7a3930f7cf
This PR introduces 4 new virtual tables aimed at replacing nodetool commands, working towards the long-term goal of replacing nodetool completely at least for cluster information retrieval purposes. As you may have noticed, most of these replacement are not exact matches. This is on purpose. I feel that the nodetool commands are somewhat chaotic: they might have had a clear plan on what command prints what but after years of organic development they are a mess of fields that feel like don't belong. In addition to this, they are centered on C* terminology which often sounds strange or doesn't make any sense for scylla (off-heap memory, counter cache, etc.). So in this PR I tried to do a few things: * Drop all fields that don't make sense for scylla; * Rename/reformat/rephrase fields that have a corresponding concept in scylla, so that it uses the scylla terminology; * Group information in tables based on some common theme; With these guidelines in mind lets look at the virtual tables introduced in this PR: * `system.snapshots` - replacement for `nodetool listnapshots`; * `system.protocol_servers`- replacement for `nodetool statusbinary` as well as `Thrift active` and `Native Transport active` from `nodetool info`; * `system.runtime_info` - replacement for `nodetool info`, not an exact match: some fields were removed, some were refactored to make sense for scylla; * `system.versions` - replacement for `nodetool version`, prints all versions, including build-id; Closes #9517 * github.com:scylladb/scylla: test/cql-pytest: add virtual_tables.py test/cql-pytest: nodetool.py: add take_snapshot() db/system_keyspace: add versions table configure.py: move release.cc and build_id.cc to scylla_core db/system_keyspace: add runtime_info table db/system_keyspace: add protocol_servers table service: storage_service: s/client_shutdown_hooks/protocol_servers/ service: storage_service: remove unused unregister_client_shutdown_hook redis: redis_service: implement the protocol_server interface alternator: controller: implement the protocol_server interface transport: controller: implement the protocol_server interface thrift: controller: implement the protocol_server interface Add protocol_server interface db/system_keyspace: add snapshots virtual table db/virtual_table: remove _db member db/system_keyspace: propagate distributed<> database and storage_service to register_virtual_tables() docs/design-notes/system_keyspace.md: add listing of existing virtual tables docs/guides: add virtual-tables.md
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 APIs - CQL and Thrift. 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 users mailing list 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.