Commit Graph

429 Commits

Author SHA1 Message Date
Andrey Zagrebin
2c7422aa65 Summary:
This PR addresses issue #3865 and implements the following approach to fix it:
 - adds `MergeContext::GetOperandsDirectionForward` and `MergeContext::GetOperandsDirectionBackward` to query merge operands in a specific order
 - `MergeContext::GetOperands` becomes a shortcut for `MergeContext::GetOperandsDirectionForward`
 - pass `MergeContext::GetOperandsDirectionBackward` to `MergeOperator::ShouldMerge` and document the order
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4266

Differential Revision: D9360750

Pulled By: sagar0

fbshipit-source-id: 20cb73ff017760b062ecdcf4382560767086e092
2018-08-21 17:57:45 -07:00
Yi Wu
086bae0599 Bump version to 5.15.5 and update history 2018-08-16 16:45:05 -07:00
Yanqin Jin
e28e2fff13 Bump version and update history 2018-08-11 21:52:41 -07:00
Maysam Yabandeh
3b66d4b617 Fix wrong partitioned index size recorded in properties block (#4259)
Summary:
After refactoring in https://github.com/facebook/rocksdb/pull/4158 the properties block is written after the index block. This breaks the existing logic in estimating the index size in partitioned indexes. The patch fixes that by using the accurate index block size, which is available since by the time we write the properties block, the index block is already written.
The patch also fixes an issue in estimating the partition size with format_version=3 which was resulting into partitions smaller than the configured metadata_block_size.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4259

Differential Revision: D9274454

Pulled By: maysamyabandeh

fbshipit-source-id: c82d045505cca3e7ed1a44ee1eaa26e4f25a4272
2018-08-10 17:04:39 -07:00
Yanqin Jin
421be4af42 Bump version and update HISTORY.md 2018-08-09 09:35:24 -07:00
Andrew Kryczka
f9fc1f483a bump version and update history 2018-08-01 15:28:24 -07:00
Yi Wu
decf7e52b0 Fix write get stuck when pipelined write is enabled (#4143)
Summary:
Fix the issue when pipelined write is enabled, writers can get stuck indefinitely and not able to finish the write. It can show with the following example: Assume there are 4 writers W1, W2, W3, W4 (W1 is the first, W4 is the last).

T1: all writers pending in WAL writer queue:
WAL writer queue: W1, W2, W3, W4
memtable writer queue: empty

T2. W1 finish WAL writer and move to memtable writer queue:
WAL writer queue: W2, W3, W4,
memtable writer queue: W1

T3. W2 and W3 finish WAL write as a batch group. W2 enter ExitAsBatchGroupLeader and move the group to memtable writer queue, but before wake up next leader.
WAL writer queue: W4
memtable writer queue: W1, W2, W3

T4. W1, W2, W3 finish memtable write as a batch group. Note that W2 still in the previous ExitAsBatchGroupLeader, although W1 have done memtable write for W2.
WAL writer queue: W4
memtable writer queue: empty

T5. The thread corresponding to W3 create another writer W3' with the same address as W3.
WAL writer queue: W4, W3'
memtable writer queue: empty

T6. W2 continue with ExitAsBatchGroupLeader. Because the address of W3' is the same as W3, the last writer in its group, it thinks there are no pending writers, so it reset newest_writer_ to null, emptying the queue. W4 and W3' are deleted from the queue and will never be wake up.

The issue exists since pipelined write was introduced in 5.5.0.

Closes #3704
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4143

Differential Revision: D8871599

Pulled By: yiwu-arbug

fbshipit-source-id: 3502674e51066a954a0660257e24ac588f815e2a
2018-07-18 10:18:50 -07:00
Yanqin Jin
be91970d59 Release 5.15. 2018-07-17 17:37:19 -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
Sagar Vemuri
991120fa10 Allow ttl to be changed dynamically (#4133)
Summary:
Allow ttl to be changed dynamically.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4133

Differential Revision: D8845440

Pulled By: sagar0

fbshipit-source-id: c8c87ae643b3a8c4123e4c037c4645efc094a2d3
2018-07-16 14:27:53 -07:00
Siying Dong
17027aeffc Change default value of bytes_max_delete_chunk to 0 in NewSstFileManager() (#4092)
Summary:
Now by default, with NewSstFileManager, checkpoints may be corrupted. Disable this feature to avoid this issue.
Closes https://github.com/facebook/rocksdb/pull/4092

Differential Revision: D8729856

Pulled By: siying

fbshipit-source-id: 914c321d6eaf52d8c5981171322d85dd29088307
2018-07-03 17:57:37 -07:00
Zhichao Cao
1f6efabe23 Add bottommost_compression_opts to for bottommost_compression (#3985)
Summary:
…ression

 For `CompressionType` we have options `compression` and `bottommost_compression`. Thus, to make the compression options consitent with the compression type when bottommost_compression is enabled, we add the bottommost_compression_opts
Closes https://github.com/facebook/rocksdb/pull/3985

Reviewed By: riversand963

Differential Revision: D8385911

Pulled By: zhichao-cao

fbshipit-source-id: 07bc533dd61bcf1cef5927d8d62901c13d38d5fc
2018-06-27 17:42:38 -07:00
Maysam Yabandeh
235ab9dd32 Pin mmap files in ReadOnlyDB (#4053)
Summary:
https://github.com/facebook/rocksdb/pull/3881 fixed a bug where PinnableSlice pin mmap files which could be deleted with background compaction. This is however a non-issue for ReadOnlyDB when there is no compaction running and max_open_files is -1. This patch reenables the pinning feature for that case.
Closes https://github.com/facebook/rocksdb/pull/4053

Differential Revision: D8662546

Pulled By: maysamyabandeh

fbshipit-source-id: 402962602eb0f644e17822748332999c3af029fd
2018-06-27 17:13:34 -07:00
Nikhil Benesch
17339dc2f3 Add table property tracking number of range deletions (#4016)
Summary:
Add a new table property, rocksdb.num.range-deletions, which tracks the
number of range deletions in a block-based table. Range deletions are no
longer counted in rocksdb.num.entries; as discovered in PR #3778, there
are various code paths that implicitly assume that rocksdb.num.entries
counts only true keys, not range deletions.

/cc ajkr nvanbenschoten
Closes https://github.com/facebook/rocksdb/pull/4016

Differential Revision: D8527575

Pulled By: ajkr

fbshipit-source-id: 92e7edbe78fda53756a558013c9fb496e7764fd7
2018-06-26 20:27:35 -07:00
Maysam Yabandeh
80ade9ad83 Pin top-level index on partitioned index/filter blocks (#4037)
Summary:
Top-level index in partitioned index/filter blocks are small and could be pinned in memory. So far we use that by cache_index_and_filter_blocks to false. This however make it difficult to keep account of the total memory usage. This patch introduces pin_top_level_index_and_filter which in combination with cache_index_and_filter_blocks=true keeps the top-level index in cache and yet pinned them to avoid cache misses and also cache lookup overhead.
Closes https://github.com/facebook/rocksdb/pull/4037

Differential Revision: D8596218

Pulled By: maysamyabandeh

fbshipit-source-id: 3a5f7f9ca6b4b525b03ff6bd82354881ae974ad2
2018-06-22 15:27:46 -07:00
Sagar Vemuri
7103559f49 Improve direct IO range scan performance with readahead (#3884)
Summary:
This PR extends the improvements in #3282 to also work when using Direct IO.
We see **4.5X performance improvement** in seekrandom benchmark doing long range scans, when using direct reads, on flash.

**Description:**
This change improves the performance of iterators doing long range scans (e.g. big/full index or table scans in MyRocks) by using readahead and prefetching additional data on each disk IO, and storing in a local buffer. This prefetching is automatically enabled on noticing more than 2 IOs for the same table file during iteration. The readahead size starts with 8KB and is exponentially increased on each additional sequential IO, up to a max of 256 KB. This helps in cutting down the number of IOs needed to complete the range scan.

**Implementation Details:**
- Used `FilePrefetchBuffer` as the underlying buffer to store the readahead data. `FilePrefetchBuffer` can now take file_reader, readahead_size and max_readahead_size as input to the constructor, and automatically do readahead.
- `FilePrefetchBuffer::TryReadFromCache` can now call `FilePrefetchBuffer::Prefetch` if readahead is enabled.
- `AlignedBuffer` (which is the underlying store for `FilePrefetchBuffer`) now takes a few additional args in `AlignedBuffer::AllocateNewBuffer` to allow copying data from the old buffer.
- Made sure not to re-read partial chunks of data that were already available in the buffer, from device again.
- Fixed a couple of cases where `AlignedBuffer::cursize_` was not being properly kept up-to-date.

**Constraints:**
- Similar to #3282, this gets currently enabled only when ReadOptions.readahead_size = 0 (which is the default value).
- Since the prefetched data is stored in a temporary buffer allocated on heap, this could increase the memory usage if you have many iterators doing long range scans simultaneously.
- Enabled only for user reads, and disabled for compactions. Compaction reads are controlled by the options `use_direct_io_for_flush_and_compaction` and `compaction_readahead_size`, and the current feature takes precautions not to mess with them.

**Benchmarks:**
I used the same benchmark as used in #3282.
Data fill:
```
TEST_TMPDIR=/data/users/$USER/benchmarks/iter ./db_bench -benchmarks=fillrandom -num=1000000000 -compression_type="none" -level_compaction_dynamic_level_bytes
```

Do a long range scan: Seekrandom with large number of nexts
```
TEST_TMPDIR=/data/users/$USER/benchmarks/iter ./db_bench -benchmarks=seekrandom -use_direct_reads -duration=60 -num=1000000000 -use_existing_db -seek_nexts=10000 -statistics -histogram
```

```
Before:
seekrandom   :   37939.906 micros/op 26 ops/sec;   29.2 MB/s (1636 of 1999 found)
With this change:
seekrandom   :   8527.720 micros/op 117 ops/sec;  129.7 MB/s (6530 of 7999 found)
```
~4.5X perf improvement. Taken on an average of 3 runs.
Closes https://github.com/facebook/rocksdb/pull/3884

Differential Revision: D8082143

Pulled By: sagar0

fbshipit-source-id: 4d7a8561cbac03478663713df4d31ad2620253bb
2018-06-21 11:13:08 -07:00
Maysam Yabandeh
28a9d8910b Fix the bug with duplicate prefix in partition filters (#4024)
Summary:
https://github.com/facebook/rocksdb/pull/3764 introduced an optimization feature to skip duplicate prefix entires in full bloom filters. Unfortunately it also introduces a bug in partitioned full filters, where the duplicate prefix should still be inserted if it is in a new partition. The patch fixes the bug by resetting the duplicate detection logic each time a partition is cut.
This bug could result into false negatives, which means that DB could skip an existing key.
Closes https://github.com/facebook/rocksdb/pull/4024

Differential Revision: D8518866

Pulled By: maysamyabandeh

fbshipit-source-id: 044f4d988e606a330ecafd8c79daceb68b8796bf
2018-06-19 14:12:46 -07:00
Andrew Kryczka
fea2b1dfb2 Copy Get() result when file reads use mmap
Summary:
For iterator reads, a `SuperVersion` is pinned to preserve a snapshot of SST files, and `Block`s are pinned to allow `key()` and `value()` to return pointers directly into a RocksDB memory region. This works for both non-mmap reads, where the block owns the memory region, and mmap reads, where the file owns the memory region.

For point reads with `PinnableSlice`, only the `Block` object is pinned. This works for non-mmap reads because the block owns the memory region, so even if the file is deleted after compaction, the memory region survives. However, for mmap reads, file deletion causes the memory region to which the `PinnableSlice` refers to be unmapped.   The result is usually a segfault upon accessing the `PinnableSlice`, although sometimes it returned wrong results (I repro'd this a bunch of times with `db_stress`).

This PR copies the value into the `PinnableSlice` when it comes from mmap'd memory. We can tell whether the `Block` owns its memory using `Block::cachable()`, which is unset when reads do not use the provided buffer as is the case with mmap file reads. When that is false we ensure the result of `Get()` is copied.

This feels like a short-term solution as ideally we'd have the `PinnableSlice` pin the mmap'd memory so we can do zero-copy reads. It seemed hard so I chose this approach to fix correctness in the meantime.
Closes https://github.com/facebook/rocksdb/pull/3881

Differential Revision: D8076288

Pulled By: ajkr

fbshipit-source-id: 31d78ec010198723522323dbc6ea325122a46b08
2018-06-01 16:57:58 -07:00
maoyouxiang
a35451eaa4 fix deadlock with enable_pipelined_write=true and max_successive_merges > 0
Summary:
fix this https://github.com/facebook/rocksdb/issues/3916
Closes https://github.com/facebook/rocksdb/pull/3923

Differential Revision: D8215192

Pulled By: yiwu-arbug

fbshipit-source-id: a4c2f839a91d92dc70906d2b7c6de0fe014a2422
2018-05-31 11:13:14 -07:00
Maysam Yabandeh
402b7aa07f Exclude seq from index keys
Summary:
Index blocks have the same format as data blocks. The keys therefore similarly to the keys in the data blocks are internal keys, which means that in addition to the user key it also has 8 bytes that encodes sequence number and value type. This extra 8 bytes however is not necessary in index blocks since the index keys act as an separator between two data blocks. The only exception is when the last key of a block and the first key of the next block share the same user key, in which the sequence number is required to act as a separator.
The patch excludes the sequence from index keys only if the above special case does not happen for any of the index keys. It then records that in the property block. The reader looks at the property block to see if it should expect sequence numbers in the keys of the index block.s
Closes https://github.com/facebook/rocksdb/pull/3894

Differential Revision: D8118775

Pulled By: maysamyabandeh

fbshipit-source-id: 915479f028b5799ca91671d67455ecdefbd873bd
2018-05-25 18:42:43 -07:00
Yi Wu
bc7e8d472e LRUCache midpoint insertion
Summary:
Implement midpoint insertion strategy where new blocks will be insert to the middle of LRU list, then move the head on the first hit in cache.
Closes https://github.com/facebook/rocksdb/pull/3877

Differential Revision: D8100895

Pulled By: yiwu-arbug

fbshipit-source-id: f4bd83cb8be469e5d02072cfc8bd66011391f3da
2018-05-24 15:57:33 -07:00
Andrew Kryczka
01bcc34896 Introduce library-independent default compression level
Summary:
Previously we were using -1 as the default for every library, which was legacy from our zlib options. That worked for a while, but after zstd introduced a146ee04ae, it started giving poor compression ratios by default in zstd.

This PR adds a constant to RocksDB public API, `CompressionOptions::kDefaultCompressionLevel`, which will get translated to the default value specific to the compression library being used in "util/compression.h". The constant uses a number that appears to be larger than any library's maximum compression level.
Closes https://github.com/facebook/rocksdb/pull/3895

Differential Revision: D8125780

Pulled By: ajkr

fbshipit-source-id: 2db157a89118cd4f94577c2f4a0a5ff31c8391c6
2018-05-23 18:42:08 -07:00
Zhongyi Xie
c3ebc75843 Move prefix_extractor to MutableCFOptions
Summary:
Currently it is not possible to change bloom filter config without restart the db, which is causing a lot of operational complexity for users.
This PR aims to make it possible to dynamically change bloom filter config.
Closes https://github.com/facebook/rocksdb/pull/3601

Differential Revision: D7253114

Pulled By: miasantreble

fbshipit-source-id: f22595437d3e0b86c95918c484502de2ceca120c
2018-05-21 14:43:11 -07:00
Andrew Kryczka
508a09fd62 Print histogram count and sum in statistics string
Summary:
Previously it only printed percentiles, even though our histogram keeps track of count and sum (and more). There have been many times we want to know more than the percentiles. For example, we currently want sum of "rocksdb.compression.times.nanos" and sum of "rocksdb.decompression.times.nanos", which would allow us to know the relative cost of compression vs decompression.

This PR adds count and sum to the string printed by `StatisticsImpl::ToString`. This is a bit risky as there are definitely parsers assuming the old format. I will mention it in HISTORY.md and hope for the best...
Closes https://github.com/facebook/rocksdb/pull/3863

Differential Revision: D8038831

Pulled By: ajkr

fbshipit-source-id: 0465b72e4b0cbf18ef965f4efe402601d16d5b5c
2018-05-21 11:12:47 -07:00
Siying Dong
17af09fcce Implement key shortening functions in ReverseBytewiseComparator
Summary:
Right now ReverseBytewiseComparator::FindShortestSeparator() doesn't really shorten key, and ReverseBytewiseComparator::FindShortestSuccessor() seems to return wrong results. The code is confusing too as it uses BytewiseComparatorImpl::FindShortestSeparator() but the function actually won't do anything if the the first key is larger than the second.

Implement ReverseBytewiseComparator::FindShortestSeparator() and override ReverseBytewiseComparator::FindShortestSuccessor() to be empty.
Closes https://github.com/facebook/rocksdb/pull/3836

Differential Revision: D7959762

Pulled By: siying

fbshipit-source-id: 93acb621c16ce6f23e087ae4e19f7d84d1254683
2018-05-17 18:27:16 -07:00
Fosco Marotto
fa43948cbc Update HISTORY and version for upcoming 5.14
Summary: Closes https://github.com/facebook/rocksdb/pull/3866

Differential Revision: D8043563

Pulled By: gfosco

fbshipit-source-id: da4af20e604534602ac0e07943135513fd9a9f53
2018-05-17 14:27:17 -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
Andrew Kryczka
3d7dc75b36 Bottommost level-based compactions in bottom-pri pool
Summary:
This feature was introduced for universal compaction in cc01985d. At that point we thought it'd be used only to prevent long-running universal full compactions from blocking short-lived upper-level compactions. Now we have a level compaction user who could benefit from it since they use more expensive compression algorithm in the bottom level. So enable it for level.
Closes https://github.com/facebook/rocksdb/pull/3835

Differential Revision: D7957179

Pulled By: ajkr

fbshipit-source-id: 177285d2cef3b650b6a4d81dc5db84bc441c9fe4
2018-05-14 14:57:15 -07:00
Andrew Kryczka
072ae671a7 Apply use_direct_io_for_flush_and_compaction to writes only
Summary:
Previously `DBOptions::use_direct_io_for_flush_and_compaction=true` combined with `DBOptions::use_direct_reads=false` could cause RocksDB to simultaneously read from two file descriptors for the same file, where background reads used direct I/O and foreground reads used buffered I/O. Our measurements found this mixed-mode I/O negatively impacted foreground read perf, compared to when only buffered I/O was used.

This PR makes the mixed-mode I/O situation impossible by repurposing `DBOptions::use_direct_io_for_flush_and_compaction` to only apply to background writes, and `DBOptions::use_direct_reads` to apply to all reads. There is no risk of direct background direct writes happening simultaneously with buffered reads since we never read from and write to the same file simultaneously.
Closes https://github.com/facebook/rocksdb/pull/3829

Differential Revision: D7915443

Pulled By: ajkr

fbshipit-source-id: 78bcbf276449b7e7766ab6b0db246f789fb1b279
2018-05-09 19:42:58 -07:00
Siying Dong
3690276e74 Disallow to open RandomRW file if the file doesn't exist
Summary:
The only use of RandomRW is to change seqno when bulkloading, and in this use case, the file should exist. We should fail the file opening in this case.
Closes https://github.com/facebook/rocksdb/pull/3827

Differential Revision: D7913719

Pulled By: siying

fbshipit-source-id: 62cf6734f1a6acb9e14f715b927da388131c3492
2018-05-09 10:27:26 -07:00
Siying Dong
63c965cdb4 Sync parent directory after deleting a file in delete scheduler
Summary:
sync parent directory after deleting a file in delete scheduler. Otherwise, trim speed may not be as smooth as what we want.
Closes https://github.com/facebook/rocksdb/pull/3767

Differential Revision: D7760136

Pulled By: siying

fbshipit-source-id: ec131d53b61953f09c60d67e901e5eeb2716b05f
2018-04-26 13:58:20 -07:00
Gabriel Wicke
090c78a0d7 Support lowering CPU priority of background threads
Summary:
Background activities like compaction can negatively affect
latency of higher-priority tasks like request processing. To avoid this,
rocksdb already lowers the IO priority of background threads on Linux
systems. While this takes care of typical IO-bound systems, it does not
help much when CPU (temporarily) becomes the bottleneck. This is
especially likely when using more expensive compression settings.

This patch adds an API to allow for lowering the CPU priority of
background threads, modeled on the IO priority API. Benchmarks (see
below) show significant latency and throughput improvements when CPU
bound. As a result, workloads with some CPU usage bursts should benefit
from lower latencies at a given utilization, or should be able to push
utilization higher at a given request latency target.

A useful side effect is that compaction CPU usage is now easily visible
in common tools, allowing for an easier estimation of the contribution
of compaction vs. request processing threads.

As with IO priority, the implementation is limited to Linux, degrading
to a no-op on other systems.
Closes https://github.com/facebook/rocksdb/pull/3763

Differential Revision: D7740096

Pulled By: gwicke

fbshipit-source-id: e5d32373e8dc403a7b0c2227023f9ce4f22b413c
2018-04-24 08:41:51 -07:00
Mike Kolupaev
affe01b0d5 Improve write time breakdown stats
Summary:
There's a group of stats in PerfContext for profiling the write path. They break down the write time into WAL write, memtable insert, throttling, and everything else. We use these stats a lot for figuring out the cause of slow writes.

These stats got a bit out of date and are now categorizing some interesting things as "everything else", and also do some double counting. This PR fixes it and adds two new stats: time spent waiting for other threads of the batch group, and time spent waiting for scheduling flushes/compactions. Probably these will be enough to explain all the occasional abnormally slow (multiple seconds) writes that we're seeing.
Closes https://github.com/facebook/rocksdb/pull/3602

Differential Revision: D7251562

Pulled By: al13n321

fbshipit-source-id: 0a2d0f5a4fa5677455e1f566da931cb46efe2a0d
2018-04-23 17:58:54 -07:00
Anand Ananthabhotla
dbdaa4662e Add a stat for MultiGet keys found, update memtable hit/miss stats
Summary:
1. Add a new ticker stat rocksdb.number.multiget.keys.found to track the
number of keys successfully read
2. Update rocksdb.memtable.hit/miss in DBImpl::MultiGet(). It was being done in
DBImpl::GetImpl(), but not MultiGet
Closes https://github.com/facebook/rocksdb/pull/3730

Differential Revision: D7677364

Pulled By: anand1976

fbshipit-source-id: af22bd0ef8ddc5cf2b4244b0a024e539fe48bca5
2018-04-20 15:28:19 -07:00
Yi Wu
ad511684b2 Add block cache related DB properties
Summary:
Add DB properties "rocksdb.block-cache-capacity", "rocksdb.block-cache-usage", "rocksdb.block-cache-pinned-usage" to show block cache usage.
Closes https://github.com/facebook/rocksdb/pull/3734

Differential Revision: D7657180

Pulled By: yiwu-arbug

fbshipit-source-id: dd34a019d5878dab539c51ee82669e97b2b745fd
2018-04-18 21:42:25 -07:00
Andrew Kryczka
3cea61392f include thread-pool priority in thread names
Summary:
Previously threads were named "rocksdb:bg\<index in thread pool\>", so the first thread in all thread pools would be named "rocksdb:bg0". Users want to be able to distinguish threads used for flush (high-pri) vs regular compaction (low-pri) vs compaction to bottom-level (bottom-pri). So I changed the thread naming convention to include the thread-pool priority.
Closes https://github.com/facebook/rocksdb/pull/3702

Differential Revision: D7581415

Pulled By: ajkr

fbshipit-source-id: ce04482b6acd956a401ef22dc168b84f76f7d7c1
2018-04-18 17:27:56 -07:00
Maysam Yabandeh
d15397ba10 WritePrepared Txn: rollback_merge_operands hack
Summary:
This is a hack as temporary fix of MyRocks with rollbacking  the merge operands. The way MyRocks uses merge operands is without protection of locks, which violates the assumption behind the rollback algorithm. They are ok with not being rolled back as it would just create a gap in the autoincrement column. The hack add an option to disable the rollback of merge operands by default and only enables it to let the unit test pass.
Closes https://github.com/facebook/rocksdb/pull/3711

Differential Revision: D7597177

Pulled By: maysamyabandeh

fbshipit-source-id: 544be0f666c7e7abb7f651ec8b23124e05056728
2018-04-12 11:58:11 -07:00
Maysam Yabandeh
d2bcd7611f Fix the memory leak with pinned partitioned filters
Summary:
The existing unit test did not set the level so the check for pinned partitioned filter/index being properly released from the block cache was not properly exercised as they only take effect in level 0. As a result a memory leak in pinned partitioned filters was hidden. The patch fix the test as well as the bug.
Closes https://github.com/facebook/rocksdb/pull/3692

Differential Revision: D7559763

Pulled By: maysamyabandeh

fbshipit-source-id: 55eff274945838af983c764a7d71e8daff092e4a
2018-04-09 16:28:19 -07:00
Adam Retter
ca87aef82d Added support for SstFileManager to RocksJava
Summary: Closes https://github.com/facebook/rocksdb/pull/3666

Differential Revision: D7457634

Pulled By: sagar0

fbshipit-source-id: 47741e2ee66e9255c580f4e38cfb86b284c27c2f
2018-04-06 21:26:32 -07:00
Andrew Kryczka
faba3fb53d protect valid backup files when max_valid_backups_to_open is set
Summary:
When `max_valid_backups_to_open` is set, the `BackupEngine` doesn't know about the files referenced by existing backups. This PR prevents us from deleting valid files when that option is set, in cases where we are unable to accurately determine refcount. There are warnings logged when we may miss deleting unreferenced files, and a recommendation in the header for users to periodically unset this option and run a full `GarbageCollect`.
Closes https://github.com/facebook/rocksdb/pull/3518

Differential Revision: D7008331

Pulled By: ajkr

fbshipit-source-id: 87907f964dc9716e229d08636a895d2fc7b72305
2018-04-05 21:13:21 -07:00
Sagar Vemuri
04c11b867d Level Compaction with TTL
Summary:
Level Compaction with TTL.

As of today, a file could exist in the LSM tree without going through the compaction process for a really long time if there are no updates to the data in the file's key range. For example, in certain use cases, the keys are not actually "deleted"; instead they are just set to empty values. There might not be any more writes to this "deleted" key range, and if so, such data could remain in the LSM for a really long time resulting in wasted space.

Introducing a TTL could solve this problem. Files (and, in turn, data) older than TTL will be scheduled for compaction when there is no other background work. This will make the data go through the regular compaction process and get rid of old unwanted data.
This also has the (good) side-effect of all the data in the non-bottommost level being newer than ttl, and all data in the bottommost level older than ttl. It could lead to more writes while reducing space.

This functionality can be controlled by the newly introduced column family option -- ttl.

TODO for later:
- Make ttl mutable
- Extend TTL to Universal compaction as well? (TTL is already supported in FIFO)
- Maybe deprecate CompactionOptionsFIFO.ttl in favor of this new ttl option.
Closes https://github.com/facebook/rocksdb/pull/3591

Differential Revision: D7275442

Pulled By: sagar0

fbshipit-source-id: dcba484717341200d419b0953dafcdf9eb2f0267
2018-04-02 22:14:28 -07:00
Anand Ananthabhotla
f9f4d40f93 Align SST file data blocks to avoid spanning multiple pages
Summary:
Provide a block_align option in BlockBasedTableOptions to allow
alignment of SST file data blocks. This will avoid higher
IOPS/throughput load due to < 4KB data blocks spanning 2 4KB pages.
When this option is set to true, the block alignment is set to lower of
block size and 4KB.
Closes https://github.com/facebook/rocksdb/pull/3502

Differential Revision: D7400897

Pulled By: anand1976

fbshipit-source-id: 04cc3bd144e88e3431a4f97604e63ad7a0f06d44
2018-03-26 20:26:10 -07:00
Maysam Yabandeh
35a4469bbf Fix race condition via concurrent FlushWAL
Summary:
Currently log_writer->AddRecord in WriteImpl is protected from concurrent calls via FlushWAL only if two_write_queues_ option is set. The patch fixes the problem by i) skip log_writer->AddRecord in FlushWAL if manual_wal_flush is not set, ii) protects log_writer->AddRecord in WriteImpl via log_write_mutex_ if manual_wal_flush_ is set but two_write_queues_ is not.

Fixes #3599
Closes https://github.com/facebook/rocksdb/pull/3656

Differential Revision: D7405608

Pulled By: maysamyabandeh

fbshipit-source-id: d6cc265051c77ae49c7c6df4f427350baaf46934
2018-03-26 16:29:56 -07:00
Sagar Vemuri
7ffce2805b Add Java-API-Changes section to History
Summary:
We have not been updating our HISTORY.md change log with the RocksJava changes. Going forward, lets add Java changes also to HISTORY.md.
There is an old java/HISTORY-JAVA.md, but it hasn't been updated in years. It is much easier to remember to update the change log in a single file, HISTORY.md.

I added information about shared block cache here, which was introduced in #3623.
Closes https://github.com/facebook/rocksdb/pull/3647

Differential Revision: D7384448

Pulled By: sagar0

fbshipit-source-id: 9b6e569f44e6df5cb7ba06413d9975df0b517d20
2018-03-23 12:28:51 -07:00
Sagar Vemuri
2e3d407778 Fsync after writing global seq number in ExternalSstFileIngestionJob
Summary:
Fsync after writing global sequence number to the ingestion file in ExternalSstFileIngestionJob. Otherwise the file metadata could be incorrect.
Closes https://github.com/facebook/rocksdb/pull/3644

Differential Revision: D7373813

Pulled By: sagar0

fbshipit-source-id: 4da2c9e71a8beb5c08b4ac955f288ee1576358b8
2018-03-22 17:42:56 -07:00
Siying Dong
118058ba69 SstFileManager: add bytes_max_delete_chunk
Summary:
Add `bytes_max_delete_chunk` in SstFileManager so that we can drop a large file in multiple batches.
Closes https://github.com/facebook/rocksdb/pull/3640

Differential Revision: D7358679

Pulled By: siying

fbshipit-source-id: ef17f0da2f5723dbece2669485a9b91b3edc0bb7
2018-03-22 15:58:37 -07:00
Fosco Marotto
de6cf95a53 Update history for future 5.13 release
Summary: Closes https://github.com/facebook/rocksdb/pull/3631

Differential Revision: D7367519

Pulled By: gfosco

fbshipit-source-id: 57826cc1c9ffc9f2b351075567b8ad929809cb74
2018-03-22 14:59:27 -07:00
Andrew Kryczka
0cdaa1a804 Fix WAL corruption from checkpoint/backup race condition
Summary:
`Writer::WriteBuffer` was always called at the beginning of checkpoint/backup. But that log writer has no internal synchronization, which meant the same buffer could be flushed twice in a race condition case, causing a WAL entry to be duplicated. Then subsequent WAL entries would be at unexpected offsets, causing the 32KB block boundaries to be overlapped and manifesting as a corruption.

This PR fixes the behavior to only use `WriteBuffer` (via `FlushWAL`) in checkpoint/backup when manual WAL flush is enabled. In that case, users are responsible for providing synchronization between WAL flushes. We can also consider removing the call entirely.
Closes https://github.com/facebook/rocksdb/pull/3603

Differential Revision: D7277447

Pulled By: ajkr

fbshipit-source-id: 1b15bd7fd930511222b075418c10de0aaa70a35a
2018-03-14 16:12:50 -07:00
Bruce Mitchener
a3a3f5497c Fix some typos in comments and docs.
Summary: Closes https://github.com/facebook/rocksdb/pull/3568

Differential Revision: D7170953

Pulled By: siying

fbshipit-source-id: 9cfb8dd88b7266da920c0e0c1e10fb2c5af0641c
2018-03-08 10:27:25 -08:00
amytai
0a3db28d98 Disallow compactions if there isn't enough free space
Summary:
This diff handles cases where compaction causes an ENOSPC error.
This does not handle corner cases where another background job is started while compaction is running, and the other background job triggers ENOSPC, although we do allow the user to provision for these background jobs with SstFileManager::SetCompactionBufferSize.
It also does not handle the case where compaction has finished and some other background job independently triggers ENOSPC.

Usage: Functionality is inside SstFileManager. In particular, users should set SstFileManager::SetMaxAllowedSpaceUsage, which is the reference highwatermark for determining whether to cancel compactions.
Closes https://github.com/facebook/rocksdb/pull/3449

Differential Revision: D7016941

Pulled By: amytai

fbshipit-source-id: 8965ab8dd8b00972e771637a41b4e6c645450445
2018-03-06 16:27:54 -08:00