cf30d4cbcf
This pull request introduces global secondary-indexing for non-frozen collections. The intent is to enable such queries: ``` CREATE TABLE test(int id, somemap map<int, int>, somelist<int>, someset<int>, PRIMARY KEY(id)); CREATE INDEX ON test(keys(somemap)); CREATE INDEX ON test(values(somemap)); CREATE INDEX ON test(entries(somemap)); CREATE INDEX ON test(values(somelist)); CREATE INDEX ON test(values(someset)); -- index on test(c) is the same as index on (values(c)) CREATE INDEX IF NOT EXISTS ON test(somelist); CREATE INDEX IF NOT EXISTS ON test(someset); CREATE INDEX IF NOT EXISTS ON test(somemap); SELECT * FROM test WHERE someset CONTAINS 7; SELECT * FROM test WHERE somelist CONTAINS 7; SELECT * FROM test WHERE somemap CONTAINS KEY 7; SELECT * FROM test WHERE somemap CONTAINS 7; SELECT * FROM test WHERE somemap[7] = 7; ``` We use here all-familiar materialized views (MVs). Scylla treats all the collections the same way - they're a list of pairs (key, value). In case of sets, the value type is dummy one. In case of lists, the key type is TIMEUUID. When describing the design, I will forget that there is more than one collection type. Suppose that the columns in the base table were as follows: ``` pkey int, ckey1 int, ckey2 int, somemap map<int, text>, PRIMARY KEY(pkey, ckey1, ckey2) ``` The MV schema is as follows (the names of columns which are not the same as in base might be different). All the columns here form the primary key. ``` -- for index over entries indexed_coll (int, text), idx_token long, pkey int, ckey1 int, ckey2 int -- for index over keys indexed_coll int, idx_token long, pkey int, ckey1 int, ckey2 int -- for index over values indexed_coll text, idx_token long, pkey int, ckey1 int, ckey2 int, coll_keys_for_values_index int ``` The reason for the last additional column is that the values from a collection might not be unique. Fixes #2962 Fixes #8745 Fixes #10707 This patch does not implement **local** secondary indexes for collection columns: Refs #10713. Closes #10841 * github.com:scylladb/scylladb: test/cql-pytest: un-xfail yet another passing collection-indexing test secondary index: fix paging in map value indexing test/cql-pytest: test for paging with collection values index cql, view: rename and explain bytes_with_action cql, index: make collection indexing a cluster feature test/cql-pytest: failing tests for oversized key values in MV and SI cql: fix secondary index "target" when column name has special characters cql, index: improve error messages cql, index: fix default index name for collection index test/cql-pytest: un-xfail several collecting indexing tests test/cql-pytest/test_secondary_index: verify that local index on collection fails. docs/design-notes/secondary_index: add `VALUES` to index target list test/cql-pytest/test_secondary_index: add randomized test for indexes on collections cql-pytest/cassandra_tests/.../secondary_index_test: fix error message in test ported from Cassandra cql-pytest/cassandra_tests/.../secondary_index_on_map_entries,select_test: test ported from Cassandra is expected to fail, since Scylla assumes that comparison with null doesn't throw error, just evaluates to false. Since it's not a bug, but expected behavior from the perspective of Scylla, we don't mark it as xfail. test/boost/secondary_index_test: update for non-frozen indexes on collections test/cql-pytest: Uncomment collection indexes tests that should be working now cql, index: don't use IS NOT NULL on collection column cql3/statements/select_statement: for index on values of collection, don't emit duplicate rows cql/expr/expression, index/secondary_index_manager: needs_filtering and index_supports_expression rewrite to accomodate for indexes over collections cql3, index: Use entries() indexes on collections for queries cql3, index: Use keys() and values() indexes on collections for queries. types/tuple: Use std::begin() instead of .begin() in tuple_type_impl::build_value_fragmented cql3/statements/index_target: throw exception to signalize that we didn't miss returning from function db/view/view.cc: compute view_updates for views over collections view info: has_computed_column_depending_on_base_non_primary_key column_computation: depends_on_non_primary_key_column schema, index/secondary_index_manager: make schema for index-induced mv index/secondary_index_manager: extract keys, values, entries types from collection cql3/statements/: validate CREATE INDEX for index over a collection cql3/statements/create_index_statement,index_target: rewrite index target for collection column_computation.hh, schema.cc: collection_column_computation column_computation.hh, schema.cc: compute_value interface refactor Cql.g, treewide: support cql syntax `INDEX ON table(VALUES(collection))`
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.