71542206bc
When a partition key or clustering key value exceeds the 64 KiB limit (65535 bytes serialized), Scylla used to raise a generic std::runtime_error "Key size too large: N > M" from the low-level compound-key serializer. That error surfaced to clients as a CQL server error (code 0x0000, "NoHostAvailable"-looking), which is both ugly and incompatible with Cassandra - Cassandra returns a clean InvalidRequest with the message "Key length of N is longer than maximum of M". Fix this at the single chokepoint: compound_type::serialize_value in keys/compound.hh. The serializer is on every path that materializes a key - INSERT/UPDATE/DELETE/BATCH build mutations through it, and SELECT builds partition and clustering ranges through it - so a single throw replacement produces a clean InvalidRequest consistently across all paths and all key shapes (single, compound PK, composite CK). The previous approach on this PR branch patched three call sites in cql3/restrictions/statement_restrictions.cc, which only covered SELECT, duplicated the check, and placed it mid-restrictions code (flagged in review). Dropping those changes in favour of the root-cause fix here. Un-xfail the tests this fixes: - test/cqlpy/test_key_length.py: test_insert_65k_pk, test_insert_65k_ck, test_where_65k_pk, test_where_65k_ck, test_insert_65k_ck_composite, test_insert_total_compound_pk_err, test_insert_total_composite_ck_err. - test/cqlpy/cassandra_tests/.../insert_test.py: testPKInsertWithValueOver64K, testCKInsertWithValueOver64K. - test/cqlpy/cassandra_tests/.../select_test.py: testPKQueryWithValueOver64K. test_insert_65k_pk_compound stays xfail: its oversized value gets rejected by the Python driver's CQL wire-protocol encoder (see CASSANDRA-19270) before reaching the server, so the fix can't apply. Updated its reason. testCKQueryWithValueOver64K stays xfail with an updated reason: Cassandra silently returns empty for an oversized clustering key in WHERE, while Scylla now throws InvalidRequest - a deliberate choice mirroring the partition-key case, documented in the discussion on #10366. Add three tight-boundary tests (addressing review feedback on the previous revision) that pin MAX+1 behaviour for SELECT and INSERT of both partition and clustering keys. Update test/cluster/dtest/limits_test.py to match the new message ("Key length of \\d+ is longer than maximum of 65535"). fixes #10366 fixes #12247 Co-authored-by: Alexander Turetskiy <someone.tur@gmail.com> Closes scylladb/scylladb#23433
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 ScyllaDB.
- The developers mailing list is for developers and people interested in following the development of ScyllaDB to discuss technical topics.