Skip to content

Merge unique operator #1429

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
wants to merge 1 commit into
base: cypher-5
Choose a base branch
from
Open

Merge unique operator #1429

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
61 changes: 56 additions & 5 deletions modules/ROOT/pages/planning-and-tuning/operators/operators-detail.adoc
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@

Understanding the roles of different operators in an execution plan can be an important step in making queries more efficient.
This page contains details and examples for each of the operators used by the Cypher planner.
For an overview of how the Cypher planner uses operators, see xref:planning-and-tuning/execution-plans.adoc#reading-execution-plans[ Understanding execution plans -> Reading execution plans].
For an overview of how the Cypher planner uses operators, see xref:planning-and-tuning/execution-plans.adoc#reading-execution-plans[ Understanding execution plans -> Reading execution plans].

The operators are grouped into categories based on the role they fulfill in executing a Cypher query:

Expand Down Expand Up @@ -1187,7 +1187,7 @@ Total database accesses: 1, total allocated memory: 184
======

[[query-plan-directed-all-relationships-scan]]
=== Directed All Relationships Scan
=== Directed All Relationships Scan

The `DirectedAllRelationshipsScan` operator fetches all relationships and their start and end nodes in the database.

Expand Down Expand Up @@ -2611,7 +2611,7 @@ Allows Cypher to use xref:indexes/search-performance-indexes/using-indexes.adoc#
.Query
[source, cypher]
----
PROFILE
PROFILE
WITH "Person" AS label
MATCH (people:$(label))
RETURN people.name
Expand Down Expand Up @@ -2657,7 +2657,7 @@ Allows Cypher to use xref:indexes/search-performance-indexes/using-indexes.adoc#
.Query
[source, cypher]
----
PROFILE
PROFILE
WITH "FRIENDS_WITH" AS relType
MATCH ()-[r:$(relType)]->()
RETURN count(r) as relCount
Expand Down Expand Up @@ -2703,7 +2703,7 @@ Allows Cypher to use xref:indexes/search-performance-indexes/using-indexes.adoc#
.Query
[source, cypher]
----
PROFILE
PROFILE
WITH "FRIENDS_WITH" AS relType
MATCH ()-[r:$(relType)]-()
RETURN count(r) as relCount
Expand Down Expand Up @@ -6087,6 +6087,57 @@ Total database accesses: 15, total allocated memory: 2232

======


[role=label--new-2025.11]
[[query-plan-merge-unique-node]]
=== Merge Unique Node

////
[source, cypher, role=test-setup]
----
CREATE CONSTRAINT team_name IF NOT EXISTS FOR (t:Team) REQUIRE (t.name) IS UNIQUE
----
////

The `MergeUniqueNode` operator is similar to the xref:planning-and-tuning/operators/operators-detail.adoc#query-plan-merge[`Merge`] operator, but is used when there is a property uniqueness constraint on the property used in the `MERGE` statement.

.MergeUniqueNode
======

.Query
[source, cypher]
----
PROFILE
MERGE (t:Team {name: 'Engineering'})
----

.Query Plan
[role="queryplan", subs="attributes+"]
----
Planner COST

Runtime PIPELINED

Runtime version {neo4j-version}

Batch size 128

+------------------+----+---------------------------------------------------+----------------+------+---------+----------------+------------------------+-----------+---------------------+--------------+
| Operator | Id | Details | Estimated Rows | Rows | DB Hits | Memory (Bytes) | Page Cache Hits/Misses | Time (ms) | Pipeline | Indexes Used |
+------------------+----+---------------------------------------------------+----------------+------+---------+----------------+------------------------+-----------+---------------------+--------------+
| +ProduceResults | 0 | | 1 | 0 | 0 | 0 | | | | |
| | +----+---------------------------------------------------+----------------+------+---------+----------------+ | | +--------------+
| +EmptyResult | 1 | | 1 | 0 | 0 | | | | | |
| | +----+---------------------------------------------------+----------------+------+---------+----------------+ | | +--------------+
| +MergeUniqueNode | 2 | UNIQUE t:Team(name) WHERE name = $autostring_0, | 1 | 1 | 2 | 248 | 1/0 | 2.922 | Fused in Pipeline 0 | team_name: 1 |
+------------------+----+---------------------------------------------------+----------------+------+---------+----------------+------------------------+-----------+---------------------+--------------+

Total database accesses: 2, total allocated memory: 312
----

======


[role=label--new-2025.09]
[[query-plan-lock-nodes]]
=== Lock Nodes
Expand Down