mirror of
https://github.com/facebook/rocksdb.git
synced 2026-07-07 14:47:40 +08:00
Peter Dillinger
741539da9b
Summary: D110140135/https://github.com/facebook/rocksdb/issues/14896 worked around a db_stress failure by disabling test_backward_scan whenever embedded-blob SSTs are ingested. The real limitation was in EmbeddedBlobResolvingIterator: DBIter requires the underlying iterator's value to be pinned for backward iteration (Prev/SeekForPrev), and rebuilt wide-column entity values (with same-file blob columns) were stored in an iterator-owned std::string that was cleared on every reposition, so IsValuePinned() returned false and DBIter returned NotSupported (or tripped the IsValuePinned() assertion in FindValueForCurrentKeyUsingSeek). Whole-value same-file blobs were already pinned and worked. This change makes the rebuilt wide-column value pinnable like a whole-value blob: it is moved into a heap buffer and pinned into resolved_pinned_value_, whose cleanup ResetState() hands to the PinnedIteratorsManager across repositioning so the value survives backward iteration. The now-redundant resolved_value_ member is removed and value()/IsValuePinned() simplified. The Get/MultiGet resolution path (MaybeResolveEmbeddedValue) is unchanged. The db_stress test_backward_scan workaround is removed now that backward iteration over embedded blobs (including wide-column entities) is supported. Pull Request resolved: https://github.com/facebook/rocksdb/pull/14902 Test Plan: Added DBBlobIndexTest.EmbeddedBlobBackwardIteration: ingests an embedded-blob SST with whole-value blobs plus a mixed wide-column entity (inline default column + embedded same-file blob column), then iterates backward via SeekToLast/Prev and SeekForPrev, verifying values and columns. Verified it fails before the fix (NotSupported at the entity) and passes after. Full db_blob_index_test and sst_file_reader_test suites pass. make format-auto clean. Direct db_stress run with ingest_external_file_with_embedded_blobs=1, use_put_entity_one_in=3, test_backward_scan=1, iterpercent>0 ran with no divergence/NotSupported/ assert. Reviewed By: anand1976 Differential Revision: D110271453 Pulled By: pdillinger fbshipit-source-id: 501a50d3c97bac9a217b604c43c8748abbb563c9