# Gremlin query hints
<a name="gremlin-query-hints"></a>

You can use query hints to specify optimization and evaluation strategies for a particular Gremlin query in Amazon Neptune. 

Query hints are specified by adding a `withSideEffect` step to the query with the following syntax.

```
g.withSideEffect(hint, value)
```
+ *hint* – Identifies the type of the hint to apply.
+ *value* – Determines the behavior of the system aspect under consideration.

For example, the following shows how to include a `repeatMode` hint in a Gremlin traversal.

**Note**  
All Gremlin query hints side effects are prefixed with `Neptune#`.

```
g.withSideEffect('Neptune#repeatMode', 'DFS').V("3").repeat(out()).times(10).limit(1).path()
```

The preceding query instructs the Neptune engine to traverse the graph *Depth First* (`DFS`) rather than the default Neptune, *Breadth First* (`BFS`).

The following sections provide more information about the available query hints and their usage.

**Topics**
+ [Gremlin repeatMode query hint](gremlin-query-hints-repeatMode.md)
+ [Gremlin noReordering query hint](gremlin-query-hints-noReordering.md)
+ [Gremlin typePromotion query hint](gremlin-query-hints-typePromotion.md)
+ [Gremlin useDFE query hint](gremlin-query-hints-useDFE.md)
+ [Gremlin query hints for using the results cache](gremlin-query-hints-results-cache.md)