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Curtis Allen edited comment on TINKERPOP3-479 at 3/31/15 4:58 PM:
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Thanks Matt,
True some use cases wouldn't care if the Vertex was created or not. However the
{{ensure}} method is going to have to check for vertex existence even if it
doesn't return a {{created}} property, {{ensure}} inherently will require
queries of distributed state how else would it know to create the vertex or
return a found vertex?
I'd argue that regardless of {{ensure}} or {{ensureBlind}} the method will have
to pay the cost of reading before writing which can be an anti pattern on
distributed backends like Cassandra. Unless I'm missing something here.
UPDATE:
I guess with cql 3 you can actually upsert
http://beckje01.com/blog/2014/08/13/cassandra-upsert-everything/
Titan backed by Cassandra could possibly use a similar approach on
{{ensureBlind}} to Matt's point.
The {{ensure}} method would incur more of a cost because it would have to check
if the vertex existed before inserting.
So it looks like the two methods {{ensure}} and {{ensureBlind}} would have a
different performance cost.
was (Author: curtissallen):
Thanks Matt,
True some use cases wouldn't care if the Vertex was created or not. However the
{{ensure}} method is going to have to check for vertex existence even if it
doesn't return a {{created}} property, {{ensure}} inherently will require
queries of distributed state how else would it know to create the vertex or
return a found vertex?
I'd argue that regardless of {{ensure}} or {{ensureBlind}} the method will have
to pay the cost of reading before writing which can be an anti pattern on
distributed backends like Cassandra. Unless I'm missing something here.
> Consider Providing "getOrCreate" Functionality
> ----------------------------------------------
>
> Key: TINKERPOP3-479
> URL: https://issues.apache.org/jira/browse/TINKERPOP3-479
> Project: TinkerPop 3
> Issue Type: Improvement
> Components: structure
> Reporter: stephen mallette
>
> One of the most commonly written functions used is good ol' "getOrCreate"
> where you want to get a {{Vertex}} if it exists or create it with supplied
> properties if it does not. We currently have a "helper" function for this on
> {{ElementHelper}}
> https://github.com/tinkerpop/tinkerpop3/blob/6d0f00865f673cb0739f6f310e1868425f732924/gremlin-core/src/main/java/com/tinkerpop/gremlin/structure/util/ElementHelper.java#L62
> but perhaps it is time to treat this issue as a first class citizen as part
> of the Graph API. I think that some vendors might actually be able to
> optimize this function as well.
> Another aspect of "getOrCreate" is "upsert" as well as options to ensure
> uniqueness. All of these things we've at some point or another built
> variations of outside of TinkerPop for applications, data loading, etc.
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