Operators

This page provides an overview of the available operators in Cypher®. An operator is a specialized execution module that is responsible for some type of transformation to the data in a query execution plan before passing it on to the next operator, until the desired graph pattern has been matched.

For information about how to understand execution plans (and the role operators play in them), see Understanding execution plans.

For more information about each operator, see Operators in detail.

Summary of operators

This table comprises all the execution plan operators ordered lexicographically.

  • Leaf operators, in most cases, locate the starting nodes and relationships required in order to execute the query.

  • Updating operators are used in queries that update the graph.

  • Eager operators accumulate all their rows before piping them to the next operator.

Name Description Leaf? Updating? Considerations

AllNodesScan

Reads all nodes from the node store.

Yes

Anti

Tests for the absence of a pattern.

AntiSemiApply

Performs a nested loop. Tests for the absence of a pattern predicate.

Apply

Performs a nested loop. Yields rows from both the left-hand and right-hand side operators.

Argument

Indicates the variable to be used as an argument to the right-hand side of an Apply operator.

Yes

AssertSameNode

Ensures that no node property uniqueness constraints are violated.

AssertSameRelationship

Ensures that no relationship property uniqueness constraints are violated.

AssertingMultiNodeIndexSeek

Used to ensure that no property uniqueness constraints are violated.

Yes

CacheProperties

Reads node or relationship properties and caches them.

CartesianProduct

Produces a cartesian product of the inputs from the left-hand and right-hand operators.

Create

Creates nodes and relationships.

Yes

CreateIndex

Creates an index for either nodes or relationships.

Yes

CreateConstraint

Creates a constraint for either nodes or relationships.

Yes

Delete

Deletes a node or relationship.

Yes

DetachDelete

Deletes a node and its relationships.

Yes

DirectedAllRelationshipsScan

Fetches all relationships and their start and end nodes in the database.

Yes

DirectedRelationshipByIdSeek

Reads one or more relationships by id from the relationship store.

Yes

DirectedRelationshipIndexContainsScan

Examines all values stored in an index, searching for entries containing a specific string; for example, in queries including CONTAINS.

Yes

DirectedRelationshipIndexEndsWithScan

Examines all values stored in an index, searching for entries ending in a specific string; for example, in queries containing ENDS WITH.

Yes

DirectedRelationshipIndexScan

Examines all values stored in an index, returning all relationships and their start and end nodes with a particular relationship type and a specified property.

Yes

DirectedRelationshipIndexSeek

Finds relationships and their start and end nodes using an index seek.

Yes

DirectedRelationshipIndexSeekByRange

Finds relationships and their start and end nodes using an index seek where the value of the property matches a given prefix string.

Yes

DirectedRelationshipTypeScan

Fetches all relationships and their start and end nodes with a specific type from the relationship type index.

Yes

DirectedUnionRelationshipTypesScan

Fetches all relationships and their start and end nodes with at least one of the provided types from the relationship type index.

Distinct

Drops duplicate rows from the incoming stream of rows.

Eager

DoNothingIfExists(CONSTRAINT)

Checks if a constraint already exists, if it does then it stops the execution, if not it continues.

Yes

DoNothingIfExists(INDEX)

Checks if an index already exists, if it does then it stops the execution, if not it continues.

Yes

DropConstraint

Drops a constraint using its name.

Yes

Yes

DropIndex

Drops an index using its name.

Yes

Yes

Eager

For isolation purposes, Eager ensures that operations affecting subsequent operations are executed fully for the whole dataset before continuing execution.

Eager

EagerAggregation

Evaluates a grouping expression.

Eager

EmptyResult

Eagerly loads all incoming data and discards it.

Eager

EmptyRow

Returns a single row with no columns.

Yes

ExhaustiveLimit

The ExhaustiveLimit operator is similar to the Limit operator, but always exhausts the input. Used when combining LIMIT and updates.

Expand(All)

Traverses incoming or outgoing relationships from a given node.

Expand(Into)

Finds all relationships between two nodes.

Filter

Filters each row coming from the child operator, only passing through rows that evaluate the predicates to true.

Foreach

Performs a nested loop. Yields rows from the left-hand operator and discards rows from the right-hand operator.

IntersectionNodeByLabelsScan

Fetches all nodes that have all of the provided labels from the node label index.

Yes

LetAntiSemiApply

Performs a nested loop. Tests for the absence of a pattern predicate in queries containing multiple pattern predicates.

LetSelectOrAntiSemiApply

Performs a nested loop. Tests for the absence of a pattern predicate that is combined with other predicates.

LetSelectOrSemiApply

Performs a nested loop. Tests for the presence of a pattern predicate that is combined with other predicates.

LetSemiApply

Performs a nested loop. Tests for the presence of a pattern predicate in queries containing multiple pattern predicates.

Limit

Returns the first n rows from the incoming input.

LoadCSV

Loads data from a CSV source into the query.

Yes

LockingMerge

Similar to the Merge operator but will lock the start and end node when creating a relationship if necessary.

Merge

The Merge operator will either read or create nodes and/or relationships.

MultiNodeIndexSeek

Finds nodes using multiple index seeks.

Yes

NodeByElementIdSeek

Reads one or more nodes by ID from the node store, specified via the function elementId().

Yes

NodeByIdSeek

Reads one or more nodes by ID from the node store, specified via the function id().

Yes

NodeByLabelScan

Fetches all nodes with a specific label from the node label index.

Yes

NodeCountFromCountStore

Uses the count store to answer questions about node counts.

Yes

NodeHashJoin

Executes a hash join on node ID.

Eager

NodeIndexContainsScan

Examines all values stored in an index, searching for entries containing a specific string.

Yes

NodeIndexEndsWithScan

Examines all values stored in an index, searching for entries ending in a specific string.

Yes

NodeIndexScan

Examines all values stored in an index, returning all nodes with a particular label with a specified property.

Yes

NodeIndexSeek

Finds nodes using an index seek.

Yes

NodeIndexSeekByRange

Finds nodes using an index seek where the value of the property matches the given prefix string.

Yes

NodeLeftOuterHashJoin

Executes a left outer hash join.

Eager

NodeRightOuterHashJoin

Executes a right outer hash join.

Eager

NodeUniqueIndexSeek

Finds nodes using an index seek within a unique index.

Yes

NodeUniqueIndexSeekByRange

Finds nodes using an index seek within a unique index where the value of the property matches the given prefix string.

Yes

Optional

Yields a single row with all columns set to null if no data is returned by its source.

OptionalExpand(All)

Traverses relationships from a given node, producing a single row with the relationship and end node set to null if the predicates are not fulfilled.

OptionalExpand(Into)

Traverses all relationships between two nodes, producing a single row with the relationship and end node set to null if no matching relationships are found (the start node is the node with the smallest degree).

OrderedAggregation

Like EagerAggregation but relies on the ordering of incoming rows. Is not eager.

OrderedDistinct

Like Distinct but relies on the ordering of incoming rows.

PartialSort

Sorts a row by multiple columns if there is already an ordering.

PartialTop

Returns the first n rows sorted by multiple columns if there is already an ordering.

ProcedureCall

Calls a procedure.

ProduceResults

Prepares the result so that it is consumable by the user.

ProjectEndpoints

Projects the start and end node of a relationship.

Projection

Evaluates a set of expressions, producing a row with the results thereof.

RelationshipCountFromCountStore

Uses the count store to answer questions about relationship counts.

Yes

Repeat(Trail)

Solves quantified path patterns.

RemoveLabels

Deletes labels from a node.

Yes

RollUpApply

Performs a nested loop. Executes a pattern expression or pattern comprehension.

SelectOrAntiSemiApply

Performs a nested loop. Tests for the absence of a pattern predicate if an expression predicate evaluates to false.

SelectOrSemiApply

Performs a nested loop. Tests for the presence of a pattern predicate if an expression predicate evaluates to false.

SemiApply

Performs a nested loop. Tests for the presence of a pattern predicate.

SetLabels

Sets labels on a node.

Yes

SetNodePropertiesFromMap

Sets properties from a map on a node.

Yes

SetProperty

Sets a property on a node or relationship.

Yes

SetRelationshipPropertiesFromMap

Sets properties from a map on a relationship.

Yes

ShortestPath

Finds one or all shortest paths between two previously matches node variables.

ShowConstraints

Lists the available constraints.

Yes

ShowFunctions

Lists the available functions.

Yes

ShowIndexes

Lists the available indexes.

Yes

ShowProcedures

Lists the available procedures.

Yes

ShowSettings

Lists the available configuration settings.

Yes

ShowTransactions

Lists the available transactions on the current server.

Yes

Skip

Skips n rows from the incoming rows.

Sort

Sorts rows by a provided key.

Eager

TerminateTransactions

Terminate transactions with the given IDs.

Yes

Top

Returns the first 'n' rows sorted by a provided key.

Eager

TriadicBuild

The TriadicBuild operator is used in conjunction with TriadicFilter to solve triangular queries.

TriadicFilter

The TriadicFilter operator is used in conjunction with TriadicBuild to solve triangular queries.

TriadicSelection

Solves triangular queries, such as the very common 'find my friend-of-friends that are not already my friend'.

UndirectedAllRelationshipsScan

Fetches all relationships and their start and end nodes in the database.

Yes

UndirectedRelationshipByIdSeek

Reads one or more relationships by ID from the relationship store.

Yes

UndirectedRelationshipIndexContainsScan

Examines all values stored in an index, searching for entries containing a specific string; for example, in queries including CONTAINS.

Yes

UndirectedRelationshipIndexEndsWithScan

Examines all values stored in an index, searching for entries ending in a specific string; for example, in queries containing ENDS WITH.

Yes

UndirectedRelationshipIndexScan

Examines all values stored in an index, returning all relationships and their start and end nodes with a particular relationship type and a specified property.

Yes

UndirectedRelationshipIndexSeek

Finds relationships and their start and end nodes using an index seek.

Yes

UndirectedRelationshipIndexSeekByRange

Finds relationships and their start and end nodes using an index seek where the value of the property matches a given prefix string.

Yes

UndirectedRelationshipTypeScan

Fetches all relationships and their start and end nodes with a specific type from the relationship type index.

Yes

UndirectedUnionRelationshipTypesScan

Fetches all relationships and their start and end nodes with at least one of the provided types from the relationship type index.

Yes

Union

Concatenates the results from the right-hand operator with the results from the left-hand operator.

UnionNodeByLabelsScan

Fetches all nodes that have at least one of the provided labels from the node label index.

Yes

Unwind

Returns one row per item in a list.

ValueHashJoin

Executes a hash join on arbitrary values.

Eager

VarLengthExpand(All)

Traverses variable-length relationships from a given node.

VarLengthExpand(Into)

Finds all variable-length relationships between two nodes.

VarLengthExpand(Pruning)

Traverses variable-length relationships from a given node and only returns unique end nodes.

VarLengthExpand(Pruning,BFS)

Traverses variable-length relationships from a given node and only returns unique end nodes.

Database hits

Each operator will send a request to the storage engine to do work such as retrieving or updating data. A database hit (DBHits) is an abstract unit of this storage engine work.

These are all the actions that trigger one or more database hits:

  • Create actions

    • Create a node.

    • Create a relationship.

    • Create a new node label.

    • Create a new relationship type.

    • Create a new ID for property keys with the same name.

  • Delete actions

    • Delete a node.

    • Delete a relationship.

  • Update actions

    • Set one or more labels on a node.

    • Remove one or more labels from a node.

  • Node-specific actions

    • Get a node by its ID.

    • Get the degree of a node.

    • Determine whether a node is dense.

    • Determine whether a label is set on a node.

    • Get the labels of a node.

    • Get a property of a node.

    • Get an existing node label.

    • Get the name of a label by its ID, or its ID by its name.

  • Relationship-specific actions

    • Get a relationship by its ID.

    • Get a property of a relationship.

    • Get an existing relationship type.

    • Get a relationship type name by its ID, or its ID by its name.

  • General actions

    • Get the name of a property key by its ID, or its ID by the key name.

    • Find a node or relationship through an index seek or index scan.

    • Find a path in a variable-length expand.

    • Find a shortest path.

    • Ask the count store for a value.

  • Schema actions

    • Add an index.

    • Drop an index.

    • Get the reference of an index.

    • Create a constraint.

    • Drop a constraint.

  • Call a procedure.

  • Call a user-defined function.