16ff92745f
The perf_simple_query tool is extended with another protocol
aside from CQL - alternator. The alternative (pun intended) benchmark
can be executed by using the `--alternator X` parameter, where X
specifies one of the alternator's mandatory write isolation options:
- "forbid_rmw" - forbids RMW (read-modify-write) requests
- "unsafe" - never uses LWT (lightweight transactions), even for RMW
- "always_use_lwt" - uses LWT even for non-RMW requests
- "only_rmw_uses_lwt" - that one's rather self-explanatory
Alternator cooperates with existing `--write` and `--delete` parameters.
Aside from being able to check for improvements/regressions
in the alternator module, it's also possible to check how different
isolation levels influence the number of allocations and overall
performance, or to compare alternator against CQL.
Example output showing the difference in isolation levels:
```bash
$ ./build/release/test/perf/perf_simple_query_g --smp 1 \
--write --alternator only_rmw_uses_lwt --default-log-level error
random-seed=1235000092
Started alternator executor
10873.76 tps (202.9 allocs/op, 12.4 tasks/op, 369921 insns/op)
11096.09 tps (202.7 allocs/op, 12.1 tasks/op, 374792 insns/op)
11100.09 tps (203.0 allocs/op, 12.1 tasks/op, 376469 insns/op)
11068.98 tps (203.1 allocs/op, 12.1 tasks/op, 377132 insns/op)
11081.24 tps (203.2 allocs/op, 12.1 tasks/op, 377290 insns/op)
median 11081.24 tps (203.2 allocs/op, 12.1 tasks/op, 377290 insns/op)
median absolute deviation: 14.85
maximum: 11100.09
minimum: 10873.76
$ ./build/release/test/perf/perf_simple_query_g --smp 1 \
--random-seed 1235000092 --write --alternator always_use_lwt \
--default-log-level error
random-seed=1235000092
Started alternator executor
3605.35 tps (877.4 allocs/op, 174.6 tasks/op, 986666 insns/op)
3555.71 tps (890.0 allocs/op, 174.4 tasks/op, 1006945 insns/op)
3530.20 tps (899.7 allocs/op, 174.1 tasks/op, 1021908 insns/op)
3437.65 tps (908.2 allocs/op, 174.6 tasks/op, 1033992 insns/op)
3409.88 tps (913.2 allocs/op, 174.4 tasks/op, 1041240 insns/op)
median 3530.20 tps (899.7 allocs/op, 174.1 tasks/op, 1021908 insns/op)
median absolute deviation: 75.15
maximum: 3605.35
minimum: 3409.88
```
Closes #8656
* github.com:scylladb/scylla:
perf: add alternator frontend to perf_simple_query
cdc: make metadata.hh self-sufficient
test: add minimal alternator_test_env
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.