[Question]: Any Benefit to Exposing a Workflow as a QueryEngine?

[brycecf]

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Question

@logan-markewich had mentioned awhile ago that the original plan for the Query Engines going forward was to reimplement them using Workflows. That was later dropped as being unnecessary.

With that being said, is there a particular benefit to exposing a Workflow as a BaseQueryEngine (beyond when a BaseQueryEngine type may be expected by some class/function?

There is a definite downside in that it is rather tricky for a QueryEngine to support multi-inputs, which can be done with both QueryPipeline and Workflow, so it can limit that when exposed as a QueryEngine. Consequently, I'm trying to understand if anything would offset that sacrifice.

[dosubot[bot]]

Exposing a Workflow as a BaseQueryEngine can offer several benefits, particularly in terms of flexibility and modularity. Here are some potential advantages:

1. Unified Interface: By exposing a Workflow as a BaseQueryEngine, you can provide a consistent interface for querying, which can simplify integration with other components that expect a BaseQueryEngine type. This can be particularly useful in scenarios where the BaseQueryEngine type is required or expected by certain classes or functions in the codebase, such as the QueryEngineComponent class ^[1].

2. Modular Design: Workflows are inherently modular and can be composed of multiple steps, each handling a specific part of the query process. This modularity can be beneficial when you want to break down complex queries into manageable parts, as seen in examples like the MultiStepQueryEngine ^[2].

3. Asynchronous Processing: Workflows can handle inputs and outputs asynchronously, allowing for non-blocking operations and potentially improving performance in scenarios where queries involve long-running tasks or need to wait for external data ^[3].

However, as you mentioned, a downside is the limitation in handling multi-inputs when exposed as a BaseQueryEngine, which can be more naturally supported by QueryPipeline and Workflow. The decision to expose a Workflow as a BaseQueryEngine should weigh these benefits against the potential limitations in multi-input handling.

To continue talking to Dosu, mention @dosu.

[logan-markewich]

I think the only downside is the types as you mentioned. Having an expected interface is nice so that the workflow plays nice with things that expect a query engine

That being said, there's nothing stopping you from using CustomQueryEngine and wrapping a workflow into it if you need the query engine type