Ben Clay [Fri, 15 Sep 2017 01:18:49 +0000 (18:18 -0700)]
JNI support for ReadOptions::iterate_upper_bound
Summary:
Plumbed ReadOptions::iterate_upper_bound through JNI.
Made the following design choices:
* Used Slice instead of AbstractSlice due to the anticipated usecase (key / key prefix). Can change this if anyone disagrees.
* Used Slice instead of raw byte[] which seemed cleaner but necessitated the package-private handle-based Slice constructor. Followed WriteBatch as an example.
* We need a copy constructor for ReadOptions, as we create one base ReadOptions for a particular usecase and clone -> change the iterate_upper_bound on each slice operation. Shallow copy seemed cleanest.
* Hold a reference to the upper bound slice on ReadOptions, in contrast to Snapshot.
Signed a Facebook CLA this morning.
Closes https://github.com/facebook/rocksdb/pull/2872
Summary:
Three small optimizations:
(1) iter_->IsKeyPinned() shouldn't be called if read_options.pin_data is not true. This may trigger function call all the way down the iterator tree.
(2) reuse the iterator key object in DBIter::FindNextUserEntryInternal(). The constructor of the class has some overheads.
(3) Move the switching direction logic in MergingIterator::Next() to a separate function.
These three in total improves readseq performance by about 3% in my benchmark setting.
Closes https://github.com/facebook/rocksdb/pull/2880
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
Remove 'experimental' comment around level_compaction_dynamic_level_bytes option
Summary:
Remove misleading 'experimental' comment around `level_compaction_dynamic_level_bytes` option. This is not experimental anymore and is ready for wider adoption. MyRocks is already using it in production.
Closes https://github.com/facebook/rocksdb/pull/2878
Non-empty `level0_compactions_in_progress_` was aborting `CompactFiles` after incrementing `bg_compaction_scheduled_`, and in that case we never decremented it. This blocked future compactions and prevented DB close as we wait for scheduled compactions to finish/abort during close.
I eliminated `CompactFiles`'s dependency on `level0_compactions_in_progress_`. Since it takes a contiguous span of L0 files -- through the last L0 file if any L1+ files are included -- it's fine to run in parallel with other compactions involving L0. We make the same assumption in intra-L0 compaction.
Closes https://github.com/facebook/rocksdb/pull/2849
Summary:
We had two proposals for lock-free commit maps. This patch implements the latter one that was simpler. We can later experiment with both proposals.
In this impl each entry is an std::atomic of uint64_t, which are accessed via memory_order_acquire/release. In x86_64 arch this is compiled to simple reads and writes from memory.
Closes https://github.com/facebook/rocksdb/pull/2861
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