b228ddabb7
The series is on top of "wire up schema raft state machine". It will apply without, but will not work obviously (when raft is disabled it does nothing anyway). This series does not provide any linearisability just yet though. It only uses raft as a means to distribute schema mutations. To achieve linearisability more work is needed. We need to at lease make sure that schema mutation use monotonically increasing timestamps and, since schema altering statement are RMW, no modification to schema were done between schema mutation creation and application. If there were an operation needs to be restarted. * scylla-dev/gleb/raft-schema-v5: (59 commits) cql3: cleanup mutation creation code in ALTER TYPE cql3: use migration_manager::schema_read_barrier() before accessing a schema in altering statements cql3: bounce schema altering statement to shard 0 migration_manager: add is_raft_enabled() to check if raft is enabled on a cluster migration_manager: add schema_read_barrier() function migration_manager: make announce() raft aware migration_manager: co-routinize announce() function migration_manager: pass raft_gr to the migration manager migration_manager: drop view_ptr array from announce_column_family_update() mm: drop unused announce_ methods cql3: drop schema_altering_statement::announce_migration() cql3: drop has_prepare_schema_mutations() from schema altering statement cql3: drop announce_migration() usage from schema_altering_statement cql3: move DROP AGGREGATE statement to prepare_schema_mutations() api migration_manager: add prepare_aggregate_drop_announcement() function cql3: move DROP FUNCTION statement to prepare_schema_mutations() api migration_manager: add prepare_function_drop_announcement() function cql3: move CREATE AGGREGATE statement to prepare_schema_mutations() api migration_manager: add prepare_new_aggregate_announcement() function cql3: move CREATE FUNCTION statement to prepare_schema_mutations() api ...
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.