YDB

https://github.com/ydb-platform/ydb
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### Expected output of the quickstart example

Source: https://github.com/ydb-platform/ydb/blob/main/contrib/libs/simdjson/README.md

This shows the expected output after running the quickstart C++ program.

```text
100 results.
```

--------------------------------

### Configure Installation Prefix

Source: https://github.com/ydb-platform/ydb/blob/main/contrib/libs/jemalloc/INSTALL.md

Example of setting the base directory for installation using the --prefix option.

```bash
./configure --prefix=/usr/local
```

--------------------------------

### Example YDB Connection and Authentication Setup

Source: https://github.com/ydb-platform/ydb/blob/main/ydb/docs/en/core/dev/example-app/rust/_includes/run_custom.md

An example demonstrating how to set environment variables for token-based authentication and a specific YDB connection string. This is used to run the 'basic' example.

```bash
export YDB_ACCESS_TOKEN_CREDENTIALS="t1.9euelZqOnJuJlc..."
export YDB_CONNECTION_STRING="grpcs://ydb.example.com:2135/somepath/somelocation"
cd ydb-rs-sdk/ydb
cargo run --example basic
```

--------------------------------

### Example Key-Value Load Initialization

Source: https://github.com/ydb-platform/ydb/blob/main/ydb/docs/en/core/reference/ydb-cli/workload-kv.md

An example command to initialize a Key-Value load table with 1000 upsert operations during setup.

```bash
{{ ydb-cli }} workload kv init --init-upserts 1000
```

--------------------------------

### Install IDNA Library using setup.py

Source: https://github.com/ydb-platform/ydb/blob/main/contrib/python/idna/py2/README.rst

Alternative installation method for the idna library using the bundled setup script.

```bash
$ python setup.py install
```

--------------------------------

### Compile and run the simdjson quickstart example

Source: https://github.com/ydb-platform/ydb/blob/main/contrib/libs/simdjson/README.md

Compile the C++ code with simdjson.cpp and then run the executable to see the parsing results.

```bash
c++ -o quickstart quickstart.cpp simdjson.cpp
```

```bash
./quickstart
```

--------------------------------

### Example `main.cpp` with Profiling Setup

Source: https://github.com/ydb-platform/ydb/blob/main/yt/yt/library/ytprof/README.md

This C++ code demonstrates setting up the profiler by configuring sampling intervals and creating a server. It includes a loop that generates CPU load for profiling.

```cpp
int main(int argc, char* argv[]) {
    NBacktrace::SetAbslStackUnwinder();
    tcmalloc::MallocExtension::SetProfileSamplingInterval(2_MB);

    try {
        if (argc != 2 && argc != 3) {
            throw yexception() << "usage: " << argv[0] << " PORT";
        }

        auto port = FromString<int>(argv[1]);
        auto poller = CreateThreadPoolPoller(1, "Example");
        auto server = CreateServer(port, poller);

        Register(server, "");
        server->Start();

        THashMap<TString, std::vector<int>> data;
        for (int i = 0; i < 1024 * 16; i++) {
            data[ToString(i)].resize(1024);
        }

        ui64 value = 0;
        while (true) {
            THash<TString> hasher;
            for (int i = 0; i < 10000000; i++) {
                value += hasher(ToString(i));
            }

            std::vector<TString> data;
            for (int i = 0; i < 10000; i++) {
                data.push_back(TString(1024, 'x'));
            }

            if (value == 1) {
                Sleep(TDuration::Seconds(1));
            }
        }
    } catch (const std::exception& ex) {
        Cerr << ex.what() << Endl;
        _exit(1);
    }

}
```

--------------------------------

### Create Profile for Test Database

Source: https://github.com/ydb-platform/ydb/blob/main/ydb/docs/en/core/reference/ydb-cli/profile/_includes/create.md

Example of creating a 'quickstart' profile to connect to a single-node YDB cluster. Requires specifying the endpoint and database path.

```bash
ydb config profile create quickstart --endpoint grpc://localhost:2136 --database <path_database>
```

--------------------------------

### Install oneTBB with Multi-Configuration Generators (Windows)

Source: https://github.com/ydb-platform/ydb/blob/main/contrib/libs/tbb/INSTALL.md

Example for installing oneTBB using multi-configuration generators on Windows, specifying build configurations.

```batch
cd %TMP%
git clone https://github.com/uxlfoundation/oneTBB.git
cd oneTBB
mkdir build && cd build
cmake -DCMAKE_INSTALL_PREFIX=%TMP%\my_installed_onetbb -DTBB_TEST=OFF ..
cmake --build . --config relwithdebinfo
cmake --install . --config relwithdebinfo
```

--------------------------------

### Install Cobra Library

Source: https://github.com/ydb-platform/ydb/blob/main/vendor/github.com/spf13/cobra/README.md

Use 'go get' to install the latest version of the Cobra library.

```go
go get -u github.com/spf13/cobra@latest
```

--------------------------------

### Running the jsonator Example

Source: https://github.com/ydb-platform/ydb/blob/main/vendor/github.com/pseudomuto/protokit/examples/jsonator/README.md

Execute these commands to generate and view the output JSON file. Ensure you have Go installed and the necessary protokit dependencies.

```bash
go generate && cat output.json
```

--------------------------------

### Build and Install Developer Sources

Source: https://github.com/ydb-platform/ydb/blob/main/contrib/libs/jemalloc/INSTALL.md

Command sequence for building and installing jemalloc when starting from unpackaged developer sources.

```bash
./autogen.sh
make
make install
```

--------------------------------

### Build and Run YTProf Example

Source: https://github.com/ydb-platform/ydb/blob/main/yt/yt/library/ytprof/README.md

Builds the example profiler application and runs it. Ensure 'ya' is not started via a wrapper for interactive pprof mode.

```bash
# All commands run from Repository root

# Build the example
ya make --build=profile yt/yt/library/ytprof/example

# Run the example in a separate terminal on port 10003
./yt/yt/library/ytprof/example/example 10003

# Check memory usage
ya tool pprof -symbolize=none http://localhost:10003/heap
Fetching profile over HTTP from http://localhost:10003/heap
Saved profile in /home/prime/pprof/pprof.example.allocations.space.002.pb.gz
File: example
generated by ytprof 0.2
Type: space
Entering interactive mode (type "help" for commands, "o" for options)
(pprof) list main
Total: 64.80MB
ROUTINE ======================== main in /home/prime/arc/yt/yt/library/ytprof/example/main.cpp
         0    62.38MB (flat, cum) 96.25% of Total
         .          .     30:        Register(server, "");
         .          .     31:        server->Start();
         .          .     32:
         .          .     33:        THashMap<TString, std::vector<int>> data;
         .          .     34:        for (int i = 0; i < 1024 * 16; i++) {
         .    62.38MB     35:            data[ToString(i)].resize(1024);
         .          .     36:        }
         .          .     37:
         .          .     38:        ui64 value = 0;
         .          .     39:        while (true) {
         .          .     40:            THash<TString> hasher;

```

--------------------------------

### Example Project Profile Configuration

Source: https://github.com/ydb-platform/ydb/blob/main/ydb/docs/en/core/integrations/migration/dbt.md

Configure the profiles.yml for the jaffle_shop example project, specifying connection details for a single-node YDB installation.

```text
profile_name:
   target: dev
   outputs:
      dev:
      type: ydb
      host: localhost # YDB host
      port: 2136 # YDB port
      database: /local # YDB database
      schema: jaffle_shop
```

--------------------------------

### Install protoc-gen-doc Locally

Source: https://github.com/ydb-platform/ydb/blob/main/vendor/github.com/pseudomuto/protoc-gen-doc/README.md

Install the protoc-gen-doc plugin locally using go get. Ensure your Go environment is set up correctly.

```bash
go get -u github.com/pseudomuto/protoc-gen-doc/cmd/protoc-gen-doc
```

--------------------------------

### Run Automatic YDB EM Installation

Source: https://github.com/ydb-platform/ydb/blob/main/ydb/docs/en/core/devops/enterprise-manager/initial-deployment.md

Execute the automatic installation script located in the `examples` directory to deploy YDB EM components.

```bash
cd examples
./install.sh
```

--------------------------------

### Kqprun Tool Example

Source: https://github.com/ydb-platform/ydb/blob/main/ydb/tests/functional/ydb_cli/benchmarks/README.md

Example of using the 'kqprun' tool, which can be used as a database for the benchmark. Adjust the port and shared database name as necessary.

```bash
./kqprun -M 33000 -G 12345 --shared shared_database
```

--------------------------------

### Build with Meson

Source: https://github.com/ydb-platform/ydb/blob/main/contrib/libs/lcms2/BUILDING.md

Meson support is currently in testing. Requires meson and ninja. Specify a custom installation prefix using the --prefix option during setup.

```bash
meson setup build
ninja -C build
meson test -C build
meson install -C build
```

```bash
meson setup build --prefix=/your/prefix
```

--------------------------------

### Installation Logic

Source: https://github.com/ydb-platform/ydb/blob/main/ydb/library/nmslib/src/CMakeLists.txt

Installs header files to their respective subdirectories and the compiled library to the lib directory.

```cmake
string(LENGTH ${PROJECT_SOURCE_DIR} PREFIX_LEN) 
MATH(EXPR PREFIX_LEN "${PREFIX_LEN}+1")
foreach(F ${PROJ_HDR_FILES}) 
  GET_FILENAME_COMPONENT(FP ${F} PATH)
  string(SUBSTRING ${FP} ${PREFIX_LEN} -1 FS)
  #message(${PREFIX_LEN} ":" ${FS})
  install(FILES "${F}" DESTINATION ${FS})
endforeach(F)

install(TARGETS NonMetricSpaceLib   
  ARCHIVE DESTINATION lib
  LIBRARY DESTINATION lib
  COMPONENT library
)
```

--------------------------------

### Build and Serve Documentation

Source: https://github.com/ydb-platform/ydb/blob/main/ydb/docs/README.md

Commands to build the documentation and start a local HTTP server for previewing.

```bash
# Build and serve from a temporary directory
./run.sh

# Build and serve from a specific directory
./run.sh /path/to/output
```

--------------------------------

### Installing protoc-gen-govalidators

Source: https://github.com/ydb-platform/ydb/blob/main/vendor/github.com/mwitkow/go-proto-validators/README.md

Installs the protoc-gen-govalidators plugin using go get.

```sh
go get github.com/mwitkow/go-proto-validators/protoc-gen-govalidators
```

--------------------------------

### SQL/JSON Regex Example

Source: https://github.com/ydb-platform/ydb/blob/main/yql/essentials/docs/ru/_includes/pg_functions.md

Example of a case-insensitive regex match for strings starting with a vowel.

```sql
$[*] ? (@ like_regex "^[aeiou]" flag "i")
```

--------------------------------

### Forbidden side effect in GET handler

Source: https://github.com/ydb-platform/ydb/blob/main/ydb/agents/developer-ui-security-guidelines.md

Example of an insecure GET handler that performs destructive actions, which is prohibited as GET requests are not CSRF-protected.

```cpp
void RenderPage(IOutputStream& str, const TCgiParameters& params) {
    if (params.Has("action")) {
        DoSomethingDestructive(); // ← side effect triggered by GET!
    }
    // ... render HTML
}
```

--------------------------------

### Stock Workload Initialization Examples

Source: https://github.com/ydb-platform/ydb/blob/main/ydb/docs/en/core/reference/ydb-cli/commands/workload/_includes/stock.md

Examples of running the initialization command with specific product, quantity, order, and partition configurations.

```bash
{{ ydb-cli }} workload stock init -p 1000 -q 10000 -o 0
```

```bash
{{ ydb-cli }} workload stock init -p 10 -q 100 -o 10 --min-partitions 100
```

--------------------------------

### Install xstrings Go Package

Source: https://github.com/ydb-platform/ydb/blob/main/vendor/github.com/huandu/xstrings/README.md

Use 'go get' to install the xstrings library. This command fetches and installs the package into your Go workspace.

```go
go get github.com/huandu/xstrings
```

--------------------------------

### View ClickBench initialization help

Source: https://github.com/ydb-platform/ydb/blob/main/ydb/docs/en/core/reference/ydb-cli/workload-click-bench.md

Display available parameters and help documentation for the initialization command.

```bash
{{ ydb-cli }} workload clickbench init --help
```

--------------------------------

### Example of resolving VersionConflict

Source: https://github.com/ydb-platform/ydb/blob/main/contrib/python/grpcio/py2/README.rst

An example demonstrating how to fix a VersionConflict with the 'six' package by forcing its installation.

```bash
sudo pip install --ignore-installed six
```

--------------------------------

### Running the Simple Click Example

Source: https://github.com/ydb-platform/ydb/blob/main/contrib/python/click/py2/README.rst

Example of how to run the 'hello' Click application and interact with its prompts and options.

```text
$ python hello.py --count=3
Your name: Click
Hello, Click!
Hello, Click!
Hello, Click!
```

--------------------------------

### Run Example App with Custom Endpoint and Database

Source: https://github.com/ydb-platform/ydb/blob/main/ydb/docs/en/core/dev/example-app/python/_includes/run_custom.md

Use this command to run the example application, providing the endpoint and database path. Authentication mode and credentials can be set via environment variables if required.

```bash
<auth_mode_var>="<auth_mode_value>" \
python3 ydb-python-sdk/examples/basic_example_v1/ -e <endpoint> -d <database>
```

```bash
YDB_ACCESS_TOKEN_CREDENTIALS="t1.9euelZqOnJuJlc..." \
python3 ydb-python-sdk/examples/basic_example_v1/ -e grpcs://ydb.example.com:2135 -d /path/db
```

--------------------------------

### Install Boto3 using Pip

Source: https://github.com/ydb-platform/ydb/blob/main/contrib/python/boto3/py2/README.rst

Install the Boto3 library directly using pip for quick setup.

```sh
$ python -m pip install boto3
```

--------------------------------

### Install Boto from Source

Source: https://github.com/ydb-platform/ydb/blob/main/contrib/python/boto/py3/README.rst

Clone the boto repository and install it using setup.py. This method is useful for development or if you need to modify the source code.

```bash
git clone git://github.com/boto/boto.git
cd boto
python setup.py install
```

--------------------------------

### Get Start of Month

Source: https://github.com/ydb-platform/ydb/blob/main/yql/essentials/docs/en/udf/list/datetime.md

Calculates the start of the month for a given timestamp. Returns NULL if the result is invalid.

```yql
DateTime::MakeDate(DateTime::StartOfMonth(Timestamp("2019-06-06T01:02:03.456789Z")))
```

--------------------------------

### Get Start of Year

Source: https://github.com/ydb-platform/ydb/blob/main/yql/essentials/docs/en/udf/list/datetime.md

Calculates the start of the year for a given date. Returns NULL if the result is invalid.

```yql
SELECT
    DateTime::MakeDate(DateTime::StartOfYear(Date("2019-06-06")))
```

--------------------------------

### Advanced to_char formatting examples

Source: https://github.com/ydb-platform/ydb/blob/main/yql/essentials/docs/ru/_includes/pg_functions.md

Comprehensive examples demonstrating various formatting patterns for dates and numbers.

```sql
to_char('2000-06-06 05:39:18'::timestamp, 'Day, DD  HH12:MI:SS') → 'Tuesday  , 06  05:39:18'
to_char('2000-06-06 05:39:18'::timestamp, 'FMDay, FMDD  HH12:MI:SS') → 'Tuesday, 6  05:39:18'
to_char(-0.1, '99.99') → '  -.10'
to_char(-0.1, 'FM9.99') → '-.1'
to_char(-0.1, 'FM90.99') → '-0.1'
to_char(0.1, '0.9') → ' 0.1'
to_char(12, '9990999.9') → '    0012.0'
to_char(12, 'FM9990999.9') → '0012.'
to_char(485, '999') → ' 485'
to_char(-485, '999') → '-485'
to_char(485, '9 9 9') → ' 4 8 5'
to_char(1485, '9,999') → ' 1,485'
to_char(1485, '9G999') → ' 1,485'
to_char(148.5, '999.999') → ' 148.500'
to_char(148.5, 'FM999.999') → '148.5'
to_char(148.5, 'FM999.990') → '148.500'
to_char(148.5, '999D999') → ' 148.500'
to_char(3148.5, '9G999D999') → ' 3,148.500'
to_char(-485, '999S') → '485-'
to_char(-485, '999MI') → '485-'
to_char(485, '999MI') → '485 '
to_char(485, 'FM999MI') → '485'
to_char(485, 'PL999') → '+ 485'
to_char(485, 'SG999') → '+485'
to_char(-485, 'SG999') → '-485'
to_char(-485, '9SG99') → '4-85'
to_char(-485, '999PR') → '<485>'
to_char(485, 'L999') → '  485'
to_char(485, 'RN') → '        CDLXXXV'
to_char(485, 'FMRN') → 'CDLXXXV'
to_char(5.2, 'FMRN') → 'V'
to_char(482, '999th') → ' 482nd'
to_char(485, '"Good number:"999') → 'Good number: 485'
to_char(485.8, '"Pre:"999" Post:" .999') → 'Pre: 485 Post: .800'
to_char(12, '99V999') → ' 12000'
to_char(12.4, '99V999') → ' 12400'
to_char(12.45, '99V9') → ' 125'
to_char(0.0004859, '9.99EEEE') → ' 4.86e-04'
```

--------------------------------

### Start Local FQ Connector

Source: https://github.com/ydb-platform/ydb/blob/main/ydb/tests/tools/kqprun/README.md

Use this script to start a local FQ connector, specifying the connector port.

```bash
./scripts/start_connector.sh <connector port>
```

--------------------------------

### Get Start of Day

Source: https://github.com/ydb-platform/ydb/blob/main/yql/essentials/docs/en/udf/list/datetime.md

Calculates the start of the day for a given datetime, resetting time components to midnight.

```yql
DateTime::MakeDatetime(DateTime::StartOfDay(Datetime("2019-06-06T01:02:03Z")))
```

--------------------------------

### Start Prometheus UI

Source: https://github.com/ydb-platform/ydb/blob/main/ydb/tests/tools/kqprun/README.md

Starts the Prometheus web UI for visualizing counters. Ensure kqprun is run with the '-M <monitoring port>' flag.

```bash
./scripts/start_prometheus.sh <kqprun monitoring port> <web UI port> [config path]
```

--------------------------------

### Compile and Run Example

Source: https://github.com/ydb-platform/ydb/blob/main/contrib/restricted/expected-lite/README.md

Shows the command to compile and run the basic expected<int, std::string> example, demonstrating successful conversion and error handling.

```Shell
prompt> g++ -std=c++14 -Wall -I../include -o 01-basic.exe 01-basic.cpp && 01-basic.exe 123 && 01-basic.exe abc
'123' is 123, Error: 'abc' isn't a number
```

--------------------------------

### Example: Clone and Build oneTBB from Source

Source: https://github.com/ydb-platform/ydb/blob/main/contrib/libs/tbb/INSTALL.md

Demonstrates cloning the oneTBB repository, creating a build directory, and preparing for an out-of-source build.

```bash
# Do our experiments in /tmp
cd /tmp
# Clone oneTBB repository
git clone https://github.com/uxlfoundation/oneTBB.git
cd oneTBB
# Create binary directory for out-of-source build
mkdir build && cd build
```

--------------------------------

### Get Start of Week (Valid Case)

Source: https://github.com/ydb-platform/ydb/blob/main/yql/essentials/docs/en/udf/list/datetime.md

Calculates the start of the week for a given date, returning the preceding Monday.

```yql
DateTime::MakeTimestamp(DateTime::StartOfWeek(Date("2019-01-01")))
```

--------------------------------

### Get Start of Day (Timezone Valid Case)

Source: https://github.com/ydb-platform/ydb/blob/main/yql/essentials/docs/en/udf/list/datetime.md

Calculates the start of the day in a specific timezone for a timezone-aware timestamp.

```yql
DateTime::MakeTzTimestamp(DateTime::StartOfDay(TzTimestamp("1970-01-02T05:00:00.000000,Europe/Moscow")))
```

--------------------------------

### Run Example from Examples Folder

Source: https://github.com/ydb-platform/ydb/blob/main/contrib/python/kubernetes/README.md

Execute a specific example script located within the 'examples' folder of the client library. Replace 'example1' with the desired filename.

```shell
python -m examples.example1
```

--------------------------------

### Date/Time Arithmetic Examples

Source: https://github.com/ydb-platform/ydb/blob/main/yql/essentials/docs/ru/_includes/pg_functions.md

Examples of calculating differences between timestamps and using the age function.

```sql
EXTRACT(EPOCH FROM timestamptz '2013-07-01 12:00:00') - EXTRACT(EPOCH FROM timestamptz '2013-03-01 12:00:00') ~→ 10537200.000000
(EXTRACT(EPOCH FROM timestamptz '2013-07-01 12:00:00') - EXTRACT(EPOCH FROM timestamptz '2013-03-01 12:00:00')) / 60 / 60 / 24 ~→ 121.9583333333333333
timestamptz '2013-07-01 12:00:00' - timestamptz '2013-03-01 12:00:00' ~→ 121 days 23:00:00
age(timestamptz '2013-07-01 12:00:00', timestamptz '2013-03-01 12:00:00') → 4 mons
```

--------------------------------

### TLI Chain Finder Example Usage

Source: https://github.com/ydb-platform/ydb/blob/main/ydb/tools/tli_analysis/README.md

Example command to run the TLI Chain Finder tool with a specific victim query span ID and log file.

```bash
python3 find_tli_chain.py 39941355799977664 tli.log
```

--------------------------------

### POST /api/scheduler/start

Source: https://github.com/ydb-platform/ydb/blob/main/ydb/tests/stability/nemesis/README.md

Starts the boundary scheduler.

```APIDOC
## POST /api/scheduler/start

### Description
Starts the boundary scheduler with the provided profile configuration.

### Method
POST

### Endpoint
/api/scheduler/start
```

--------------------------------

### Start Grafana

Source: https://github.com/ydb-platform/ydb/blob/main/ydb/tests/tools/kqprun/README.md

Starts Grafana to work with an existing Prometheus instance. Specify the Prometheus port, web UI port, and optionally additional dashboard directories.

```bash
./scripts/start_grafana.sh <prometheus port> <web UI port> [additional dashboards dirs]
```

--------------------------------

### Run Go Example with Authentication Token

Source: https://github.com/ydb-platform/ydb/blob/main/ydb/docs/en/core/dev/example-app/go/_includes/run_custom.md

Example of running a Go application with a specific endpoint and database path, using an access token for authentication.

```bash
( export YDB_ACCESS_TOKEN_CREDENTIALS="t1.9euelZqOnJuJlc..." && cd ydb-go-sdk/examples && \
go run ./basic -ydb="grpcs://ydb.example.com:2135/somepath/somelocation" )
```

--------------------------------

### YQL VALUES Example

Source: https://github.com/ydb-platform/ydb/blob/main/yql/essentials/docs/en/syntax/values.md

A simple example demonstrating the VALUES operator to create a table with two rows and two columns.

```yql
VALUES (1,2), (3,4);
```

--------------------------------

### Example Metric with Bundle Tag

Source: https://github.com/ydb-platform/ydb/blob/main/yt/yt/library/profiling/README.md

A basic example of a metric with a 'bundle' tag, often used for system-level aggregation.

```promql
request_count{bundle=sys}
```

--------------------------------

### Build and Test Quickstart

Source: https://github.com/ydb-platform/ydb/blob/main/contrib/libs/simdjson/HACKING.md

Use these CMake commands for a quick build and test cycle on non-Windows systems. Ensure SIMDJSON_DEVELOPER_MODE is enabled for full functionality.

```bash
cmake -B -D SIMDJSON_DEVELOPER_MODE=ON ..
cmake --build build
ctest --test-dir build
```

--------------------------------

### Start fqrun with gRPC Endpoint

Source: https://github.com/ydb-platform/ydb/blob/main/ydb/tests/tools/fqrun/README.md

Start fqrun exposing a gRPC endpoint on the specified port. This allows connection via ydb CLI.

```bash
./fqrun -G 32000
```

--------------------------------

### Pire Function Examples

Source: https://github.com/ydb-platform/ydb/blob/main/yql/essentials/docs/en/udf/list/pire.md

Provides concrete examples of using various Pire functions, including Match, Grep, MultiMatch, Capture, and Replace, with sample input strings and expected outputs.

```APIDOC
#### Examples

```yql
$value = "xaaxaaxaa";
$match = Pire::Match("a.*.*");
$grep = Pire::Grep("axa");
$insensitive_grep = Pire::Grep("(?i)axa");
$multi_match = Pire::MultiMatch(@@a.*
.*x.*
.*axa.*@@);
$capture = Pire::Capture(".*x(a).*");
$capture_many = Pire::Capture(".*x(a+).*");
$replace = Pire::Replace(".*x(a).*", "b");

SELECT
  $match($value) AS match,                        -- false
  $grep($value) AS grep,                          -- true
  $insensitive_grep($value) AS insensitive_grep,  -- true
  $multi_match($value) AS multi_match,            -- (false, true, true)
  $multi_match($value).0 AS some_multi_match,     -- false
  $capture($value) AS capture,                    -- "a"
  $capture_many($value) AS capture_many,          -- "aa"
  $replace($value) AS replace;               -- "xaaxaaxba"
```
```

--------------------------------

### Sum Aggregate Examples

Source: https://github.com/ydb-platform/ydb/blob/main/yql/essentials/docs/ru/_includes/pg_functions.md

Examples of computing the sum of non-null input values for different data types.

```sql
SELECT sum(x::smallint) FROM (VALUES (1),(2),(3)) a(x) → 6
SELECT sum(x::integer) FROM (VALUES (1),(2),(3)) a(x) → 6
SELECT sum(x::bigint) FROM (VALUES (1),(2),(3)) a(x) → 6
SELECT sum(x::real) FROM (VALUES (1),(2),(3)) a(x) → 6
SELECT sum(x::double precision) FROM (VALUES (1),(2),(3)) a(x) → 6
SELECT sum(x::numeric) FROM (VALUES (1),(2),(3)) a(x) → 6
SELECT sum(x) FROM (VALUES (interval '1' day),(interval '2' day),(interval '3' day)) a(x) → 6 days
```

--------------------------------

### Install copystructure Go Library

Source: https://github.com/ydb-platform/ydb/blob/main/vendor/github.com/mitchellh/copystructure/README.md

Use `go get` to install the copystructure library. This is the standard method for obtaining Go packages.

```bash
go get github.com/mitchellh/copystructure
```

--------------------------------

### Clone Example Project and Navigate

Source: https://github.com/ydb-platform/ydb/blob/main/ydb/docs/en/core/integrations/migration/dbt.md

Clone the dbt-ydb example project from GitHub and navigate into its directory.

```bash
git clone https://github.com/ydb-platform/dbt-ydb.git
cd dbt-ydb/examples/jaffle_shop
```

--------------------------------

### Start Default Workloads

Source: https://github.com/ydb-platform/ydb/blob/main/ydb/tests/stability/tool/how_to.md

Initiate the default set of stability workloads. This command starts all workloads except for the log workload.

```bash
./tool start_default_workloads --cluster_path=<path_to_cluster.yaml> --ydbd_path=<repo_root>/ydb/apps/ydbd/ydbd
```

--------------------------------

### Example: Initialize Topic-to-Table Load with Custom Parameters

Source: https://github.com/ydb-platform/ydb/blob/main/ydb/docs/en/core/reference/ydb-cli/workload-transfer.md

This example demonstrates initializing the load transfer environment with specific configurations for consumers, topic partitions, and table partitions. It shows how to override default values for a tailored test.

```bash
{{ ydb-cli }} --profile quickstart workload transfer topic-to-table init --consumers 2 --topic-partitions 143 --table-partitions 237
```

--------------------------------

### DateTime::Update Examples

Source: https://github.com/ydb-platform/ydb/blob/main/yql/essentials/docs/en/udf/list/datetime.md

Demonstrates various use cases for the DateTime::Update function, including updating individual components, handling invalid dates, and adjusting timezones. The examples show how to convert the updated resource back to different date/time types.

```yql
$tm = DateTime::Split(Timestamp("2019-01-01T01:02:03.456789Z"));

SELECT
    DateTime::MakeDate(DateTime::Update($tm, 2012)), -- 2012-01-01
    DateTime::MakeDate(DateTime::Update($tm, 2000, 6, 6)), -- 2000-06-06
    DateTime::MakeDate(DateTime::Update($tm, NULL, 2, 30)), -- NULL (February 30)
    DateTime::MakeDatetime(DateTime::Update($tm, NULL, NULL, 31)), -- 2019-01-31T01:02:03Z
    DateTime::MakeDatetime(DateTime::Update($tm, 15 as Hour, 30 as Minute)), -- 2019-01-01T15:30:03Z
    DateTime::MakeTimestamp(DateTime::Update($tm, 999999 as Microsecond)), -- 2019-01-01T01:02:03.999999Z
    DateTime::MakeTimestamp(DateTime::Update($tm, "Europe/Moscow" as Timezone)), -- 2018-12-31T22:02:03.456789Z (conversion to UTC)
    DateTime::MakeTzTimestamp(DateTime::Update($tm, "Europe/Moscow" as Timezone)); -- 2019-01-01T01:02:03.456789,Europe/Moscow
```

--------------------------------

### Sample Scenario Test Class in Python

Source: https://github.com/ydb-platform/ydb/blob/main/ydb/tests/olap/docs/scenario_tests/introduction.md

Demonstrates a basic scenario test class setup, including class-level setup and teardown, schema definition, table creation, data upsert, and table dropping. Use this as a template for writing your own scenarios.

```python
class TestSchenarioSimple(BaseTestSet):
    @classmethod
    def setup_class(cls):
        sth.drop_if_exist(['testTable'], DropTable)

    @classmethod
    def teardown_class(cls):
        sth.drop_if_exist(['testTable'], DropTable)

    schema1 = (
        sth.Schema()
        .with_column(name='id', type=PrimitiveType.Int32, not_null=True)
        .with_column(name='level', type=PrimitiveType.Uint32)
        .with_key_columns('id')
    )

    def scenario_table(self):
        table_name = 'testTable'
        sth.execute_scheme_query(CreateTable(table_name).with_schema(self.schema1))
        sth.bulk_upsert_data(
            table_name,
            self.schema1,
            [
                {'id': 1, 'level': 3},
                {'id': 2, 'level': None},
            ],
            comment="with ok scheme",
        )
        assert sth.get_table_rows_count(table_name) == 2
        sth.bulk_upsert(table_name, dg.DataGeneratorPerColumn(self.schema1, 100), comment="100 sequetial ids")
        sth.execute_scheme_query(DropTable(table_name), retries=5)
```

--------------------------------

### Install Boto3 from Source

Source: https://github.com/ydb-platform/ydb/blob/main/contrib/python/boto3/py2/README.rst

Clone the repository, set up a virtual environment, and install dependencies to build Boto3 locally.

```sh
$ git clone https://github.com/boto/boto3.git
$ cd boto3
$ virtualenv venv
...
$ . venv/bin/activate
$ python -m pip install -r requirements.txt
$ python -m pip install -e .
```

--------------------------------

### Install OpenTelemetry Adapter for Go SDK

Source: https://github.com/ydb-platform/ydb/blob/main/ydb/docs/en/core/reference/ydb-sdk/observability/metrics/opentelemetry.md

Use the go get command to install the necessary OpenTelemetry adapter for the YDB Go SDK.

```bash
go get github.com/ydb-platform/ydb-go-sdk-otel
```

--------------------------------

### Min Aggregate Array Examples

Source: https://github.com/ydb-platform/ydb/blob/main/yql/essentials/docs/ru/_includes/pg_functions.md

Examples of using the min aggregate function on various array types.

```sql
SELECT min(array[x,x]::smallint[]) FROM (VALUES (1),(2),(3)) a(x) → {1,1}
SELECT min(array[x,x]::integer[]) FROM (VALUES (1),(2),(3)) a(x) → {1,1}
SELECT min(array[x,x]::bigint[]) FROM (VALUES (1),(2),(3)) a(x) → {1,1}
SELECT min(array[x,x]::real[]) FROM (VALUES (1),(2),(3)) a(x) → {1,1}
SELECT min(array[x,x]::double precision[]) FROM (VALUES (1),(2),(3)) a(x) → {1,1}
SELECT min(array[x,x]::numeric[]) FROM (VALUES (1),(2),(3)) a(x) → {1,1}
SELECT min(array[x,x]) FROM (VALUES ('a'),('b'),('c')) a(x) → {a,a}
SELECT min(array[x,x]::date[]) FROM (VALUES ('2001-01-01'),('2001-02-03'),('2002-01-01')) a(x) → {2001-01-01,2001-01-01}
SELECT min(array[x,x]::timestamp[]) FROM (VALUES ('2001-01-01 23:05:04'),('2001-01-01 23:06:03'),('2001-01-01 23:59:00')) a(x) → {"2001-01-01 23:05:04","2001-01-01 23:05:04"}
SELECT min(array[x,x]::time[]) FROM (VALUES ('10:00:05'),('11:00:01'),('12:50:00')) a(x) → {10:00:05,10:00:05}
SELECT min(array[x,x]) FROM (VALUES (interval '1' day),(interval '2' day),(interval '3' day)) a(x) → {"1 day","1 day"}
```

--------------------------------

### PG Interval Input Examples

Source: https://github.com/ydb-platform/ydb/blob/main/yt/yql/tests/sql/suites/blocks/input_to_pg_interval.txt

These examples show various inputs being converted to PG interval format. They cover zero values, large positive values, and large negative values.

```text
{"a"=0;"b"=0};
```

```text
{"a"=4291747199999999;"b"=9223339708799999999};
```

```text
{"a"=-4291747199999999;"b"=-9223339708799999999};
```

--------------------------------

### Get Start of Quarter

Source: https://github.com/ydb-platform/ydb/blob/main/yql/essentials/docs/en/udf/list/datetime.md

Calculates the start of the quarter for a given datetime, resetting time components to zero. Returns NULL if the result is invalid.

```yql
DateTime::MakeDatetime(DateTime::StartOfQuarter(Datetime("2019-06-06T01:02:03Z")))
```

--------------------------------

### requests-mock: Basic Session Setup

Source: https://github.com/ydb-platform/ydb/blob/main/contrib/python/requests-mock/py2/README.rst

Demonstrates how to create a requests Session, mount a requests_mock Adapter, and register a URI to stub HTTP requests. Use this when you need fine-grained control over the adapter.

```python
>>> import requests
>>> import requests_mock

>>> session = requests.Session()
>>> adapter = requests_mock.Adapter()
>>> session.mount('mock://', adapter)

>>> adapter.register_uri('GET', 'mock://test.com', text='data')
>>> resp = session.get('mock://test.com')
>>> resp.status_code, resp.text
(200, 'data')
```
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