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Using Gremlin with the Amazon Neptune DFE query engine

You can enable Neptune's alternative query engine, known as DFE, in two ways:

When DFE is enabled, Neptune translates read-only Gremlin queries and traversals into an intermediate logical representation and runs them on DFE whenever possible.

Starting with Neptune engine release 1.5.0.0, DFE natively supports most Gremlin steps. When a step isn't supported by DFE, Neptune falls back to TinkerPop to run the step. The explain and profile reports include warnings when this happens.

Query planning interleaving

When Neptune encounters a Gremlin step without a corresponding native DFE operator, it runs as much of the traversal on DFE as possible. It then falls back to TinkerPop only for the unsupported step.

Neptune represents any intermediate, non-prefix query translation as a NeptuneInterleavingStep in the explain and profile outputs.

For performance comparison, you can turn off interleaving in a query while still using the DFE engine to run the prefix part. You can also use only the TinkerPop engine for non-prefix query execution. To do this, use the disableInterleaving query hint.

Just as the useDFE query hint with a value of false prevents a query from being run on the DFE at all, the disableInterleaving query hint with a value of true turns off DFE interleaving for translation of a query. For example:

g.with('Neptune#disableInterleaving', true)
 .V().has('genre','drama').in('likes')

Updated Gremlin explain and profile output

Gremlin explain provides details about the optimized traversal that Neptune uses to run a query. See the sample DFE explain output for an example of what explain output looks like when DFE is enabled.

The Gremlin profile API runs a specified Gremlin traversal, collects various metrics about the run, and produces a profile report that contains details about the optimized query plan and the runtime statistics of various operators. See sample DFE profile output for an example of what profile output looks like when DFE is enabled.