Package org.elasticsearch.xpack.esql.view

Class ViewResolver

java.lang.Object

org.elasticsearch.xpack.esql.view.ViewResolver

public class ViewResolver
extends Object

Resolves view references in a logical plan by expanding each view into the plan parsed from its definition. As part of the same traversal it also rewrites InSubquery expressions (in Filter conditions) into SemiJoin/AntiJoin/ MarkJoin nodes, so a single pass fully expands the plan — including views referenced from inside IN subqueries and IN subqueries nested in view bodies.

Resolution (see replaceViews(org.elasticsearch.xpack.esql.plan.logical.LogicalPlan, java.lang.String, java.util.function.BiFunction<java.lang.String, java.lang.String, org.elasticsearch.xpack.esql.plan.logical.LogicalPlan>, org.elasticsearch.action.ActionListener<org.elasticsearch.xpack.esql.view.ViewResolver.ViewResolutionResult>)) is a depth-first, top-down (pre-order) traversal of the plan tree. During traversal it intercepts specific node types:

• UnresolvedRelation: Resolves views and replaces them with their query plans, then recursively processes those plans
• Fork: Recursively processes each child branch
• UnionAll: Skipped (assumes rewriting is already complete)
• AbstractSubqueryJoin: Recursively processes the left and right sides
• Filter: Calls InSubqueryResolver to expand any InSubquery into a SemiJoin/AntiJoin/ MarkJoin, then recurses into the newly created subquery plans to resolve view references nested there
• ViewUnionAll: Skipped (already the result of view resolution)

View resolution may introduce new nodes that need further processing, so explicit recursive calls are made on newly resolved view plans. The traversal tracks circular references and enforces the maximum view depth (MAX_VIEW_DEPTH_SETTING).

TODO: ViewResolver needs rename or refactor, as it does two tasks - view resolution and IN subquery resolution. Keep the core of view resolution in ViewResolver, and have a ViewAndSubqueryResolver drive the plan tree traversal, call ViewResolver and InSubqueryResolver to do the view and IN subquery resolution respectively.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static final record	ViewResolver.OriginViewsResolution
static final record	ViewResolver.ViewResolutionResult	Result of view resolution containing the rewritten plan, the view queries, and whether any InSubquery expression was rewritten into a SemiJoin/AntiJoin/MarkJoin during resolution.

Field Summary

Fields

Modifier and Type	Field	Description
protected Logger	log
static final Setting<Integer>	MAX_VIEW_DEPTH_SETTING

Constructor Summary

Constructors

Constructor	Description
ViewResolver()	Public constructor for NOOP instance (in release mode, when component is not registered, but TransportEsqlQueryAction still needs it)
ViewResolver(ThreadPool threadPool, ClusterService clusterService, ProjectResolver projectResolver, Client client, CrossProjectModeDecider crossProjectModeDecider)

Method Summary

Modifier and Type	Method	Description
protected void	doEsqlResolveViewsRequest(EsqlResolveViewAction.Request request, ActionListener<EsqlResolveViewAction.Response> listener)
void	replaceViews(LogicalPlan plan, String projectRouting, BiFunction<String,String,LogicalPlan> parser, ActionListener<ViewResolver.ViewResolutionResult> listener)	Entry point for view + IN subquery resolution; see the ViewResolver class documentation for the traversal model and the node types it intercepts.
protected boolean	viewsFeatureEnabled()

Methods inherited from class java.lang.Object

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

Field Details

log

protected Logger log

MAX_VIEW_DEPTH_SETTING

public static final Setting<Integer> MAX_VIEW_DEPTH_SETTING

Constructor Details

ViewResolver

public ViewResolver()

Public constructor for NOOP instance (in release mode, when component is not registered, but TransportEsqlQueryAction still needs it)

ViewResolver

public ViewResolver(ThreadPool threadPool,
 ClusterService clusterService,
 ProjectResolver projectResolver,
 Client client,
 CrossProjectModeDecider crossProjectModeDecider)

Method Details

viewsFeatureEnabled

protected boolean viewsFeatureEnabled()

replaceViews

public void replaceViews(LogicalPlan plan,
 String projectRouting,
 BiFunction<String,String,LogicalPlan> parser,
 ActionListener<ViewResolver.ViewResolutionResult> listener)

Entry point for view + IN subquery resolution; see the ViewResolver class documentation for the traversal model and the node types it intercepts. Produces a ViewResolver.ViewResolutionResult containing the rewritten (uncompacted) plan, the map of resolved view names to their queries, and — via ViewResolver.ViewResolutionResult.hasInSubquery() — whether any IN subquery was rewritten during resolution.

Parameters:

plan - the logical plan to process

parser - function to parse view query strings into logical plans

listener - callback that receives the ViewResolver.ViewResolutionResult

doEsqlResolveViewsRequest

protected void doEsqlResolveViewsRequest(EsqlResolveViewAction.Request request,
 ActionListener<EsqlResolveViewAction.Response> listener)