Apache Flink

https://nightlies.apache.org/flink/flink-docs-release-1.19/
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### Getting Started Example Constructor

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/table/examples/java/basics/GettingStartedExample.html

The default constructor for the GettingStartedExample class. It initializes the example class.

```java
public GettingStartedExample()
```

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

### Simple HybridSource Example

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/connector/base/source/hybrid/HybridSource.html

Demonstrates a basic HybridSource setup chaining FileSource and KafkaSource with a fixed Kafka starting position. Use this for straightforward sequential source transitions.

```java
FileSource<String> fileSource = FileSource.forRecordStreamFormat(new TextLineInputFormat(), Path.fromLocalFile(testDir)).build();
KafkaSource<String> kafkaSource = KafkaSource.<String>builder()
        .setBootstrapServers("localhost:9092")
        .setGroupId("MyGroup")
        .setTopics(Arrays.asList("quickstart-events"))
        .setDeserializer(
                KafkaRecordDeserializer.valueOnly(StringDeserializer.class))
        .setStartingOffsets(OffsetsInitializer.earliest())
        .build();
HybridSource<String> hybridSource = HybridSource.builder(fileSource)
        .addSource(kafkaSource)
        .build();
```

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

### Setup Flink Project with Quickstart Script

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/docs/connectors/datastream/formats/azure_table_storage

Use the Flink quickstart script to set up a new Flink project.

```bash
curl https://flink.apache.org/q/quickstart.sh | bash
```

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

### Minimal Elasticsearch7Sink Setup

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/python/reference/pyflink.datastream/api/pyflink.datastream.connectors.elasticsearch.Elasticsearch7SinkBuilder.html

This example shows the minimal setup required to create an ElasticsearchSink. It configures the hosts and an emitter for dynamic indexing. The sink will submit actions on checkpoint or when 1000 actions are buffered.

```python
>>> sink = Elasticsearch7SinkBuilder() \
...     .set_hosts('localhost:9200') \
...     .set_emitter(ElasticsearchEmitter.dynamic_index("index_col", "key_col")) \
...     .build()

```

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

### Getting Started Example Class

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/table/examples/java/basics/GettingStartedExample.html

The main class for the getting started example. It extends Object and serves as the entry point for demonstrating Flink's Table & SQL API.

```java
public final class GettingStartedExample
extends Object
```

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

### setup Method

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/io/network/api/writer/RoundRobinChannelSelector.html

Initializes the channel selector with the number of output channels.

```APIDOC
## setup(int numberOfChannels)

### Description
Initializes the channel selector with the number of output channels.

### Method
`void setup(int numberOfChannels)`

### Parameters
#### Path Parameters
- **numberOfChannels** (int) - Required - the total number of output channels which are attached to respective output gate.
```

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

### setup()

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/io/network/partition/consumer/SingleInputGate.html

Sets up the input gate. This can be a heavy-weight, blocking operation.

```APIDOC
## setup()

### Description
Sets up the input gate. This can be a heavy-weight, blocking operation compared to just creation.

### Method
public void setup() throws IOException

### Throws
- IOException: If an I/O error occurs during setup.
```

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

### Method: setup

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/operators/AllReduceDriver.html

Sets up the driver with the provided task context before execution.

```APIDOC
## setup

### Description
Initializes the driver with the given task context. This method is called before the user code is opened.

### Method
`public void setup(TaskContext<ReduceFunction<T>, T> context)`

### Parameters
* **context** (`TaskContext<ReduceFunction<T>, T>`) - The context for the task.

### Specified By
`setup` in interface `Driver<ReduceFunction<T>, T>`
```

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

### open Method Initialization Example

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/table/runtime/operators/over/ProcTimeRowsBoundedPrecedingFunction.html

The open method is used for one-time setup work before the function starts processing elements. It's suitable for initializing values based on configuration provided in OpenContext.

```java
publicvoidopen(OpenContextopenContext)
          throws Exception
```

```java
publicclassMyFilterextendsRichFilterFunction<String>{

     privateStringsearchString;

     publicvoidopen(OpenContextopenContext) {
         // initialize the value of searchString
     }

     publicbooleanfilter(Stringvalue) {
         returnvalue.equals(searchString);
     }
 }
 
```

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

### Initialize KafkaSource

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/python/_modules/pyflink/datastream/connectors/kafka.html

Example of creating a KafkaSource with various configurations including bootstrap servers, group ID, topics, deserializer, and starting offsets.

```python
source = KafkaSource \
    .builder() \
    .set_bootstrap_servers('MY_BOOTSTRAP_SERVERS') \
    .set_group_id('MY_GROUP') \
    .set_topics('TOPIC1', 'TOPIC2') \
    .set_value_only_deserializer(SimpleStringSchema()) \
    .set_starting_offsets(KafkaOffsetsInitializer.earliest()) \
    .build()
```

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

### createLeaderRetrievalDriver

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/kubernetes/highavailability/KubernetesLeaderRetrievalDriverFactory.html

Create a specific LeaderRetrievalDriver and start the necessary services. For example, NodeCache in Zookeeper, ConfigMap watcher in Kubernetes. They could get the leader information change events and need to notify the leader listener by LeaderRetrievalEventHandler.

```APIDOC
## createLeaderRetrievalDriver

### Description
Create a specific `LeaderRetrievalDriver` and start the necessary services. For example, NodeCache in Zookeeper, ConfigMap watcher in Kubernetes. They could get the leader information change events and need to notify the leader listener by `LeaderRetrievalEventHandler`.

### Method Signature
```java
public LeaderRetrievalDriver createLeaderRetrievalDriver(LeaderRetrievalEventHandler leaderEventHandler, FatalErrorHandler fatalErrorHandler)
```

### Parameters
* **leaderEventHandler** (LeaderRetrievalEventHandler) - handler for the leader retrieval driver to notify leader change events.
* **fatalErrorHandler** (FatalErrorHandler) - fatal error handler
```

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

### Get Configuration

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/taskexecutor/TaskManagerConfiguration.html

Gets the Flink Configuration object that the TaskManager was started with.

```java
publicConfigurationgetConfiguration()
```

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

### Configure SQL Gateway with Properties

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/docs/dev/table/sql-gateway/overview

Demonstrates how to start the SQL Gateway and configure it using -D properties.

```bash
$ ./sql-gateway -Dkey=value

```

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

### setup Method

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/cep/operator/CepOperator.html

Initializes the operator, setting up access to the task context and output.

```APIDOC
## setup Method

### Description
Initializes the operator. Sets access to the context and the output.

### Parameters
* **containingTask** (StreamTask<?,?>) - The task containing this operator.
* **config** (StreamConfig) - The configuration for the stream operator.
* **output** (Output<StreamRecord<OUT>>) - The output collector for processed records.
```

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

### Get Start Delay

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/rest/messages/checkpoints/SubtaskCheckpointStatistics.CompletedSubtaskCheckpointStatistics.html

Retrieves the delay before the checkpoint started in milliseconds.

```java
publiclonggetStartDelay()
```

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

### setup Method

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/operators/NoOpChainedDriver.html

Sets up the driver with the parent invokable task.

```APIDOC
## setup(AbstractInvokable parent)

### Description
Sets up the driver with the parent invokable task.

### Method
public void setup(AbstractInvokable parent)

### Parameters
* **parent** (AbstractInvokable) - The parent invokable task.
```

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

### Get Start KeyGroup of Range

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/state/KeyGroupRange.html

Retrieves the starting key-group index of this range.

```java
publicintgetStartKeyGroup()
```

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

### setup

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/io/network/partition/hybrid/tiered/storage/SortBufferAccumulator.html

Sets up the accumulator with a buffer flusher.

```APIDOC
## setup

### Description
Setup the accumulator. This method is called once before receiving any records.

### Method
```java
public void setup(TriConsumer<TieredStorageSubpartitionId, Buffer, Integer> bufferFlusher)
```

### Parameters
* **bufferFlusher** (TriConsumer<TieredStorageSubpartitionId, Buffer, Integer>) - Accepts the accumulated buffers. The first field is the subpartition id, the second is the accumulated buffer to flush, and the third is the number of remaining buffers to be written consecutively to the same segment.
```

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

### Get Initialization Start Timestamp

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/checkpoint/SubTaskInitializationMetricsBuilder.html

Retrieves the start timestamp of the subtask initialization.

```java
public long getInitializationStartTs()
```

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

### Get Span Start Timestamp

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/traces/Span.html

Retrieves the start timestamp of the span in milliseconds since the epoch.

```java
long getStartTsMillis()
```

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

### Get Window Start Columns

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/table/planner/plan/trait/RelWindowProperties.html

Retrieves the ImmutableBitSet representing the columns that define the start of the window.

```java
public org.apache.calcite.util.ImmutableBitSet getWindowStartColumns()
```

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

### CREATE TABLE Statement Examples

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/docs/dev/table/hive-compatibility/hive-dialect/create

Examples demonstrate creating non-partitioned, partitioned, and tables with specific storage formats or row formats. Also shows creating a table from a SELECT statement.

```sql
-- creaet non-partition table
CREATE TABLE t1(key string, value string);

-- creaet partitioned table
CREATE TABLE pt1(key string, value string) PARTITIONED BY (year int, month int);

-- creaet table with specifc format
CREATE TABLE t1(key string, value string) STORED AS ORC;

-- create table with specifc rowfromat
CREATE TABLE t1(m MAP<BIGINT, STRING>) 
  ROW FROMAT DELIMITED COLLECTION ITEMS TERMINATED BY ';'
  MAP KEYS TERMINATED BY ':';

-- create table as select
CREATE TABLE t2 AS SELECT key, COUNT(1) FROM t1 GROUP BY key;
```

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

### Get Async Checkpoint Start Delay

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/streaming/runtime/tasks/StreamTask.html

Retrieves the delay in nanoseconds before starting an asynchronous checkpoint.

```java
protected long getAsyncCheckpointStartDelayNanos()
```

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

### SQL Gateway Start Command Help

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/docs/dev/table/sql-gateway/overview

Shows detailed help for the 'start' command of the sql-gateway.sh script, including configuration options.

```bash
$ ./bin/sql-gateway.sh start --help

```

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

### Get Window Start Time

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/table/api/internal/BaseExpressions.html

Returns the inclusive start time of a window when applied on a window reference.

```java
public OutType start()
```

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

### setup Method

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/streaming/api/connector/sink2/GlobalCommitterOperator.html

Initializes the operator, setting up access to the containing task, configuration, and output.

```APIDOC
## setup Method

### Description
Initializes the operator. Sets access to the context and the output.

### Signature
```java
public void setup(StreamTask<?,?> containingTask, StreamConfig config, Output<StreamRecord<Void>> output)
```

### Overrides
`setup` in class `AbstractStreamOperator<Void>`

### Parameters
* **containingTask** - The `StreamTask` that contains this operator.
* **config** - The `StreamConfig` for this operator.
* **output** - The `Output` to which this operator sends records.
```

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

### Get TimeWindow Start Timestamp

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/streaming/api/windowing/windows/TimeWindow.html

Retrieves the starting timestamp of the window. This is the first timestamp that belongs to this window.

```java
public long getStart()
```

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

### setup()

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/iterative/concurrent/SuperstepBarrier.html

Sets up the barrier, which must be called at the beginning of each superstep.

```APIDOC
## setup()

### Description
Setup the barrier, has to be called at the beginning of each superstep.

### Signature
```java
public void setup()
```
```

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

### Setup Partitions and Gates

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/taskmanager/Task.html

Initializes partitions and input gates for a task. This method is annotated for testing purposes.

```java
public static void setupPartitionsAndGates(ResultPartitionWriter[] producedPartitions,
                                                              InputGate[] inputGates)
                                                       throws IOException
```

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

### Get Range Start

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/state/changelog/inmemory/InMemoryChangelogStateHandle.html

Retrieves the start of the range managed by this handle. This is specific to changelog state handles.

```java
public long getFrom()
```

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

### start()

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/io/network/partition/hybrid/tiered/tier/disk/DiskTierConsumerAgent.html

Starts the DiskTierConsumerAgent, enabling it to begin fetching data.

```APIDOC
## start()

### Description
Start the consumer agent. This method initiates the operations of the DiskTierConsumerAgent.

### Method
`void start()`

### Implements
`TierConsumerAgent.start()`
```

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

### Get Checkpoint Start Delay Stats

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/checkpoint/TaskStateStats.TaskStateStatsSummary.html

Retrieves the statistics summary for checkpoint start delays. This measures the time between the checkpoint trigger and the actual start of the checkpoint.

```java
publicStatsSummarygetCheckpointStartDelayStats()
```

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

### setup Method

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/operators/AllGroupCombineDriver.html

Called before the user code is opened. It is specified by the Driver interface.

```java
public
void
setup(TaskContext<GroupCombineFunction<IN,OUT>,OUT>
context)
```

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

### Example: Set Kafka Option

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/table/api/TableDescriptor.Builder.html

This example demonstrates how to set a startup mode option for a Kafka connector using the `option` method.

```java
TableDescriptor.forConnector("kafka")
   .option("scan.startup.mode", "latest-offset")
   .build();
```

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

### Default Filter Implementation Example

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/api/common/io/FilePathFilter.html

An example of how a filter path might be implemented to exclude files starting with '.' or containing '_COPYING_'.

```APIDOC
## Example Implementation of filterPath

```java
public boolean filterPath(Path filePath) {
    return filePath.getName().startsWith(".") || filePath.getName().contains("_COPYING_");
}
```
```

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

### filterPath Method Implementation Example

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/api/common/io/FilePathFilter.html

Example implementation of the filterPath method. This logic ignores files starting with '.' or containing '_COPYING_'.

```java
public boolean filterPaths(Path filePath) {
    return filePath.getName().startsWith(".") || filePath.getName().contains("_COPYING_");
}
```

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

### start()

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/test/util/TestProcessBuilder.html

Starts the configured process and returns a TestProcess object.

```APIDOC
## start()

### Description
Starts the configured process and returns a `TestProcess` object which contains the running process and its output.

### Returns
- **TestProcess** - An instance of `TestProcess` representing the started process.
```

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

### Get FlinkResource with Setup

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/tests/util/flink/FlinkResource.html

Retrieves the configured FlinkResource implementation, applying the provided setup instructions. Defaults to LocalStandaloneFlinkResource if no configuration is specified.

```java
static FlinkResource get(FlinkResourceSetup setup)
```

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

### Setup and Initialization

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/io/network/partition/ResultPartition.html

Methods related to the setup and initialization of a ResultPartition.

```APIDOC
## Setup Methods

### setup

```java
public void setup() throws IOException
```

Registers a buffer pool with this result partition. There is one pool for each result partition, which is shared by all its sub partitions. The pool is registered with the partition *after* it has been constructed in order to conform to the life-cycle of task registrations in the `TaskExecutor`.

Specified by:
`setup` in interface `ResultPartitionWriter`

Throws:
`IOException`

### setupInternal

```java
protected abstract void setupInternal() throws IOException
```

Performs the subclass's specific setup operation. This is an abstract method intended to be implemented by concrete subclasses to handle their unique initialization logic.
```

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

### Setup Method

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/operators/CoGroupWithSolutionSetFirstDriver.html

Sets up the driver with the provided TaskContext. This method is specified by the Driver interface.

```java
publicr voidr setup(TaskContext<CoGroupFunction<IT1,IT2,OT>,OT>r context)
```

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

### Get TaskManager Configuration

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/taskexecutor/TaskManagerConfiguration.html

Retrieves the configuration that the TaskManager was started with.

```APIDOC
## getConfiguration

### Description
Gets the configuration that the TaskManager was started with.

### Method
public Configuration getConfiguration()

### Returns
The configuration that the TaskManager was started with.
```

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

### Example: Partition by two columns, no ORDER BY

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/docs/dev/table/hive-compatibility/hive-dialect/queries/window-functions

Shows how to use multiple columns for partitioning in a window function when no ordering is specified.

```sql
SELECT a, COUNT(b) OVER (PARTITION BY c, d) FROM t;
```

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

### getOffset()

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/core/fs/local/LocalBlockLocation.html

Get the start offset of the file associated with this block.

```APIDOC
## getOffset()

### Description
Get the start offset of the file associated with this block.

### Returns
* **long** - The start offset of the file associated with this block.
```

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

### SourceOperator setup Method

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/streaming/api/operators/SourceOperator.html

Initializes the operator with the containing task, configuration, and output. This is a core setup method called before the operator starts processing.

```java
void setup(StreamTask<?,?> containingTask,
      StreamConfig config,
      Output<StreamRecord<OUT>> output)
```

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

### setupPartitionsAndGates

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/taskmanager/Task.html

Sets up the partitions and gates for the task.

```APIDOC
## setupPartitionsAndGates

### Description
Sets up the partitions and gates for the task.

### Method
```java
static void setupPartitionsAndGates(ResultPartitionWriter[] producedPartitions, InputGate[] inputGates)
```

### Parameters
* **producedPartitions** (ResultPartitionWriter[]) - Description not available.
* **inputGates** (InputGate[]) - Description not available.
```

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

### ParquetColumnarRowInputFormat Example

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/python/_modules/pyflink/datastream/formats/parquet.html

This example demonstrates the setup for ParquetColumnarRowInputFormat, which provides a RowData iterator using ColumnarRowData. Note that only primitive types are supported for columns.

```python
row_type = DataTypes.ROW([
    DataTypes.FIELD('a', DataTypes.INT()),
    DataTypes.FIELD('b', DataTypes.STRING()),
])
```

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

### Example: Configure Key Format for Kafka

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/table/api/TableDescriptor.Builder.html

This example demonstrates configuring the key format for a Kafka connector using a specific `ConfigOption` and `FormatDescriptor`.

```java
descriptorBuilder.format(KafkaOptions.KEY_FORMAT, FormatDescriptor.forFormat("json")
   .option(JsonOptions.IGNORE_PARSE_ERRORS, true)
   .build())
```

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

### before

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/tests/util/cache/PersistingDownloadCache.html

Performs setup actions before a test.

```APIDOC
## before()

### Description
Performs setup actions before a test. This method is part of the `ExternalResource` interface.

### Method
public void before() throws IOException

### Throws
* **IOException** - if an I/O error occurs during setup
```

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

### FilePathFilter Default Filter Example

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/api/common/io/GlobFilePathFilter.html

An example of a default filter implementation from the base FilePathFilter class, which ignores files starting with '.' or containing '_COPYING_'.

```java
public boolean filterPaths(Path filePath) {
    return filePath.getName().startsWith(".") || filePath.getName().contains("_COPYING_");
}

```

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

### KvStateServer start() Method

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/query/KvStateServer.html

Initiates the operation of the KvStateServer, making it ready to serve state requests. This method can throw exceptions during startup.

```java
void start()
    throws Throwable

```

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

### Starting Input Stream with Netcat

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/docs/dev/datastream/overview

Command to start a netcat listener on port 9999 to provide input to the Flink word count example.

```bash
nc -lk 9999

```

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

### Get Window Start Index

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/table/planner/plan/logical/WindowAttachedWindowingStrategy.html

Retrieves the index of the column representing the start of the window. This is useful for understanding the physical layout of window data.

```java
public int getWindowStart()
```

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

### Example: Partition and Order by two columns

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/docs/dev/table/hive-compatibility/hive-dialect/queries/window-functions

Illustrates a window function with partitioning by two columns and ordering by two other columns.

```sql
SELECT a, SUM(b) OVER (PARTITION BY c, d ORDER BY e, f) FROM t;
```

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

### AsyncFunction Callback Example

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/streaming/api/functions/async/AsyncFunction.html

Example of implementing AsyncFunction using a callback for HBase asynchronous get operations. The result is completed via the ResultFuture.

```java
public class HBaseAsyncFunc implements AsyncFunction<String, String> {

  public void asyncInvoke(String row, ResultFuture<String> result) throws Exception {
    HBaseCallback cb = new HBaseCallback(result);
    Get get = new Get(Bytes.toBytes(row));
    hbase.asyncGet(get, cb);
  }
 }
```

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

### Get Installed Security Modules

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/security/SecurityUtils.html

Retrieves a list of all installed security modules. This can be used to inspect which security components are active in the Flink environment.

```java
public static List<SecurityModule> getInstalledModules()
```

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

### Example: Partition, Order, and Specific Window Frame

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/docs/dev/table/hive-compatibility/hive-dialect/queries/window-functions

Demonstrates a window function with partitioning, ordering, and a precisely defined window frame.

```sql
SELECT a, SUM(b) OVER (PARTITION BY c ORDER BY d ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW)
FROM t;
```

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

### start()

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/io/network/partition/hybrid/tiered/storage/TieredStorageConsumerClient.html

Starts the TieredStorageConsumerClient, enabling it to begin reading data.

```APIDOC
## start()

### Description
Starts the `TieredStorageConsumerClient`. This method should be called before attempting to read any data.

### Method
`void start()`
```

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

### Get Flink Home Path

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/connector/testframe/container/FlinkContainersSettings.html

Retrieves the Flink home directory path. This is the root directory where Flink is installed or will be installed within the container.

```java
public String getFlinkHome()
```

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

### Filesystem Sink - Basic Streaming and Batch Example

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/docs/connectors/table/filesystem

Demonstrates creating a Kafka source table and a filesystem sink table, then inserting streaming data into the filesystem table. Includes an example of selecting data with partition pruning in batch mode.

```sql
CREATE TABLE kafka_table (
  user_id STRING,
  order_amount DOUBLE,
  log_ts TIMESTAMP(3),
  WATERMARK FOR log_ts AS log_ts - INTERVAL '5' SECOND
) WITH (...);

CREATE TABLE fs_table (
  user_id STRING,
  order_amount DOUBLE,
  dt STRING,
  `hour` STRING
) PARTITIONED BY (dt, `hour`) WITH (
  'connector'='filesystem',
  'path'='...',
  'format'='parquet',
  'sink.partition-commit.delay'='1 h',
  'sink.partition-commit.policy.kind'='success-file'
);

-- streaming sql, insert into file system table
INSERT INTO fs_table 
SELECT 
    user_id, 
    order_amount, 
    DATE_FORMAT(log_ts, 'yyyy-MM-dd'),
    DATE_FORMAT(log_ts, 'HH') 
FROM kafka_table;

-- batch sql, select with partition pruning
SELECT * FROM fs_table WHERE dt='2020-05-20' and `hour`='12';
```

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

### Get Default Instance for UserDefinedFunctions Builder

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/fnexecution/v1/FlinkFnApi.UserDefinedFunctions.Builder.html

Retrieves the default instance of UserDefinedFunctions for the builder. This is typically used to get a starting point or an empty object.

```java
public
FlinkFnApi.UserDefinedFunctions getDefaultInstanceForType()

```

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

### startUp

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/connector/testframe/environment/MiniClusterTestEnvironment.html

Start up the test resource.

```APIDOC
## startUp()

### Description
Start up the test resource.

### Method
`void`

### Returns
`void`
```

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

### Python ProcessWindowFunction Example

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/docs/dev/datastream/operators/windows

Provides a Python snippet demonstrating the setup for using a ProcessWindowFunction with keyBy and window operations. This example focuses on the chaining of these operations.

```python
input = ...  # type: DataStream

input \
    .key_by(lambda v: v[0]) \
    .window(TumblingEventTimeWindows.of(Time.minutes(5))) \
    .process(MyProcessWindowFunction())
```

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

### SHOW PARTITIONS Statement Examples

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/docs/dev/table/hive-compatibility/hive-dialect/show

Demonstrates listing all partitions or specific partitions for a given table using partition specifications.

```sql
-- list all partitions
SHOW PARTITIONS t1;
```

```sql
-- specific a full partition partition spec to list specific partition
SHOW PARTITIONS t1 PARTITION (year = 2022, month = 12);
```

```sql
-- specific a partial partition spec to list all the specifc partitions
SHOW PARTITIONS t1 PARTITION (year = 2022);
```

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

### Get Region Start Offset

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/io/network/partition/hybrid/index/FileDataIndexRegionHelper.Region.html

Retrieves the file offset marking the beginning of this region. This is the physical start position in the file for the first buffer of the region.

```java
long getRegionStartOffset()
```

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

### QsStateClient Main Method

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/streaming/tests/queryablestate/QsStateClient.html

The main entry point for the QsStateClient application. This method initializes the client and starts the state querying process.

```APIDOC
## QsStateClient Main Method

### Description
This is the static main method that serves as the entry point for the QsStateClient application. It is responsible for parsing command-line arguments and initiating the state querying process.

### Signature
```java
public static void main(String[] args) throws Exception
```

### Parameters
*   `args` (String[]) - Command-line arguments passed to the application, expected to contain host, port, and job ID.
```

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

### Selecting Tumbling Window Start Timestamp

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/docs/dev/table/sql/queries/window-agg

This example demonstrates how to select the start timestamp of a tumbling window using the TUMBLE_START auxiliary function. The window start is aliased as 'wStart' and used in conjunction with a SUM aggregation.

```sql
CREATE TABLE Orders (
  user       BIGINT,
  product    STRING,
  amount     INT,
  order_time TIMESTAMP(3),
  WATERMARK FOR order_time AS order_time - INTERVAL '1' MINUTE
) WITH (...);

SELECT
  user,
  TUMBLE_START(order_time, INTERVAL '1' DAY) AS wStart,
  SUM(amount) FROM Orders
GROUP BY
  TUMBLE(order_time, INTERVAL '1' DAY),
  user

```

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

### Elasticsearch 6 Sink Builder Example

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/python/_modules/pyflink/datastream/connectors/elasticsearch.html

Minimal setup example for creating an Elasticsearch 6 sink. It configures hosts and an emitter for static index names.

```python
>>> sink = Elasticsearch6SinkBuilder() \
...     .set_hosts('localhost:9200') \
...     .set_emitter(ElasticsearchEmitter.static_index("user", "key_col")) \
...     .build()
```

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

### Setup Partition

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/io/network/partition/ResultPartition.html

Registers a buffer pool with this result partition and performs subclass-specific setup.

```APIDOC
## setup

### Description
Registers a buffer pool with this result partition and performs subclass-specific setup operations.

### Methods
- `void setup()`
- `protected abstract void setupInternal()`

### Parameters
None
```

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

### start

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/query/KvStateServer.html

Initiates the KvStateServer, making it ready to accept and process queryable state requests.

```APIDOC
## start

Starts the server.

### Method Signature
```java
void start() throws Throwable
```

### Throws
*   `Throwable`: If an error occurs during server startup.
```

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

### Get Installed Security Context

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/security/SecurityUtils.html

Retrieves the currently installed security context. This method is useful for accessing the active security settings within the Flink process.

```java
public static SecurityContext getInstalledContext()
```

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

### getAsyncCheckpointStartDelayNanos

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/streaming/runtime/tasks/StreamTask.html

Protected method to get the delay in nanoseconds before starting an asynchronous checkpoint.

```APIDOC
## getAsyncCheckpointStartDelayNanos

### Returns
long - The delay in nanoseconds.
```

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

### start()

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/io/network/partition/hybrid/tiered/tier/remote/RemoteTierConsumerAgent.html

Starts the consumer agent, enabling it to fetch data.

```APIDOC
## start()

### Description
Starts the consumer agent. This method should be called before attempting to retrieve any data.

### Method
```java
public void start()
```

### Implements
`TierConsumerAgent.start()`
```

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

### AsyncFunction Future Example

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/streaming/api/functions/async/AsyncFunction.html

Example of implementing AsyncFunction using Guava's ListenableFuture and Futures.addCallback for HBase asynchronous get operations. Results or exceptions are propagated through the ResultFuture.

```java
public class HBaseAsyncFunc implements AsyncFunction<String, String> {

  public void asyncInvoke(String row, final ResultFuture<String> result) throws Exception {
    Get get = new Get(Bytes.toBytes(row));
    ListenableFuture<Result> future = hbase.asyncGet(get);
    Futures.addCallback(future, new FutureCallback<Result>() {
      public void onSuccess(Result result) {
        List<String> ret = process(result);
        result.complete(ret);
      }
      public void onFailure(Throwable thrown) {
        result.completeExceptionally(thrown);
      }
    });
  }
 }
```

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

### Create Over Window with Partitioning and Ordering

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/python/_modules/pyflink/table/window.html

Helper class for creating over windows. This example demonstrates how to define partitioning and ordering for an over window.

```python
>>> from pyflink.table.expressions import col, UNBOUNDED_RANGE
>>> Over.partition_by(col("a")) \
...     .order_by(col("rowtime")) \
...     .preceding(UNBOUNDED_RANGE) \
...     .alias("w")
```

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

### Example Flink HA Configuration

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/docs/deployment/ha/kubernetes_ha

An example Flink configuration file demonstrating the setup for Kubernetes HA services, including cluster ID, HA type, and storage directory.

```yaml
kubernetes.cluster-id: <cluster-id>
high-availability.type: kubernetes
high-availability.storageDir: hdfs:///flink/recovery
```

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

### AllReduceDriver Setup Method

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/operators/AllReduceDriver.html

Sets up the driver with the provided TaskContext. This method is required by the Driver interface.

```java
public
void setup(TaskContext<ReduceFunction<T>,T> context)
```

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

### Run a Sample SQL Query

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/docs/dev/table/sqlclient

Executes a sample SQL query to validate setup and cluster connection. The results are visualized in the client. Press 'Q' to close the result view.

```sql
SET 'sql-client.execution.result-mode' = 'tableau';
SET 'execution.runtime-mode' = 'batch';

SELECT
  name,
  COUNT(*) AS cnt
FROM
  (VALUES ('Bob'), ('Alice'), ('Greg'), ('Bob')) AS NameTable(name)
GROUP BY name;

```

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

### open() Method Implementation Example

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/api/java/operators/translation/WrappingFunction.html

Example of implementing the open() method in a RichFilterFunction to initialize a search string. This method is called before the main working methods and is suitable for one-time setup.

```java
public class MyFilter extends RichFilterFunction<String> {

    private String searchString;

    public void open(OpenContext openContext) {
        // initialize the value of searchString
    }

    public boolean filter(String value) {
        return value.equals(searchString);
    }
 }
```

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

### start()

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/table/gateway/SqlGateway.html

Starts the SQL Gateway service.

```APIDOC
## start()

### Description
Starts the SQL Gateway service.

### Method
`void start() throws Exception`

### Throws
* `Exception` - If an error occurs during startup.
```

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

### LogicalFile getStartOffset()

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/checkpoint/filemerging/LogicalFile.html

Gets the starting offset of this logical file within its physical file.

```java
public long getStartOffset()
```

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

### start

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/queryablestate/client/proxy/KvStateClientProxyImpl.html

Starts the KvStateClientProxyImpl server, binding it to the configured address and port.

```APIDOC
## start

### Description
Starts the server by binding to the configured bind address (blocking).

### Method
public void start() throws Throwable

### Throws
* **Throwable** - If an error occurs during server startup.
```

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

### Get Checkpoint Start Delay

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/checkpoint/CheckpointMetricsBuilder.html

Retrieves the delay in nanoseconds before the checkpoint operation begins.

```java
public long getCheckpointStartDelayNanos()

```

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

### Get Offset

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/connector/file/src/FileSourceSplit.html

Returns the starting byte position (inclusive) of the file region for this split.

```java
public long offset()
```

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

### External Resource Configuration Example

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/configuration/ExternalResourceOptions.html

This example demonstrates how to configure multiple external resources, including their driver factory classes, amounts, and custom parameters. The resource names are delimited by semicolons.

```properties
external-resources = gpu;fpga

external-resource.gpu.driver-factory.class: org.apache.flink.externalresource.gpu.GPUDriverFactory
external-resource.gpu.amount: 2
external-resource.gpu.param.type: nvidia

external-resource.fpga.driver-factory.class: org.apache.flink.externalresource.fpga.FPGADriverFactory
external-resource.fpga.amount: 1
```

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

### Minimal Elasticsearch6Sink Setup

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/python/reference/pyflink.datastream/api/pyflink.datastream.connectors.elasticsearch.Elasticsearch6SinkBuilder.html

This example demonstrates the minimum configuration required to create an Elasticsearch6Sink. It sets the target hosts and a static index emitter, and the sink will build when checkpointing or when 1000 actions are buffered.

```python
sink = Elasticsearch6SinkBuilder() \
    .set_hosts('localhost:9200') \
    .set_emitter(ElasticsearchEmitter.static_index("user", "key_col")) \
    .build()
```

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

### Installing S3 FileSystem Plugin

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/docs/deployment/filesystems/s3

Provides instructions on how to install the S3 filesystem plugin (Presto or Hadoop) by copying the JAR file to the Flink plugins directory. This is necessary before Flink starts.

```bash
mkdir ./plugins/s3-fs-presto
cp ./opt/flink-s3-fs-presto-1.19.3.jar ./plugins/s3-fs-presto/
```

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

### Elasticsearch 7 Sink Builder Example

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/python/_modules/pyflink/datastream/connectors/elasticsearch.html

Minimal setup example for creating an Elasticsearch 7 sink. It configures hosts and an emitter for dynamic index names based on column values.

```python
>>> sink = Elasticsearch7SinkBuilder() \
...     .set_hosts('localhost:9200') \
...     .set_emitter(ElasticsearchEmitter.dynamic_index("index_col", "key_col")) \
...     .build()
```

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

### setup Method

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/operators/UnionWithTempOperator.html

Sets up the operator with the provided task context. This method is called before the user code is opened.

```APIDOC
## setup(TaskContext<Function,T> context)

### Description
Sets up the operator with the provided task context. This method is called before the user code is opened.

### Method
`public void setup(TaskContext<Function,T> context)`

### Implements
`setup` in interface `Driver<Function,T>`
```

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

### QuickstartExample Class

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/quickstarts/test/QuickstartExample.html

The QuickstartExample class serves as an entry point for running end-to-end tests for Flink quickstarts. It contains a main method to initiate the test execution.

```APIDOC
## Class: QuickstartExample

### Description
This class is designed for end-to-end testing of Flink quickstarts.

### Methods

#### `main(String[] args)`

##### Description
Entry point for the QuickstartExample test.

##### Signature
`public static void main(String[] args) throws Exception`

##### Throws
`Exception` - If an error occurs during test execution.
```

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

### Get Subtask Index

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/api/common/TaskInfoImpl.html

Retrieves the index of the current parallel subtask. Indices start from 0.

```java
publicintgetIndexOfThisSubtask()
```

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

### main

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/taskexecutor/TaskManagerRunner.html

The entry point for the TaskManager process. It loads the configuration and starts the TaskManager.

```APIDOC
## main

### Description
Entry point for the TaskManager process. Loads configuration and starts the TaskManager.

### Signature
```java
public static void main(String[] args)
```

### Throws
* Exception
```

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

### Get Managed Directory

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/checkpoint/filemerging/FileMergingSnapshotManagerBase.html

Retrieves the managed directory for the file-merging snapshot manager, which is initialized during setup.

```java
public Path getManagedDir(FileMergingSnapshotManager.SubtaskKey subtaskKey,
                          CheckpointedStateScope scope)
```

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

### getStubType

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/operators/AbstractOuterJoinDriver.html

Gets the class of the stub type that is run by this task. For example, a MapTask should return MapFunction.class.

```APIDOC
## getStubType

### Description
Gets the class of the stub type that is run by this task. For example, a `MapTask` should return `MapFunction.class`.

### Specified by
`getStubType` in interface `Driver<FlatJoinFunction<IT1,IT2,OT>,OT>`

### Returns
The class of the stub type run by the task.
```

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

### Get JVM Startup Options Array

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/util/EnvironmentInformation.html

Retrieves all system and environment parameters passed to the JVM on startup as an array of strings.

```APIDOC
## getJvmStartupOptionsArray

### Description
Gets the system parameters and environment parameters that were passed to the JVM on startup.

### Method
```java
public static String[] getJvmStartupOptionsArray()
```

### Returns
- An array of strings, where each string is a JVM startup option.
```

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

### start()

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/table/client/gateway/SingleSessionManager.html

Starts the SessionManager and performs necessary initialization.

```APIDOC
## start()

### Description
Starts the `SessionManager` and performs the required initialization.

### Method
```java
public void start()
```

### Specified by
`start` in interface `SessionManager`
```

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

### HBase AsyncTableFunction Example

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/table/functions/AsyncTableFunction.html

Example implementation of an AsyncTableFunction for performing asynchronous requests to Apache HBase. The 'eval' method takes a CompletableFuture and input parameters, initiating an async HBase get operation.

```java
 public class HBaseAsyncTableFunction extends AsyncTableFunction<Row> {

   // implement an "eval" method that takes a CompletableFuture as the first parameter
   // and ends with as many parameters as you want
   public void eval(CompletableFuture<Collection<Row>> result, String rowkey) {
     Get get = new Get(Bytes.toBytes(rowkey));
     ListenableFuture<Result> future = hbase.asyncGet(get);
     Futures.addCallback(future, new FutureCallback<Result>() {
       public void onSuccess(Result hbaseResult) {
         List<Row> ret = process(hbaseResult);
         result.complete(ret);
       }
       public void onFailure(Throwable thrown) {
         result.completeExceptionally(thrown);
       }
     });
   }

   // you can overload the eval method here ...
 }
```

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

### Driver Setup Method

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/operators/Driver.html

The setup method is called before user code is opened, providing access to the TaskContext. Exceptions thrown here signal task failure.

```java
void setup(TaskContext<S,OT> context)
```

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

### Get Fields

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/table/types/DataType.html

A static utility method to return an ordered list of fields starting from the provided DataType.

```java
public static List<DataTypes.Field> getFields(DataType dataType)

```

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

### WindowFrameSpec Methods

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/table/planner/delegation/hive/copy/HiveParserWindowingSpec.WindowFrameSpec.html

Provides methods to get and set the start and end boundaries, and to retrieve the window type.

```APIDOC
## Methods

### getStart

```java
public HiveParserWindowingSpec.BoundarySpec getStart()
```

Returns the start boundary specification for the window frame.
```

```APIDOC
### setStart

```java
public void setStart(HiveParserWindowingSpec.BoundarySpec start)
```

Sets the start boundary specification for the window frame.
```

```APIDOC
### getEnd

```java
public HiveParserWindowingSpec.BoundarySpec getEnd()
```

Returns the end boundary specification for the window frame.
```

```APIDOC
### setEnd

```java
public void setEnd(HiveParserWindowingSpec.BoundarySpec end)
```

Sets the end boundary specification for the window frame.
```

```APIDOC
### getWindowType

```java
public HiveParserWindowingSpec.WindowType getWindowType()
```

Returns the type of the window frame.
```

```APIDOC
### toString

```java
public String toString()
```

Returns a string representation of the `WindowFrameSpec` object.
```

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

### KvStateService Instantiation

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/taskexecutor/class-use/KvStateService.html

Demonstrates how to create an instance of KvStateService using configuration.

```APIDOC
## KvStateService.fromConfiguration

### Description
Creates and returns the KvState service.

### Method Signature
`static KvStateService fromConfiguration(TaskManagerServicesConfiguration taskManagerServicesConfiguration)`
```

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

### EXTERNAL_RESOURCE_LIST Configuration Example

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/configuration/ExternalResourceOptions.html

This example demonstrates how to configure multiple external resources, such as GPU and FPGA, using the `EXTERNAL_RESOURCE_LIST` option and related configuration keys.

```APIDOC
## Field Detail

### EXTERNAL_RESOURCE_LIST
```java
public static final ConfigOption<List<String>> EXTERNAL_RESOURCE_LIST
```

List of the resource_name of all external resources with delimiter ";", e.g. "gpu;fpga" for two external resource gpu and fpga. The resource_name will be used to splice related config options for external resource. Only the resource_name defined here will go into effect in external resource framework.
Example:
```
external-resources = gpu;fpga

external-resource.gpu.driver-factory.class: org.apache.flink.externalresource.gpu.GPUDriverFactory
external-resource.gpu.amount: 2
external-resource.gpu.param.type: nvidia

external-resource.fpga.driver-factory.class: org.apache.flink.externalresource.fpga.FPGADriverFactory
external-resource.fpga.amount: 1
```
```

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

### getRegionStartOffset Method

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/io/network/partition/hybrid/HsFileDataIndexImpl.InternalRegion.html

Gets the starting file offset for this region. Implements the getRegionStartOffset method from the FileDataIndexRegionHelper.Region interface.

```java
publiclonggetRegionStartOffset()
```

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

### Getting Previous Pattern in Sequence

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/cep/pattern/Pattern.html

Retrieves the preceding pattern in the sequence. Returns null if this is the starting pattern.

```java
public Pattern<T,? extends T> getPrevious()
```

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

### start()

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/taskexecutor/TaskManagerRunner.html

Starts the TaskManagerRunner, initializing and starting its components.

```APIDOC
## start()

### Description
Starts the TaskManagerRunner, initializing and starting its components.

### Signature
```java
public void start() throws Exception
```

### Throws
* **Exception** - If an error occurs during startup.
```

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

### EXPLAIN PLAN WITH DETAILS Output: Optimized Physical Plan With Advice

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/docs/dev/table/sql/explain

Provides the Optimized Physical Plan along with detailed cost estimations, changelog modes, and actionable advice for performance tuning, such as enabling mini-batch optimization.

```text
== Optimized Physical Plan With Advice ==
GroupAggregate(advice=[1], groupBy=[count], select=[count, COUNT(word) AS EXPR$1], changelogMode=[I,UA]): rowcount = 1.05E8, cumulative cost = {5.2E8 rows, 1.805E10 cpu, 4.0E9 io, 2.1E9 network, 0.0 memory}
+- Exchange(distribution=[hash[count]], changelogMode=[I]): rowcount = 1.05E8, cumulative cost = {4.15E8 rows, 1.7945E10 cpu, 4.0E9 io, 2.1E9 network, 0.0 memory}
   +- Union(all=[true], union=[count, word], changelogMode=[I]): rowcount = 1.05E8, cumulative cost = {3.1E8 rows, 3.05E8 cpu, 4.0E9 io, 0.0 network, 0.0 memory}
      :- Calc(select=[count, word], where=[LIKE(word, _UTF-16LE'F%')], changelogMode=[I]): rowcount = 5000000.0, cumulative cost = {1.05E8 rows, 1.0E8 cpu, 2.0E9 io, 0.0 network, 0.0 memory}
      :  +- TableSourceScan(table=[[default_catalog, default_database, MyTable1]], fields=[count, word], changelogMode=[I]): rowcount = 1.0E8, cumulative cost = {1.0E8 rows, 1.0E8 cpu, 2.0E9 io, 0.0 network, 0.0 memory}
      +- TableSourceScan(table=[[default_catalog, default_database, MyTable2]], fields=[count, word], changelogMode=[I]): rowcount = 1.0E8, cumulative cost = {1.0E8 rows, 1.0E8 cpu, 2.0E9 io, 0.0 network, 0.0 memory}

advice[1]: [ADVICE] You might want to enable local-global two-phase optimization by configuring ('table.exec.mini-batch.enabled' to 'true', 'table.exec.mini-batch.allow-latency' to a positive long value, 'table.exec.mini-batch.size' to a positive long value).

```

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

### Check Java Version

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/docs/dev/table/olap_quickstart

Verify that Java 11 or a compatible version is installed before proceeding with Flink setup.

```bash
java -version

```

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

### Get JVM Startup Options

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/util/EnvironmentInformation.html

Retrieves all system and environment parameters passed to the JVM on startup as a single string.

```APIDOC
## getJvmStartupOptions

### Description
Gets the system parameters and environment parameters that were passed to the JVM on startup.

### Method
```java
public static String getJvmStartupOptions()
```

### Returns
- A string containing all JVM startup options.
```

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

### get_index_of_this_subtask

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/python/reference/pyflink.datastream/api/pyflink.datastream.functions.RuntimeContext.get_index_of_this_subtask.html

Gets the number of this parallel subtask. The numbering starts from 0 and goes up to parallelism-1 (parallelism as returned by get_number_of_parallel_subtasks()).

```APIDOC
## get_index_of_this_subtask()

### Description
Gets the number of this parallel subtask. The numbering starts from 0 and goes up to parallelism-1 (parallelism as returned by `get_number_of_parallel_subtasks()`).

### Method
`get_index_of_this_subtask()`

### Returns
- `int`: The index of the current parallel subtask.
```

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

### Get Default TableConfig

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/python/_modules/pyflink/table/table_config.html

Retrieves a TableConfig object initialized with default settings. This is useful for starting with a standard configuration.

```python
from pyflink.table import TableConfig


def get_default() -> 'TableConfig':
    """
    :return: A TableConfig object with default settings.
    """
    return TableConfig(get_gateway().jvm.TableConfig.getDefault())
```

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

### Get JVM Startup Options Array

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/util/EnvironmentInformation.html

Retrieves the system and environment parameters passed to the JVM on startup as an array of strings.

```APIDOC
## getJvmStartupOptionsArray

### Description
Gets the system parameters and environment parameters that were passed to the JVM on startup.

### Method
```java
public static String[] getJvmStartupOptionsArray()
```

### Returns
- The options passed to the JVM on startup.
```

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

### ReporterSetup from Configuration

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/core/plugin/class-use/PluginManager.html

Details the setup of Reporters using configuration and a PluginManager.

```APIDOC
## ReporterSetup.fromConfiguration

### Description
Sets up Reporters based on the provided configuration and PluginManager.

### Method Signature
`static List<ReporterSetup> ReporterSetup.fromConfiguration(Configuration configuration, PluginManager pluginManager)`

### Parameters
* **configuration** (Configuration) - The Flink configuration.
* **pluginManager** (PluginManager) - The PluginManager instance.
```

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

### newIterator(int beginRow) Method

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/table/runtime/util/ResettableRowBuffer.html

Gets a new iterator starting from the specified row index. The beginRow is 0-indexed.

```java
ResettableRowBuffer.ResettableIterator newIterator(int beginRow)
```

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

### main method

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/streaming/examples/join/WindowJoin.html

The entry point for the WindowJoin example. It sets up and executes the windowed join job.

```APIDOC
## main(String[] args)

### Description

This is the main method that starts the Flink job for the windowed join example.

### Method
`public static void main(String[] args) throws Exception`

### Parameters
* **args** (String[]) - Command line arguments (not used in this example).
```

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

### newIterator() Method

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/table/runtime/util/ResettableRowBuffer.html

Gets a new iterator starting from the first row of the buffer. This allows iterating over the buffered data.

```java
ResettableRowBuffer.ResettableIterator newIterator()
```

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

### INSERT TABLE Examples

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/docs/dev/table/hive-compatibility/hive-dialect/insert

Demonstrates inserting data into tables using VALUES or a SELECT statement. Supports static and dynamic partition inserts.

```sql
-- insert into table using values
INSERT INTO t1 VALUES ('k1', 'v1'), ('k2', 'v2');
```

```sql
-- insert overwrite
INSERT OVERWRITE TABLE t1 VALUES ('k1', 'v1'), ('k2', 'v2');;
```

```sql
-- insert into table using select statement
INSERT INTO TABLE t1 SELECT * FROM t2;
```

```sql
-- insert into  partition
--- static partition
INSERT INTO t1 PARTITION (year = 2022, month = 12) SELECT value FROM t2;
```

```sql
--- dynamic partition 
INSERT INTO t1 PARTITION (year = 2022, month) SELECT value, month FROM t2;
```

```sql
INSERT INTO t1 PARTITION (year, month) SELECT value, 2022, month FROM t2;
```

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

### Get Start Time

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/webmonitor/threadinfo/VertexThreadInfoStats.html

Returns the timestamp when the thread info sampling was initiated. This marks the beginning of the observation period.

```java
public long getStartTime()
```

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

### Get TaskManager Configuration

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/runtime/taskmanager/TaskManagerRuntimeInfo.html

Retrieves the Configuration object used to start the TaskManager. This is useful for inspecting runtime settings.

```java
Configuration getConfiguration()
```

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

### setup Method

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/streaming/api/operators/AbstractUdfStreamOperator.html

Initializes the operator, providing access to the containing task, configuration, and output. Overrides the setup method from the base class.

```java
public
void setup(StreamTask<?,?>
containingTask,
StreamConfig
config,
Output<StreamRecord<OUT>>
output)
```

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

### Get Flink Configuration

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/connector/testutils/source/reader/TestingReaderContext.html

Retrieves the Flink configuration used to start the job. This method is specified by the SourceReaderContext interface.

```java
public Configuration getConfiguration()
```

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

### Setup Execution Environment

Source: https://nightlies.apache.org/flink/flink-docs-release-1.19/api/java/org/apache/flink/streaming/tests/DataStreamAllroundTestJobFactory.html

Static method to set up the StreamExecutionEnvironment with parameters. This method can throw exceptions during setup.

```java
public static void setupEnvironment(StreamExecutionEnvironment env,
                                    ParameterTool pt)
                             throws Exception
```
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