b72906518f
This patch makes all cql connections update theirs service level parameters automatically when:
- any service level is created or changed
- one role is granted to another
- any service level is attached to/detached from a role
First of all, the patch defines what a service level and an effective service level are 938aa10509. No new type of service levels are introduced, the commit only clarifies definitions and names what an effective service level is.
(Effective service level is created by merging all service levels which are attached to all roles granted to the user. It represents exact values of connection's parameters.)
Previously, to find an effective service level of a user, it required O(n) internal queries: O(n) queries to recursively find all granted roles (`standard_role_manager::query_granted()`) and a query for each role to get its service level (`standard_role_manager::get_attribute()`, which sums to O(n) queries).
Because we want to reload SL parameters for all opened cql connections, we don't want to do O(n) queries for every connection, every time we create or change any service level/grant one role to another/attach or detach a service level to/from a role.
To speed it up, the patch adds another layer of service level controller cache, which stored `role_name -> effective_service_level` mapping. This way finding a effective service level for a role is only a lookup to a map.
Building the new cache requires only 2 queries: one to obtain all role hierarchy one to get all roles' service level.
Fixes scylladb/scylladb#12923
Closes scylladb/scylladb#19085
* github.com:scylladb/scylladb:
test/auth_cluster/test_raft_service_levels: add test for automatic connection update
api/cql_server_test: add CQL server testing API
transport/cql_server: subscribe to sl effective cache reloaded
transport/controller: coroutinize `subscribe_server` and `unsubscribe_server`
transport/cql_server: add method to update service level params on all connections
generic_server: use async function in `for_each_gently()`
service/qos/sl_controller: use effective service levels cache
service/qos/service_level_controller: notify subscribers on effective cache reloaded
service/raft/group0_state_machine: update effective service levels cache
service/topology_coordinator: migrate service levels before auth
service/qos/service_level_controller: effective service levels cache
utils/sorting: allow to pass any container as verticies
service/qos/service_level_controller: replace shard check to assert
service/qos: define effective service level
service/qos/qos_common: use const reference in `init_effective_names()`
service/qos/service_level_controller: remove unused field
auth: return map of directly granted roles
test/auth/test_auth_v2_migration: create sl1 in the test
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++20 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.