Revision 4fc216649ddb40763963140eac3eb95890b32486 authored by Cheng Chang on 20 March 2020, 23:15:40 UTC, committed by Facebook GitHub Bot on 20 March 2020, 23:33:26 UTC
Summary: By supporting direct IO in RandomAccessFileReader::MultiRead, the benefits of parallel IO (IO uring) and direct IO can be combined. In direct IO mode, read requests are aligned and merged together before being issued to RandomAccessFile::MultiRead, so blocks in the original requests might share the same underlying buffer, the shared buffers are returned in `aligned_bufs`, which is a new parameter of the `MultiRead` API. For example, suppose alignment requirement for direct IO is 4KB, one request is (offset: 1KB, len: 1KB), another request is (offset: 3KB, len: 1KB), then since they all belong to page (offset: 0, len: 4KB), `MultiRead` only reads the page with direct IO into a buffer on heap, and returns 2 Slices referencing regions in that same buffer. See `random_access_file_reader_test.cc` for more examples. Pull Request resolved: https://github.com/facebook/rocksdb/pull/6446 Test Plan: Added a new test `random_access_file_reader_test.cc`. Reviewed By: anand1976 Differential Revision: D20097518 Pulled By: cheng-chang fbshipit-source-id: ca48a8faf9c3af146465c102ef6b266a363e78d1
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| File | Mode | Size |
|---|---|---|
| .gitignore | -rw-r--r-- | 200 bytes |
| Makefile | -rw-r--r-- | 2.5 KB |
| README.md | -rw-r--r-- | 120 bytes |
| c_simple_example.c | -rw-r--r-- | 2.6 KB |
| column_families_example.cc | -rw-r--r-- | 2.0 KB |
| compact_files_example.cc | -rw-r--r-- | 5.7 KB |
| compaction_filter_example.cc | -rw-r--r-- | 3.0 KB |
| multi_processes_example.cc | -rw-r--r-- | 11.8 KB |
| optimistic_transaction_example.cc | -rw-r--r-- | 5.0 KB |
| options_file_example.cc | -rw-r--r-- | 4.0 KB |
| rocksdb_option_file_example.ini | -rw-r--r-- | 4.6 KB |
| simple_example.cc | -rw-r--r-- | 2.4 KB |
| transaction_example.cc | -rw-r--r-- | 5.3 KB |
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