Commit graph

645 commits

Author SHA1 Message Date
Levi Tamasi 2d095b4dbc Update HISTORY.md with the recent memtable trimming fixes
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/6194

Differential Revision: D19125292

Pulled By: ltamasi

fbshipit-source-id: d41aca2755ec4bec07feedd6b561e8d18606a931
2019-12-16 15:19:52 -08:00
anand76 afa2420c2b Introduce a new storage specific Env API (#5761)
Summary:
The current Env API encompasses both storage/file operations, as well as OS related operations. Most of the APIs return a Status, which does not have enough metadata about an error, such as whether its retry-able or not, scope (i.e fault domain) of the error etc., that may be required in order to properly handle a storage error. The file APIs also do not provide enough control over the IO SLA, such as timeout, prioritization, hinting about placement and redundancy etc.

This PR separates out the file/storage APIs from Env into a new FileSystem class. The APIs are updated to return an IOStatus with metadata about the error, as well as to take an IOOptions structure as input in order to allow more control over the IO.

The user can set both ```options.env``` and ```options.file_system``` to specify that RocksDB should use the former for OS related operations and the latter for storage operations. Internally, a ```CompositeEnvWrapper``` has been introduced that inherits from ```Env``` and redirects individual methods to either an ```Env``` implementation or the ```FileSystem``` as appropriate. When options are sanitized during ```DB::Open```, ```options.env``` is replaced with a newly allocated ```CompositeEnvWrapper``` instance if both env and file_system have been specified. This way, the rest of the RocksDB code can continue to function as before.

This PR also ports PosixEnv to the new API by splitting it into two - PosixEnv and PosixFileSystem. PosixEnv is defined as a sub-class of CompositeEnvWrapper, and threading/time functions are overridden with Posix specific implementations in order to avoid an extra level of indirection.

The ```CompositeEnvWrapper``` translates ```IOStatus``` return code to ```Status```, and sets the severity to ```kSoftError``` if the io_status is retryable. The error handling code in RocksDB can then recover the DB automatically.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5761

Differential Revision: D18868376

Pulled By: anand1976

fbshipit-source-id: 39efe18a162ea746fabac6360ff529baba48486f
2019-12-13 14:48:41 -08:00
奏之章 c4ce8e637f Fix RangeDeletion bug (#6062)
Summary:
Read keys from a snapshot that a range deletion were added after the snapshot  was created and this range deletion was inside an immutable memtable, we will get wrong key set.
More detail rest in codes.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6062

Differential Revision: D18966785

Pulled By: pdillinger

fbshipit-source-id: 38a60bb1e2d0a1dbfc8ec641617200b6a02b86c3
2019-12-12 15:18:02 -08:00
ferhat elmas afdc58d478 Fix typos in history
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/6116

Differential Revision: D18935622

fbshipit-source-id: 59f7a7bc9f0116ae6354ea217896622a34329d3c
2019-12-11 11:04:46 -08:00
Yanqin Jin 09fcf4fb6b Fix a potential bug scheduling unnecessary threads (#6104)
Summary:
RocksDB should decrement the counter `unscheduled_flushes_` as soon as the bg
thread is scheduled. Before this fix, the counter is decremented only when the
bg thread starts and picks an element from the flush queue. This may cause more
than necessary bg threads to be scheduled. Not a correctness issue, but may
affect flush thread count.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6104

Test Plan:
```
make check
```

Differential Revision: D18735584

Pulled By: riversand963

fbshipit-source-id: d36272d4a08a494aeeab6200a3cff7a3d1a2dc10
2019-11-27 14:48:49 -08:00
sdong aa1857e2df Support options.max_open_files = -1 with periodic_compaction_seconds (#6090)
Summary:
options.periodic_compaction_seconds isn't supported when options.max_open_files != -1. It's because that the information of file creation time is stored in table properties and are not guaranteed to be loaded unless options.max_open_files = -1. Relax this constraint by storing the information in manifest.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6090

Test Plan: Pass all existing tests; Modify an existing test to force the manifest value to take 0 to simulate backward compatibility case; manually open the DB generated with the change by release 4.2.

Differential Revision: D18702268

fbshipit-source-id: 13e0bd94f546498a04f3dc5fc0d9dff5125ec9eb
2019-11-26 21:39:56 -08:00
anand76 496a6ae895 Fix HISTORY.md for 6.6.0 (#6096)
Summary:
Some of the entries were incorrectly listed under 6.5.0.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6096

Differential Revision: D18722801

Pulled By: gfosco

fbshipit-source-id: 18d1187deb6a9d69a8feb68b727d2f720a65f2bc
2019-11-26 19:04:49 -08:00
Peter Dillinger ca3b6c28c9 Expose and elaborate FilterBuildingContext (#6088)
Summary:
This change enables custom implementations of FilterPolicy to
wrap a variety of NewBloomFilterPolicy and select among them based on
contextual information such as table level and compaction style.

* Moves FilterBuildingContext to public API and elaborates it with more
useful data. (It would be nice to put more general options-like data,
but at the time this object is constructed, we are using internal APIs
ImmutableCFOptions and MutableCFOptions and don't have easy access to
ColumnFamilyOptions that I can tell.)

* Renames BloomFilterPolicy::GetFilterBitsBuilderInternal to
GetBuilderWithContext, because it's now public.

* Plumbs through the table's "level_at_creation" for filter building
context.

* Simplified some tests by adding GetBuilder() to
MockBlockBasedTableTester.

* Adds test as DBBloomFilterTest.ContextCustomFilterPolicy, including
sample wrapper class LevelAndStyleCustomFilterPolicy.

* Fixes a cross-test bug in DBBloomFilterTest.OptimizeFiltersForHits
where it does not reset perf context.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6088

Test Plan: make check, valgrind on db_bloom_filter_test

Differential Revision: D18697817

Pulled By: pdillinger

fbshipit-source-id: 5f987a2d7b07cc7a33670bc08ca6b4ca698c1cf4
2019-11-26 18:24:10 -08:00
Peter Dillinger 57f3032285 Allow fractional bits/key in BloomFilterPolicy (#6092)
Summary:
There's no technological impediment to allowing the Bloom
filter bits/key to be non-integer (fractional/decimal) values, and it
provides finer control over the memory vs. accuracy trade-off. This is
especially handy in using the format_version=5 Bloom filter in place
of the old one, because bits_per_key=9.55 provides the same accuracy as
the old bits_per_key=10.

This change not only requires refining the logic for choosing the best
num_probes for a given bits/key setting, it revealed a flaw in that logic.
As bits/key gets higher, the best num_probes for a cache-local Bloom
filter is closer to bpk / 2 than to bpk * 0.69, the best choice for a
standard Bloom filter. For example, at 16 bits per key, the best
num_probes is 9 (FP rate = 0.0843%) not 11 (FP rate = 0.0884%).
This change fixes and refines that logic (for the format_version=5
Bloom filter only, just in case) based on empirical tests to find
accuracy inflection points between each num_probes.

Although bits_per_key is now specified as a double, the new Bloom
filter converts/rounds this to "millibits / key" for predictable/precise
internal computations. Just in case of unforeseen compatibility
issues, we round to the nearest whole number bits / key for the
legacy Bloom filter, so as not to unlock new behaviors for it.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6092

Test Plan: unit tests included

Differential Revision: D18711313

Pulled By: pdillinger

fbshipit-source-id: 1aa73295f152a995328cb846ef9157ae8a05522a
2019-11-26 15:59:34 -08:00
sdong 77eab5c85a Make default value of options.ttl to be 30 days when it is supported. (#6073)
Summary:
By default options.ttl is disabled. We believe a better default will be 30 days, which means deleted data the database will be removed from SST files slightly after 30 days, for most of the cases.

Make the default UINT64_MAX - 1 to indicate that it is not overridden by users.

Change periodic_compaction_seconds to be UINT64_MAX - 1 to UINT64_MAX  too to be consistent. Also fix a small bug in the previous periodic_compaction_seconds default code.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6073

Test Plan: Add unit tests for it.

Differential Revision: D18669626

fbshipit-source-id: 957cd4374cafc1557d45a0ba002010552a378cc8
2019-11-26 10:00:32 -08:00
Sebastiano Peluso fcd7e03832 Ignore value of BackupableDBOptions::max_valid_backups_to_open when B… (#6072)
Summary:
This change ignores the value of BackupableDBOptions::max_valid_backups_to_open when a BackupEngine is not read-only.

Issue: https://github.com/facebook/rocksdb/issues/4997

Note on tests: I had to remove test case WriteOnlyEngine of BackupableDBTest because it was not consistent with the new semantic of BackupableDBOptions::max_valid_backups_to_open. Maybe, we should think about adding a new interface for append-only BackupEngines. On the other hand, I changed LimitBackupsOpened test case to use a read-only BackupEngine, and I added a new specific test case for the change.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6072

Reviewed By: pdillinger

Differential Revision: D18687364

Pulled By: sebastianopeluso

fbshipit-source-id: 77bc1f927d623964d59137a93de123bbd719da4e
2019-11-26 10:00:31 -08:00
sdong 0bc87442ae Update HISTORY.md for forward compatibility (#6085)
Summary:
https://github.com/facebook/rocksdb/pull/6060 broke forward compatiblity for releases from 3.10 to 4.2. Update HISTORY.md to mention it. Also remove it from the compatibility tests.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6085

Differential Revision: D18691694

fbshipit-source-id: 4ef903783dc722b8a4d3e8229abbf0f021a114c9
2019-11-26 10:00:31 -08:00
Sagar Vemuri 669ea77d9f Support ttl in Universal Compaction (#6071)
Summary:
`options.ttl` is now supported in universal compaction, similar to how periodic compactions are implemented in PR https://github.com/facebook/rocksdb/issues/5970 .
Setting `options.ttl` will simply set `options.periodic_compaction_seconds` to execute the periodic compactions code path.
Discarded PR https://github.com/facebook/rocksdb/issues/4749 in lieu of this.

This is a short term work-around/hack of falling back to periodic compactions when ttl is set.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6071

Test Plan: Added a unit test.

Differential Revision: D18668336

Pulled By: sagar0

fbshipit-source-id: e75f5b81ba949f77ef9eff05e44bb1c757f58612
2019-11-22 22:13:35 -08:00
sdong d8c28e692a Support options.ttl with options.max_open_files = -1 (#6060)
Summary:
Previously, options.ttl cannot be set with options.max_open_files = -1, because it makes use of creation_time field in table properties, which is not available unless max_open_files = -1. With this commit, the information will be stored in manifest and when it is available, will be used instead.

Note that, this change will break forward compatibility for release 5.1 and older.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6060

Test Plan: Extend existing test case to options.max_open_files != -1, and simulate backward compatility in one test case by forcing the value to be 0.

Differential Revision: D18631623

fbshipit-source-id: 30c232a8672de5432ce9608bb2488ecc19138830
2019-11-22 21:23:00 -08:00
Yanqin Jin 0ce0edbe12 Fix a data race between GetColumnFamilyMetaData and MarkFilesBeingCompacted (#6056)
Summary:
Use db mutex to protect the execution of Version::GetColumnFamilyMetaData()
called in DBImpl::GetColumnFamilyMetaData().
Without mutex, GetColumnFamilyMetaData() races with MarkFilesBeingCompacted()
for access to FileMetaData::being_compacted.
Other than mutex, there are several more alternatives.

- Make FileMetaData::being_compacted an atomic variable. This will make
  FileMetaData non-copy-able.

- Separate being_compacted from FileMetaData. This requires re-organizing data
  structures that are already used in many places.

Test Plan (dev server):
```
make check
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6056

Differential Revision: D18620488

Pulled By: riversand963

fbshipit-source-id: 87f89660b5d5e2ab4ef7962b7b2a7d00e346aa3b
2019-11-20 16:36:29 -08:00
Little-Wallace ec3e3c3e02 Fix corruption with intra-L0 on ingested files (#5958)
Summary:
## Problem Description

Our process was abort when it call `CheckConsistency`. And the information in  `stderr` show that "`L0 files seqno 3001491972 3004797440 vs. 3002875611 3004524421` ".  Here are the causes of the accident I investigated.

* RocksDB will call `CheckConsistency` whenever `MANIFEST` file is update. It will check sequence number interval of every file, except files which were ingested.
* When one file is ingested into RocksDB, it will be assigned the value of global sequence number, and the minimum and maximum seqno of this file are equal, which are both equal to global sequence number.
* `CheckConsistency`  determines whether the file is ingested by whether the smallest and largest seqno of an sstable file are equal.
* If IntraL0Compaction picks one sst which was ingested just now and compacted it into another sst,  the `smallest_seqno` of this new file will be smaller than his `largest_seqno`.
    * If more than one ingested file was ingested before memtable schedule flush,  and they all compact into one new sstable file by `IntraL0Compaction`. The sequence interval of this new file will be included in the interval of the memtable.  So `CheckConsistency` will return a `Corruption`.
    * If a sstable was ingested after the memtable was schedule to flush, which would assign a larger seqno to it than memtable. Then the file was compacted with other files (these files were all flushed before the memtable) in L0 into one file. This compaction start before the flush job of memtable start,  but completed after the flush job finish. So this new file produced by the compaction (we call it s1) would have a larger interval of sequence number than the file produced by flush (we call it s2).  **But there was still some data in s1  written into RocksDB before the s2, so it's possible that some data in s2 was cover by old data in s1.** Of course, it would also make a `Corruption` because of overlap of seqno. There is the relationship of the files:
    > s1.smallest_seqno < s2.smallest_seqno < s2.largest_seqno  < s1.largest_seqno

So I skip pick sst file which was ingested in function `FindIntraL0Compaction `

## Reason

Here is my bug report: https://github.com/facebook/rocksdb/issues/5913

There are two situations that can cause the check to fail.

### First situation:
- First we ingest five external sst into Rocksdb, and they happened to be ingested in L0. and there had been some data in memtable, which make the smallest sequence number of memtable is less than which of sst that we ingest.

- If there had been one compaction job which compacted sst from L0 to L1, `LevelCompactionPicker` would trigger a `IntraL0Compaction` which would compact this five sst from L0 to L0. We call this sst A, which was merged from five ingested sst.

- Then some data was put into memtable, and memtable was flushed to L0. We called this sst B.
- RocksDB check consistency , and find the `smallest_seqno` of B is  less than that of A and crash. Because A was merged from five sst, the smallest sequence number of it was less than the biggest sequece number of itself, so RocksDB could not tell if A was produce by ingested.

### Secondary situaion

- First we have flushed many sst in L0,  we call them [s1, s2, s3].

- There is an immutable memtable request to be flushed, but because flush thread is busy, so it has not been picked. we call it m1.  And at the moment, one sst is ingested into L0. We call it s4. Because s4 is ingested after m1 became immutable memtable, so it has a larger log sequence number than m1.

- m1 is flushed in L0. because it is small, this flush job finish quickly. we call it s5.

- [s1, s2, s3, s4] are compacted into one sst to L0, by IntraL0Compaction.  We call it s6.
  - compacted 4@0 files to L0
- When s6 is added into manifest,  the corruption happened. because the largest sequence number of s6 is equal to s4, and they are both larger than that of s5.  But because s1 is older than m1, so the smallest sequence number of s6 is smaller than that of s5.
   - s6.smallest_seqno < s5.smallest_seqno < s5.largest_seqno < s6.largest_seqno
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5958

Differential Revision: D18601316

fbshipit-source-id: 5fe54b3c9af52a2e1400728f565e895cde1c7267
2019-11-19 15:09:11 -08:00
tabokie 20b48c6478 Fix blob context when db_iter uses seek (#6051)
Summary:
Fix: when `db_iter` falls back to using seek by `FindValueForCurrentKeyUsingSeek`, `is_blob_` flag is not properly set on encountering BlobIndex.
Also patch existing test for the mentioned code path.
Signed-off-by: tabokie <xy.tao@outlook.com>
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6051

Differential Revision: D18596274

Pulled By: ltamasi

fbshipit-source-id: 8e4714af263b99dc2c379707d50db88fe6799278
2019-11-19 11:39:02 -08:00
Peter Dillinger f059c7d9b9 New Bloom filter implementation for full and partitioned filters (#6007)
Summary:
Adds an improved, replacement Bloom filter implementation (FastLocalBloom) for full and partitioned filters in the block-based table. This replacement is faster and more accurate, especially for high bits per key or millions of keys in a single filter.

Speed

The improved speed, at least on recent x86_64, comes from
* Using fastrange instead of modulo (%)
* Using our new hash function (XXH3 preview, added in a previous commit), which is much faster for large keys and only *slightly* slower on keys around 12 bytes if hashing the same size many thousands of times in a row.
* Optimizing the Bloom filter queries with AVX2 SIMD operations. (Added AVX2 to the USE_SSE=1 build.) Careful design was required to support (a) SIMD-optimized queries, (b) compatible non-SIMD code that's simple and efficient, (c) flexible choice of number of probes, and (d) essentially maximized accuracy for a cache-local Bloom filter. Probes are made eight at a time, so any number of probes up to 8 is the same speed, then up to 16, etc.
* Prefetching cache lines when building the filter. Although this optimization could be applied to the old structure as well, it seems to balance out the small added cost of accumulating 64 bit hashes for adding to the filter rather than 32 bit hashes.

Here's nominal speed data from filter_bench (200MB in filters, about 10k keys each, 10 bits filter data / key, 6 probes, avg key size 24 bytes, includes hashing time) on Skylake DE (relatively low clock speed):

$ ./filter_bench -quick -impl=2 -net_includes_hashing # New Bloom filter
Build avg ns/key: 47.7135
Mixed inside/outside queries...
  Single filter net ns/op: 26.2825
  Random filter net ns/op: 150.459
    Average FP rate %: 0.954651
$ ./filter_bench -quick -impl=0 -net_includes_hashing # Old Bloom filter
Build avg ns/key: 47.2245
Mixed inside/outside queries...
  Single filter net ns/op: 63.2978
  Random filter net ns/op: 188.038
    Average FP rate %: 1.13823

Similar build time but dramatically faster query times on hot data (63 ns to 26 ns), and somewhat faster on stale data (188 ns to 150 ns). Performance differences on batched and skewed query loads are between these extremes as expected.

The only other interesting thing about speed is "inside" (query key was added to filter) vs. "outside" (query key was not added to filter) query times. The non-SIMD implementations are substantially slower when most queries are "outside" vs. "inside". This goes against what one might expect or would have observed years ago, as "outside" queries only need about two probes on average, due to short-circuiting, while "inside" always have num_probes (say 6). The problem is probably the nastily unpredictable branch. The SIMD implementation has few branches (very predictable) and has pretty consistent running time regardless of query outcome.

Accuracy

The generally improved accuracy (re: Issue https://github.com/facebook/rocksdb/issues/5857) comes from a better design for probing indices
within a cache line (re: Issue https://github.com/facebook/rocksdb/issues/4120) and improved accuracy for millions of keys in a single filter from using a 64-bit hash function (XXH3p). Design details in code comments.

Accuracy data (generalizes, except old impl gets worse with millions of keys):
Memory bits per key: FP rate percent old impl -> FP rate percent new impl
6: 5.70953 -> 5.69888
8: 2.45766 -> 2.29709
10: 1.13977 -> 0.959254
12: 0.662498 -> 0.411593
16: 0.353023 -> 0.0873754
24: 0.261552 -> 0.0060971
50: 0.225453 -> ~0.00003 (less than 1 in a million queries are FP)

Fixes https://github.com/facebook/rocksdb/issues/5857
Fixes https://github.com/facebook/rocksdb/issues/4120

Unlike the old implementation, this implementation has a fixed cache line size (64 bytes). At 10 bits per key, the accuracy of this new implementation is very close to the old implementation with 128-byte cache line size. If there's sufficient demand, this implementation could be generalized.

Compatibility

Although old releases would see the new structure as corrupt filter data and read the table as if there's no filter, we've decided only to enable the new Bloom filter with new format_version=5. This provides a smooth path for automatic adoption over time, with an option for early opt-in.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6007

Test Plan: filter_bench has been used thoroughly to validate speed, accuracy, and correctness. Unit tests have been carefully updated to exercise new and old implementations, as well as the logic to select an implementation based on context (format_version).

Differential Revision: D18294749

Pulled By: pdillinger

fbshipit-source-id: d44c9db3696e4d0a17caaec47075b7755c262c5f
2019-11-13 16:44:01 -08:00
anand76 6c7b1a0cc7 Batched MultiGet API for multiple column families (#5816)
Summary:
Add a new API that allows a user to call MultiGet specifying multiple keys belonging to different column families. This is mainly useful for users who want to do a consistent read of keys across column families, with the added performance benefits of batching and returning values using PinnableSlice.

As part of this change, the code in the original multi-column family MultiGet for acquiring the super versions has been refactored into a separate function that can be used by both, the batching and the non-batching versions of MultiGet.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5816

Test Plan:
make check
make asan_check
asan_crash_test

Differential Revision: D18408676

Pulled By: anand1976

fbshipit-source-id: 933e7bec91dd70e7b633be4ff623a1116cc28c8d
2019-11-12 13:52:55 -08:00
anand76 03ce7fb292 Fix a buffer overrun problem in BlockBasedTable::MultiGet (#6014)
Summary:
The calculation in BlockBasedTable::MultiGet for the required buffer length for reading in compressed blocks is incorrect. It needs to take the 5-byte block trailer into account.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6014

Test Plan: Add a unit test DBBasicTest.MultiGetBufferOverrun that fails in asan_check before the fix, and passes after.

Differential Revision: D18412753

Pulled By: anand1976

fbshipit-source-id: 754dfb66be1d5f161a7efdf87be872198c7e3b72
2019-11-11 16:59:15 -08:00
Sagar Vemuri c17384fea4 Cascade TTL Compactions to move expired key ranges to bottom levels faster (#5992)
Summary:
When users use Level-Compaction-with-TTL by setting `cf_options.ttl`, the ttl-expired data could take n*ttl time to reach the bottom level (where n is the number of levels) due to how the `creation_time` table property was calculated for the newly created files during compaction. The creation time of new files was set to a max of all compaction-input-files-creation-times which essentially resulted in resetting the ttl as the key range moves across levels. This behavior is now fixed by changing the `creation_time` to be based on minimum of all compaction-input-files-creation-times; this will cause cascading compactions across levels for the ttl-expired data to move to the bottom level, resulting in getting rid of tombstones/deleted-data faster.

This will help start cascading compactions to move the expired key range to the bottom-most level faster.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5992

Test Plan: `make check`

Differential Revision: D18257883

Pulled By: sagar0

fbshipit-source-id: 00df0bb8d0b7e14d9fc239df2cba8559f3e54cbc
2019-11-11 14:09:01 -08:00
Peter Dillinger aa63abf698 Auto-GarbageCollect on PurgeOldBackups and DeleteBackup (#6015)
Summary:
Only if there is a crash, power failure, or I/O error in
DeleteBackup, shared or private files from the backup might be left
behind that are not cleaned up by PurgeOldBackups or DeleteBackup-- only
by GarbageCollect. This makes the BackupEngine API "leaky by default."
Even if it means a modest performance hit, I think we should make
Delete and Purge do as they say, with ongoing best effort: i.e. future
calls will attempt to finish any incomplete work from earlier calls.

This change does that by having DeleteBackup and PurgeOldBackups do a
GarbageCollect, unless (to minimize performance hit) this BackupEngine
has already done a GarbageCollect and there have been no
deletion-related I/O errors in that GarbageCollect or since then.

Rejected alternative 1: remove meta file last instead of first. This would in theory turn partially deleted backups into corrupted backups, but code changes would be needed to allow the missing files and consider it acceptably corrupt, rather than failing to open the BackupEngine. This might be a reasonable choice, but I mostly rejected it because it doesn't solve the legacy problem of cleaning up existing lingering files.

Rejected alternative 2: use a deletion marker file. If deletion started with creating a file that marks a backup as flagged for deletion, then we could reliably detect partially deleted backups and efficiently finish removing them. In addition to not solving the legacy problem, this could be precarious if there's a disk full situation, and we try to create a new file in order to delete some files. Ugh.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6015

Test Plan: Updated unit tests

Differential Revision: D18401333

Pulled By: pdillinger

fbshipit-source-id: 12944e372ce6809f3f5a4c416c3b321a8927d925
2019-11-08 19:15:35 -08:00
Levi Tamasi f80050fa8f Add file number/oldest referenced blob file number to {Sst,Live}FileMetaData (#6011)
Summary:
The patch exposes the file numbers of the SSTs as well as the oldest blob
files they contain a reference to through the GetColumnFamilyMetaData/
GetLiveFilesMetaData interface.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6011

Test Plan:
Fixed and extended the existing unit tests. (The earlier ColumnFamilyMetaDataTest
wasn't really testing anything because the generated memtables were never
flushed, so the metadata structure was essentially empty.)

Differential Revision: D18361697

Pulled By: ltamasi

fbshipit-source-id: d5ed1d94ac70858b84393c48711441ddfe1251e9
2019-11-07 14:04:16 -08:00
anand76 9836a1fa33 Fix MultiGet crash when no_block_cache is set (#5991)
Summary:
This PR fixes https://github.com/facebook/rocksdb/issues/5975. In ```BlockBasedTable::RetrieveMultipleBlocks()```, we were calling ```MaybeReadBlocksAndLoadToCache()```, which is a no-op if neither uncompressed nor compressed block cache are configured.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5991

Test Plan:
1. Add unit tests that fail with the old code and pass with the new
2. make check and asan_check

Cc spetrunia

Differential Revision: D18272744

Pulled By: anand1976

fbshipit-source-id: e62fa6090d1a6adf84fcd51dfd6859b03c6aebfe
2019-11-07 12:02:21 -08:00
Peter Dillinger 18f57f5ef8 Add new persistent 64-bit hash (#5984)
Summary:
For upcoming new SST filter implementations, we will use a new
64-bit hash function (XXH3 preview, slightly modified). This change
updates hash.{h,cc} for that change, adds unit tests, and out-of-lines
the implementations to keep hash.h as clean/small as possible.

In developing the unit tests, I discovered that the XXH3 preview always
returns zero for the empty string. Zero is problematic for some
algorithms (including an upcoming SST filter implementation) if it
occurs more often than at the "natural" rate, so it should not be
returned from trivial values using trivial seeds. I modified our fork
of XXH3 to return a modest hash of the seed for the empty string.

With hash function details out-of-lines in hash.h, it makes sense to
enable XXH_INLINE_ALL, so that direct calls to XXH64/XXH32/XXH3p
are inlined. To fix array-bounds warnings on some inline calls, I
injected some casts to uintptr_t in xxhash.cc. (Issue reported to Yann.)
Revised: Reverted using XXH_INLINE_ALL for now.  Some Facebook
checks are unhappy about #include on xxhash.cc file. I would
fix that by rename to xxhash_cc.h, but to best preserve history I want
to do that in a separate commit (PR) from the uintptr casts.

Also updated filter_bench for this change, improving the performance
predictability of dry run hashing and adding support for 64-bit hash
(for upcoming new SST filter implementations, minor dead code in the
tool for now).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5984

Differential Revision: D18246567

Pulled By: pdillinger

fbshipit-source-id: 6162fbf6381d63c8cc611dd7ec70e1ddc883fbb8
2019-10-31 16:36:35 -07:00
sdong aa6f7d0995 Support periodic compaction in universal compaction (#5970)
Summary:
Previously, periodic compaction is not supported in universal compaction. Add the support using following approach: if any file is marked as qualified for periodid compaction, trigger a full compaction. If a full compaction is prevented by files being compacted, try to compact the higher levels than files currently being compacted. If in this way we can only compact the last sorted run and none of the file to be compacted qualifies for periodic compaction, skip the compact. This is to prevent the same single level compaction from being executed again and again.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5970

Test Plan: Add several test cases.

Differential Revision: D18147097

fbshipit-source-id: 8ecc308154d9aca96fb192c51fbceba3947550c1
2019-10-31 11:31:37 -07:00
sdong 2a9e5caffe Make FIFO compaction take default 30 days TTL by default (#5987)
Summary:
Right now, by default FIFO compaction has no TTL. We believe that a default TTL of 30 days will be better. With this patch, the default will be changed to 30 days. Default of Options.periodic_compaction_seconds will mean the same as options.ttl. If Options.ttl and Options.periodic_compaction_seconds left default, a default 30 days TTL will be used. If both options are set, the stricter value of the two will be used.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5987

Test Plan: Add an option sanitize test to cover the case.

Differential Revision: D18237935

fbshipit-source-id: a6dcea1f36c3849e13c0a69e413d73ad8eab58c9
2019-10-31 11:13:12 -07:00
Sagar Vemuri 4c9aa30a62 Auto enable Periodic Compactions if a Compaction Filter is used (#5865)
Summary:
- Periodic compactions are auto-enabled if a compaction filter or a compaction filter factory is set, in Level Compaction.
- The default value of `periodic_compaction_seconds` is changed to UINT64_MAX, which lets RocksDB auto-tune periodic compactions as needed. An explicit value of 0 will still work as before ie. to disable periodic compactions completely. For now, on seeing a compaction filter along with a UINT64_MAX value for `periodic_compaction_seconds`, RocksDB will make SST files older than 30 days to go through periodic copmactions.

Some RocksDB users make use of compaction filters to control when their data can be deleted, usually with a custom TTL logic. But it is occasionally possible that the compactions get delayed by considerable time due to factors like low writes to a key range, data reaching bottom level, etc before the TTL expiry. Periodic Compactions feature was originally built to help such cases. Now periodic compactions are auto enabled by default when compaction filters or compaction filter factories are used, as it is generally helpful to all cases to collect garbage.

`periodic_compaction_seconds` is set to a large value, 30 days, in `SanitizeOptions` when RocksDB sees that a `compaction_filter` or `compaction_filter_factory` is used.

This is done only for Level Compaction style.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5865

Test Plan:
- Added a new test `DBCompactionTest.LevelPeriodicCompactionWithCompactionFilters` to make sure that `periodic_compaction_seconds` is set if either `compaction_filter` or `compaction_filter_factory` options are set.
- `COMPILE_WITH_ASAN=1 make check`

Differential Revision: D17659180

Pulled By: sagar0

fbshipit-source-id: 4887b9cf2e53cf2dc93a7b658c6b15e1181217ee
2019-10-29 15:05:51 -07:00
Vijay Nadimpalli 79018ba51b Upgrading version to 6.6.0 on Master (#5965)
Summary:
Upgrading version to 6.6.0 on Master.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5965

Differential Revision: D18119839

Pulled By: vjnadimpalli

fbshipit-source-id: 4adbcbb82b108d2f626e88c786453baad8455f4e
2019-10-28 13:14:45 -07:00
Yanqin Jin 2309fd63bf Update column families' log number altogether after flushing during recovery (#5856)
Summary:
A bug occasionally shows up in crash test, and https://github.com/facebook/rocksdb/issues/5851 reproduces it.
The bug can surface in the following way.
1. Database has multiple column families.
2. Between one DB restart, the last log file is corrupted in the middle (not the tail)
3. During restart, DB crashes between flushing between two column families.

Then DB will fail to be opened again with error "SST file is ahead of WALs".
Solution is to update the log number associated with each column family altogether after flushing all column families' memtables. The version edits should be written to a new MANIFEST. Only after writing to all these version edits succeed does RocksDB (atomically) points the CURRENT file to the new MANIFEST.

Test plan (on devserver):
```
$make all && make check
```
Specifically
```
$make db_test2
$./db_test2 --gtest_filter=DBTest2.CrashInRecoveryMultipleCF
```
Also checked for compatibility as follows.
Use this branch, run DBTest2.CrashInRecoveryMultipleCF and preserve the db directory.
Then checkout 5.4, build ldb, and dump the MANIFEST.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5856

Differential Revision: D17620818

Pulled By: riversand963

fbshipit-source-id: b52ce5969c9a8052cacec2bd805fcfb373589039
2019-10-24 18:29:30 -07:00
Levi Tamasi f7e7b34ebe Propagate SST and blob file numbers through the EventListener interface (#5962)
Summary:
This patch adds a number of new information elements to the FlushJobInfo and
CompactionJobInfo structures that are passed to EventListeners via the
OnFlush{Begin, Completed} and OnCompaction{Begin, Completed} callbacks.
Namely, for flushes, the file numbers of the new SST and the oldest blob file it
references are propagated. For compactions, the new pieces of information are
the file number, level, and the oldest blob file referenced by each compaction
input and output file.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5962

Test Plan:
Extended the EventListener unit tests with logic that checks that these information
elements are correctly propagated from the corresponding FileMetaData.

Differential Revision: D18095568

Pulled By: ltamasi

fbshipit-source-id: 6874359a6aadb53366b5fe87adcb2f9bd27a0a56
2019-10-24 14:44:15 -07:00
Peter Dillinger 27a124571f Fix memory leak on error opening PlainTable (#5951)
Summary:
Several error paths in opening of a plain table would leak memory. PR https://github.com/facebook/rocksdb/issues/5940 opened the leak to one more error path, which happens to have been (mistakenly) exercised by CuckooTableDBTest.AdaptiveTable. That test has been fixed, and the exercising of
plain table error cases (more than before) has been added as BadOptions1 and BadOptions2
to PlainTableDBTest. This effectively moved the memory leak to plain_table_db_test.

Also here is a cheap fix for the memory leak, without (yet?) changing the signature of
ReadTableProperties. This fixes ASAN on unit tests.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5951

Test Plan: make COMPILE_WITH_ASAN=1 check

Differential Revision: D18051940

Pulled By: pdillinger

fbshipit-source-id: e2952930c09a2b46c4f1ff09818c5090426929de
2019-10-21 16:53:06 -07:00
sdong a0cd920026 LevelIterator to avoid gap after prefix bloom filters out a file (#5861)
Summary:
Right now, when LevelIterator::Seek() is called, when a file is filtered out by prefix bloom filter, the position is put to the beginning of the next file. This is a confusing internal interface because many keys in the levels are skipped. Avoid this behavior by checking the key of the next file against the seek key, and invalidate the whole iterator if the prefix doesn't match.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5861

Test Plan: Add a new unit test to validate the behavior; run all exsiting tests; run crash_test

Differential Revision: D17918213

fbshipit-source-id: f06b47d937c7cc8919001f18dcc3af5b28c9cdac
2019-10-21 11:40:57 -07:00
Levi Tamasi 69bd8a2859 Update HISTORY.md with recent BlobDB adjacent changes
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/5939

Differential Revision: D18009096

Pulled By: ltamasi

fbshipit-source-id: 032a48a302f9da38aecf4055b5a8d4e1dffd9dc7
2019-10-18 10:24:23 -07:00
Yi Wu 1f9d7c0f54 Fix OnFlushCompleted fired before flush result write to MANIFEST (#5908)
Summary:
When there are concurrent flush job on the same CF, `OnFlushCompleted` can be called before the flush result being install to LSM. Fixing the issue by passing `FlushJobInfo` through `MemTable`, and the thread who commit the flush result can fetch the `FlushJobInfo` and fire `OnFlushCompleted` on behave of the thread actually writing the SST.

Fix https://github.com/facebook/rocksdb/issues/5892
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5908

Test Plan: Add new test. The test will fail without the fix.

Differential Revision: D17916144

Pulled By: riversand963

fbshipit-source-id: e18df67d9533b5baee52ae3605026cdeb05cbe10
2019-10-16 10:40:23 -07:00
Maysam Yabandeh 2c9e9f2a59 Update HISTORY for SeekForPrev bug fix (#5925)
Summary:
Update history for the bug fix in https://github.com/facebook/rocksdb/pull/5907
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5925

Differential Revision: D17952605

Pulled By: maysamyabandeh

fbshipit-source-id: 609afcbb2e4087f9153822c4d11193a75a7b0e7a
2019-10-16 07:59:26 -07:00
Yanqin Jin 6febfd8451 OnTableFileCreationCompleted use "(nil)" for empty file during flush (#5905)
Summary:
Compaction can call OnTableFileCreationCompleted(). If file is empty, "(nil)"
is used as the file name.
Do the same for flush.

Test plan (dev server):
```
make all
make check
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5905

Differential Revision: D17883285

Pulled By: riversand963

fbshipit-source-id: 6565884adbb00e8023d88b17dfb3b6eb92220b59
2019-10-14 09:54:10 -07:00
Yanqin Jin 167cdc9f17 Support custom env in sst_dump (#5845)
Summary:
This PR allows for the creation of custom env when using sst_dump. If
the user does not set options.env or set options.env to nullptr, then sst_dump
will automatically try to create a custom env depending on the path to the sst
file or db directory. In order to use this feature, the user must call
ObjectRegistry::Register() beforehand.

Test Plan (on devserver):
```
$make all && make check
```
All tests must pass to ensure this change does not break anything.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5845

Differential Revision: D17678038

Pulled By: riversand963

fbshipit-source-id: 58ecb4b3f75246d52b07c4c924a63ee61c1ee626
2019-10-08 19:19:12 -07:00
Tomas Kolda e3a93c9ee1 Fix crash when background task fails (#5879)
Summary:
Fixing crash. Full story in issue: https://github.com/facebook/rocksdb/issues/5878
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5879

Differential Revision: D17812299

Pulled By: anand1976

fbshipit-source-id: 14e5a4fc502ade974583da9692d0ed6e5014613a
2019-10-08 14:20:01 -07:00
sdong 846e05005d Revert "Merging iterator to avoid child iterator reseek for some cases (#5286)" (#5871)
Summary:
This reverts commit 9fad3e21eb.

Iterator verification in stress tests sometimes fail for assertion
table/block_based/block_based_table_reader.cc:2973: void rocksdb::BlockBasedTableIterator<TBlockIter, TValue>::FindBlockForward() [with TBlockIter = rocksdb::DataBlockIter; TValue = rocksdb::Slice]: Assertion `!next_block_is_out_of_bound || user_comparator_.Compare(*read_options_.iterate_upper_bound, index_iter_->user_key()) <= 0' failed.

It is likely to be linked to https://github.com/facebook/rocksdb/pull/5286 together with https://github.com/facebook/rocksdb/pull/5468 as the former PR makes some child iterator's seek being avoided, so that upper bound condition fails to be updated there. Strictly speaking, the former PR was merged before the latter one, but the latter one feels a more important improvement so I choose to revert the former one for now.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5871

Differential Revision: D17689196

fbshipit-source-id: 4ded5be68f67bee2782d31a29cb72ea68f59dd8c
2019-10-01 11:22:41 -07:00
Yanqin Jin ae45835703 Add TryCatchUpWithPrimary to StackableDB (#5855)
Summary:
as title.

Test Plan (on devserver):
```
$make all && make check
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5855

Differential Revision: D17615125

Pulled By: riversand963

fbshipit-source-id: bd6ed8cf59eafff41f0d1fc044f39e8f3573172a
2019-09-26 17:00:55 -07:00
Maysam Yabandeh 6652c94f59 Fix a bug in format_version 3 + partition filters + prefix search (#5835)
Summary:
Partitioned filters make use of a top-level index to find the partition in which the filter resides. The top-level index has a key per partition. The key is guaranteed to be larger or equal than any key in that partition. When used with format_version 3, which excludes the sequence number form index keys, the separator key in the index could be equal to the prefix of the keys in the next partition. In this way, when searching for the key, the top-level index will lead us to the previous partition, which has no key with that prefix. The prefix bloom test thus returns false, although the prefix exists in the bloom of the next partition.
The patch fixes that by a hack: It always adds the prefix of the first key of the next partition to the bloom of the current partition. In this way, in the corner cases that the index will lead us to the previous partition, we still can find the bloom filter there.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5835

Differential Revision: D17513585

Pulled By: maysamyabandeh

fbshipit-source-id: e2d1ff26c759e6e03875c4d57f4228316ecf50e9
2019-09-24 14:00:11 -07:00
WangQingping 02554b3c38 Update HISTORY.md for stop manual compaction
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/5837

Differential Revision: D17529753

fbshipit-source-id: 98bbf22c690384b2f440286151dffdaaa744e97c
2019-09-23 15:03:39 -07:00
Maysam Yabandeh 6ec6a4a9a4 Remove snap_refresh_nanos option (#5826)
Summary:
The snap_refresh_nanos option didn't bring much benefit. Remove the feature to simplify the code.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5826

Differential Revision: D17467147

Pulled By: maysamyabandeh

fbshipit-source-id: 4f950b046990d0d1292d7fc04c2ccafaf751c7f0
2019-09-18 20:26:04 -07:00
Maysam Yabandeh 638d239507 Charge block cache for cache internal usage (#5797)
Summary:
For our default block cache, each additional entry has extra memory overhead. It include LRUHandle (72 bytes currently) and the cache key (two varint64, file id and offset). The usage is not negligible. For example for block_size=4k, the overhead accounts for an extra 2% memory usage for the cache. The patch charging the cache for the extra usage, reducing untracked memory usage outside block cache. The feature is enabled by default and can be disabled by passing kDontChargeCacheMetadata to the cache constructor.
This PR builds up on https://github.com/facebook/rocksdb/issues/4258
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5797

Test Plan:
- Existing tests are updated to either disable the feature when the test has too much dependency on the old way of accounting the usage or increasing the cache capacity to account for the additional charge of metadata.
- The Usage tests in cache_test.cc are augmented to test the cache usage under kFullChargeCacheMetadata.

Differential Revision: D17396833

Pulled By: maysamyabandeh

fbshipit-source-id: 7684ccb9f8a40ca595e4f5efcdb03623afea0c6f
2019-09-16 15:26:21 -07:00
Peter (Stig) Edwards 54fc617891 Mention sst_dump cmd=recompress changes (#5807)
Summary:
As requested by siying in https://github.com/facebook/rocksdb/pull/5791#issuecomment-531417468
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5807

Differential Revision: D17399349

fbshipit-source-id: 5986c3894f356becd393fee0f1aeadcd9affc798
2019-09-16 10:45:03 -07:00
Lingjing You 9ba88a1e5d Update history.md for option memtable_insert_hint_per_batch (#5799)
Summary:
Update history.md for option memtable_insert_hint_per_batch
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5799

Differential Revision: D17369186

fbshipit-source-id: 71d82f9d99d9a52d1475d1b0153670957b6111e9
2019-09-13 10:51:32 -07:00
Ronak Sisodia 27f516acc8 Update HISTORY.md for option to make write group size configurable (#5798)
Summary:
Update HISTORY.md for option to make write group size configurable .
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5798

Differential Revision: D17369062

fbshipit-source-id: 390a3fa0b01675e91879486a729cf2cc7624d106
2019-09-13 10:43:09 -07:00
Peter Dillinger b55b2f45d0 Faster new DynamicBloom implementation (for memtable) (#5762)
Summary:
Since DynamicBloom is now only used in-memory, we're free to
change it without schema compatibility issues. The new implementation
is drawn from (with manifest permission)
303542a767/bloom_simulation_tests/foo.cc (L613)

This has several speed advantages over the prior implementation:
* Uses fastrange instead of %
* Minimum logic to determine first (and all) probed memory addresses
* (Major) Two probes per 64-bit memory fetch/write.
* Very fast and effective (murmur-like) hash expansion/re-mixing. (At
least on recent CPUs, integer multiplication is very cheap.)

While a Bloom filter with 512-bit cache locality has about a 1.15x FP
rate penalty (e.g. 0.84% to 0.97%), further restricting to two probes
per 64 bits incurs an additional 1.12x FP rate penalty (e.g. 0.97% to
1.09%). Nevertheless, the unit tests show no "mediocre" FP rate samples,
unlike the old implementation with more erratic FP rates.

Especially for the memtable, we expect speed to outweigh somewhat higher
FP rates. For example, a negative table query would have to be 1000x
slower than a BF query to justify doubling BF query time to shave 10% off
FP rate (working assumption around 1% FP rate). While that seems likely
for SSTs, my data suggests a speed factor of roughly 50x for the memtable
(vs. BF; ~1.5% lower write throughput when enabling memtable Bloom
filter, after this change).  Thus, it's probably not worth even 5% more
time in the Bloom filter to shave off 1/10th of the Bloom FP rate, or 0.1%
in absolute terms, and it's probably at least 20% slower to recoup that
much FP rate from this new implementation. Because of this, we do not see
a need for a 'locality' option that affects the MemTable Bloom filter
and have decoupled the MemTable Bloom filter from Options::bloom_locality.

Note that just 3% more memory to the Bloom filter (10.3 bits per key vs.
just 10) is able to make up for the ~12% FP rate drop in the new
implementation:

[] # Nearly "ideal" FP-wise but reasonably fast cache-local implementation
[~/wormhashing/bloom_simulation_tests] ./foo_gcc_IMPL_CACHE_WORM64_FROM32_any.out 10000000 6 10 $RANDOM 100000000
./foo_gcc_IMPL_CACHE_WORM64_FROM32_any.out time: 3.29372 sampled_fp_rate: 0.00985956 ...

[] # Close match to this new implementation
[~/wormhashing/bloom_simulation_tests] ./foo_gcc_IMPL_CACHE_MUL64_BLOCK_FROM32_any.out 10000000 6 10.3 $RANDOM 100000000
./foo_gcc_IMPL_CACHE_MUL64_BLOCK_FROM32_any.out time: 2.10072 sampled_fp_rate: 0.00985655 ...

[] # Old locality=1 implementation
[~/wormhashing/bloom_simulation_tests] ./foo_gcc_IMPL_CACHE_ROCKSDB_DYNAMIC_any.out 10000000 6 10 $RANDOM 100000000
./foo_gcc_IMPL_CACHE_ROCKSDB_DYNAMIC_any.out time: 3.95472 sampled_fp_rate: 0.00988943 ...

Also note the dramatic speed improvement vs. alternatives.

--

Performance unit test: DynamicBloomTest.concurrent_with_perf is updated
to report more precise timing data. (Measure running time of each
thread, not just longest running thread, etc.) Results averaged over
various sizes enabled with --enable_perf and 20 runs each; old dynamic
bloom refers to locality=1, the faster of the old:

old dynamic bloom, avg add latency = 65.6468
new dynamic bloom, avg add latency = 44.3809
old dynamic bloom, avg query latency = 50.6485
new dynamic bloom, avg query latency = 43.2186
old avg parallel add latency = 41.678
new avg parallel add latency = 24.5238
old avg parallel hit latency = 14.6322
new avg parallel hit latency = 12.3939
old avg parallel miss latency = 16.7289
new avg parallel miss latency = 12.2134

Tested on a dedicated 64-bit production machine at Facebook. Significant
improvement all around.

Despite now using std::atomic<uint64_t>, quick before-and-after test on
a 32-bit machine (Intel Atom N270, released 2008) shows no regression in
performance, in some cases modest improvement.

--

Performance integration test (synthetic): with DEBUG_LEVEL=0, used
TEST_TMPDIR=/dev/shm ./db_bench --benchmarks=fillrandom,readmissing,readrandom,stats --num=2000000
and optionally with -memtable_whole_key_filtering -memtable_bloom_size_ratio=0.01
300 runs each configuration.

Write throughput change by enabling memtable bloom:
Old locality=0: -3.06%
Old locality=1: -2.37%
New:            -1.50%
conclusion -> seems to substantially close the gap

Readmissing throughput change by enabling memtable bloom:
Old locality=0: +34.47%
Old locality=1: +34.80%
New:            +33.25%
conclusion -> maybe a small new penalty from FP rate

Readrandom throughput change by enabling memtable bloom:
Old locality=0: +31.54%
Old locality=1: +31.13%
New:            +30.60%
conclusion -> maybe also from FP rate (after memtable flush)

--

Another conclusion we can draw from this new implementation is that the
existing 32-bit hash function is not inherently crippling the Bloom
filter speed or accuracy, below about 5 million keys. For speed, the
implementation is essentially the same whether starting with 32-bits or
64-bits of hash; it just determines whether the first multiplication
after fastrange is a pseudorandom expansion or needed re-mix. Note that
this multiplication can occur while memory is fetching.

For accuracy, in a standard configuration, you need about 5 million
keys before you have about a 1.1x FP penalty due to using a
32-bit hash vs. 64-bit:

[~/wormhashing/bloom_simulation_tests] ./foo_gcc_IMPL_CACHE_MUL64_BLOCK_FROM32_any.out $((5 * 1000 * 1000 * 10)) 6 10 $RANDOM 100000000
./foo_gcc_IMPL_CACHE_MUL64_BLOCK_FROM32_any.out time: 2.52069 sampled_fp_rate: 0.0118267 ...
[~/wormhashing/bloom_simulation_tests] ./foo_gcc_IMPL_CACHE_MUL64_BLOCK_any.out $((5 * 1000 * 1000 * 10)) 6 10 $RANDOM 100000000
./foo_gcc_IMPL_CACHE_MUL64_BLOCK_any.out time: 2.43871 sampled_fp_rate: 0.0109059
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5762

Differential Revision: D17214194

Pulled By: pdillinger

fbshipit-source-id: ad9da031772e985fd6b62a0e1db8e81892520595
2019-09-05 14:59:25 -07:00
Affan Dar 229e6fbe0e Adding DB::GetCurrentWalFile() API as a repliction/backup helper (#5765)
Summary:
Adding a light weight API to get last live WAL file name and size. Meant to be used as a helper for backup/restore tooling in a larger ecosystem such as MySQL with a MyRocks storage engine.

Specifically within MySQL's backup/restore mechanism, this call can be made with a write lock on the mysql db to get a transactionally consistent snapshot of the current WAL file position along with other non-rocksdb log/data files.

Without this, the alternative would be to take the aforementioned lock, scan the WAL dir for all files, find the last file and note its exact size as the rocksdb 'checkpoint'.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5765

Differential Revision: D17172717

Pulled By: affandar

fbshipit-source-id: f2fabafd4c0e6fc45f126670c8c88a9f84cb8a37
2019-09-04 12:10:17 -07:00