ClickHouse, an open source OLAP database with excellent performance, has become more and more popular in recent years. In addition to taking root in major Internet companies, it has also attracted a large number of enthusiastic contributors. As of v21 In version 10, CH has 1064 contributors worldwide.
SELECT count(1) FROM system.contributors Query id: 7cdf54f1-cb50-45c0-99b9-14d73d283e39 ┌─count()─┐ │ 1064 │ └─────────┘
To contribute code to the community, we must first go through a complete development, compilation and testing process. The text will summarize some tools and skills commonly used in the above process, hoping to be helpful to students who are interested in contributing CH code.
For development environment configuration, refer to the following articles
Download the latest code before compiling
git clone https://github.com/clickhouse/clickhouse
Then connect git submodule three times and pull the third-party library code
git submodule update --init --recursive git submodule foreach git checkout . git submodule sync --recursive
The next step is to compile. Since the community clearly does not support gcc, it is recommended to compile with clang-12 or clang-13.
mkdir -p build_clang cd build_clang cmake -G Ninja "-DCMAKE_C_COMPILER=$(command -v clang-13)" "-DCMAKE_CXX_COMPILER=$(command -v clang++-13)" -DCMAKE_BUILD_TYPE=Debug -DENABLE_TESTS=0 -DENABLE_UTILS=0 -DENABLE_THINLTO=0 -DENABLE_NURAFT=0 -DDISABLE_HERMETIC_BUILD=1 .. ninja clickhouse
For the construction of commissioning environment, please refer to: vscode c + + remote debugging practice
In addition, it is better to ignore SIGUSR1 and SIGUSR2 signals during CH debugging (these signals are used to count some indicators of query), otherwise you will find that the debugging process is always interrupted by these signals.
When the debugger is gdb, set:
handle SIGUSR1 noprint nostop handle SIGUSR2 noprint nostop
When the debugger is lldb, set:
pro hand -p false -s false -n false SIGUSR1 pro hand -p false -s false -n false SIGUSR1
Although the community already has github actions to check the newly submitted PR, it is certainly not as fast as the local check. Here are some common test tools:
Check style is used to check the code style. CH still has high requirements for the code, so it is recommended to run through the check style tool after writing the code to see what does not meet the requirements of the community.
./utils/check-style/check-style | tee style.log
There are two common mistakes for novices:
Braces are not wrapped
There are spaces at the end of the line
The most common and commonly used test case in CH. the input is sql or shell file and the output is sql execution result. If it is found that the expected execution result of sql is different from the actual result, it is determined that the functional test fails.
So how to run functional test? There are two cases
For functional test entered as sql:
export CLICKHOUSE_CLIENT="/path/to/clickhouse client --host XX --port XX --user XX --password XX -m" cat tests/queries/0_stateless/XXX.sql | $CLICKHOUSE_CLIENT
For input as shell:
export CLICKHOUSE_CLIENT="/path/to/clickhouse client --host XX --port XX --user XX --password XX -m" bash -x tests/queries/0_stateless/01675_distributed_bytes_to_delay_insert_long.sh
It is used by the community for rapid verification of PR. it will compile and run some functional tests. When you find that the submitted PR fails the fast test, the best way is to reproduce it in the local environment.
export LLVM_VERSION=13 export PULL_REQUEST_NUMBER=31104 export stage="" # The stage has "" and clone in order_ root, run, clone_ submodules, run_ cmake, build, configure, run_ Test and other options, you can set the stage parameters as needed. export FASTTEST_WORKSPACE=/path/to/fasttest/workspace #fast test will download PR code in this directory and compile and run it cd ./docker/test/fasttest bash -x run.sh | tee run.log
In CH, many tests depend on the cluster environment or other components (mysql, zookeeper, hdfs, etc.). At this time, functional test will not work, so the community introduced integration test
Locally, we can still run integration tests to test_ storage_ Take HDFS as an example:
cd $prefix/tests/integration sudo ./runner --binary $prefix/build_clang/programs/clickhouse --odbc-bridge-binary $prefix/build_clang/programs/clickhouse-odbc-bridge --base-configs-dir $prefix/programs/server 'test_storage_hdfs -ss'