Summary:
While trying to reuse PinData() / ReleasePinnedData() .. to optimize away some memcpys I realized that there is a significant overhead for using PinData() / ReleasePinnedData if they were called many times.
This diff refactor the pinning logic by introducing PinnedIteratorsManager a centralized component that will be created once and will be notified whenever we need to Pin an Iterator. This implementation have much less overhead than the original implementation
Test Plan:
make check -j64
COMPILE_WITH_ASAN=1 make check -j64
Reviewers: yhchiang, sdong, andrewkr
Reviewed By: andrewkr
Subscribers: andrewkr, dhruba
Differential Revision: https://reviews.facebook.net/D56493
Summary:
After introducing Iterator::PinData(), we have extra overhead of deleting the pinned iterators that we track in a std::set
This patch avoid inserting to the std::set if we have only one iterator (normal use case when no iterators are pinned)
Before this change
```
DEBUG_LEVEL=0 make db_bench -j64 && ./db_bench --benchmarks="newiterator" --db="/tmp/rocksdbtest-8616/dbbench" --use_existing_db --disable_auto_compactions
newiterator : 1.006 micros/op 994013 ops/sec;
newiterator : 0.994 micros/op 1006295 ops/sec;
newiterator : 0.990 micros/op 1010422 ops/sec;
```
After change
```
DEBUG_LEVEL=0 make db_bench -j64 && ./db_bench --benchmarks="newiterator" --db="/tmp/rocksdbtest-8616/dbbench" --use_existing_db --disable_auto_compactions
newiterator : 0.754 micros/op 1326588 ops/sec;
newiterator : 0.759 micros/op 1317394 ops/sec;
newiterator : 0.691 micros/op 1446704 ops/sec;
```
Test Plan: make check -j64
Reviewers: yhchiang, rven, anthony, sdong
Reviewed By: sdong
Subscribers: dhruba
Differential Revision: https://reviews.facebook.net/D52761
Summary:
This patch update the Iterator API to introduce new functions that allow users to keep the Slices returned by key() valid as long as the Iterator is not deleted
ReadOptions::pin_data : If true keep loaded blocks in memory as long as the iterator is not deleted
Iterator::IsKeyPinned() : If true, this mean that the Slice returned by key() is valid as long as the iterator is not deleted
Also add a new option BlockBasedTableOptions::use_delta_encoding to allow users to disable delta_encoding if needed.
Benchmark results (using https://phabricator.fb.com/P20083553)
```
// $ du -h /home/tec/local/normal.4K.Snappy/db10077
// 6.1G /home/tec/local/normal.4K.Snappy/db10077
// $ du -h /home/tec/local/zero.8K.LZ4/db10077
// 6.4G /home/tec/local/zero.8K.LZ4/db10077
// Benchmarks for shard db10077
// _build/opt/rocks/benchmark/rocks_copy_benchmark \
// --normal_db_path="/home/tec/local/normal.4K.Snappy/db10077" \
// --zero_db_path="/home/tec/local/zero.8K.LZ4/db10077"
// First run
// ============================================================================
// rocks/benchmark/RocksCopyBenchmark.cpp relative time/iter iters/s
// ============================================================================
// BM_StringCopy 1.73s 576.97m
// BM_StringPiece 103.74% 1.67s 598.55m
// ============================================================================
// Match rate : 1000000 / 1000000
// Second run
// ============================================================================
// rocks/benchmark/RocksCopyBenchmark.cpp relative time/iter iters/s
// ============================================================================
// BM_StringCopy 611.99ms 1.63
// BM_StringPiece 203.76% 300.35ms 3.33
// ============================================================================
// Match rate : 1000000 / 1000000
```
Test Plan: Unit tests
Reviewers: sdong, igor, anthony, yhchiang, rven
Reviewed By: rven
Subscribers: dhruba, lovro, adsharma
Differential Revision: https://reviews.facebook.net/D48999
Summary:
Separate a new class InternalIterator from class Iterator, when the look-up is done internally, which also means they operate on key with sequence ID and type.
This change will enable potential future optimizations but for now InternalIterator's functions are still the same as Iterator's.
At the same time, separate the cleanup function to a separate class and let both of InternalIterator and Iterator inherit from it.
Test Plan: Run all existing tests.
Reviewers: igor, yhchiang, anthony, kradhakrishnan, IslamAbdelRahman, rven
Reviewed By: rven
Subscribers: leveldb, dhruba
Differential Revision: https://reviews.facebook.net/D48549
Summary: It turns out that -Wshadow has different rules for gcc than clang. Previous commit fixed clang. This commits fixes the rest of the warnings for gcc.
Test Plan: compiles
Reviewers: ljin, yhchiang, rven, sdong
Reviewed By: sdong
Subscribers: dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D28131
Summary:
In this patch, try to allocate the whole iterator tree starting from DBIter from an arena
1. ArenaWrappedDBIter is created when serves as the entry point of an iterator tree, with an arena in it.
2. Add an option to create iterator from arena for following iterators: DBIter, MergingIterator, MemtableIterator, all mem table's iterators, all table reader's iterators and two level iterator.
3. MergeIteratorBuilder is created to incrementally build the tree of internal iterators. It is passed to mem table list and version set and add iterators to it.
Limitations:
(1) Only DB::NewIterator() without tailing uses the arena. Other cases, including readonly DB and compactions are still from malloc
(2) Two level iterator itself is allocated in arena, but not iterators inside it.
Test Plan: make all check
Reviewers: ljin, haobo
Reviewed By: haobo
Subscribers: leveldb, dhruba, yhchiang, igor
Differential Revision: https://reviews.facebook.net/D18513
Summary:
Forward iterator puts everything together in a flat structure instead of
a hierarchy of nested iterators. this should simplify the code and
provide better performance. It also enables more optimization since all
information are accessiable in one place.
Init evaluation shows about 6% improvement
Test Plan: db_test and db_bench
Reviewers: dhruba, igor, tnovak, sdong, haobo
Reviewed By: haobo
Subscribers: sdong, leveldb
Differential Revision: https://reviews.facebook.net/D18795
Summary:
Use autovector in MergingIterator so that if there are 4 or less child iterators in it, iterator wrappers are inline, which is more likely to be cache friendly.
Based on one test run with a shadow traffic of one product, it reduces CPU of MergingIterator::Seek() by half.
Test Plan: make all check
Reviewers: haobo, yhchiang, igor, dhruba
Reviewed By: igor
CC: leveldb
Differential Revision: https://reviews.facebook.net/D18531
Summary:
Change namespace from leveldb to rocksdb. This allows a single
application to link in open-source leveldb code as well as
rocksdb code into the same process.
Test Plan: compile rocksdb
Reviewers: emayanke
Reviewed By: emayanke
CC: leveldb
Differential Revision: https://reviews.facebook.net/D13287
Minor changes:
* Reformat the bodies of the iterator interface routines in IteratorWrapper to
make them a bit easier to read
* Switched the default in the leveldb makefile to be optimized mode, rather
than debug mode
* Fix build problem in chromium port
git-svn-id: https://leveldb.googlecode.com/svn/trunk@30 62dab493-f737-651d-591e-8d6aee1b9529
* Patch LevelDB to build for OSX and iOS
* Fix race condition in memtable iterator deletion.
* Other small fixes.
git-svn-id: https://leveldb.googlecode.com/svn/trunk@29 62dab493-f737-651d-591e-8d6aee1b9529
