Commit Graph

21 Commits

Author SHA1 Message Date
LingBin
72942ad7a4 Recommit "Avoid adding tombstones of the same file to RangeDelAggregator multiple times"
Summary:
The origin commit #3635  will hurt performance for users who aren't using range deletions, because unneeded std::set operations, so it was reverted by commit 44653c7b7a. (see #3672)

To fix this, move the set to  and add a check in , i.e., file will be added only if  is non-nullptr.

The db_bench command which find the performance regression:
> ./db_bench --benchmarks=fillrandom,seekrandomwhilewriting --threads=1 --num=1000000 --reads=150000 --key_size=66 > --value_size=1262 --statistics=0 --compression_ratio=0.5 --histogram=1 --seek_nexts=1 --stats_per_interval=1 > --stats_interval_seconds=600 --max_background_flushes=4 --num_multi_db=1 --max_background_compactions=16 --seed=1522388277 > -write_buffer_size=1048576 --level0_file_num_compaction_trigger=10000 --compression_type=none

Before and after the modification, I re-run this command on the machine, the results of are as follows:

  **fillrandom**
 Table | P50 | P75 | P99 | P99.9 | P99.99 |
  ---- | --- | --- | --- | ----- | ------ |
 before commit | 5.92 | 8.57 | 19.63 | 980.97 | 12196.00 |
 after commit  | 5.91 | 8.55 | 19.34 | 965.56 | 13513.56 |

 **seekrandomwhilewriting**
  Table | P50 | P75 | P99 | P99.9 | P99.99 |
   ---- | --- | --- | --- | ----- | ------ |
 before commit | 1418.62 | 1867.01 | 3823.28 | 4980.99 | 9240.00 |
 after commit  | 1450.54 | 1880.61 | 3962.87 | 5429.60 | 7542.86 |
Closes https://github.com/facebook/rocksdb/pull/3800

Differential Revision: D7874245

Pulled By: ajkr

fbshipit-source-id: 2e8bec781b3f7399246babd66395c88619534a17
2018-05-04 16:45:15 -07:00
Zhongyi Xie
44653c7b7a Revert "Avoid adding tombstones of the same file to RangeDelAggregato…
Summary:
…r multiple times"

This reverts commit e80709a33a.

lingbin PR https://github.com/facebook/rocksdb/pull/3635 is causing some performance regression for seekrandom workloads
I'm reverting the commit for now but feel free to submit new patches 😃

To reproduce the regression, you can run the following db_bench command
> ./db_bench --benchmarks=fillrandom,seekrandomwhilewriting --threads=1 --num=1000000 --reads=150000 --key_size=66 --value_size=1262 --statistics=0 --compression_ratio=0.5 --histogram=1 --seek_nexts=1 --stats_per_interval=1 --stats_interval_seconds=600 --max_background_flushes=4 --num_multi_db=1 --max_background_compactions=16 --seed=1522388277 -write_buffer_size=1048576 --level0_file_num_compaction_trigger=10000 --compression_type=none

write stats printed by db_bench:

Table | | | | | | | | | | |
 --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
revert commit | Percentiles: | P50: | 80.77  | P75: |102.94  |P99: | 1786.44 | P99.9: | 1892.39 |P99.99: 2645.10 |
keep commit | Percentiles: | P50: | 221.72 | P75: | 686.62 | P99: | 1842.57 | P99.9: | 1899.70|  P99.99: 2814.29|
Closes https://github.com/facebook/rocksdb/pull/3672

Differential Revision: D7463315

Pulled By: miasantreble

fbshipit-source-id: 8e779c87591127f2c3694b91a56d9b459011959d
2018-04-02 19:58:04 -07:00
LingBin
e80709a33a Avoid adding tombstones of the same file to RangeDelAggregator multiple times
Summary:
RangeDelAggregator will remember the files whose range tombstones have been added,
so the caller can check whether the file has been added before call AddTombstones.

Closes https://github.com/facebook/rocksdb/pull/3635

Differential Revision: D7354604

Pulled By: ajkr

fbshipit-source-id: 9b9f7ec130556028df417e650711554b46d8d107
2018-03-23 12:43:06 -07:00
Andrew Kryczka
1bdb44de95 optimize file ingestion checks for range deletion overlap
Summary:
Before we were checking every file in the level which was unnecessary. We can piggyback onto the code for checking point-key overlap, which already opens all the files that could possibly contain overlapping range deletions. This PR makes us check just the range deletions from those files, so no extra ones will be opened.
Closes https://github.com/facebook/rocksdb/pull/3179

Differential Revision: D6358125

Pulled By: ajkr

fbshipit-source-id: 00e200770fdb8f3cc6b1b2da232b755e4ba36279
2017-11-28 11:27:02 -08:00
Siying Dong
885b1c682e Two small refactoring for better inlining
Summary:
Move uncommon code paths in RangeDelAggregator::ShouldDelete() and IterKey::EnlargeBufferIfNeeded() to a separate function, so that the inlined strcuture can be more optimized.

Optimize it because these places show up in CPU profiling, though minimum. The performance is really hard measure. I ran db_bench with readseq benchmark against in-memory DB many times. The variation is big, but it seems to show 1% improvements.
Closes https://github.com/facebook/rocksdb/pull/2877

Differential Revision: D5828123

Pulled By: siying

fbshipit-source-id: 41a49e229f91e9f8409f85cc6f0dc70e31334e4b
2017-09-14 15:41:49 -07:00
Siying Dong
3c327ac2d0 Change RocksDB License
Summary: Closes https://github.com/facebook/rocksdb/pull/2589

Differential Revision: D5431502

Pulled By: siying

fbshipit-source-id: 8ebf8c87883daa9daa54b2303d11ce01ab1f6f75
2017-07-15 16:11:23 -07:00
Siying Dong
d616ebea23 Add GPLv2 as an alternative license.
Summary: Closes https://github.com/facebook/rocksdb/pull/2226

Differential Revision: D4967547

Pulled By: siying

fbshipit-source-id: dd3b58ae1e7a106ab6bb6f37ab5c88575b125ab4
2017-04-27 18:06:12 -07:00
Andrew Kryczka
b104b87814 Maintain position in range deletions map
Summary:
When deletion-collapsing mode is enabled (i.e., for DBIter/CompactionIterator), we maintain position in the tombstone maps across calls to ShouldDelete(). Since iterators often access keys sequentially (or reverse-sequentially), scanning forward/backward from the last position can be faster than binary-searching the map for every key.

- When Next() is invoked on an iterator, we use kForwardTraversal to scan forwards, if needed, until arriving at the range deletion containing the next key.
- Similarly for Prev(), we use kBackwardTraversal to scan backwards in the range deletion map.
- When the iterator seeks, we use kBinarySearch for repositioning
- After tombstones are added or before the first ShouldDelete() invocation, the current position is set to invalid, which forces kBinarySearch to be used.
- Non-iterator users (i.e., Get()) use kFullScan, which has the same behavior as before---scan the whole map for every key passed to ShouldDelete().
Closes https://github.com/facebook/rocksdb/pull/1701

Differential Revision: D4350318

Pulled By: ajkr

fbshipit-source-id: 5129b76
2017-01-05 10:39:12 -08:00
Andrew Kryczka
50e305de98 Collapse range deletions
Summary:
Added a tombstone-collapsing mode to RangeDelAggregator, which eliminates overlap in the TombstoneMap. In this mode, we can check whether a tombstone covers a user key using upper_bound() (i.e., binary search). However, the tradeoff is the overhead to add tombstones is now higher, so at first I've only enabled it for range scans (compaction/flush/user iterators), where we expect a high number of calls to ShouldDelete() for the same tombstones. Point queries like Get() will still use the linear scan approach.

Also in this diff I changed RangeDelAggregator's TombstoneMap to use multimap with user keys instead of map with internal keys. Callers sometimes provided ParsedInternalKey directly, from which it would've required string copying to derive an internal key Slice with which we could search the map.
Closes https://github.com/facebook/rocksdb/pull/1614

Differential Revision: D4270397

Pulled By: ajkr

fbshipit-source-id: 93092c7
2016-12-19 16:54:12 -08:00
Andrew Kryczka
7ffb10fc1a DeleteRange compaction statistics
Summary:
- "rocksdb.compaction.key.drop.range_del" - number of keys dropped during compaction due to a range tombstone covering them
- "rocksdb.compaction.range_del.drop.obsolete" - number of range tombstones dropped due to compaction to bottom level and no snapshot saving them
- s/CompactionIteratorStats/CompactionIterationStats/g since this class is no longer specific to CompactionIterator -- it's also updated for range tombstone iteration during compaction
- Move the above class into a separate .h file to avoid circular dependency.
Closes https://github.com/facebook/rocksdb/pull/1520

Differential Revision: D4187179

Pulled By: ajkr

fbshipit-source-id: 10c2103
2016-11-28 11:54:12 -08:00
Andrew Kryczka
fd43ee09da Range deletion microoptimizations
Summary:
- Made RangeDelAggregator's InternalKeyComparator member a reference-to-const so we don't need to copy-construct it. Also added InternalKeyComparator to ImmutableCFOptions so we don't need to construct one for each DBIter.
- Made MemTable::NewRangeTombstoneIterator and the table readers' NewRangeTombstoneIterator() functions return nullptr instead of NewEmptyInternalIterator to avoid the allocation. Updated callers accordingly.
Closes https://github.com/facebook/rocksdb/pull/1548

Differential Revision: D4208169

Pulled By: ajkr

fbshipit-source-id: 2fd65cf
2016-11-21 12:24:13 -08:00
Andrew Kryczka
fe349db57b Remove Arena in RangeDelAggregator
Summary:
The Arena construction/destruction introduced significant overhead to read-heavy workload just by creating empty vectors for its blocks, so avoid it in RangeDelAggregator.
Closes https://github.com/facebook/rocksdb/pull/1547

Differential Revision: D4207781

Pulled By: ajkr

fbshipit-source-id: 9d1c130
2016-11-19 14:24:12 -08:00
Andrew Kryczka
3f62215210 Lazily initialize RangeDelAggregator's map and pinning manager
Summary:
Since a RangeDelAggregator is created for each read request, these heap-allocating member variables were consuming significant CPU (~3% total) which slowed down request throughput. The map and pinning manager are only necessary when range deletions exist, so we can defer their initialization until the first range deletion is encountered. Currently lazy initialization is done for reads only since reads pass us a single snapshot, which is easier to store on the stack for later insertion into the map than the vector passed to us by flush or compaction.

Note the Arena member variable is still expensive, I will figure out what to do with it in a subsequent diff. It cannot be lazily initialized because we currently use this arena even to allocate empty iterators, which is necessary even when no range deletions exist.
Closes https://github.com/facebook/rocksdb/pull/1539

Differential Revision: D4203488

Pulled By: ajkr

fbshipit-source-id: 3b36279
2016-11-18 17:09:11 -08:00
Andrew Kryczka
760ef68a69 fix deleterange asan issue
Summary:
pinned_iters_mgr_ pins iterators allocated with arena_, so we should order the
instance variable declarations such that the pinned iterators have their destructors
executed before the arena is destroyed.
Closes https://github.com/facebook/rocksdb/pull/1528

Differential Revision: D4191984

Pulled By: ajkr

fbshipit-source-id: 1386f20
2016-11-16 14:09:07 -08:00
Andrew Kryczka
ec2f64794b Consider subcompaction boundaries when updating file boundaries for range deletion
Summary:
Adjusted AddToBuilder() to take lower_bound and upper_bound, which serve two purposes: (1) only range deletions overlapping with the interval [lower_bound, upper_bound) will be added to the output file, and (2) the output file's boundaries will not be extended before lower_bound or after upper_bound. Our computation of lower_bound/upper_bound consider both subcompaction boundaries and previous/next files within the subcompaction.

Test cases are here (level subcompactions: https://gist.github.com/ajkr/63c7eae3e9667c5ebdc0a7efb74ac332, and universal subcompactions: https://gist.github.com/ajkr/5a62af77c4ebe4052a1955c496d51fdb) but can't be included in this diff as they depend on committing the API first. They fail before this change and pass after.
Closes https://github.com/facebook/rocksdb/pull/1501

Reviewed By: yhchiang

Differential Revision: D4171685

Pulled By: ajkr

fbshipit-source-id: ee99db8
2016-11-14 20:24:21 -08:00
Andrew Kryczka
4e20c5da20 Store internal keys in TombstoneMap
Summary:
This fixes a correctness issue where ranges with same begin key would overwrite each other.

This diff uses InternalKey as TombstoneMap's key such that all tombstones have unique keys even when their start keys overlap. We also update TombstoneMap to use an internal key comparator.

End-to-end tests pass and are here (https://gist.github.com/ajkr/851ffe4c1b8a15a68d33025be190a7d9) but cannot be included yet since the DeleteRange() API is yet to be checked in. Note both tests failed before this fix.
Closes https://github.com/facebook/rocksdb/pull/1484

Differential Revision: D4155248

Pulled By: ajkr

fbshipit-source-id: 304b4b9
2016-11-09 15:09:18 -08:00
Andrew Kryczka
9e7cf3469b DeleteRange user iterator support
Summary:
Note: reviewed in  https://reviews.facebook.net/D65115

- DBIter maintains a range tombstone accumulator. We don't cleanup obsolete tombstones yet, so if the user seeks back and forth, the same tombstones would be added to the accumulator multiple times.
- DBImpl::NewInternalIterator() (used to make DBIter's underlying iterator) adds memtable/L0 range tombstones, L1+ range tombstones are added on-demand during NewSecondaryIterator() (see D62205)
- DBIter uses ShouldDelete() when advancing to check whether keys are covered by range tombstones
Closes https://github.com/facebook/rocksdb/pull/1464

Differential Revision: D4131753

Pulled By: ajkr

fbshipit-source-id: be86559
2016-11-04 12:09:22 -07:00
Andrew Kryczka
f998c9790f DeleteRange Get support
Summary:
During Get()/MultiGet(), build up a RangeDelAggregator with range
tombstones as we search through live memtable, immutable memtables, and
SST files. This aggregator is then used by memtable.cc's SaveValue() and
GetContext::SaveValue() to check whether keys are covered.

added tests for Get on memtables/files; end-to-end tests mainly in https://reviews.facebook.net/D64761
Closes https://github.com/facebook/rocksdb/pull/1456

Differential Revision: D4111271

Pulled By: ajkr

fbshipit-source-id: 6e388d4
2016-11-03 18:54:20 -07:00
Andrew Kryczka
2946cadc46 Improve RangeDelAggregator documentation
Summary:
as requested in D62259
Closes https://github.com/facebook/rocksdb/pull/1434

Differential Revision: D4099047

Pulled By: ajkr

fbshipit-source-id: a258cfb
2016-10-28 15:54:21 -07:00
Andrew Kryczka
a0ba0aa877 Fix uninitialized variable gcc error for MyRocks
Summary: make sure seq_ is properly initialized even if ParseInternalKey() fails.

Test Plan: run myrocks release tests

Reviewers: lightmark, mung, sdong

Reviewed By: sdong

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D65199
2016-10-19 10:59:46 -07:00
Andrew Kryczka
6fbe96baf8 Compaction Support for Range Deletion
Summary:
This diff introduces RangeDelAggregator, which takes ownership of iterators
provided to it via AddTombstones(). The tombstones are organized in a two-level
map (snapshot stripe -> begin key -> tombstone). Tombstone creation avoids data
copy by holding Slices returned by the iterator, which remain valid thanks to pinning.

For compaction, we create a hierarchical range tombstone iterator with structure
matching the iterator over compaction input data. An aggregator based on that
iterator is used by CompactionIterator to determine which keys are covered by
range tombstones. In case of merge operand, the same aggregator is used by
MergeHelper. Upon finishing each file in the compaction, relevant range tombstones
are added to the output file's range tombstone metablock and file boundaries are
updated accordingly.

To check whether a key is covered by range tombstone, RangeDelAggregator::ShouldDelete()
considers tombstones in the key's snapshot stripe. When this function is used outside of
compaction, it also checks newer stripes, which can contain covering tombstones. Currently
the intra-stripe check involves a linear scan; however, in the future we plan to collapse ranges
within a stripe such that binary search can be used.

RangeDelAggregator::AddToBuilder() adds all range tombstones in the table's key-range
to a new table's range tombstone meta-block. Since range tombstones may fall in the gap
between files, we may need to extend some files' key-ranges. The strategy is (1) first file
extends as far left as possible and other files do not extend left, (2) all files extend right
until either the start of the next file or the end of the last range tombstone in the gap,
whichever comes first.

One other notable change is adding release/move semantics to ScopedArenaIterator
such that it can be used to transfer ownership of an arena-allocated iterator, similar to
how unique_ptr is used for malloc'd data.

Depends on D61473

Test Plan: compaction_iterator_test, mock_table, end-to-end tests in D63927

Reviewers: sdong, IslamAbdelRahman, wanning, yhchiang, lightmark

Reviewed By: lightmark

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D62205
2016-10-18 12:04:56 -07:00