Adam Retter [Thu, 8 Mar 2018 19:16:46 +0000 (11:16 -0800)]
Java wrapper for Native Comparators
Summary:
This is an abstraction for working with custom Comparators implemented in native C++ code from Java. Native code must directly extend `rocksdb::Comparator`. When the native code comparator is compiled into the RocksDB codebase, you can then create a Java Class, and JNI stub to wrap it.
Useful if the C++/JNI barrier overhead is too much for your applications comparator performance.
An example is provided in `java/rocksjni/native_comparator_wrapper_test.cc` and `java/src/main/java/org/rocksdb/NativeComparatorWrapperTest.java`.
Closes https://github.com/facebook/rocksdb/pull/3334
Summary:
`ReadaheadRandomAccessFile` is used by iterators for file reads in several cases, like in compaction when `compaction_readahead_size > 0` or `use_direct_io_for_flush_and_compaction == true`, or in user iterator when `ReadOptions::readahead_size > 0`. `ReadaheadRandomAccessFile` maintains an internal buffer for readahead data. It assumes that, if the buffer's length is less than `ReadaheadRandomAccessFile::readahead_size_`, which is fixed in the constructor, then EOF has been reached so it doesn't try reading further.
Recently, d938226af405681c592f25310f41c0c933bcdb19 started calling `RandomAccessFile::Prefetch` with various lengths: 8KB, 16KB, etc. When the `RandomAccessFile` is a `ReadaheadRandomAccessFile`, it triggers the above condition and incorrectly determines EOF. If a block is partially in the readahead buffer and EOF is incorrectly decided, the result is a truncated data block.
Summary:
Use the rsync tempfile naming convention in our `BackupEngine`. The temp file follows the format, `.<filename>.<suffix>`, which is later renamed to `<filename>`. We fix `tmp` as the `<suffix>` as we don't need to use random bytes for now. The benefit is gluster treats this tempfile naming convention specially and applies hashing only to `<filename>`, so the file won't need to be linked or moved when it's renamed. Our gluster team suggested this will make things operationally easier.
Closes https://github.com/facebook/rocksdb/pull/3463
This is due to two reasons:
1. The new Snappy packages should now be downloaded from https://github.com/google/snappy/archive/<pkg.tar.gz> instead of https://github.com/google/snappy/releases/download/<pkg.tar.gz> which we are using now.
1. In addition to the the above URL change, Snappy changed its build from using autotools to CMake based : https://github.com/google/snappy/blame/e69d9f880677f2aa3488c80b953ec4309f0dfa2e/README.md#L65-L72
So more changes are needed if we are going to upgrade to 1.1.7. Hence reverting the version upgrade until we figure them out.
Closes https://github.com/facebook/rocksdb/pull/3363
Sagar Vemuri [Wed, 21 Feb 2018 03:05:21 +0000 (19:05 -0800)]
Add rocksdb.iterator.internal-key property
Summary:
Added a new iterator property: `rocksdb.iterator.internal-key` to get the internal-key (converted to user key) at which the iterator stopped.
Closes https://github.com/facebook/rocksdb/pull/3525
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