Purpose of system_metadata_service_v1 and graph_service_v1 indices

Original Slack Thread

Hi All -

Anybody knows what is the purpose of these 2 indices? We can see other entity-based indexes for datasets, users, charts etc. but not sure what these two are -
system_metadata_service_v1
graph_service_v1attachment

Graph service mainly stores lineage relationship
https://github.com/datahub-project/datahub/blob/master/metadata-service/services/src/main/java/com/linkedin/metadata/graph/GraphService.java
https://github.com/datahub-project/datahub/blob/master/metadata-io/src/main/java/com/linkedin/metadata/graph/elastic/ElasticSearchGraphService.java

And system metadata service is where information about ingestion runs is stored
https://github.com/datahub-project/datahub/blob/master/metadata-service/services/src/main/java/com/linkedin/metadata/systemmetadata/SystemMetadataService.java|https://github.com/datahub-project/datahub/blob/master/metadata-service/services/s[…]com/linkedin/metadata/systemmetadata/SystemMetadataService.java
https://github.com/datahub-project/datahub/blob/master/metadata-io/src/main/java/com/linkedin/metadata/systemmetadata/ElasticSearchSystemMetadataService.java|https://github.com/datahub-project/datahub/blob/master/metadata-io/src/main/java/c[…]metadata/systemmetadata/ElasticSearchSystemMetadataService.java