CODEWITHSUNDEEP
databasegraphtitangremlin
Daniel Wardin
Daniel Wardin

Reputation: 1858

TitanDB - Build a property index in descending order by timestamp

TitanDB 1.0.0 (on top of DynamoDB)

Gremlin 3

I've got a set of vertices with a label a. I have a property of type long on those vertices which corresponds to the time in milliseconds from 1970 UTC (timestamp of when the vertex was created.) When I pull back those vertices I want to be able to pull them back in decsending order.

How can I create an index on that property in the decr order in Titan Management System?

Documentation seems vague on that.

Closest thing I found is

public RelationTypeIndex buildPropertyIndex(PropertyKey key, String name, Order sortOrder, PropertyKey... sortKeys)

But what do I put in as the key and sortKeys? I want to be able to pull the whole vertex ordered by the timestamp property

Edit: The only way I know of doing this at the minute is by duplicating that property on the edge and using a vertex centric index on the edge to increase the performance.

Upvotes: 2

Views: 417

Answers (1)

Filipe Teixeira
Filipe Teixeira

Reputation: 3565

I do something similar as I order by the release date of a particular product. If you want to execute order().by("Value", decr) efficiently then I highly recommend reading into mixed indices specified here. Mixed indices allow these operations to be done quickly.

An example of what you may be looking for:

TitanGraph graph = TitanFactory.open(config);
TitanManagement mgmt = graph.openManagement();
PropertyKey key = mgmt.makePropertyKey("TimeStamp").dataType(Long.class).make();
mgmt.buildIndex("timeStampIndex", Vertex.class).addKey(key).buildMixedIndex("search");
mgmt.commit();

The above index lets me execute the following query very quickly:

g.V().order().by("TimeStamp", decr);

Which gets me the time stamps in descending order. The above traversal will work without indexing but can be slow in large graphs.

Upvotes: 9

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