org.apache.flink.table.delegation

Interface Planner

@Internal
public interface Planner

This interface serves two purposes:

• SQL parser via getParser() - transforms a SQL string into a Table API specific objects e.g. tree of Operations
• relational planner - provides a way to plan, optimize and transform tree of ModifyOperation into a runnable form (Transformation)

The Planner is execution agnostic. It is up to the TableEnvironment to ensure that if any of the QueryOperation pull any runtime configuration, all those configurations are equivalent. Example: If some of the QueryOperations scan DataStreams, all those DataStreams must come from the same StreamExecutionEnvironment, because the result of translate(List) will strip any execution configuration from the DataStream information.

All Tables referenced in either Parser.parse(String) or translate(List) should be previously registered in a CatalogManager, which will be provided during instantiation of the Planner.

Method Summary

Modifier and Type	Method and Description
SelectTableSink	createSelectTableSink(TableSchema tableSchema) Creates a SelectTableSink for a select query.
String	explain(List<Operation> operations, ExplainDetail... extraDetails) Returns the AST of the specified Table API and SQL queries and the execution plan to compute the result of the given collection of QueryOperations.
String[]	getCompletionHints(String statement, int position) Returns completion hints for the given statement at the given cursor position.
Parser	getParser() Retrieves a Parser that provides methods for parsing a SQL string.
List<Transformation<?>>	translate(List<ModifyOperation> modifyOperations) Converts a relational tree of ModifyOperations into a set of runnable Transformations.

Method Detail

getParser

Parser getParser()

Retrieves a Parser that provides methods for parsing a SQL string.

Returns:

initialized Parser

translate

List<Transformation<?>> translate(List<ModifyOperation> modifyOperations)

Converts a relational tree of ModifyOperations into a set of runnable Transformations.

This method accepts a list of ModifyOperations to allow reusing common subtrees of multiple relational queries. Each query's top node should be a ModifyOperation in order to pass the expected properties of the output Transformation such as output mode (append, retract, upsert) or the expected output type.

Parameters:

modifyOperations - list of relational operations to plan, optimize and convert in a single run.

Returns:

list of corresponding Transformations.

createSelectTableSink

SelectTableSink createSelectTableSink(TableSchema tableSchema)

Creates a SelectTableSink for a select query.

Parameters:

tableSchema - the table schema of select result.

Returns:

The SelectTableSink for the select query.

explain

String explain(List<Operation> operations,
               ExplainDetail... extraDetails)

Returns the AST of the specified Table API and SQL queries and the execution plan to compute the result of the given collection of QueryOperations.

Parameters:

operations - The collection of relational queries for which the AST and execution plan will be returned.

extraDetails - The extra explain details which the explain result should include, e.g. estimated cost, changelog mode for streaming

getCompletionHints

String[] getCompletionHints(String statement,
                            int position)

Returns completion hints for the given statement at the given cursor position. The completion happens case insensitively.

Parameters:

statement - Partial or slightly incorrect SQL statement

position - cursor position

Returns:

completion hints that fit at the current cursor position