Summary:
... when compiled with ASSERT_STATUS_CHECKED = 1.
The main change is in iterator_wrapper.h. The remaining changes are just fixing existing unit tests. Adding this check to IteratorWrapper gives a good coverage as the class is used in many places, including child iterators under merging iterator, merging iterator under DB iter, file_iter under level iterator, etc. This change can catch the bug fixed in https://github.com/facebook/rocksdb/issues/11782.
Future follow up: enable `ASSERT_STATUS_CHECKED=1` for stress test and for DEBUG_LEVEL=0.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/11975
Test Plan:
* `ASSERT_STATUS_CHECKED=1 DEBUG_LEVEL=2 make -j32 J=32 check`
* I tried to run stress test with `ASSERT_STATUS_CHECKED=1`, but there are a lot of existing stress code that ignore status checking, and fail without the change in this PR. So defer that to a follow up task.
Reviewed By: ajkr
Differential Revision: D50383790
Pulled By: cbi42
fbshipit-source-id: 1a28ce0f5fdf1890f93400b26b3b1b3a287624ce
Summary:
This PR resolves https://github.com/facebook/rocksdb/issues/10487 & https://github.com/facebook/rocksdb/issues/10536, user code needs to call Refresh() periodically.
The main code change is to support range deletions. A range tombstone iterator uses a sequence number as upper bound to decide which range tombstones are effective. During Iterator refresh, this sequence number upper bound needs to be updated for all range tombstone iterators under DBIter and LevelIterator. LevelIterator may create new table iterators and range tombstone iterator during scanning, so it needs to be aware of iterator refresh. The code path that propagates this change is `db_iter_->set_sequence(read_seq) -> MergingIterator::SetRangeDelReadSeqno() -> TruncatedRangeDelIterator::SetRangeDelReadSeqno() and LevelIterator::SetRangeDelReadSeqno()`.
This change also fixes an issue where range tombstone iterators created by LevelIterator may access ReadOptions::snapshot, even though we do not explicitly require users to keep a snapshot alive after creating an Iterator.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10594
Test Plan:
* New unit tests.
* Add Iterator::Refresh(snapshot) to stress test. Note that this change only adds tests for refreshing to the same snapshot since this is the main target use case.
TODO in a following PR:
* Stress test Iterator::Refresh() to different snapshots or no snapshot.
Reviewed By: ajkr
Differential Revision: D48456896
Pulled By: cbi42
fbshipit-source-id: 2e642c04e91235cc9542ef4cd37b3c20823bd779
Summary:
Tests a scenario where range tombstone reseek used to cause MergingIterator to discard non-ok status.
Ran on main without https://github.com/facebook/rocksdb/issues/11786:
```
./db_range_del_test --gtest_filter="*RangeDelReseekAfterFileReadError*"
Note: Google Test filter = *RangeDelReseekAfterFileReadError*
[==========] Running 1 test from 1 test case.
[----------] Global test environment set-up.
[----------] 1 test from DBRangeDelTest
[ RUN ] DBRangeDelTest.RangeDelReseekAfterFileReadError
db/db_range_del_test.cc:3577: Failure
Value of: iter->Valid()
Actual: true
Expected: false
[ FAILED ] DBRangeDelTest.RangeDelReseekAfterFileReadError (64 ms)
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/11790
Reviewed By: ajkr
Differential Revision: D48972869
Pulled By: cbi42
fbshipit-source-id: b1a71867533b0fb60af86f8ce8a9e391ba84dd57
Summary:
Add a mutable column family option `memtable_max_range_deletions`. When non-zero, RocksDB will try to flush the current memtable after it has at least `memtable_max_range_deletions` range deletions. Java API is added and crash test is updated accordingly to randomly enable this option.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/11358
Test Plan:
* New unit test: `DBRangeDelTest.MemtableMaxRangeDeletions`
* Ran crash test `python3 ./tools/db_crashtest.py whitebox --simple --memtable_max_range_deletions=20` and saw logs showing flushed memtables usually with 20 range deletions.
Reviewed By: ajkr
Differential Revision: D46582680
Pulled By: cbi42
fbshipit-source-id: f23d6fa8d8264ecf0a18d55c113ba03f5e2504da
Summary:
Fix the test added in https://github.com/facebook/rocksdb/issues/11459 that is failing.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/11512
Test Plan: `./db_range_del_test --gtest_filter="*NonBottommostCompactionDropRangetombstone"`
Reviewed By: pdillinger
Differential Revision: D46451450
Pulled By: cbi42
fbshipit-source-id: bcad20b8fd21c4f71924cec6cb045ee4b2038b90
Summary:
Similar to point tombstones, we can drop a range tombstone during compaction when we know its range does not exist in any higher level. This PR adds this optimization. Some existing test in db_range_del_test is fixed to work under this optimization.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/11459
Test Plan:
* Add unit test `DBRangeDelTest, NonBottommostCompactionDropRangetombstone`.
* Ran crash test that issues range deletion for a few hours: `python3 tools/db_crashtest.py blackbox --simple --write_buffer_size=1048576 --delrangepercent=10 --writepercent=31 --readpercent=40`
Reviewed By: ajkr
Differential Revision: D46007904
Pulled By: cbi42
fbshipit-source-id: 3f37205b6778b7d55ed106369ca41b0632a6d0fd
Summary:
A second attempt after https://github.com/facebook/rocksdb/issues/10802, with bug fixes and refactoring. This PR updates compaction logic to take range tombstones into account when determining whether to cut the current compaction output file (https://github.com/facebook/rocksdb/issues/4811). Before this change, only point keys were considered, and range tombstones could cause large compactions. For example, if the current compaction outputs is a range tombstone [a, b) and 2 point keys y, z, they would be added to the same file, and may overlap with too many files in the next level and cause a large compaction in the future. This PR also includes ajkr's effort to simplify the logic to add range tombstones to compaction output files in `AddRangeDels()` ([https://github.com/facebook/rocksdb/issues/11078](https://github.com/facebook/rocksdb/pull/11078#issuecomment-1386078861)).
The main change is for `CompactionIterator` to emit range tombstone start keys to be processed by `CompactionOutputs`. A new class `CompactionMergingIterator` is introduced to replace `MergingIterator` under `CompactionIterator` to enable emitting of range tombstone start keys. Further improvement after this PR include cutting compaction output at some grandparent boundary key (instead of the next output key) when cutting within a range tombstone to reduce overlap with grandparents.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/11113
Test Plan:
* added unit test in db_range_del_test
* crash test with a small key range: `python3 tools/db_crashtest.py blackbox --simple --max_key=100 --interval=600 --write_buffer_size=262144 --target_file_size_base=256 --max_bytes_for_level_base=262144 --block_size=128 --value_size_mult=33 --subcompactions=10 --use_multiget=1 --delpercent=3 --delrangepercent=2 --verify_iterator_with_expected_state_one_in=2 --num_iterations=10`
Reviewed By: ajkr
Differential Revision: D42655709
Pulled By: cbi42
fbshipit-source-id: 8367e36ef5640e8f21c14a3855d4a8d6e360a34c
Summary:
We haven't been actively mantaining RocksDB LITE recently and the size must have been gone up significantly. We are removing the support.
Most of changes were done through following comments:
unifdef -m -UROCKSDB_LITE `git grep -l ROCKSDB_LITE | egrep '[.](cc|h)'`
by Peter Dillinger. Others changes were manually applied to build scripts, CircleCI manifests, ROCKSDB_LITE is used in an expression and file db_stress_test_base.cc.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/11147
Test Plan: See CI
Reviewed By: pdillinger
Differential Revision: D42796341
fbshipit-source-id: 4920e15fc2060c2cd2221330a6d0e5e65d4b7fe2
Summary:
in `CompactionOutputs::AddRangeDels()`, range tombstones with the same start and end key but different sequence numbers all contribute to compensated range tombstone size. This PR removes this redundancy. This PR also includes a fix from https://github.com/facebook/rocksdb/issues/11067 where a range tombstone that is not within a file's range was being added to the file. This fixes an assertion failure for `icmp.Compare(start, end) <= 0` in VersionSet::ApproximateSize() when calculating compensated range tombstone size. Assertions and a comment/essay was added to reason that no such range tombstone will be added after this fix.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/11091
Test Plan:
- Added unit tests
- Stress test with small key range: `python3 tools/db_crashtest.py blackbox --simple --max_key=100 --interval=600 --write_buffer_size=262144 --target_file_size_base=256 --max_bytes_for_level_base=262144 --block_size=128 --value_size_mult=33 --subcompactions=10`
Reviewed By: ajkr
Differential Revision: D42521588
Pulled By: cbi42
fbshipit-source-id: 5bda3fe38997995314e1f7592319af12b69bc4f8
Summary:
This reverts commit f02c708aa3 since it introduced several bugs (see https://github.com/facebook/rocksdb/issues/11078 and https://github.com/facebook/rocksdb/issues/11067 for attempts to fix them) and that I do not have a high confidence to fix all of them and ensure no further ones before the next release branch cut. There are also come existing issue found during bug fixing. We will work on it and try to merge it to the release after.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/11089
Test Plan: existing CI.
Reviewed By: ajkr
Differential Revision: D42505972
Pulled By: cbi42
fbshipit-source-id: 2f66dcde6b85dc94977b317c2ce513872cfbc153
Summary:
compensate file sizes in compaction picking so files with range tombstones are preferred, such that they get compacted down earlier as they tend to delete a lot of data. This PR adds a `compensated_range_deletion_size` field in FileMeta that is computed during Flush/Compaction and persisted in MANIFEST. This value is added to `compensated_file_size` which will be used for compaction picking. Currently, for a file in level L, `compensated_range_deletion_size` is set to the estimated bytes deleted by range tombstone of this file in all levels > L. This helps to reduce space amp when data in older levels are covered by range tombstones in level L.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10734
Test Plan:
- Added unit tests.
- benchmark to check if the above definition `compensated_range_deletion_size` is reducing space amp as intended, without affecting write amp too much. The experiment set up favorable for this optimization: large range tombstone issued infrequently. Command used:
```
./db_bench -benchmarks=fillrandom,waitforcompaction,stats,levelstats -use_existing_db=false -avoid_flush_during_recovery=true -write_buffer_size=33554432 -level_compaction_dynamic_level_bytes=true -max_background_jobs=8 -max_bytes_for_level_base=134217728 -target_file_size_base=33554432 -writes_per_range_tombstone=500000 -range_tombstone_width=5000000 -num=50000000 -benchmark_write_rate_limit=8388608 -threads=16 -duration=1800 --max_num_range_tombstones=1000000000
```
In this experiment, each thread wrote 16 range tombstones over the duration of 30 minutes, each range tombstone has width 5M that is the 10% of the key space width. Results shows this PR generates a smaller DB size.
Compaction stats from this PR:
```
Level Files Size Score Read(GB) Rn(GB) Rnp1(GB) Write(GB) Wnew(GB) Moved(GB) W-Amp Rd(MB/s) Wr(MB/s) Comp(sec) CompMergeCPU(sec) Comp(cnt) Avg(sec) KeyIn KeyDrop Rblob(GB) Wblob(GB)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
L0 2/0 31.54 MB 0.5 0.0 0.0 0.0 8.4 8.4 0.0 1.0 0.0 63.4 135.56 110.94 544 0.249 0 0 0.0 0.0
L4 3/0 96.55 MB 0.8 18.5 6.7 11.8 18.4 6.6 0.0 2.7 65.3 64.9 290.08 284.03 108 2.686 284M 1957K 0.0 0.0
L5 15/0 404.41 MB 1.0 19.1 7.7 11.4 18.8 7.4 0.3 2.5 66.6 65.7 292.93 285.34 220 1.332 293M 3808K 0.0 0.0
L6 143/0 4.12 GB 0.0 45.0 7.5 37.5 41.6 4.1 0.0 5.5 71.2 65.9 647.00 632.66 251 2.578 739M 47M 0.0 0.0
Sum 163/0 4.64 GB 0.0 82.6 21.9 60.7 87.2 26.5 0.3 10.4 61.9 65.4 1365.58 1312.97 1123 1.216 1318M 52M 0.0 0.0
```
Compaction stats from main:
```
Level Files Size Score Read(GB) Rn(GB) Rnp1(GB) Write(GB) Wnew(GB) Moved(GB) W-Amp Rd(MB/s) Wr(MB/s) Comp(sec) CompMergeCPU(sec) Comp(cnt) Avg(sec) KeyIn KeyDrop Rblob(GB) Wblob(GB)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
L0 0/0 0.00 KB 0.0 0.0 0.0 0.0 8.4 8.4 0.0 1.0 0.0 60.5 142.12 115.89 569 0.250 0 0 0.0 0.0
L4 3/0 85.68 MB 1.0 17.7 6.8 10.9 17.6 6.7 0.0 2.6 62.7 62.3 289.05 281.79 112 2.581 272M 2309K 0.0 0.0
L5 11/0 293.73 MB 1.0 18.8 7.5 11.2 18.5 7.2 0.5 2.5 64.9 63.9 296.07 288.50 220 1.346 288M 4365K 0.0 0.0
L6 130/0 3.94 GB 0.0 51.5 7.6 43.9 47.9 3.9 0.0 6.3 67.2 62.4 784.95 765.92 258 3.042 848M 51M 0.0 0.0
Sum 144/0 4.31 GB 0.0 88.0 21.9 66.0 92.3 26.3 0.5 11.0 59.6 62.5 1512.19 1452.09 1159 1.305 1409M 58M 0.0 0.0```
Reviewed By: ajkr
Differential Revision: D39834713
Pulled By: cbi42
fbshipit-source-id: fe9341040b8704a8fbb10cad5cf5c43e962c7e6b
Summary:
This PR is the first step for Issue https://github.com/facebook/rocksdb/issues/4811. Currently compaction output files are cut at point keys, and the decision is made mainly in `CompactionOutputs::ShouldStopBefore()`. This makes it possible for range tombstones to cause large compactions that does not respect `max_compaction_bytes`. For example, we can have a large range tombstone that overlaps with too many files from the next level. Another example is when there is a gap between a range tombstone and another key. The first issue may be more acceptable, as a lot of data is deleted. This PR address the second issue by calling `ShouldStopBefore()` for range tombstone start keys. The main change is for `CompactionIterator` to emit range tombstone start keys to be processed by `CompactionOutputs`. A new `CompactionMergingIterator` is introduced and only used under `CompactionIterator` for this purpose. Further improvement after this PR include 1) cut compaction output at some grandparent boundary key instead of at the next point key or range tombstone start key and 2) cut compaction output file within a large range tombstone (it may be easier and reasonable to only do it for range tombstones at the end of a compaction output).
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10802
Test Plan:
- added unit tests in db_range_del_test.
- stress test: `python3 tools/db_crashtest.py whitebox --[simple|enable_ts] --verify_iterator_with_expected_state_one_in=5 --delrangepercent=5 --prefixpercent=2 --writepercent=58 --readpercen=21 --duration=36000 --range_deletion_width=1000000`
Reviewed By: ajkr, jay-zhuang
Differential Revision: D40308827
Pulled By: cbi42
fbshipit-source-id: a8fd6f70a3f09d0ef7a40e006f6c964bba8c00df
Summary:
Currently, `iterate_upper_bound` is not checked for range tombstone keys in MergingIterator. This may impact performance when there is a large number of range tombstones right after `iterate_upper_bound`. This PR fixes this issue by checking `iterate_upper_bound` in MergingIterator for range tombstone keys.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10966
Test Plan:
- added unit test
- stress test: `python3 tools/db_crashtest.py whitebox --simple --verify_iterator_with_expected_state_one_in=5 --delrangepercent=5 --prefixpercent=18 --writepercent=48 --readpercen=15 --duration=36000 --range_deletion_width=100`
- ran different stress tests over sandcastle
- Falcon team ran some test traffic and saw reduced CPU usage on processing range tombstones.
Reviewed By: ajkr
Differential Revision: D41414172
Pulled By: cbi42
fbshipit-source-id: 9b2c29eb3abb99327c6a649bdc412e70d863f981
Summary:
Ran `find ./db/ -type f | xargs clang-format -i`. Excluded minor changes it tried to make on db/db_impl/. Everything else it changed was directly under db/ directory. Included minor manual touchups mentioned in PR commit history.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10910
Reviewed By: riversand963
Differential Revision: D40880683
Pulled By: ajkr
fbshipit-source-id: cfe26cda05b3fb9a72e3cb82c286e21d8c5c4174
Summary:
To make it consistent with the compaction picker which uses the `sstableKeyCompare()` to pick the overlap files. For example, without this change, it may cut L1 files like:
```
L1: [2-21] [22-30]
L2: [1-10] [21-30]
```
Because "21" on L1 is smaller than "21" on L2. But for compaction, these 2 files are overlapped.
`sstableKeyCompare()` also take range delete into consideration which may cut file for the same key.
It also makes the `max_compaction_bytes` calculation more accurate for cases like above, the overlapped bytes was under estimated. Also make sure the 2 keys won't be splitted to 2 files because of reaching `max_compaction_bytes`.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10763
Reviewed By: cbi42
Differential Revision: D39971904
Pulled By: cbi42
fbshipit-source-id: bcc309e9c3dc61a8f50667a6f633e6132c0154a8
Summary:
Add user-defined timestamp support for range deletion. The new API is `DeleteRange(opt, cf, begin_key, end_key, ts)`. Most of the change is to update the comparator to compare without timestamp. Other than that, major changes are
- internal range tombstone data structures (`FragmentedRangeTombstoneList`, `RangeTombstone`, etc.) to store timestamps.
- Garbage collection of range tombstones and range tombstone covered keys during compaction.
- Get()/MultiGet() to return the timestamp of a range tombstone when needed.
- Get/Iterator with range tombstones bounded by readoptions.timestamp.
- timestamp crash test now issues DeleteRange by default.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10661
Test Plan:
- Added unit test: `make check`
- Stress test: `python3 tools/db_crashtest.py --enable_ts whitebox --readpercent=57 --prefixpercent=4 --writepercent=25 -delpercent=5 --iterpercent=5 --delrangepercent=4`
- Ran `db_bench` to measure regression when timestamp is not enabled. The tests are for write (with some range deletion) and iterate with DB fitting in memory: `./db_bench--benchmarks=fillrandom,seekrandom --writes_per_range_tombstone=200 --max_write_buffer_number=100 --min_write_buffer_number_to_merge=100 --writes=500000 --reads=500000 --seek_nexts=10 --disable_auto_compactions -disable_wal=true --max_num_range_tombstones=1000`. Did not see consistent regression in no timestamp case.
| micros/op | fillrandom | seekrandom |
| --- | --- | --- |
|main| 2.58 |10.96|
|PR 10661| 2.68 |10.63|
Reviewed By: riversand963
Differential Revision: D39441192
Pulled By: cbi42
fbshipit-source-id: f05aca3c41605caf110daf0ff405919f300ddec2
Summary:
Try to align the compaction output file boundaries to the next level ones
(grandparent level), to reduce the level compaction write-amplification.
In level compaction, there are "wasted" data at the beginning and end of the
output level files. Align the file boundary can avoid such "wasted" compaction.
With this PR, it tries to align the non-bottommost level file boundaries to its
next level ones. It may cut file when the file size is large enough (at least
50% of target_file_size) and not too large (2x target_file_size).
db_bench shows about 12.56% compaction reduction:
```
TEST_TMPDIR=/data/dbbench2 ./db_bench --benchmarks=fillrandom,readrandom -max_background_jobs=12 -num=400000000 -target_file_size_base=33554432
# baseline:
Flush(GB): cumulative 25.882, interval 7.216
Cumulative compaction: 285.90 GB write, 162.36 MB/s write, 269.68 GB read, 153.15 MB/s read, 2926.7 seconds
# with this change:
Flush(GB): cumulative 25.882, interval 7.753
Cumulative compaction: 249.97 GB write, 141.96 MB/s write, 233.74 GB read, 132.74 MB/s read, 2534.9 seconds
```
The compaction simulator shows a similar result (14% with 100G random data).
As a side effect, with this PR, the SST file size can exceed the
target_file_size, but is capped at 2x target_file_size. And there will be
smaller files. Here are file size statistics when loading 100GB with the target
file size 32MB:
```
baseline this_PR
count 1.656000e+03 1.705000e+03
mean 3.116062e+07 3.028076e+07
std 7.145242e+06 8.046139e+06
```
The feature is enabled by default, to revert to the old behavior disable it
with `AdvancedColumnFamilyOptions.level_compaction_dynamic_file_size = false`
Also includes https://github.com/facebook/rocksdb/issues/1963 to cut file before skippable grandparent file. Which is for
use case like user adding 2 or more non-overlapping data range at the same
time, it can reduce the overlapping of 2 datasets in the lower levels.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10655
Reviewed By: cbi42
Differential Revision: D39552321
Pulled By: jay-zhuang
fbshipit-source-id: 640d15f159ab0cd973f2426cfc3af266fc8bdde2
Summary:
when a new internal iterator is constructed during iterator refresh, pointer to the previous memtable range tombstone iterator was not cleared. This could cause segfault for future `Refresh()` calls when they try to free the memtable range tombstones. This PR fixes this issue.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10739
Test Plan: added a unit test in db_range_del_test.cc to reproduce this issue.
Reviewed By: ajkr, riversand963
Differential Revision: D39825283
Pulled By: cbi42
fbshipit-source-id: 3b59a2b73865aed39e28cdd5c1b57eed7991b94c
Summary:
when there is a single memtable without range tombstones and no SST files in the database, DBIter should wrap memtable iterator directly. Currently we create a merging iterator on top of the memtable iterator, and have DBIter wrap around it. This causes iterator regression and this PR fixes this issue.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10705
Test Plan:
- `make check`
- Performance:
- Set up: `./db_bench -benchmarks=filluniquerandom -write_buffer_size=$((1 << 30)) -num=10000`
- Benchmark: `./db_bench -benchmarks=seekrandom -use_existing_db=true -avoid_flush_during_recovery=true -write_buffer_size=$((1 << 30)) -num=10000 -threads=16 -duration=60 -seek_nexts=$seek_nexts`
```
seek_nexts main op/sec https://github.com/facebook/rocksdb/issues/10705 RocksDB v7.6
0 5746568 5749033 5786180
30 2411690 3006466 2837699
1000 102556 128902 124667
```
Reviewed By: ajkr
Differential Revision: D39644221
Pulled By: cbi42
fbshipit-source-id: 8063ff611ba31b0e5670041da3927c8c54b2097d
Summary:
Delete range logic is moved from `DBIter` to `MergingIterator`, and `MergingIterator` will seek to the end of a range deletion if possible instead of scanning through each key and check with `RangeDelAggregator`.
With the invariant that a key in level L (consider memtable as the first level, each immutable and L0 as a separate level) has a larger sequence number than all keys in any level >L, a range tombstone `[start, end)` from level L covers all keys in its range in any level >L. This property motivates optimizations in iterator:
- in `Seek(target)`, if level L has a range tombstone `[start, end)` that covers `target.UserKey`, then for all levels > L, we can do Seek() on `end` instead of `target` to skip some range tombstone covered keys.
- in `Next()/Prev()`, if the current key is covered by a range tombstone `[start, end)` from level L, we can do `Seek` to `end` for all levels > L.
This PR implements the above optimizations in `MergingIterator`. As all range tombstone covered keys are now skipped in `MergingIterator`, the range tombstone logic is removed from `DBIter`. The idea in this PR is similar to https://github.com/facebook/rocksdb/issues/7317, but this PR leaves `InternalIterator` interface mostly unchanged. **Credit**: the cascading seek optimization and the sentinel key (discussed below) are inspired by [Pebble](https://github.com/cockroachdb/pebble/blob/master/merging_iter.go) and suggested by ajkr in https://github.com/facebook/rocksdb/issues/7317. The two optimizations are mostly implemented in `SeekImpl()/SeekForPrevImpl()` and `IsNextDeleted()/IsPrevDeleted()` in `merging_iterator.cc`. See comments for each method for more detail.
One notable change is that the minHeap/maxHeap used by `MergingIterator` now contains range tombstone end keys besides point key iterators. This helps to reduce the number of key comparisons. For example, for a range tombstone `[start, end)`, a `start` and an `end` `HeapItem` are inserted into the heap. When a `HeapItem` for range tombstone start key is popped from the minHeap, we know this range tombstone becomes "active" in the sense that, before the range tombstone's end key is popped from the minHeap, all the keys popped from this heap is covered by the range tombstone's internal key range `[start, end)`.
Another major change, *delete range sentinel key*, is made to `LevelIterator`. Before this PR, when all point keys in an SST file are iterated through in `MergingIterator`, a level iterator would advance to the next SST file in its level. In the case when an SST file has a range tombstone that covers keys beyond the SST file's last point key, advancing to the next SST file would lose this range tombstone. Consequently, `MergingIterator` could return keys that should have been deleted by some range tombstone. We prevent this by pretending that file boundaries in each SST file are sentinel keys. A `LevelIterator` now only advance the file iterator once the sentinel key is processed.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10449
Test Plan:
- Added many unit tests in db_range_del_test
- Stress test: `./db_stress --readpercent=5 --prefixpercent=19 --writepercent=20 -delpercent=10 --iterpercent=44 --delrangepercent=2`
- Additional iterator stress test is added to verify against iterators against expected state: https://github.com/facebook/rocksdb/issues/10538. This is based on ajkr's previous attempt https://github.com/facebook/rocksdb/pull/5506#issuecomment-506021913.
```
python3 ./tools/db_crashtest.py blackbox --simple --write_buffer_size=524288 --target_file_size_base=524288 --max_bytes_for_level_base=2097152 --compression_type=none --max_background_compactions=8 --value_size_mult=33 --max_key=5000000 --interval=10 --duration=7200 --delrangepercent=3 --delpercent=9 --iterpercent=25 --writepercent=60 --readpercent=3 --prefixpercent=0 --num_iterations=1000 --range_deletion_width=100 --verify_iterator_with_expected_state_one_in=1
```
- Performance benchmark: I used a similar setup as in the blog [post](http://rocksdb.org/blog/2018/11/21/delete-range.html) that introduced DeleteRange, "a database with 5 million data keys, and 10000 range tombstones (ignoring those dropped during compaction) that were written in regular intervals after 4.5 million data keys were written". As expected, the performance with this PR depends on the range tombstone width.
```
# Setup:
TEST_TMPDIR=/dev/shm ./db_bench_main --benchmarks=fillrandom --writes=4500000 --num=5000000
TEST_TMPDIR=/dev/shm ./db_bench_main --benchmarks=overwrite --writes=500000 --num=5000000 --use_existing_db=true --writes_per_range_tombstone=50
# Scan entire DB
TEST_TMPDIR=/dev/shm ./db_bench_main --benchmarks=readseq[-X5] --use_existing_db=true --num=5000000 --disable_auto_compactions=true
# Short range scan (10 Next())
TEST_TMPDIR=/dev/shm/width-100/ ./db_bench_main --benchmarks=seekrandom[-X5] --use_existing_db=true --num=500000 --reads=100000 --seek_nexts=10 --disable_auto_compactions=true
# Long range scan(1000 Next())
TEST_TMPDIR=/dev/shm/width-100/ ./db_bench_main --benchmarks=seekrandom[-X5] --use_existing_db=true --num=500000 --reads=2500 --seek_nexts=1000 --disable_auto_compactions=true
```
Avg over of 10 runs (some slower tests had fews runs):
For the first column (tombstone), 0 means no range tombstone, 100-10000 means width of the 10k range tombstones, and 1 means there is a single range tombstone in the entire DB (width is 1000). The 1 tombstone case is to test regression when there's very few range tombstones in the DB, as no range tombstone is likely to take a different code path than with range tombstones.
- Scan entire DB
| tombstone width | Pre-PR ops/sec | Post-PR ops/sec | ±% |
| ------------- | ------------- | ------------- | ------------- |
| 0 range tombstone |2525600 (± 43564) |2486917 (± 33698) |-1.53% |
| 100 |1853835 (± 24736) |2073884 (± 32176) |+11.87% |
| 1000 |422415 (± 7466) |1115801 (± 22781) |+164.15% |
| 10000 |22384 (± 227) |227919 (± 6647) |+918.22% |
| 1 range tombstone |2176540 (± 39050) |2434954 (± 24563) |+11.87% |
- Short range scan
| tombstone width | Pre-PR ops/sec | Post-PR ops/sec | ±% |
| ------------- | ------------- | ------------- | ------------- |
| 0 range tombstone |35398 (± 533) |35338 (± 569) |-0.17% |
| 100 |28276 (± 664) |31684 (± 331) |+12.05% |
| 1000 |7637 (± 77) |25422 (± 277) |+232.88% |
| 10000 |1367 |28667 |+1997.07% |
| 1 range tombstone |32618 (± 581) |32748 (± 506) |+0.4% |
- Long range scan
| tombstone width | Pre-PR ops/sec | Post-PR ops/sec | ±% |
| ------------- | ------------- | ------------- | ------------- |
| 0 range tombstone |2262 (± 33) |2353 (± 20) |+4.02% |
| 100 |1696 (± 26) |1926 (± 18) |+13.56% |
| 1000 |410 (± 6) |1255 (± 29) |+206.1% |
| 10000 |25 |414 |+1556.0% |
| 1 range tombstone |1957 (± 30) |2185 (± 44) |+11.65% |
- Microbench does not show significant regression: https://gist.github.com/cbi42/59f280f85a59b678e7e5d8561e693b61
Reviewed By: ajkr
Differential Revision: D38450331
Pulled By: cbi42
fbshipit-source-id: b5ef12e8d8c289ed2e163ccdf277f5039b511fca
Summary:
In leveled compaction, try to trivial move more than one files if possible, up to 4 files or max_compaction_bytes. This is to allow higher write throughput for some use cases where data is loaded in sequential order, where appying compaction results is the bottleneck.
When pick up a file to compact and it doesn't have overlapping files in the next level, try to expand to the next file if there is still no overlapping.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10190
Test Plan:
Add some unit tests.
For performance, Try to run
./db_bench_multi_move --benchmarks=fillseq --compression_type=lz4 --write_buffer_size=5000000 --num=100000000 --value_size=1000 -level_compaction_dynamic_level_bytes
Together with https://github.com/facebook/rocksdb/pull/10188 , stalling will be eliminated in this benchmark.
Reviewed By: jay-zhuang
Differential Revision: D37230647
fbshipit-source-id: 42b260f545c46abc5d90335ac2bbfcd09602b549
Summary:
ToString() is created as some platform doesn't support std::to_string(). However, we've already used std::to_string() by mistake for 16 months (in db/db_info_dumper.cc). This commit just remove ToString().
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9955
Test Plan: Watch CI tests
Reviewed By: riversand963
Differential Revision: D36176799
fbshipit-source-id: bdb6dcd0e3a3ab96a1ac810f5d0188f684064471
Summary:
Right now we still don't fully use std::numeric_limits but use a macro, mainly for supporting VS 2013. Right now we only support VS 2017 and up so it is not a problem. The code comment claims that MinGW still needs it. We don't have a CI running MinGW so it's hard to validate. since we now require C++17, it's hard to imagine MinGW would still build RocksDB but doesn't support std::numeric_limits<>.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9954
Test Plan: See CI Runs.
Reviewed By: riversand963
Differential Revision: D36173954
fbshipit-source-id: a35a73af17cdcae20e258cdef57fcf29a50b49e0
Summary:
As disscussed in (https://github.com/facebook/rocksdb/issues/9223), Here added a new API named DB::OpenAndTrimHistory, this API will open DB and trim data to the timestamp specofied by **trim_ts** (The data with newer timestamp than specified trim bound will be removed). This API should only be used at a timestamp-enabled db instance recovery.
And this PR implemented a new iterator named HistoryTrimmingIterator to support trimming history with a new API named DB::OpenAndTrimHistory. HistoryTrimmingIterator wrapped around the underlying InternalITerator such that keys whose timestamps newer than **trim_ts** should not be returned to the compaction iterator while **trim_ts** is not null.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9410
Reviewed By: ltamasi
Differential Revision: D34410207
Pulled By: riversand963
fbshipit-source-id: e54049dc234eccd673244c566b15df58df5a6236
Summary:
This commit introduces incremental compaction in univeral style for space amplification. This follows the first improvement mentioned in https://rocksdb.org/blog/2021/04/12/universal-improvements.html . The implemention simply picks up files about size of max_compaction_bytes to compact and execute if the penalty is not too big. More optimizations can be done in the future, e.g. prioritizing between this compaction and other types. But for now, the feature is supposed to be functional and can often reduce frequency of full compactions, although it can introduce penalty.
In order to add cut files more efficiently so that more files from upper levels can be included, SST file cutting threshold (for current file + overlapping parent level files) is set to 1.5X of target file size. A 2MB target file size will generate files like this: https://gist.github.com/siying/29d2676fba417404f3c95e6c013c7de8 Number of files indeed increases but it is not out of control.
Two set of write benchmarks are run:
1. For ingestion rate limited scenario, we can see full compaction is mostly eliminated: https://gist.github.com/siying/959bc1186066906831cf4c808d6e0a19 . The write amp increased from 7.7 to 9.4, as expected. After applying file cutting, the number is improved to 8.9. In another benchmark, the write amp is even better with the incremental approach: https://gist.github.com/siying/d1c16c286d7c59c4d7bba718ca198163
2. For ingestion rate unlimited scenario, incremental compaction turns out to be too expensive most of the time and is not executed, as expected.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8655
Test Plan: Add unit tests to the functionality.
Reviewed By: ajkr
Differential Revision: D31787034
fbshipit-source-id: ce813e63b15a61d5a56e97bf8902a1b28e011beb
Summary:
This PR does the following:
-> Makes the MemTableRepFactory into a Customizable class and creatable/configurable via CreateFromString
-> Makes the existing implementations compatible with configurations
-> Moves the "SpecialRepFactory" test class into testutil, accessible via the ObjectRegistry or a NewSpecial API
New tests were added to validate the functionality and all existing tests pass. db_bench and memtablerep_bench were hand-tested to verify the functionality in those tools.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8419
Reviewed By: zhichao-cao
Differential Revision: D29558961
Pulled By: mrambacher
fbshipit-source-id: 81b7229636e4e649a0c914e73ac7b0f8454c931c
Summary:
This appears to be little used code so not a major bug, but is
blocking https://github.com/facebook/rocksdb/issues/8544
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8589
Test Plan:
Added regression test to the end of
DBRangeDelTest::TableEvictedDuringScan. Without this fix, ASAN reports
memory leak.
Reviewed By: ajkr
Differential Revision: D29943623
Pulled By: pdillinger
fbshipit-source-id: f7115fa6d4440aef83888ff609aa03d09216463b
Summary:
The PerThreadDBPath has already specified a slash. It does not need to be specified when initializing the test path.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8555
Reviewed By: ajkr
Differential Revision: D29758399
Pulled By: jay-zhuang
fbshipit-source-id: 6d2b878523e3e8580536e2829cb25489844d9011
Summary:
Fix a bug that for manual compaction, `max_compaction_bytes` is only
limit the SST files from input level, but not overlapped files on output
level.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8269
Test Plan: `make check`
Reviewed By: ajkr
Differential Revision: D28231044
Pulled By: jay-zhuang
fbshipit-source-id: 9d7d03004f30cc4b1b9819830141436907554b7c
Summary:
Return early in case there are zero data blocks when
`BlockBasedTableBuilder::EnterUnbuffered()` is called. This crash can
only be triggered by applying dictionary compression to SST files that
contain only range tombstones. It cannot be triggered by a low buffer
limit alone since we only consider entering unbuffered mode after
buffering a data block causing the limit to be breached, or `Finish()`ing the file. It also cannot
be triggered by a totally empty file because those go through
`Abandon()` rather than `Finish()` so unbuffered mode is never entered.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8141
Test Plan: added a unit test that repro'd the "Floating point exception"
Reviewed By: riversand963
Differential Revision: D27495640
Pulled By: ajkr
fbshipit-source-id: a463cfba476919dc5c5c380800a75a86c31ffa23
Summary:
Consider the following sequence of events:
1. Db flushed an SST with file number N, appended to MANIFEST, and tried to sync the MANIFEST.
2. Syncing MANIFEST failed and db crashed.
3. Db tried to recover with this MANIFEST. In the meantime, no entry about the newly-flushed SST was found in the MANIFEST. Therefore, RocksDB replayed WAL and tried to flush to an SST file reusing the same file number N. This failed because file system does not support overwrite. Then Db deleted this file.
4. Db crashed again.
5. Db tried to recover. When db read the MANIFEST, there was an entry referencing N.sst. This could happen probably because the append in step 1 finally reached the MANIFEST and became visible. Since N.sst had been deleted in step 3, recovery failed.
It is possible that N.sst created in step 1 is valid. Although step 3 would still fail since the MANIFEST was not synced properly in step 1 and 2, deleting N.sst would make it impossible for the db to recover even if the remaining part of MANIFEST was appended and visible after step 5.
After this PR, in step 3, immediately after recovering from MANIFEST, a new MANIFEST is created, then we find that N.sst is not referenced in the MANIFEST, so we delete it, and we'll not reuse N as file number. Then in step 5, since the new MANIFEST does not contain N.sst, the recovery failure situation in step 5 won't happen.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7621
Test Plan:
1. some tests are updated, because these tests assume that new MANIFEST is created after WAL recovery.
2. a new unit test is added in db_basic_test to simulate step 3.
Reviewed By: riversand963
Differential Revision: D24668144
Pulled By: cheng-chang
fbshipit-source-id: 90d7487fbad2bc3714f5ede46ea949895b15ae3b
Summary:
When a WAL is synced, an edit is written to MANIFEST.
After flushing memtables, the obsoleted WALs are piggybacked to MANIFEST while writing the new L0 files to MANIFEST.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7601
Test Plan:
`track_and_verify_wals_in_manifest` is enabled by default for all tests extending `DBBasicTest`, and in db_stress_test.
Unit test `wal_edit_test`, `version_edit_test`, and `version_set_test` are also updated.
Watch all tests to pass.
Reviewed By: ltamasi
Differential Revision: D24553957
Pulled By: cheng-chang
fbshipit-source-id: 66a569ff1bdced38e22900bd240b73113906e040
Summary:
This test often times out in internal test infra.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7637
Test Plan: watch test to pass
Reviewed By: ajkr
Differential Revision: D24763939
Pulled By: cheng-chang
fbshipit-source-id: 6564ee2ef637e9faf6688d4b6a5d74a72a51c5e8
Summary:
After https://github.com/facebook/rocksdb/pull/7036, we still see extra DBTest that can timeout when running 10 or 20 in parallel. Expand skip-fsync mode in whole DBTest. Still preserve other tests from doing this mode to be conservative.
This commit reinstates https://github.com/facebook/rocksdb/issues/7049, whose un-revert was lost in an automatic
infrastructure mis-merge.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7274
Test Plan: Run all existing files.
Reviewed By: pdillinger
Differential Revision: D23177444
fbshipit-source-id: 1f61690b2ac6333c3b2c87176fef6b2cba086b33
Summary:
Cleans up some of the dependencies on test code in the Makefile while building tools:
- Moves the test::RandomString, DBBaseTest::RandomString into Random
- Moves the test::RandomHumanReadableString into Random
- Moves the DestroyDir method into file_utils
- Moves the SetupSyncPointsToMockDirectIO into sync_point.
- Moves the FaultInjection Env and FS classes under env
These changes allow all of the tools to build without dependencies on test_util, thereby simplifying the build dependencies. By moving the FaultInjection code, the dependency in db_stress on different libraries for debug vs release was eliminated.
Tested both release and debug builds via Make and CMake for both static and shared libraries.
More work remains to clean up how the tools are built and remove some unnecessary dependencies. There is also more work that should be done to get the Makefile and CMake to align in their builds -- what is in the libraries and the sizes of the executables are different.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7097
Reviewed By: riversand963
Differential Revision: D22463160
Pulled By: pdillinger
fbshipit-source-id: e19462b53324ab3f0b7c72459dbc73165cc382b2
Summary:
After https://github.com/facebook/rocksdb/pull/7036, we still see extra DBTest that can timeout when running 10 or 20 in parallel. Expand skip-fsync mode in whole DBTest. Still preserve other tests from doing this mode to be conservative.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7049
Test Plan: Run all existing files.
Reviewed By: pdillinger
Differential Revision: D22301700
fbshipit-source-id: f9a9e3b3b26ce640665a47cb8bff33ba0c89b565
Summary:
x.size() -1 or y - 1 can overflow to an extremely large value when x.size() pr y is 0 when they are unsigned type. The end condition of i in the for loop will be extremely large, potentially causes segment fault. Fix them.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6902
Test Plan: pass make asan_check
Reviewed By: ajkr
Differential Revision: D21843767
Pulled By: zhichao-cao
fbshipit-source-id: 5b8b88155ac5a93d86246d832e89905a783bb5a1
Summary:
We found some files containing nothing but negative range tombstones,
and unsurprisingly their metadata specified a negative range, which made
things crash. Time to add a bit of user input validation.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6788
Reviewed By: zhichao-cao
Differential Revision: D21343719
Pulled By: ajkr
fbshipit-source-id: f1c16e4c3e9fa150958c8c866176632a3206fb74
Summary:
When dynamically linking two binaries together, different builds of RocksDB from two sources might cause errors. To provide a tool for user to solve the problem, the RocksDB namespace is changed to a flag which can be overridden in build time.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6433
Test Plan: Build release, all and jtest. Try to build with ROCKSDB_NAMESPACE with another flag.
Differential Revision: D19977691
fbshipit-source-id: aa7f2d0972e1c31d75339ac48478f34f6cfcfb3e
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
Summary:
For more information on the original problem see this [link](https://github.com/facebook/rocksdb/issues/3977).
This change adds two new tests. They are identical other than one uses range tombstones and the other does not. Each test generates sub files at L2 which overlap with keys L3. The test that uses range tombstones generates a single file at L2. This single file will generate a very large range overlap that will in turn create excessively large compaction.
1: T001 - T005
2: 000 - 005
In contrast, the test that uses key ranges generates 3 files at L2. As a single file is compacted at a time, those 3 files will generate less work per compaction iteration.
1: 001 - 002
1: 003 - 004
1: 005
2: 000 - 005
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5956
Differential Revision: D18071631
Pulled By: dlambrig
fbshipit-source-id: 12abae75fb3e0b022d228c6371698aa5e53385df
Summary:
Flush/compaction use `MergeUntil` which has a special code path to
handle a merge ending with a non-`Merge` point key. In particular if
that key is a `Put` we forgot to check whether it is covered by a range
tombstone. If it is covered then we must not include it in the following call
to `TimedFullMerge`.
Fixes#5392.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5406
Differential Revision: D15611144
Pulled By: sagar0
fbshipit-source-id: ba6a7863ca2d043f591de78fd0c4f4561f0c500e
Summary:
There are too many types of files under util/. Some test related files don't belong to there or just are just loosely related. Mo
ve them to a new directory test_util/, so that util/ is cleaner.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5377
Differential Revision: D15551366
Pulled By: siying
fbshipit-source-id: 0f5c8653832354ef8caa31749c0143815d719e2c
Summary:
Depending on the config, manual compaction (leveled compaction style) does following compactions:
L0->L1
L1->L2
...
Ln-1 -> Ln
Ln -> Ln
The final Ln -> Ln compaction is partly unnecessary as it recompacts all the files that were just generated by the Ln-1 -> Ln. We should avoid recompacting such files. This rule should be applied to Lmax only.
Resolves issue https://github.com/facebook/rocksdb/issues/4995
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5138
Differential Revision: D14940106
Pulled By: miasantreble
fbshipit-source-id: 8d3cf5507a17e76f3333cfd4bac5256d005636e5
