rocksdb/env
Andrew Kryczka 072ae671a7 Apply use_direct_io_for_flush_and_compaction to writes only
Summary:
Previously `DBOptions::use_direct_io_for_flush_and_compaction=true` combined with `DBOptions::use_direct_reads=false` could cause RocksDB to simultaneously read from two file descriptors for the same file, where background reads used direct I/O and foreground reads used buffered I/O. Our measurements found this mixed-mode I/O negatively impacted foreground read perf, compared to when only buffered I/O was used.

This PR makes the mixed-mode I/O situation impossible by repurposing `DBOptions::use_direct_io_for_flush_and_compaction` to only apply to background writes, and `DBOptions::use_direct_reads` to apply to all reads. There is no risk of direct background direct writes happening simultaneously with buffered reads since we never read from and write to the same file simultaneously.
Closes https://github.com/facebook/rocksdb/pull/3829

Differential Revision: D7915443

Pulled By: ajkr

fbshipit-source-id: 78bcbf276449b7e7766ab6b0db246f789fb1b279
2018-05-09 19:42:58 -07:00
..
env.cc Apply use_direct_io_for_flush_and_compaction to writes only 2018-05-09 19:42:58 -07:00
env_basic_test.cc Move some files under util/ to separate dirs 2017-04-05 19:09:16 -07:00
env_chroot.cc Change RocksDB License 2017-07-15 16:11:23 -07:00
env_chroot.h Change RocksDB License 2017-07-15 16:11:23 -07:00
env_encryption.cc Fix some typos in comments and docs. 2018-03-08 10:27:25 -08:00
env_hdfs.cc Disallow compactions if there isn't enough free space 2018-03-06 16:27:54 -08:00
env_posix.cc Disallow to open RandomRW file if the file doesn't exist 2018-05-09 10:27:26 -07:00
env_test.cc Disallow to open RandomRW file if the file doesn't exist 2018-05-09 10:27:26 -07:00
io_posix.cc Second attempt at db_stress crash-recovery verification 2018-04-30 12:27:34 -07:00
io_posix.h Second attempt at db_stress crash-recovery verification 2018-04-30 12:27:34 -07:00
mock_env.cc Add virtual Truncate method to Env 2018-04-26 21:12:51 -07:00
mock_env.h Add virtual Truncate method to Env 2018-04-26 21:12:51 -07:00
mock_env_test.cc Move some files under util/ to separate dirs 2017-04-05 19:09:16 -07:00
posix_logger.h Disallow compactions if there isn't enough free space 2018-03-06 16:27:54 -08:00