rocksdb/utilities/blob_db
Peter Dillinger ef443cead4 Refactor to avoid confusing "raw block" (#10408)
Summary:
We have a lot of confusing code because of mixed, sometimes
completely opposite uses of of the term "raw block" or "raw contents",
sometimes within the same source file. For example, in `BlockBasedTableBuilder`,
`raw_block_contents` and `raw_size` generally referred to uncompressed block
contents and size, while `WriteRawBlock` referred to writing a block that
is already compressed if it is going to be. Meanwhile, in
`BlockBasedTable`, `raw_block_contents` either referred to a (maybe
compressed) block with trailer, or a maybe compressed block maybe
without trailer. (Note: left as follow-up work to use C++ typing to
better sort out the various kinds of BlockContents.)

This change primarily tries to apply some consistent terminology around
the kinds of block representations, avoiding the unclear "raw". (Any
meaning of "raw" assumes some bias toward the storage layer or toward
the logical data layer.) Preferred terminology:

* **Serialized block** - bytes that go into storage. For block-based table
(usually the case) this includes the block trailer. WART: block `size` may or
may not include the trailer; need to be clear about whether it does or not.
* **Maybe compressed block** - like a serialized block, but without the
trailer (or no promise of including a trailer). Must be accompanied by a
CompressionType.
* **Uncompressed block** - "payload" bytes that are either stored with no
compression, used as input to compression function, or result of
decompression function.
* **Parsed block** - an in-memory form of a block in block cache, as it is
used by the table reader. Different C++ types are used depending on the
block type (see block_like_traits.h).

Other refactorings:
* Misc corrections/improvements of internal API comments
* Remove a few misleading / unhelpful / redundant comments.
* Use move semantics in some places to simplify contracts
* Use better parameter names to indicate which parameters are used for
outputs
* Remove some extraneous `extern`
* Various clean-ups to `CacheDumperImpl` (mostly unnecessary code)

Pull Request resolved: https://github.com/facebook/rocksdb/pull/10408

Test Plan: existing tests

Reviewed By: akankshamahajan15

Differential Revision: D38172617

Pulled By: pdillinger

fbshipit-source-id: ccb99299f324ac5ca46996d34c5089621a4f260c
2022-09-22 11:25:32 -07:00
..
blob_compaction_filter.cc Cleanup includes in dbformat.h (#8930) 2021-09-29 04:04:40 -07:00
blob_compaction_filter.h Use SystemClock* instead of std::shared_ptr<SystemClock> in lower level routines (#8033) 2021-03-15 04:34:11 -07:00
blob_db.cc Cleanup includes in dbformat.h (#8930) 2021-09-29 04:04:40 -07:00
blob_db.h Revise APIs related to user-defined timestamp (#8946) 2022-02-01 22:19:01 -08:00
blob_db_gc_stats.h Fix and detect headers with missing dependencies (#8893) 2021-09-10 10:00:26 -07:00
blob_db_impl.cc Refactor to avoid confusing "raw block" (#10408) 2022-09-22 11:25:32 -07:00
blob_db_impl.h Revise APIs related to user-defined timestamp (#8946) 2022-02-01 22:19:01 -08:00
blob_db_impl_filesnapshot.cc Fix FileStorageInfo fields from GetLiveFilesMetaData (#9769) 2022-03-29 14:36:35 -07:00
blob_db_iterator.h Use SystemClock* instead of std::shared_ptr<SystemClock> in lower level routines (#8033) 2021-03-15 04:34:11 -07:00
blob_db_listener.h Make EventListener into a Customizable Class (#8473) 2021-07-27 07:47:02 -07:00
blob_db_test.cc Remove own ToString() (#9955) 2022-05-06 13:03:58 -07:00
blob_dump_tool.cc Refactor to avoid confusing "raw block" (#10408) 2022-09-22 11:25:32 -07:00
blob_dump_tool.h Move blob_log_{format,reader,writer}.{cc,h} to db/blob/ (#6960) 2020-06-09 15:16:05 -07:00
blob_file.cc Add rate limiter priority to ReadOptions (#9424) 2022-02-16 23:18:14 -08:00
blob_file.h Remove Legacy and Custom FileWrapper classes from header files (#7851) 2021-01-28 22:10:32 -08:00