Marko A. Rodriguez created TINKERPOP-1343:
---------------------------------------------
Summary: A more efficient StarGraph serialization representation.
Key: TINKERPOP-1343
URL: https://issues.apache.org/jira/browse/TINKERPOP-1343
Project: TinkerPop
Issue Type: Improvement
Components: process
Affects Versions: 3.2.0-incubating
Reporter: Marko A. Rodriguez
{{StarGraph}} is used by the Hadoop {{GraphComputers}} and represents a vertex,
its properties, its incident edges, and their properties. In essence, one "row
of an adjacency list."
Here are some ideas on how to make the next version of the serialization format
more efficient.
1. For all Element ids, we currently use {{kryo.readClassAndObject(...)}}. This
is bad because we have to write the class with each id. It would be better if
the {{StarGraph}} had metadata like {{vertexIdClass}},
{{vertexPropertyIdClass}}, and {{edgeIdClass}}. Now for every vertex we are
serializing three class, but the benefit is that every id class is now known
and we can use {{kryo.readObject(..., xxxIdClass)}}.
2. Edges and VertexProperties are written out as
{{[label[edge[id,otherVertexId]*]*}} and
{{[label[vertexProperty[id,value]*]*}}, respectively. This ensures we don't
write so many strings as all edges/vertex properties are grouped by label.
However, we do NOT do this for edge properties nor vertex property properties.
We simply write out the {{Map<Object,Map<String,Object>>}} which is
{{Map<EdgeId,Map<PropertyKey,PropertyValue>>}}. Since we have to choose between
grouping by edgeId or by propertyKey, we should keep it as it is, but create a
"meta map" that allows us to represent all property keys in a, e.g., {{int}}
space. Thus, {{Map<EdgeId,Map<PropertyKeyIntegerId,PropertyValue>>}} where we
also have a {{Map<PropertyKeyIntegerId,String>}} that is serialized with the
{{StarGraph}}.
There are a few other tickets around optimizing {{StarGraph}} here:
https://issues.apache.org/jira/browse/TINKERPOP-1128 (making {{GraphFilters}}
more efficient)
https://issues.apache.org/jira/browse/TINKERPOP-1122 (pointless bits and
{{StarGraph}} should never auto-generate IDs as the ID space is distributed).
https://issues.apache.org/jira/browse/TINKERPOP-1287 (related to heap usage and
clock cycles -- not serialization).
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
