Chunk deletion

Backend-specific chunk-deletion strategies for the regulation graph indexer.

BaseChunkSubgraphDeleter

Bases: ABC

Deletes a chunk and its exclusively-owned subgraph from one backend.

Implementations encapsulate the backend-specific queries that enforce the regulation indexer's ownership rule: content a chunk exclusively owns is removed, while content shared with other chunks is preserved.

delete_chunk_subgraph(chunk_id, index_name) abstractmethod

Delete the subgraph owned exclusively by chunk_id.

Parameters:

Name	Type	Description	Default
chunk_id	str	Identifier of the chunk to delete.	required
index_name	str	Namespace scoping the deletion to one pipeline.	required

Returns:

Type	Description
tuple[int, int]	tuple[int, int]: nodes_deleted & edges_deleted, the counts of deleted graph elements.

Raises:

Type	Description
NotImplementedError	Always raised by the base implementation.

Neo4jChunkSubgraphDeleter(capability)

Bases: BaseChunkSubgraphDeleter

Neo4j implementation of :class:BaseChunkSubgraphDeleter.

Borrows (does not own) a :class:Neo4jGraphCapability and issues Cypher through its read-write :meth:~Neo4jGraphCapability.query path. Holding the capability rather than subclassing it keeps the deletion strategy decoupled from how the capability is constructed (Neo4jDataStore.with_graph()).

Attributes:

Name	Type	Description
capability	Neo4jGraphCapability	Capability used to execute Cypher.

Initialize the deleter.

Parameters:

Name	Type	Description	Default
capability	Neo4jGraphCapability	Neo4j capability used to run Cypher.	required

delete_chunk_subgraph(chunk_id, index_name)

Delete all nodes and edges owned by chunk_id in a single Cypher query.

Runs three operations atomically in one round-trip:

1. Delete content nodes exclusively MENTIONS-ed by this chunk (shared nodes are preserved). Ownership is scoped to index_name to avoid cross-index interference.
2. Delete edges whose chunk_id property matches. By design only reference edges (CITES, MENTIONS_CONCEPT, CONTAINS_OBLIGATION) carry chunk_id (see OWNED_EDGE_TYPES in the generator), so this step removes exactly the chunk's reference edges whose endpoints may outlive it. Containment edges (HAS_*, AMENDS, MENTIONS) carry no chunk_id and are left to DETACH DELETE of their endpoint node — this avoids over-deleting containment edges still shared by other chunks.
3. Delete the Chunk node itself (DETACH DELETE removes remaining MENTIONS edges).

Parameters:

Name	Type	Description	Default
chunk_id	str	Identifier of the chunk to delete.	required
index_name	str	Namespace scoping the deletion to one pipeline.	required

Returns:

Type	Description
tuple[int, int]	tuple[int, int]: nodes_deleted & edges_deleted, the counts of deleted graph elements.

get_chunk_deleter(capability)

Get a chunk deleter strategy for a given graph capability.

Parameters:

Name	Type	Description	Default
capability	BaseGraphCapability	The indexer's graph capability.	required

Returns:

Name	Type	Description
BaseChunkSubgraphDeleter	BaseChunkSubgraphDeleter	A deletion strategy bound to capability.

Raises:

Type	Description
TypeError	If no deletion strategy is registered for the capability's backend.