Public API Change
- Scheduling flushes and compactions in the same thread pool is no longer supported by setting
max_background_flushes=0. Instead, users can achieve this by configuring their high-pri thread pool to have zero threads. See https://github.com/facebook/rocksdb/wiki/Thread-Pool for more details.
Options::max_background_jobs, which automatically decides how many threads to allocate towards flush/compaction.
- options.delayed_write_rate by default take the value of options.rate_limiter rate.
- Replace global variable
IOStatsContext* get_iostats_context(); replace global variable
- Change ticker/histogram statistics implementations to use core-local storage. This improves aggregation speed compared to our previous thread-local approach, particularly for applications with many threads. See http://rocksdb.org/blog/2017/05/14/core-local-stats.html for more details.
- Users can pass a cache object to write buffer manager, so that they can cap memory usage for memtable and block cache using one single limit.
- Flush will be triggered when 7/8 of the limit introduced by write_buffer_manager or db_write_buffer_size is triggered, so that the hard threshold is hard to hit. See https://github.com/facebook/rocksdb/wiki/Write-Buffer-Manager for more details.
- Introduce WriteOptions.low_pri. If it is true, low priority writes will be throttled if the compaction is behind. See https://github.com/facebook/rocksdb/wiki/Low-Priority-Write for more details.
DB::IngestExternalFile()now supports ingesting files into a database containing range deletions.
- Shouldn’t ignore return value of fsync() in flush.