Package org.elasticsearch.xpack.esql.expression.function.grouping

Class TStep

java.lang.Object

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

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

org.elasticsearch.xpack.esql.core.expression.function.Function

org.elasticsearch.xpack.esql.expression.function.grouping.GroupingFunction

org.elasticsearch.xpack.esql.expression.function.grouping.GroupingFunction.EvaluatableGroupingFunction

org.elasticsearch.xpack.esql.expression.function.grouping.TStep

All Implemented Interfaces:

NamedWriteable, Writeable, PostAnalysisPlanVerificationAware, PostAnalysisVerificationAware, Resolvable, EvaluatorMapper, ConfigurationFunction, TimestampAware, TimestampBoundsAware<Expression>, TimestampBoundsAware.OfExpression, TwoOptionalArguments, OnlySurrogateExpression, SurrogateExpression

public class TStep
extends GroupingFunction.EvaluatableGroupingFunction
implements OnlySurrogateExpression, TimestampAware, TimestampBoundsAware.OfExpression, TwoOptionalArguments, ConfigurationFunction

Groups @timestamp into fixed-width time buckets for aggregation, labeling each bucket by its end instant.

The grid is anchored using the start of the @timestamp range from the request query filter (see TimestampBoundsAware). TSTEP is not compatible with TRANGE in the same query at the moment.

TBucket aligns buckets to calendar boundaries or an epoch-based grid in the configured time zone. TSTEP uses a contiguous step-wide grid in UTC and returns end-labeled bucket timestamps.

Nested Class Summary

Nested classes/interfaces inherited from class org.elasticsearch.xpack.esql.expression.function.grouping.GroupingFunction

GroupingFunction.EvaluatableGroupingFunction, GroupingFunction.NonEvaluatableGroupingFunction

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.xpack.esql.evaluator.mapper.EvaluatorMapper

EvaluatorMapper.ToEvaluator

Nested classes/interfaces inherited from interface org.elasticsearch.xpack.esql.expression.function.TimestampBoundsAware

TimestampBoundsAware.OfExpression, TimestampBoundsAware.OfLogicalPlan

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 FunctionDefinition	DEFINITION
static final String	NAME

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

TO_STRING_MAX_LINES, TO_STRING_MAX_WIDTH

Constructor Summary

Constructors

Constructor	Description
TStep(Source source, Expression stepOrBuckets, Expression from, Expression to, Expression timestamp, Configuration configuration)
TStep(Source source, Expression stepOrBuckets, Expression timestamp, Configuration configuration)

Method Summary

Modifier and Type	Method	Description
Configuration	configuration()
DataType	dataType()	The DataType returned by executing the tree rooted at this expression.
boolean	equals(Object obj)
String	getWriteableName()
int	hashCode()
protected NodeInfo<? extends Expression>	info()	Normally, you want to use one of the static create methods to implement this.
boolean	needsTimestampBounds()	Returns true if this node still needs timestamp bounds to be injected.
void	postAnalysisVerification(Failures failures)	Allows the implementer to validate itself.
Expression	replaceChildren(List<Expression> newChildren)
protected Expression.TypeResolution	resolveType()	The implementation of Expression.typeResolved(), which is just a caching wrapper around this method.
Expression	surrogate()	Replace TStep with a right-closed Bucket: interval (label-step, label].
Expression	timestamp()
ExpressionEvaluator.Factory	toEvaluator(EvaluatorMapper.ToEvaluator toEvaluator)	Convert this into an ExpressionEvaluator.
String	toString()
Expression	withTimestampBounds(Literal startBound, Literal endBound)	Returns a copy of this node with the given timestamp bounds applied.
void	writeTo(StreamOutput out)

Methods inherited from class org.elasticsearch.xpack.esql.expression.function.grouping.GroupingFunction.EvaluatableGroupingFunction

fold

Methods inherited from class org.elasticsearch.xpack.esql.expression.function.grouping.GroupingFunction

postAnalysisPlanVerification

Methods inherited from class org.elasticsearch.xpack.esql.core.expression.function.Function

arguments, functionName, nodeString, nullable

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

canonical, canonicalize, childrenResolved, foldable, propertiesToString, references, resolved, semanticEquals, semanticHash, 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

Methods inherited from interface org.elasticsearch.xpack.esql.evaluator.mapper.EvaluatorMapper

fold

Methods inherited from interface org.elasticsearch.xpack.esql.capabilities.PostAnalysisVerificationAware

postAnalysisVerification

Field Details

NAME

public static final String NAME

See Also:

• Constant Field Values

DEFINITION

public static final FunctionDefinition DEFINITION

Constructor Details

TStep

public TStep(Source source,
 Expression stepOrBuckets,
 @Nullable
 Expression from,
 @Nullable
 Expression to,
 Expression timestamp,
 Configuration configuration)

TStep

public TStep(Source source,
 Expression stepOrBuckets,
 Expression timestamp,
 Configuration configuration)

Method Details

writeTo

public void writeTo(StreamOutput out)
             throws IOException

Specified by:

writeTo in interface Writeable

Throws:

IOException

getWriteableName

public String getWriteableName()

Specified by:

getWriteableName in interface NamedWriteable

toEvaluator

public ExpressionEvaluator.Factory toEvaluator(EvaluatorMapper.ToEvaluator toEvaluator)

Description copied from interface: EvaluatorMapper

Convert this into an ExpressionEvaluator.

Note for implementors: If you are implementing this function, you should call the passed-in lambda on your children, after doing any other manipulation (casting, etc.) necessary.

Note for Callers: If you are attempting to call this method, and you have an Expression and a Layout, you likely want to call EvalMapper.toEvaluator(org.elasticsearch.xpack.esql.core.expression.FoldContext, org.elasticsearch.xpack.esql.core.expression.Expression, org.elasticsearch.xpack.esql.planner.Layout) instead. On the other hand, if you already have something that looks like the parameter for this method, you should call this method with that function.

Build an ExpressionEvaluator.Factory for the tree of expressions rooted at this node. This is only guaranteed to return a sensible evaluator if this node has a valid type. If this node is a subclass of Expression then "valid type" means that Expression.typeResolved() returns a non-error resolution. If Expression.typeResolved() returns an error then this method may throw. Or return an evaluator that produces garbage. Or return an evaluator that throws when run.

Specified by:

toEvaluator in interface EvaluatorMapper

needsTimestampBounds

public boolean needsTimestampBounds()

Description copied from interface: TimestampBoundsAware

Returns true if this node still needs timestamp bounds to be injected.

Specified by:

needsTimestampBounds in interface TimestampBoundsAware<Expression>

withTimestampBounds

public Expression withTimestampBounds(Literal startBound,
 Literal endBound)

Description copied from interface: TimestampBoundsAware

Returns a copy of this node with the given timestamp bounds applied.

Specified by:

withTimestampBounds in interface TimestampBoundsAware<Expression>

postAnalysisVerification

public void postAnalysisVerification(Failures failures)

Description copied from interface: PostAnalysisVerificationAware

Allows the implementer to validate itself. This usually involves checking its internal setup, which often means checking the parameters it received on construction: their data or syntactic type, class, their count, expressions' structure etc. The discovered failures are added to the given Failures object.

It is often more useful to perform the checks as extended as it makes sense, over stopping at the first failure. This will allow the author to progress faster to a correct query.

Example: the Filter class, which models the WHERE command, checks that the expression it filters on - condition - is of a Boolean or NULL type:

     
     @Override
     void postAnalysisVerification(Failures failures) {
          if (condition.dataType() != NULL && condition.dataType() != BOOLEAN) {
              failures.add(fail(condition, "Condition expression needs to be boolean, found [{}]", condition.dataType()));
          }
     }
     
     

Specified by:

postAnalysisVerification in interface PostAnalysisVerificationAware

Parameters:

failures - the object to add failures to.

surrogate

public Expression surrogate()

Replace TStep with a right-closed Bucket: interval (label-step, label].

When stepOrBuckets is a bucket count, derive the step width from the query range first.

Specified by:

surrogate in interface SurrogateExpression

resolveType

protected Expression.TypeResolution resolveType()

Description copied from class: Expression

The implementation of Expression.typeResolved(), which is just a caching wrapper around this method. See it's javadoc for what this method should return.

Implementations will rarely interact with the Expression.TypeResolution class directly, instead usually calling the utility methods on TypeResolutions.

Implementations should fail if Expression.childrenResolved() returns false.

Overrides:

resolveType in class Expression

dataType

public DataType dataType()

Description copied from class: Expression

The DataType returned by executing the tree rooted at this expression. If Expression.typeResolved() returns an error then the behavior of this method is undefined. It may return a valid type. Or it may throw an exception. Or it may return a totally nonsensical type.

Specified by:

dataType in class Expression

replaceChildren

public Expression replaceChildren(List<Expression> newChildren)

Specified by:

replaceChildren in class Node<Expression>

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>

configuration

public Configuration configuration()

timestamp

public Expression timestamp()

Specified by:

timestamp in interface TimestampAware

toString

public String toString()

Overrides:

toString in class Expression

hashCode

public int hashCode()

Overrides:

hashCode in class Function

equals

public boolean equals(Object obj)

Overrides:

equals in class Function