The fastest way to query edges

[Andrey Yesyev]

Hi there,

I need to find an edge between 2 vertices. In my schema there can be only one edge between 2 vertices.

I tried this 2 options

1. Using query

select from RELATED where in = :target and out = :src

RELATED is a class of the edge I'm looking for. 

2. Using API

vSrc.getEdges(vTarget, Direction.BOTH, RelationType.RELATED.name())

Both are extremely slow. My guess is because query goes over all RELATED edges, checking conditions for each of them.

I feel like I have to use TRAVERSE, but I can't come up with a query to do this.

Please help!

Thanks!

-Andrey

[Andrey Yesyev]

I'll proceed with my search.

Now, I try to use index for edge, here is how I created it

OrientEdgeType edgeType = graph.createEdgeType(RelationType.RELATED.name());

edgeType.createProperty("in", OType.LINK);

edgeType.createProperty("out", OType.LINK);

edgeType.createIndex("relations", OClass.INDEX_TYPE.UNIQUE, "in", "out");

so, I changed my query to use this index

select from index:relations where Key = [ :target, :src ] or Key = [ :src, :target ]

but execution of this query throws an exception

com.orientechnologies.orient.core.exception.OCommandExecutionException: 'Key' field is required for queries against indexes

at com.orientechnologies.orient.core.sql.OCommandExecutorSQLSelect.searchInIndex(OCommandExecutorSQLSelect.java:1127)

at com.orientechnologies.orient.core.sql.OCommandExecutorSQLSelect.assignTarget(OCommandExecutorSQLSelect.java:358)

at com.orientechnologies.orient.core.sql.OCommandExecutorSQLSelect.executeSearch(OCommandExecutorSQLSelect.java:330)

at com.orientechnologies.orient.core.sql.OCommandExecutorSQLSelect.execute(OCommandExecutorSQLSelect.java:315)

at com.orientechnologies.orient.core.sql.OCommandExecutorSQLDelegate.execute(OCommandExecutorSQLDelegate.java:57)

at com.orientechnologies.orient.core.storage.OStorageEmbedded.executeCommand(OStorageEmbedded.java:96)

What's wrong with it?

[Andrey Yesyev]

Okay, looks like everything after OR was excessive.

Query works in this shape

select from index:relations where key = [ :target, :src ]

Using index, performance improved 10 times. 

Not bad.

[ste...@activitystream.com]

Hi,

Out of curiosity, why are you creating a in/out property for the edge manually?

Regards,

 -Stefan

[Andrey Yesyev]

Hm, good question. I found a post here, where I saw how the author of that post did, so I just copy/past it. I'll try to do this without it. Or maybe someone from orienttechnologies will comment on it.

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[Andrey Yesyev]

Here is that topic https://groups.google.com/forum/#!msg/orient-database/BGEZjg8m2RE/3FrCWyamVIoJ