Consider tree like graph represented by "Node" verticies and "childOf"
edges (oriented from child to parent) and command:
Iterable<OrientVertex> roots = (Iterable<OrientVertex>) graph.command(new
OCommandSQL("select from Node where key = 'root' fetchplan
in_childOf:-1")).execute();
Now when I traverse the tree by Vertex.getVerticies(Direction.IN,
"childOf")/ODocument.field("in_childOf") I expect there won't be any
further remote lookup calls, because verticies have been already fetched by
fetch plan.
But is it really the case?
I was trying to find out how accessing related records (edges) works:
The edges are represented as ORidBag:
ORidBag ridBag = (ORidBag) root.getRecord().field("in_childOf");
The ORidBag is a collection of OIdentifiable implemented by ORecordId:
ORecordId rid = (ORecordId) ridBag.iterator().next();
Now I can access the record (implemented by ODocument) representing the
edge:
ODocument inChild = (ODocument) rid.getRecord();
The implementation of ORecordId.getRecord() is quite simple. It basically
delegates the record retrieval to current ODatabaseDocument implemented by
ODatabaseDocumentTx:
return (T) db.load(this);
There the things are getting complicated, but if I summarize my foundings,
the record is either taken from local cache or requested to be fetched by
ORemoteStorage.
As you can see I was able to find out only one place where the related
record is not requested from the storage again and that is obtaining a
record from local cache by ODatabaseDocumentTx.
However I checked that the related records are not present in local cache
after the command is executed, so local cache also isn't responsible for
accessing eagerly fetched records.
So am I really working with fetched records or are they fetched again when
traversing graph with Document/Graph API in remote mode?
If yes, which component (ODocument/ORidBag/ODatabase/OStorage) is
responsible for obtaining a record which is possibly loaded eagerly via
fetch plan?
And is there a way to tell if the related record (represented for example
by ORecordId) is already fetched?
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