Summary:
Some APIs for getting live files, which are used by Checkpoint
and BackupEngine, can optionally trigger and wait for a flush. These
would deadlock when used on a read-only DB. Here we fix that by assuming
the user wants the overall operation to succeed and is OK without
flushing (because the DB is read-only).
Follow-up work: the same or other issues can be hit by directly invoking
some DB functions that are clearly not appropriate for read-only
instance, but are not covered by overrides in DBImplReadOnly and
CompactedDBImpl. These should be fixed to avoid similar problems on
accidental misuse. (Long term, it would be nice to have a DBReadOnly
class without those members, like BackupEngineReadOnly.)
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10569
Test Plan: tests updated to catch regression (hang before the fix)
Reviewed By: riversand963
Differential Revision: D38995759
Pulled By: pdillinger
fbshipit-source-id: f5f8bc7123e13cb45bd393dd974d7d6eda20bc68
Peter Dillinger
c5afbbfe4b