81e214237f
This pull request adds support for calculation and storing CRC32 digests for all SSTable components. This change replaces plain file_writer with crc32_digest_file_writer for all SSTable components that should be checksummed. The resulting component digests are stored in the sstable structure and later persisted to disk as part of the Scylla metadata component during writer::consume_end_of_stream. Several test cases where introduced to verify expected behaviour. Additionally, this PR adds new rewrite component mechanism for safe sstable component rewriting. Previously, rewriting an sstable component (e.g., via rewrite_statistics) created a temporary file that was renamed to the final name after sealing. This allowed crash recovery by simply removing the temporary file on startup. However, with component digests stored in scylla_metadata (#20100), replacing a component like Statistics requires atomically updating both the component and scylla_metadata with the new digest - impossible with POSIX rename. The new mechanism creates a clone sstable with a fresh generation: - Hard-links all components from the source except the component being rewritten and scylla_metadata - Copies original sstable components pointer and recognized components from the source - Invokes a modifier callback to adjust the new sstable before rewriting - Writes the modified component along with updated scylla_metadata containing the new digest - Seals the new sstable with a temporary TOC - Replaces the old sstable atomically, the same way as it is done in compaction This is built on the rewrite_sstables compaction framework to support batch operations (e.g., following incremental repair). In case of any failure durning the whole process, sstable will be automatically deleted on the node startup due to temporary toc persistence. Backport is not required, it is a new feature Fixes https://github.com/scylladb/scylladb/issues/20100, https://github.com/scylladb/scylladb/issues/27453 Closes scylladb/scylladb#28338 * github.com:scylladb/scylladb: docs: document components_digests subcomponent and trailing digest in Scylla.db sstable_compaction_test: Add tests for perform_component_rewrite sstable_test: add verification testcases of SSTable components digests persistance sstables: store digest of all sstable components in scylla metadata sstables: replace rewrite_statistics with new rewrite component mechanism sstables: add new rewrite component mechanism for safe sstable component rewriting compaction: add compaction_group_view method to specify sstable version sstables: add null_data_sink and serialized_checksum for checksum-only calculation sstables: extract default write open flags into a constant sstables: Add write_simple_with_digest for component checksumming sstables: Extract file writer closing logic into separate methods sstables: Implement CRC32 digest-only writer
ScyllaDB Documentation
This repository contains the source files for ScyllaDB documentation.
- The
devfolder contains developer-oriented documentation related to the ScyllaDB code base. It is not published and is only available via GitHub. - All other folders and files contain user-oriented documentation related to ScyllaDB and are sources for docs.scylladb.com/manual.
To report a documentation bug or suggest an improvement, open an issue in GitHub issues for this project.
To contribute to the documentation, open a GitHub pull request.
Key Guidelines for Contributors
- The user documentation is written in reStructuredText (RST) - a plaintext markup language similar to Markdown. If you're not familiar with RST, see ScyllaDB RST Examples.
- The developer documentation is written in Markdown. See Basic Markdown Syntax for reference.
- Follow the ScyllaDB Style Guide.
To prevent the build from failing:
-
If you add a new file, ensure it's added to an appropriate toctree, for example:
.. toctree:: :maxdepth: 2 :hidden: Page X </folder1/article1> Page Y </folder1/article2> Your New Page </folder1/your-new-article> -
Make sure the link syntax is correct. See the guidelines on creating links
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Make sure the section headings are correct. See the guidelines on creating headings Note that the markup must be at least as long as the text in the heading. For example:
---------------------- Prerequisites ----------------------
Building User Documentation
Prerequisites
- Python
- poetry
- make
See the ScyllaDB Sphinx Theme prerequisites to check which versions of the above are currently required.
Mac OS X
You must have a working Homebrew in order to install the needed tools.
You also need the standard utility make.
Check if you have these two items with the following commands:
brew help
make -h
Linux Distributions
Building the user docs should work out of the box on most Linux distributions.
Windows
Use "Bash on Ubuntu on Windows" for the same tools and capabilities as on Linux distributions.
Building the Docs
- Run
make previewin thedocs/directory to build the documentation. - Preview the built documentation locally at http://127.0.0.1:5500/.
Cleanup
You can clean up all the build products and auto-installed Python stuff with:
make pristine
Information for Contributors
If you are interested in contributing to Scylla docs, please read the Scylla open source page at http://www.scylladb.com/opensource/ and complete a Scylla contributor agreement if needed. We can only accept documentation pull requests if we have a contributor agreement on file for you.
Third-party Documentation
-
Do any copying as a separate commit. Always commit an unmodified version first and then do any editing in a separate commit.
-
We already have a copy of the Apache license in our tree, so you do not need to commit a copy of the license.
-
Include the copyright header from the source file in the edited version. If you are copying an Apache Cassandra document with no copyright header, use:
This document includes material from Apache Cassandra.
Apache Cassandra is Copyright 2009-2014 The Apache Software Foundation.