7900aa5319
Previously, the scheduling_group column was updated during the switch_tenant function, which meant the update occurred only after the tenant change operation completed—updating rows one by one. With this change, the scheduling_group column is now updated before the switch_tenant logic runs, ensuring that the table reflects the correct scheduling groups for all rows as early as possible. fixes: #26060 fixes: #27295 backport: not required this is a minor bug fix. Internal logic worked but the user couldnt see the change in the table if they would read the system.clients table Closes scylladb/scylladb#26404 * github.com:scylladb/scylladb: test: cqlpy: Remove test_switch_tenants and add test in cluster testing. The test needs to run twice, in two separate Scylla runs, using two different modes: gossip and raft. The cluster framework supports this setup, while cqlpy only runs against Scylla instances in raft mode. Therefore, the test was moved from cqlpy to the cluster-based framework. This commit both adds the test in cluster/ and removes the old version in cqlpy/. server: Refactor update_control_connection_scheduling_group functionality This refactoring moves the logic that retrieves the scheduling group for driver_service_level_name out of switch_tenant. This change is possible because the scheduling group for the driver is retrieved from a map (LOOKUP). The lookup function is fully synchronized, non-coroutine, and returns immediately. For that reason, it’s better to perform this lookup outside of the switch_tenant function. server: Refactor scheduling group update functionality. This change generalizes the scheduling-group update functionality and removes some copy-paste code, improving overall readability and maintainability. To achieve this, capturing lambdas were introduced. As a result, self-deducing this was added to those lambdas to avoid coroutine-related issues (“coroutine fiasco”). server: Fix switch_tenant problem, When running on a V2 server, service-level data comes from service level cache. Because of this, we can use synchronized function to get the schedualing group. Since we are transitioning to a Raft-based architecture where all servers will be V2, we can safely implement this fix specifically for that case. This change adds get_cached_user_scheduling_group functionality and moves its usage out of switch_tenant function in update_scheduling_group_v2 usage. server: Add update_service_level_scheduling_group_v1 functions to create placehholder for functionality that will introduce v2 implementation. The new functionality will allow usage of service level cache
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.