org.apache.druid.sql

Class DirectStatement

java.lang.Object

org.apache.druid.sql.AbstractStatement

org.apache.druid.sql.DirectStatement

All Implemented Interfaces:

Closeable, AutoCloseable, SqlLifecycleManager.Cancelable

Direct Known Subclasses:

HttpStatement

public class DirectStatement
extends AbstractStatement
implements SqlLifecycleManager.Cancelable

Lifecycle for direct SQL statement execution, which means that the query is planned and executed in a single step, with no "prepare" step. Callers need call only:

• execute() to execute the query. The caller must close the returned Sequence.
• close() to report metrics, or AbstractStatement.closeQuietly() otherwise.

The cancel() method may be called from any thread and cancels the query.

All other methods are optional and are generally for introspection.

The class supports two threading models. In the simple case, the same thread creates this object and executes the query. In the split model, a request thread creates this object and plans the query. A separate response thread consumes results and performs any desired logging, etc. The object is transferred between threads, with no overlapping access.

As statement holds no resources and need not be called. Only the Sequence returned from execute() need be closed.

Use this class for tests and JDBC execution. Use the HTTP variant, HttpStatement for HTTP requests.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	DirectStatement.ResultSet Represents the execution plan for a query with the ability to run that plan (once).

Field Summary

Fields

Modifier and Type	Field and Description
protected PrepareResult	prepareResult
protected DirectStatement.ResultSet	resultSet

Fields inherited from class org.apache.druid.sql.AbstractStatement

cancellationResourceActions, fullResourceActions, plannerContext, queryPlus, reporter, sqlToolbox

Constructor Summary

Constructors

Constructor and Description
DirectStatement(SqlToolbox lifecycleToolbox, SqlQueryPlus sqlRequest)
DirectStatement(SqlToolbox lifecycleToolbox, SqlQueryPlus queryPlus, String remoteAddress)

Method Summary

Modifier and Type	Method and Description
void	cancel()
void	close() Releases resources and emits logs and metrics as defined the associated reporter.
void	closeWithError(Throwable e) Convenience method to close the statement and report an error associated with the statement.
protected PlannerResult	createPlan(DruidPlanner planner) Plan the query, which also produces the sequence that runs the query.
protected DirectStatement.ResultSet	createResultSet(PlannerResult plannerResult) Wrapper around result set creation for the sole purpose of tests which inject failures.
Sequence<Object[]>	execute() Convenience method to perform Direct execution of a query.
DirectStatement.ResultSet	plan() Prepares and plans a query for execution, returning a result set to execute the query.
PrepareResult	prepareResult()

Methods inherited from class org.apache.druid.sql.AbstractStatement

allResources, authorize, authorizer, closeQuietly, query, reporter, resources, sqlQueryId, validate

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.druid.sql.SqlLifecycleManager.Cancelable

resources

Field Detail

prepareResult

protected PrepareResult prepareResult

resultSet

protected DirectStatement.ResultSet resultSet

Constructor Detail

DirectStatement

public DirectStatement(SqlToolbox lifecycleToolbox,
                       SqlQueryPlus queryPlus,
                       String remoteAddress)

DirectStatement

public DirectStatement(SqlToolbox lifecycleToolbox,
                       SqlQueryPlus sqlRequest)

Method Detail

execute

public Sequence<Object[]> execute()

Convenience method to perform Direct execution of a query. Does both the plan() step and the DirectStatement.ResultSet.run() step.

Returns:

sequence which delivers query results

plan

public DirectStatement.ResultSet plan()

Prepares and plans a query for execution, returning a result set to execute the query. In Druid, prepare and plan are different: prepare provides information about the query, but plan does the "real" preparation to create an actual executable plan.

• Create the planner.
• Parse the statement.
• Provide parameters using a "query optimized" structure.
• Validate the query against the Druid catalog.
• Authorize access to the resources which the query needs.
• Plan the query.

Call DirectStatement.ResultSet.run() to run the resulting plan.

createPlan

protected PlannerResult createPlan(DruidPlanner planner)

Plan the query, which also produces the sequence that runs the query.

createResultSet

protected DirectStatement.ResultSet createResultSet(PlannerResult plannerResult)

Wrapper around result set creation for the sole purpose of tests which inject failures.

prepareResult

public PrepareResult prepareResult()

cancel

public void cancel()

Specified by:

cancel in interface SqlLifecycleManager.Cancelable

close

public void close()

Description copied from class: AbstractStatement

Releases resources and emits logs and metrics as defined the associated reporter.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class AbstractStatement

closeWithError

public void closeWithError(Throwable e)

Description copied from class: AbstractStatement

Convenience method to close the statement and report an error associated with the statement. Same as calling:stmt.reporter().failed(e); stmt.close();

Overrides:

closeWithError in class AbstractStatement