix range

**Test:**
1. Added the unit test of analyzing Get, Put, Delete, SingleDelete, DeleteRange, Merge
2. Generated the trace and analyze the trace

**Implemented but not tested (due to the limitation of trace_replay):**
1. Analyzing Iterator, supporting Seek() and SeekForPrev() analyzing
2. Analyzing the number of Key found by Get

**Future Work:**
1.  Support execution time analyzing of each requests
2.  Support cache hit situation and block read situation of Get
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4091

Differential Revision: D9256157

Pulled By: zhichao-cao

fbshipit-source-id: f0ceacb7eedbc43a3eee6e85b76087d7832a8fe6
2018-08-13 11:44:02 -07:00
Yi Wu
140f256da2 BlobDB: Cleanup TTLExtractor interface (#4229)
Summary:
Cleanup TTLExtractor interface. The original purpose of it is to allow our users keep using existing `Write()` interface but allow it to accept TTL via `TTLExtractor`. However the interface is confusing. Will replace it with something like `WriteWithTTL(batch, ttl)` in the future.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4229

Differential Revision: D9174390

Pulled By: yiwu-arbug

fbshipit-source-id: 68201703d784408b851336ab4dd9b84188245b2d
2018-08-06 11:58:05 -07:00
Sagar Vemuri
12b6cdeed3 Trace and Replay for RocksDB (#3837)
Summary:
A framework for tracing and replaying RocksDB operations.

A binary trace file is created by capturing the DB operations, and it can be replayed back at the same rate using db_bench.

- Column-families are supported
- Multi-threaded tracing is supported.
- TraceReader and TraceWriter are exposed to the user, so that tracing to various destinations can be enabled (say, to other messaging/logging services). By default, a FileTraceReader and FileTraceWriter are implemented to capture to a file and replay from it.
- This is not yet ideal to be enabled in production due to large performance overhead, but it can be safely tried out in a shadow setup, say, for analyzing RocksDB operations.

Currently supported DB operations:
- Writes:
-- Put
-- Merge
-- Delete
-- SingleDelete
-- DeleteRange
-- Write
- Reads:
-- Get (point lookups)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/3837

Differential Revision: D7974837

Pulled By: sagar0

fbshipit-source-id: 8ec65aaf336504bc1f6ed0feae67f6ed5ef97a72
2018-08-01 00:27:08 -07:00
Fenggang Wu
8805ec2f49 DataBlockHashIndex: Standalone Implementation with Unit Test (#4139)
Summary:
The first step of the `DataBlockHashIndex` implementation. A string based hash table is implemented and unit-tested.

`DataBlockHashIndexBuilder`: `Add()` takes pairs of `<key, restart_index>`, and formats it into a string when `Finish()` is called.
`DataBlockHashIndex`: initialized by the formatted string, and can interpret it as a hash table. Lookup for a key is supported by iterator operation.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4139

Reviewed By: sagar0

Differential Revision: D8866764

Pulled By: fgwu

fbshipit-source-id: 7f015f0098632c65979a22898a50424384730b10
2018-07-24 11:43:37 -07:00
Chang Su
374c37da5b move static msgs out of Status class (#4144)
Summary:
The member msgs of class Status contains all types of status messages.
When users dump a Status object, msgs will confuse users. So move it out
of class Status by making it as file-local static variable.

Closes #3831 .
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4144

Differential Revision: D8941419

Pulled By: sagar0

fbshipit-source-id: 56b0510258465ff26db15aa6b04e01532e053e3d
2018-07-23 15:44:16 -07:00
Siying Dong
ddc07b40fc Remove managed iterator
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/4124

Differential Revision: D8829910

Pulled By: siying

fbshipit-source-id: f3e952ccf3a631071a5d77c48e327046f8abb560
2018-07-17 14:43:18 -07:00
Siying Dong
a61ff876a1 Remove two CI tests (#4110)
Summary:
Two CI tests never pass because of the environment problem. Delete them.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4110

Differential Revision: D8805713

Pulled By: siying

fbshipit-source-id: 6eb4813dc2094ee2045ec8ede7fe8967d546d6e8
2018-07-12 11:43:25 -07:00
Anand Ananthabhotla
52d4c9b7f6 Allow DB resume after background errors (#3997)
Summary:
Currently, if RocksDB encounters errors during a write operation (user requested or BG operations), it sets DBImpl::bg_error_ and fails subsequent writes. This PR allows the DB to be resumed for certain classes of errors. It consists of 3 parts -
1. Introduce Status::Severity in rocksdb::Status to indicate whether a given error can be recovered from or not
2. Refactor the error handling code so that setting bg_error_ and deciding on severity is in one place
3. Provide an API for the user to clear the error and resume the DB instance

This whole change is broken up into multiple PRs. Initially, we only allow clearing the error for Status::NoSpace() errors during background flush/compaction. Subsequent PRs will expand this to include more errors and foreground operations such as Put(), and implement a polling mechanism for out-of-space errors.
Closes https://github.com/facebook/rocksdb/pull/3997

Differential Revision: D8653831

Pulled By: anand1976

fbshipit-source-id: 6dc835c76122443a7668497c0226b4f072bc6afd
2018-06-28 12:34:40 -07:00
Yi Wu
58c221440c Update TARGETS file (#4028)
Summary:
-Wshorten-64-to-32 is invalid flag in fbcode. Changing it to -Warrowing.
Closes https://github.com/facebook/rocksdb/pull/4028

Differential Revision: D8553694

Pulled By: yiwu-arbug

fbshipit-source-id: 1523cbcb4c76cf1d2b10a4d28b5f58c78e6cb876
2018-06-21 14:42:39 -07:00
Dmitri Smirnov
f4b72d7056 Provide a way to override windows memory allocator with jemalloc for ZSTD
Summary:
Windows does not have LD_PRELOAD mechanism to override all memory allocation functions and ZSTD makes use of C-tuntime calloc. During flushes and compactions default system allocator fragments and the system slows down considerably.

For builds with jemalloc we employ an advanced ZSTD context creation API that re-directs memory allocation to jemalloc. To reduce the cost of context creation on each block we cache ZSTD context within the block based table builder while a new SST file is being built, this will help all platform builds including those w/o jemalloc. This avoids system allocator fragmentation and improves the performance.

The change does not address random reads and currently on Windows reads with ZSTD regress as compared with SNAPPY compression.
Closes https://github.com/facebook/rocksdb/pull/3838

Differential Revision: D8229794

Pulled By: miasantreble

fbshipit-source-id: 719b622ab7bf4109819bc44f45ec66f0dd3ee80d
2018-06-04 12:12:48 -07:00
Manuel Ung
01e3c30def Extend existing unit tests to run with WriteUnprepared as well
Summary:
As titled.

I have not extended the Compatibility tests because the new WAL markers are still unimplemented.
Closes https://github.com/facebook/rocksdb/pull/3941

Differential Revision: D8238394

Pulled By: lth

fbshipit-source-id: 980e3d44837bbf2cfa64047f9738f559dfac4b1d
2018-06-01 14:58:41 -07:00
Manuel Ung
aaac6cd16f Add write unprepared classes by inheriting from write prepared
Summary: Closes https://github.com/facebook/rocksdb/pull/3907

Differential Revision: D8218325

Pulled By: lth

fbshipit-source-id: ff32d8dab4a159cd2762876cba4b15e3dc51ff3b
2018-05-31 10:47:42 -07:00
Mike Kolupaev
8bf555f487 Change and clarify the relationship between Valid(), status() and Seek*() for all iterators. Also fix some bugs
Summary:
Before this PR, Iterator/InternalIterator may simultaneously have non-ok status() and Valid() = true. That state means that the last operation failed, but the iterator is nevertheless positioned on some unspecified record. Likely intended uses of that are:
 * If some sst files are corrupted, a normal iterator can be used to read the data from files that are not corrupted.
 * When using read_tier = kBlockCacheTier, read the data that's in block cache, skipping over the data that is not.

However, this behavior wasn't documented well (and until recently the wiki on github had misleading incorrect information). In the code there's a lot of confusion about the relationship between status() and Valid(), and about whether Seek()/SeekToLast()/etc reset the status or not. There were a number of bugs caused by this confusion, both inside rocksdb and in the code that uses rocksdb (including ours).

This PR changes the convention to:
 * If status() is not ok, Valid() always returns false.
 * Any seek operation resets status. (Before the PR, it depended on iterator type and on particular error.)

This does sacrifice the two use cases listed above, but siying said it's ok.

Overview of the changes:
 * A commit that adds missing status checks in MergingIterator. This fixes a bug that actually affects us, and we need it fixed. `DBIteratorTest.NonBlockingIterationBugRepro` explains the scenario.
 * Changes to lots of iterator types to make all of them conform to the new convention. Some bug fixes along the way. By far the biggest changes are in DBIter, which is a big messy piece of code; I tried to make it less big and messy but mostly failed.
 * A stress-test for DBIter, to gain some confidence that I didn't break it. It does a few million random operations on the iterator, while occasionally modifying the underlying data (like ForwardIterator does) and occasionally returning non-ok status from internal iterator.

To find the iterator types that needed changes I searched for "public .*Iterator" in the code. Here's an overview of all 27 iterator types:

Iterators that didn't need changes:
 * status() is always ok(), or Valid() is always false: MemTableIterator, ModelIter, TestIterator, KVIter (2 classes with this name anonymous namespaces), LoggingForwardVectorIterator, VectorIterator, MockTableIterator, EmptyIterator, EmptyInternalIterator.
 * Thin wrappers that always pass through Valid() and status(): ArenaWrappedDBIter, TtlIterator, InternalIteratorFromIterator.

Iterators with changes (see inline comments for details):
 * DBIter - an overhaul:
    - It used to silently skip corrupted keys (`FindParseableKey()`), which seems dangerous. This PR makes it just stop immediately after encountering a corrupted key, just like it would for other kinds of corruption. Let me know if there was actually some deeper meaning in this behavior and I should put it back.
    - It had a few code paths silently discarding subiterator's status. The stress test caught a few.
    - The backwards iteration code path was expecting the internal iterator's set of keys to be immutable. It's probably always true in practice at the moment, since ForwardIterator doesn't support backwards iteration, but this PR fixes it anyway. See added DBIteratorTest.ReverseToForwardBug for an example.
    - Some parts of backwards iteration code path even did things like `assert(iter_->Valid())` after a seek, which is never a safe assumption.
    - It used to not reset status on seek for some types of errors.
    - Some simplifications and better comments.
    - Some things got more complicated from the added error handling. I'm open to ideas for how to make it nicer.
 * MergingIterator - check status after every operation on every subiterator, and in some places assert that valid subiterators have ok status.
 * ForwardIterator - changed to the new convention, also slightly simplified.
 * ForwardLevelIterator - fixed some bugs and simplified.
 * LevelIterator - simplified.
 * TwoLevelIterator - changed to the new convention. Also fixed a bug that would make SeekForPrev() sometimes silently ignore errors from first_level_iter_.
 * BlockBasedTableIterator - minor changes.
 * BlockIter - replaced `SetStatus()` with `Invalidate()` to make sure non-ok BlockIter is always invalid.
 * PlainTableIterator - some seeks used to not reset status.
 * CuckooTableIterator - tiny code cleanup.
 * ManagedIterator - fixed some bugs.
 * BaseDeltaIterator - changed to the new convention and fixed a bug.
 * BlobDBIterator - seeks used to not reset status.
 * KeyConvertingIterator - some small change.
Closes https://github.com/facebook/rocksdb/pull/3810

Differential Revision: D7888019

Pulled By: al13n321

fbshipit-source-id: 4aaf6d3421c545d16722a815b2fa2e7912bc851d
2018-05-17 02:56:56 -07:00
Siying Dong
d59549298f Skip deleted WALs during recovery
Summary:
This patch record min log number to keep to the manifest while flushing SST files to ignore them and any WAL older than them during recovery. This is to avoid scenarios when we have a gap between the WAL files are fed to the recovery procedure. The gap could happen by for example out-of-order WAL deletion. Such gap could cause problems in 2PC recovery where the prepared and commit entry are placed into two separate WAL and gap in the WALs could result into not processing the WAL with the commit entry and hence breaking the 2PC recovery logic.

Before the commit, for 2PC case, we determined which log number to keep in FindObsoleteFiles(). We looked at the earliest logs with outstanding prepare entries, or prepare entries whose respective commit or abort are in memtable. With the commit, the same calculation is done while we apply the SST flush. Just before installing the flush file, we precompute the earliest log file to keep after the flush finishes using the same logic (but skipping the memtables just flushed), record this information to the manifest entry for this new flushed SST file. This pre-computed value is also remembered in memory, and will later be used to determine whether a log file can be deleted. This value is unlikely to change until next flush because the commit entry will stay in memtable. (In WritePrepared, we could have removed the older log files as soon as all prepared entries are committed. It's not yet done anyway. Even if we do it, the only thing we loss with this new approach is earlier log deletion between two flushes, which does not guarantee to happen anyway because the obsolete file clean-up function is only executed after flush or compaction)

This min log number to keep is stored in the manifest using the safely-ignore customized field of AddFile entry, in order to guarantee that the DB generated using newer release can be opened by previous releases no older than 4.2.
Closes https://github.com/facebook/rocksdb/pull/3765

Differential Revision: D7747618

Pulled By: siying

fbshipit-source-id: d00c92105b4f83852e9754a1b70d6b64cb590729
2018-05-03 15:43:09 -07:00
Fosco Marotto
d9bfb35d31 Update buckifier and TARGETS
Summary:
Some flags used via make were not applied in the buckifier/targets file, causing some failures to be missed by testing infra ( ie the one fixed by #3434 )
Closes https://github.com/facebook/rocksdb/pull/3452

Differential Revision: D7457419

Pulled By: gfosco

fbshipit-source-id: e4aed2915ca3038c1485bbdeebedfc33d5704a49
2018-03-30 14:26:53 -07:00
Yanqin Jin
1f5def1653 Fix race condition causing double deletion of ssts
Summary:
Possible interleaved execution of background compaction thread calling `FindObsoleteFiles (no full scan) / PurgeObsoleteFiles` and user thread calling `FindObsoleteFiles (full scan) / PurgeObsoleteFiles` can lead to race condition on which RocksDB attempts to delete a file twice. The second attempt will fail and return `IO error`. This may occur to other files,  but this PR targets sst.
Also add a unit test to verify that this PR fixes the issue.

The newly added unit test `obsolete_files_test` has a test case for this scenario, implemented in `ObsoleteFilesTest#RaceForObsoleteFileDeletion`. `TestSyncPoint`s are used to coordinate the interleaving the `user_thread` and background compaction thread. They execute as follows
```
timeline              user_thread                background_compaction thread
t1   |                                          FindObsoleteFiles(full_scan=false)
t2   |     FindObsoleteFiles(full_scan=true)
t3   |                                          PurgeObsoleteFiles
t4   |     PurgeObsoleteFiles
     V
```
When `user_thread` invokes `FindObsoleteFiles` with full scan, it collects ALL files in RocksDB directory, including the ones that background compaction thread have collected in its job context. Then `user_thread` will see an IO error when trying to delete these files in `PurgeObsoleteFiles` because background compaction thread has already deleted the file in `PurgeObsoleteFiles`.
To fix this, we make RocksDB remember which (SST) files have been found by threads after calling `FindObsoleteFiles` (see `DBImpl#files_grabbed_for_purge_`). Therefore, when another thread calls `FindObsoleteFiles` with full scan, it will not collect such files.

ajkr could you take a look and comment? Thanks!
Closes https://github.com/facebook/rocksdb/pull/3638

Differential Revision: D7384372

Pulled By: riversand963

fbshipit-source-id: 01489516d60012e722ee65a80e1449e589ce26d3
2018-03-28 10:29:59 -07:00
Dmitri Smirnov
53d66df0c4 Refactor sync_point to make implementation either customizable or replaceable
Summary: Closes https://github.com/facebook/rocksdb/pull/3637

Differential Revision: D7354373

Pulled By: ajkr

fbshipit-source-id: 6816c7bbc192ed0fb944942b11c7074bf24eddf1
2018-03-23 12:56:52 -07:00
Siying Dong
8bc41f4f5d Update TARGETS
Summary:
Watch the build
Closes https://github.com/facebook/rocksdb/pull/3533

Differential Revision: D7063777

Pulled By: siying

fbshipit-source-id: db9cdfc362a8d281dada6513ab034a6d6f0d552e
2018-03-06 12:27:28 -08:00
Yi Wu
b864bc9b5b Blob DB: Improve FIFO eviction
Summary:
Improving blob db FIFO eviction with the following changes,
* Change blob_dir_size to max_db_size. Take into account SST file size when computing DB size.
* FIFO now only take into account live sst files and live blob files. It is normal for disk usage to go over max_db_size because there are obsolete sst files and blob files pending deletion.
* FIFO eviction now also evict TTL blob files that's still open. It doesn't evict non-TTL blob files.
* If FIFO is triggered, it will pass an expiration and the current sequence number to compaction filter. Compaction filter will then filter inlined keys to evict those with an earlier expiration and smaller sequence number. So call LSM FIFO.
* Compaction filter also filter those blob indexes where corresponding blob file is gone.
* Add an event listener to listen compaction/flush event and update sst file size.
* Implement DB::Close() to make sure base db, as well as event listener and compaction filter, destruct before blob db.
* More blob db statistics around FIFO.
* Fix some locking issue when accessing a blob file.
Closes https://github.com/facebook/rocksdb/pull/3556

Differential Revision: D7139328

Pulled By: yiwu-arbug

fbshipit-source-id: ea5edb07b33dfceacb2682f4789bea61de28bbfa
2018-03-06 11:57:42 -08:00
Pooya Shareghi
0a2354ca8f Added bytes XOR merge operator
Summary:
Closes https://github.com/facebook/rocksdb/pull/575

I fixed the merge conflicts etc.
Closes https://github.com/facebook/rocksdb/pull/3065

Differential Revision: D7128233

Pulled By: sagar0

fbshipit-source-id: 2c23a48c9f0432c290b0cd16a12fb691bb37820c
2018-03-06 10:27:36 -08:00
Maysam Yabandeh
0faa026db6 WritePrepared Txn: make buck tests parallel
Summary:
The TSAN version of tests could take quite long. Make the buck tests parallel to avoid timeouts.
Closes https://github.com/facebook/rocksdb/pull/3280

Differential Revision: D6581594

Pulled By: maysamyabandeh

fbshipit-source-id: 3f8476d8c69f0183e394fa8a2089dd8d4e90c90c
2017-12-18 14:42:09 -08:00
Siying Dong
2f1a3a4d74 Refactor ReadBlockContents()
Summary:
Divide ReadBlockContents() to multiple sub-functions. Maintaining the input and intermediate data in a new class BlockFetcher.
I hope in general it makes the code easier to maintain.
Another motivation to do it is to clearly divide the logic before file reading and after file reading. The refactor will help us evaluate how can we make I/O async in the future.
Closes https://github.com/facebook/rocksdb/pull/3244

Differential Revision: D6520983

Pulled By: siying

fbshipit-source-id: 338d90bc0338472d46be7a7682028dc9114b12e9
2017-12-11 15:27:32 -08:00
Andres Suarez
fad14050ae Remove import use from TARGETS
Summary:
We're moving away from `import`. The equivalent internal construct that
gets the directory from `fbcode/` is `package_name()`. This is a
Skylark friendly wrapper around [`get_base_path`].

The additional whitespace change is from running `python ./buckifier/buckify_rocksdb.py`.

[`get_base_path`]: https://buckbuild.com/function/get_base_path.html
Closes https://github.com/facebook/rocksdb/pull/3210

Reviewed By: yiwu-arbug

Differential Revision: D6451242

Pulled By: zertosh

fbshipit-source-id: 445757261de0ec89d5d332c1ba9af097086326dc
2017-11-30 15:27:34 -08:00
Yi Wu
54095d3389 TARGETS file not include tests in opt mode
Summary:
Do not build the tests in opt mode, since SyncPoint and other test code will not be included.
Closes https://github.com/facebook/rocksdb/pull/3204

Differential Revision: D6431154

Pulled By: yiwu-arbug

fbshipit-source-id: c404ef042c1a6f679e5c1dc57600b3d8cb52fc28
2017-11-30 10:56:58 -08:00
Yi Wu
dd49f89466 Fix TARGETS lint warnings.
Summary:
Fix buckifier script and regenerate TARGETS file with no lint warnings.
Closes https://github.com/facebook/rocksdb/pull/3170

Differential Revision: D6328993

Pulled By: yiwu-arbug

fbshipit-source-id: 17d0e4ed92f676f35fed76659386611cc72b00b2
2017-11-15 14:28:34 -08:00
Yi Wu
42564ada53 Blob DB: not using PinnableSlice move assignment
Summary:
The current implementation of PinnableSlice move assignment have an issue #3163. We are moving away from it instead of try to get the move assignment right, since it is too tricky.
Closes https://github.com/facebook/rocksdb/pull/3164

Differential Revision: D6319201

Pulled By: yiwu-arbug

fbshipit-source-id: 8f3279021f3710da4a4caa14fd238ed2df902c48
2017-11-13 18:12:20 -08:00
Maysam Yabandeh
60d83df23d WritePrepared Txn: Move DB class to its own file
Summary:
Move  WritePreparedTxnDB from pessimistic_transaction_db.h to its own header, write_prepared_txn_db.h
Closes https://github.com/facebook/rocksdb/pull/3114

Differential Revision: D6220987

Pulled By: maysamyabandeh

fbshipit-source-id: 18893fb4fdc6b809fe117dabb544080f9b4a301b
2017-11-02 11:14:30 -07:00
Yi Wu
31d3e41810 PinnableSlice move assignment
Summary:
Allow `std::move(pinnable_slice)`.
Closes https://github.com/facebook/rocksdb/pull/2997

Differential Revision: D6036782

Pulled By: yiwu-arbug

fbshipit-source-id: 583fb0419a97e437ff530f4305822341cd3381fa
2017-10-12 18:28:24 -07:00
Yi Wu
d1b74b0c82 WritePrepared Txn: Compaction/Flush
Summary:
Update Compaction/Flush to support WritePreparedTxnDB: Add SnapshotChecker which is a proxy to query WritePreparedTxnDB::IsInSnapshot. Pass SnapshotChecker to DBImpl on WritePreparedTxnDB open. CompactionIterator use it to check if a key has been committed and if it is visible to a snapshot. In CompactionIterator:
* check if key has been committed. If not, output uncommitted keys AS-IS.
* use SnapshotChecker to check if key is visible to a snapshot when in need.
* do not output key with seq = 0 if the key is not committed.
Closes https://github.com/facebook/rocksdb/pull/2926

Differential Revision: D5902907

Pulled By: yiwu-arbug

fbshipit-source-id: 945e037fdf0aa652dc5ba0ad879461040baa0320
2017-10-06 10:41:53 -07:00
Yi Wu
d1cab2b64e Add ValueType::kTypeBlobIndex
Summary:
Add kTypeBlobIndex value type, which will be used by blob db only, to insert a (key, blob_offset) KV pair. The purpose is to
1. Make it possible to open existing rocksdb instance as blob db. Existing value will be of kTypeIndex type, while value inserted by blob db will be of kTypeBlobIndex.
2. Make rocksdb able to detect if the db contains value written by blob db, if so return error.
3. Make it possible to have blob db optionally store value in SST file (with kTypeValue type) or as a blob value (with kTypeBlobIndex type).

The root db (DBImpl) basically pretended kTypeBlobIndex are normal value on write. On Get if is_blob is provided, return whether the value read is of kTypeBlobIndex type, or return Status::NotSupported() status if is_blob is not provided. On scan allow_blob flag is pass and if the flag is true, return wether the value is of kTypeBlobIndex type via iter->IsBlob().

Changes on blob db side will be in a separate patch.
Closes https://github.com/facebook/rocksdb/pull/2886

Differential Revision: D5838431

Pulled By: yiwu-arbug

fbshipit-source-id: 3c5306c62bc13bb11abc03422ec5cbcea1203cca
2017-10-03 09:11:23 -07:00
Maysam Yabandeh
26ac24f199 Add more unit test to write_prepared txns
Summary: Closes https://github.com/facebook/rocksdb/pull/2798

Differential Revision: D5724173

Pulled By: maysamyabandeh

fbshipit-source-id: fb6b782d933fb4be315b1a231a6a67a66fdc9c96
2017-08-31 09:41:27 -07:00
Andrew Gallagher
5449c0990b rocksdb: make buildable on aarch64
Summary:
- Remove default arch-specified flags.
- Move non-default arch-specific flags to arch-specific param.

Reviewed By: yiwu-arbug

Differential Revision: D5597499

fbshipit-source-id: c53108ac39c73ac36893d3fd9aaf3b5e3080f1ae
2017-08-13 17:13:54 -07:00
Maysam Yabandeh
bdc056f8aa Refactor PessimisticTransaction
Summary:
This patch splits Commit and Prepare into lock-related logic and db-write-related logic. It moves lock-related logic to PessimisticTransaction to be reused by all children classes and movies the existing impl of db-write-related to PrepareInternal, CommitSingleInternal, and CommitInternal in WriteCommittedTxnImpl.
Closes https://github.com/facebook/rocksdb/pull/2691

Differential Revision: D5569464

Pulled By: maysamyabandeh

fbshipit-source-id: d1b8698e69801a4126c7bc211745d05c636f5325
2017-08-07 16:12:29 -07:00