what is the meaning of `explicitlyDeleted=false` in LDBC?

Question

I am looking at the LDBC benchmark which has contributions from Neo4j and TigerGraph. I want to understand how entries are ingested to measure performance.

Here are two example entries from "Person_likes_Post".

{"creationDate":1296583977045,"deletionDate":1577664000000,"explicitlyDeleted":false,"PersonId":13194139533355,"PostId":412316861128}
{"creationDate":1296750065049,"deletionDate":1296750075058,"explicitlyDeleted":true,"PersonId":13194139533355,"PostId":412316861129}

Does it mean only the edge is deleted when "explicitlyDeleted":true ?

When "explicitlyDeleted":false, does it mean the src node is deleted, dst node is deleted or both?

Link to the benchmark doc:
https://ldbcouncil.org/ldbc_snb_docs/ldbc-snb-specification.pdf Download link to the example LDBC dataset containing these entries:
https://ldbcouncil.org/ldbc_snb_datagen_spark/social-network-sf0.003-bi-composite-merged-fk.zip

(I wanted to tag LDBC but there is no such an option.)

Answer 1

The explicitlyDeleted attribute indicates whether there is a delete operation that targets specifically the given entity (i.e. a node or edge in the graph). This distinction is needed because the LDBC SNB workloads have cascading deletes where the deletion of an entity may trigger the deletion of other entities.

For example, a Person_likes_Post edge can be deleted due to various explicit delete operations:

1. an explicit delete operation targeting a single Person_likes_Post edge
2. an explicit delete operation targeting its source Person
3. an explicit delete operation targeting its target Post
4. an explicit delete operation targeting a Forum that contains its target Post
5. an explicit delete operation targeting a Person whose Album/Wall (which are Forum subtypes) contains its target Post

For the Person_likes_Post edge, the explicitlyDeleted attribute is true in case 1, and false for the other cases.

Note that this attribute is only part of the raw data set. The data sets used for the actual workload executions (Interactive, BI) only contain explicit delete operations, hence they omit this attribute.