fork of https://github.com/oxigraph/rocksdb and https://github.com/facebook/rocksdb for nextgraph and oxigraph

Andrew Kryczka 0cdaa1a804 Fix WAL corruption from checkpoint/backup race condition ... Summary: `Writer::WriteBuffer` was always called at the beginning of checkpoint/backup. But that log writer has no internal synchronization, which meant the same buffer could be flushed twice in a race condition case, causing a WAL entry to be duplicated. Then subsequent WAL entries would be at unexpected offsets, causing the 32KB block boundaries to be overlapped and manifesting as a corruption. This PR fixes the behavior to only use `WriteBuffer` (via `FlushWAL`) in checkpoint/backup when manual WAL flush is enabled. In that case, users are responsible for providing synchronization between WAL flushes. We can also consider removing the call entirely. Closes https://github.com/facebook/rocksdb/pull/3603 Differential Revision: D7277447 Pulled By: ajkr fbshipit-source-id: 1b15bd7fd930511222b075418c10de0aaa70a35a		7 years ago
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checkpoint_impl.cc	Fix WAL corruption from checkpoint/backup race condition	7 years ago
checkpoint_impl.h	Change RocksDB License	8 years ago
checkpoint_test.cc	fix handling of empty string as checkpoint directory	7 years ago