6e5aaa85b6
Work in this patch is a result of two bugs - spurious MODIFY event, when remove column is used in `update_item` on non-existing item and spurious events, when batch write item mixed noop operations with operations involving actual changes (the former would still emit cdc log entries). The latter issue required rework of Piotr Wieczorek's algorithm, which fixed former issue as well. Piotr Wieczorek previously wrote checks, that should prevent unnecesary cdc events from being written. His implementation missed the fact, that a single `mutation` object passed to cdc code to be analysed for cdc log entries can contain modifications for multiple rows (with the same timestamp - for example as a result to BatchWriteItem call). His code tries to skip whole `mutation`, which in such case is not possible, because BatchWriteItem might have one item that does nothing and second item that does modification (this is the reason for the second bug). His algorithm was extended and moved. Originally it was working as follows - user would sent a `mutation` object with some changes to be "augmented". The cdc would process those changes and built a set of cdc log changes based on them, that would be added to cdc log table. Piotr added a `should_skip` function, which processes user changes and tried to determine if they all should be dropped or not. New version, instead of trying to skip adding rows to cdc log `mutation` object, builds a rows-to-ignore set. After whole cdc log `mutation` object is completed, it processes it and go through it row by row. Any row that was previously added to a `rows_to_ignore` set will now be removed. Remaining rows are written to new cdc log `mutation` with new clustering key (`cdc$batch_seq_no` index value should probably be consecutive - we just want to be safe here) and returns new `mutation` object to be sent to cdc log table. The first bug is fixed as a side effect of new algorithm, which contains more precise checks detecting, if given mutation actually made a difference. Fixes: #28368 Fixes: SCYLLADB-538 Fixes: SCYLLADB-1528 Refs: #28452
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
-
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.