Delete a subgraph from a database

Neo4j Graph Platform Cypher
8

First, you must install GDS plugin on your database.

Then, you create a graph projection on the whole database:

CALL gds.graph.project(
    "graph",            
    "*",             
    "*"               
)
YIELD graphName AS graph, nodeProjection, nodeCount AS nodes, relationshipProjection, relationshipCount AS rels

Then you run the WCC algorithm in write mode (each subgraph is a component and will have its own componentId):

CALL gds.wcc.write('graph', { writeProperty: 'componentId' })
YIELD nodePropertiesWritten, componentCount;

Then you delete the graph projection which is stored in-memory:

CALL gds.graph.drop('graph', false) YIELD graphName;

Finally, you can delete the subgraph based on the componentId (the query deletes the subgraph which has 0 as componentId) property stored on nodes (the query works on at least Neo4j 4.4 version):

MATCH (n)
WHERE n.componentId = 0
CALL {
    WITH n
    DETACH DELETE n
} IN TRANSACTIONS OF 10000 ROWS;

Or this query if you are under Neo4j 4.4 version:

CALl apoc.periodic.iterate(
    "MATCH (n) WHERE n.componentId = 0 RETURN n", 
    "DETACH DELETE n", {batchSize: 10000}
)
YIELD batches, total 
RETURN batches, total

Regards,
Cobra