Package org.elasticsearch.xpack.esql.core.expression

Class ExternalMetadataAttribute

java.lang.Object

org.elasticsearch.xpack.esql.core.tree.Node<Expression>

org.elasticsearch.xpack.esql.core.expression.Expression

org.elasticsearch.xpack.esql.core.expression.NamedExpression

org.elasticsearch.xpack.esql.core.expression.Attribute

org.elasticsearch.xpack.esql.core.expression.TypedAttribute

org.elasticsearch.xpack.esql.core.expression.ExternalMetadataAttribute

All Implemented Interfaces:

NamedWriteable, Writeable, Resolvable, VirtualAttribute

public class ExternalMetadataAttribute
extends TypedAttribute
implements VirtualAttribute

Virtual column for external data sources (file metadata, partition columns). Behaves like a regular column for resolution and filtering but is excluded from wildcard (*) expansion — users must name it explicitly.

Mirrors MetadataAttribute's shape but extends TypedAttribute directly because MetadataAttribute is final. Implements the VirtualAttribute marker so format-level pushdown rules (filter and aggregate) reject it - values are materialized by VirtualColumnIterator on the producer thread and have no presence in the underlying file's schema.

Nested Class Summary

Nested classes/interfaces inherited from class org.elasticsearch.xpack.esql.core.expression.Attribute

Attribute.IdIgnoringWrapper

Nested classes/interfaces inherited from class org.elasticsearch.xpack.esql.core.expression.Expression

Expression.TypeResolution

Nested classes/interfaces inherited from class org.elasticsearch.xpack.esql.core.tree.Node

Node.NodeStringFormat

Nested classes/interfaces inherited from interface org.elasticsearch.common.io.stream.Writeable

Writeable.Reader<V>, Writeable.Writer<V>

Field Summary

Fields

Modifier and Type	Field	Description
static final NamedWriteableRegistry.Entry	ENTRY

Fields inherited from class org.elasticsearch.xpack.esql.core.expression.Attribute

SYNTHETIC_ATTRIBUTE_NAME_PREFIX, SYNTHETIC_ATTRIBUTE_NAME_SEPARATOR

Fields inherited from class org.elasticsearch.xpack.esql.core.tree.Node

TO_STRING_MAX_LINES, TO_STRING_MAX_WIDTH

Constructor Summary

Constructors

Constructor	Description
ExternalMetadataAttribute(Source source, String name, DataType dataType)
ExternalMetadataAttribute(Source source, String name, DataType dataType, Nullability nullability, NameId id, boolean synthetic)

Method Summary

Modifier and Type	Method	Description
protected ExternalMetadataAttribute	clone(Source source, String qualifier, String name, DataType type, Nullability nullability, NameId id, boolean synthetic)
String	getWriteableName()
protected NodeInfo<? extends Expression>	info()	Normally, you want to use one of the static create methods to implement this.
boolean	isDimension()
boolean	isMetric()
protected String	label()
static ExternalMetadataAttribute	readFrom(StreamInput in)
void	writeTo(StreamOutput out)

Methods inherited from class org.elasticsearch.xpack.esql.core.expression.TypedAttribute

dataType, innerEquals, innerHashCode

Methods inherited from class org.elasticsearch.xpack.esql.core.expression.Attribute

canonicalize, checkAndSerializeQualifier, dataTypeEquals, ignoreId, nodeString, nullable, qualifiedName, qualifier, rawTemporaryName, readQualifier, references, replaceChildren, semanticEquals, semanticHash, toAttribute, toString, withDataType, withId, withLocation, withName, withNullability, withQualifier

Methods inherited from class org.elasticsearch.xpack.esql.core.expression.NamedExpression

equals, equals, hashCode, hashCode, id, name, synthetic

Methods inherited from class org.elasticsearch.xpack.esql.core.expression.Expression

canonical, childrenResolved, fold, foldable, propertiesToString, resolved, resolveType, toString, typeResolved

Methods inherited from class org.elasticsearch.xpack.esql.core.tree.Node

allMatch, anyMatch, children, collect, collect, collect, collectFirstChildren, collectLeaves, doCollectFirst, forEachDown, forEachDown, forEachDownMayReturnEarly, forEachProperty, forEachPropertyDown, forEachPropertyOnly, forEachPropertyUp, forEachUp, forEachUp, nodeName, nodeProperties, nodeString, replaceChildrenSameSize, source, sourceLocation, sourceText, toString, transformChildren, transformChildren, transformDown, transformDown, transformDown, transformDown, transformDownSkipBranch, transformNodeProps, transformPropertiesDown, transformPropertiesOnly, transformPropertiesUp, transformUp, transformUp, transformUp

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Details

ENTRY

public static final NamedWriteableRegistry.Entry ENTRY

Constructor Details

ExternalMetadataAttribute

public ExternalMetadataAttribute(Source source,
 String name,
 DataType dataType)

ExternalMetadataAttribute

public ExternalMetadataAttribute(Source source,
 String name,
 DataType dataType,
 Nullability nullability,
 @Nullable
 NameId id,
 boolean synthetic)

Method Details

writeTo

public void writeTo(StreamOutput out)
             throws IOException

Specified by:

writeTo in interface Writeable

Throws:

IOException

readFrom

public static ExternalMetadataAttribute readFrom(StreamInput in)
                                          throws IOException

Throws:

IOException

getWriteableName

public String getWriteableName()

Specified by:

getWriteableName in interface NamedWriteable

clone

protected ExternalMetadataAttribute clone(Source source,
 String qualifier,
 String name,
 DataType type,
 Nullability nullability,
 NameId id,
 boolean synthetic)

Specified by:

clone in class Attribute

label

protected String label()

Specified by:

label in class Attribute

isDimension

public boolean isDimension()

Specified by:

isDimension in class Attribute

Returns:

true if the attribute represents a TSDB dimension type

isMetric

public boolean isMetric()

Specified by:

isMetric in class Attribute

Returns:

true if the attribute represents a TSDB metric type

info

protected NodeInfo<? extends Expression> info()

Description copied from class: Node

Normally, you want to use one of the static create methods to implement this.

For QueryPlans, it is very important that the properties contain all of the expressions and references relevant to this node, and that all the properties are used in the provided constructor; otherwise query plan transformations like QueryPlan#transformExpressionsOnly(Function) will not have an effect.

Specified by:

info in class Node<Expression>