bb1867c7c7
This PR builds upon the PR for checksum validation (#20207) to further enhance scrub's corruption detection capabilities by validating digests as well. The digest (full checksum) is the checksum over the entire data, as opposed to per-chunk checksums which apply to individual chunks. Until now, digests were not examined on any code paths. This PR integrates digest checking into the compressed/checksummed data sources as an optional feature and enables it only through the validation path of the sstable layer (`sstable::validate()`). The validation path is used by the following tools: * scrub in validate mode * `sstable validate` All other reads, including normal user reads, are unaffected by this change. The PR consists of: * Extensions to the compressed and checksummed data sources to support digest checking. The data sources receive the expected digest as a parameter and calculate the actual digest incrementally across multiple get() calls. The check happens on the get() call that reaches EOF and results to an exception if the digest is invalid. A digest check requires reading the whole file range. Therefore, a partial read or skip() is treated as an internal error. * A new shareable digest component loaded on demand by the validation code. No lifecycle management. * Grouping of old scrub/validate tests for compressed and uncompressed SSTables to reduce code duplication. * scrub/validate tests for SSTables with valid checksums but invalid digests, and SSTables with no digests at all. * scrub/validate tests with 3.x Cassandra SSTables to ensure compatibility. Refs #19058. New feature, no backport is needed. Closes scylladb/scylladb#20720 * github.com:scylladb/scylladb: test: Test scrub/validate with SSTables from Cassandra compaction: Make quarantine optional for perform_sstable_scrub() test: Make random schema optional in scrub_test_framework test: Add tests for invalid digests test: Merge scrub/validate tests for compressed and uncompressed cases sstables: Verify digests on validation path sstables: Check if digest component exists sstables: Add digest in the SSTable components sstables: Add digest check in compressed data source sstables: Add digest check in checksummed data source
Scylla
What is Scylla?
Scylla is the real-time big data database that is API-compatible with Apache Cassandra and Amazon DynamoDB. Scylla embraces a shared-nothing approach that increases throughput and storage capacity to realize order-of-magnitude performance improvements and reduce hardware costs.
For more information, please see the ScyllaDB web site.
Build Prerequisites
Scylla is fairly fussy about its build environment, requiring very recent versions of the C++23 compiler and of many libraries to build. The document HACKING.md includes detailed information on building and developing Scylla, but to get Scylla building quickly on (almost) any build machine, Scylla offers a frozen toolchain, This is a pre-configured Docker image which includes recent versions of all the required compilers, libraries and build tools. Using the frozen toolchain allows you to avoid changing anything in your build machine to meet Scylla's requirements - you just need to meet the frozen toolchain's prerequisites (mostly, Docker or Podman being available).
Building Scylla
Building Scylla with the frozen toolchain dbuild is as easy as:
$ git submodule update --init --force --recursive
$ ./tools/toolchain/dbuild ./configure.py
$ ./tools/toolchain/dbuild ninja build/release/scylla
For further information, please see:
- Developer documentation for more information on building Scylla.
- Build documentation on how to build Scylla binaries, tests, and packages.
- Docker image build documentation for information on how to build Docker images.
Running Scylla
To start Scylla server, run:
$ ./tools/toolchain/dbuild ./build/release/scylla --workdir tmp --smp 1 --developer-mode 1
This will start a Scylla node with one CPU core allocated to it and data files stored in the tmp directory.
The --developer-mode is needed to disable the various checks Scylla performs at startup to ensure the machine is configured for maximum performance (not relevant on development workstations).
Please note that you need to run Scylla with dbuild if you built it with the frozen toolchain.
For more run options, run:
$ ./tools/toolchain/dbuild ./build/release/scylla --help
Testing
See test.py manual.
Scylla APIs and compatibility
By default, Scylla is compatible with Apache Cassandra and its API - CQL. There is also support for the API of Amazon DynamoDB™, which needs to be enabled and configured in order to be used. For more information on how to enable the DynamoDB™ API in Scylla, and the current compatibility of this feature as well as Scylla-specific extensions, see Alternator and Getting started with Alternator.
Documentation
Documentation can be found here. Seastar documentation can be found here. User documentation can be found here.
Training
Training material and online courses can be found at Scylla University. The courses are free, self-paced and include hands-on examples. They cover a variety of topics including Scylla data modeling, administration, architecture, basic NoSQL concepts, using drivers for application development, Scylla setup, failover, compactions, multi-datacenters and how Scylla integrates with third-party applications.
Contributing to Scylla
If you want to report a bug or submit a pull request or a patch, please read the contribution guidelines.
If you are a developer working on Scylla, please read the developer guidelines.
Contact
- The community forum and Slack channel are for users to discuss configuration, management, and operations of the ScyllaDB open source.
- The developers mailing list is for developers and people interested in following the development of ScyllaDB to discuss technical topics.