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
RocksDB: A Persistent Key-Value Store for Flash and RAM Storage
RocksDB is developed and maintained by Facebook Database Engineering Team. It is built on earlier work on LevelDB by Sanjay Ghemawat (sanjay@google.com) and Jeff Dean (jeff@google.com)
This code is a library that forms the core building block for a fast key-value server, especially suited for storing data on flash drives. It has a Log-Structured-Merge-Database (LSM) design with flexible tradeoffs between Write-Amplification-Factor (WAF), Read-Amplification-Factor (RAF) and Space-Amplification-Factor (SAF). It has multi-threaded compactions, making it especially suitable for storing multiple terabytes of data in a single database.
Start with example usage here: https://github.com/facebook/rocksdb/tree/main/examples
See the github wiki for more explanation.
The public interface is in include/. Callers should not include or
rely on the details of any other header files in this package. Those
internal APIs may be changed without warning.
Questions and discussions are welcome on the RocksDB Developers Public Facebook group and email list on Google Groups.
License
RocksDB is dual-licensed under both the GPLv2 (found in the COPYING file in the root directory) and Apache 2.0 License (found in the LICENSE.Apache file in the root directory). You may select, at your option, one of the above-listed licenses.