rocksdb/db/db_impl
Peter Dillinger 0646ec6e2d Ensure Close() before LinkFile() for WALs in Checkpoint (#12734)
Summary:
POSIX semantics for LinkFile (hard links) allow linking a file
that is still being written two, with both the source and destination
showing any subsequent writes to the source. This may not be practical
semantics for some FileSystem implementations such as remote storage.
They might only link the flushed or sync-ed file contents at time of
LinkFile, or might even have undefined behavior if LinkFile is called on
a file still open for write (not yet "sealed"). This change builds on https://github.com/facebook/rocksdb/issues/12731
to bring more hygiene to our handling of WAL files in Checkpoint.

Specifically, we now Close WAL files as soon as they are either
(a) inactive and fully synced, or (b) inactive and obsolete (so maybe
never fully synced), rather than letting Close() happen in handling
obsolete files (maybe a background thread). This should not be a
performance issue as Close() should be trivial cost relative to other
IO ops, but just in case:
* We don't Close() while holding a mutex, to avoid blocking, and
* The old behavior is available with a new kill switch option
  `background_close_inactive_wals`.

Stacked on https://github.com/facebook/rocksdb/issues/12731

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12734

Test Plan:
Extended existing unit test, especially adding a hygiene
check to FaultInjectionTestFS to detect LinkFile() on a file still open
for writes. FaultInjectionTestFS already has relevant tracking data, and
tests can opt out of the new check, as in a smoke test I have left for
the old, deprecated functionality `background_close_inactive_wals=true`.

Also ran lengthy blackbox_crash_test to ensure the hygiene check is OK
with the crash test. (The only place I can find we use LinkFile in
production is Checkpoint.)

Reviewed By: cbi42

Differential Revision: D58295284

Pulled By: pdillinger

fbshipit-source-id: 64d90ed8477e2366c19eaf9c4c5ad60b82cac5c6
2024-06-12 11:48:45 -07:00
..
compacted_db_impl.cc Run internal cpp modernizer on RocksDB repo (#12398) 2024-03-04 10:08:32 -08:00
compacted_db_impl.h Deprecate some variants of Get and MultiGet (#12327) 2024-02-16 09:21:06 -08:00
db_impl.cc Ensure Close() before LinkFile() for WALs in Checkpoint (#12734) 2024-06-12 11:48:45 -07:00
db_impl.h Add a OnManualFlushScheduled callback in event listener (#12631) 2024-06-06 17:29:01 -07:00
db_impl_compaction_flush.cc Add a OnManualFlushScheduled callback in event listener (#12631) 2024-06-06 17:29:01 -07:00
db_impl_debug.cc Prefer static_cast in place of most reinterpret_cast (#12308) 2024-02-07 10:44:11 -08:00
db_impl_experimental.cc Run internal cpp modernizer on RocksDB repo (#12398) 2024-03-04 10:08:32 -08:00
db_impl_files.cc Ensure Close() before LinkFile() for WALs in Checkpoint (#12734) 2024-06-12 11:48:45 -07:00
db_impl_follower.cc Add LDB command and option for follower instances (#12682) 2024-05-28 23:21:32 -07:00
db_impl_follower.h Implement obsolete file deletion (GC) in follower (#12657) 2024-05-17 19:13:33 -07:00
db_impl_open.cc Fix delete obsolete files on recovery not rate limited (#12590) 2024-05-01 12:26:54 -07:00
db_impl_readonly.cc Run internal cpp modernizer on RocksDB repo (#12398) 2024-03-04 10:08:32 -08:00
db_impl_readonly.h Remove the force mode for EnableFileDeletions API (#12337) 2024-02-13 18:36:25 -08:00
db_impl_secondary.cc Implement obsolete file deletion (GC) in follower (#12657) 2024-05-17 19:13:33 -07:00
db_impl_secondary.h Basic RocksDB follower implementation (#12540) 2024-04-19 19:13:31 -07:00
db_impl_write.cc Add a OnManualFlushScheduled callback in event listener (#12631) 2024-06-06 17:29:01 -07:00