49026dc319
To enable tablets replication one needs to turn on the (experimental) feature and specify the `initial_tablets: N` option when creating a keyspace. We want tablets to become default in the future and allow users to explicitly opt it out if they want to.
This PR solves this by changing the CREATE KEYSPACE syntax wrt tablets options. Now there's a new TABLETS options map and the usage is
* `CREATE KEYSPACE ...` will turn tablets on or off based on cluster feature being enabled/disabled
* `CREATE KEYSPACE ... WITH TABLETS = { 'enabled': false }` will turn tablets off regardless of what
* `CREATE KEYSPACE ... WITH TABLETS = { 'enabled': true }` will try to enable tablets with default configuration
* `CREATE KEYSPACE ... WITH TABLETS = { 'initial': <int> }` is now the replacement for `REPLICATION = { ... 'initial_tablets': <int> }` thing
fixes: #16319
Closes scylladb/scylladb#16364
* github.com:scylladb/scylladb:
code: Enable tablets if cluster feature is enabled
test: Turn off tablets feature by default
test: Move test_tablet_drain_failure_during_decommission to another suite
test/tablets: Enable tables for real on test keyspace
test/tablets: Make timestamp local
cql3: Add feature service to as_ks_metadata_update()
cql3: Add feature service to ks_prop_defs::as_ks_metadata()
cql3: Add feature service to get_keyspace_metadata()
cql: Add tablets on/off switch to CREATE KEYSPACE
cql: Move initial_tablets from REPLICATION to TABLETS in DDL
network_topology_strategy: Estimate initial_tablets if 0 is set
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 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.