[BEAM-3293] Add lazy map side input form

• Type: Improvement
• Status: Triage Needed
• Priority: P3
• Resolution: Fixed
• Fix Version/s: 2.35.0
• Component/s: sdk-go
• Assignee: Jack McCluskey
• Reporter: Henning Rohde
• Created: 05/Dec/17 21:39
• Updated: 13/Apr/23 11:08
• Resolved: 16/Nov/21 16:01

Description

Add InputKinds LazyMap and LazyMultiMap that allow map lookup without reading everything to memory. They will be accessed through functions such as:

func(K) func(*V) bool   (a keyed function that returns an iterator)
func(K) []V                         (a keyed function that returns a slice of values)

On the execution layer, the new forms would need to be added to exec/sideinput.go
https://github.com/apache/beam/blob/master/sdks/go/pkg/beam/core/runtime/exec/sideinput.go
The inputs layer, for the actual abstraction using reflection:
https://github.com/apache/beam/blob/master/sdks/go/pkg/beam/core/runtime/exec/input.go

The funcx package would need to be updated to detect the new parameter forms
https://github.com/apache/beam/blob/master/sdks/go/pkg/beam/core/funcx/fn.go
https://github.com/apache/beam/blob/master/sdks/go/pkg/beam/core/funcx/sideinput.go

as well has the DoFn graph validation code
https://github.com/apache/beam/blob/master/sdks/go/pkg/beam/core/graph/fn.go#L566

They would need to be correctly translated into the pipeline protos:
https://github.com/apache/beam/blob/master/sdks/go/pkg/beam/core/runtime/graphx/translate.go#L315
and finally back to the newly created handlers in the exec package.
https://github.com/apache/beam/blob/master/sdks/go/pkg/beam/core/runtime/exec/translate.go#L402

If implemented pre-generics, the code generator frontend, and backend would need to be updated to detect and generate code for efficient no-reflection overhead map access functions. https://github.com/apache/beam/blob/master/sdks/go/pkg/beam/util/shimx/generate.go
https://github.com/apache/beam/blob/master/sdks/go/pkg/beam/util/starcgenx/starcgenx.go

Unit must be added throughout and Integration tests should be added to verify the functionality against portable beam runners.
https://github.com/apache/beam/tree/master/sdks/go/test/integration/primitives

And of course, the user GoDoc should be updated for the support.

See this lengthy email response for a more indepth guide to how Side Inputs operate. https://lists.apache.org/thread.html/ra42dc7ee30842f11740eff33f0afcd63702695878e427127e1268381%40%3Cdev.beam.apache.org%3E 

Issue Links

• is a parent of: BEAM-13075 [Go SDK] Update side input handling in the direct runner
• links to: GitHub Pull Request #15934
• links to: GitHub Pull Request #15943
• links to: GitHub Pull Request #15960
• links to: GitHub Pull Request #15966
• links to: GitHub Pull Request #15975
• links to: GitHub Pull Request #15981
• links to: GitHub Pull Request #16006
• mentioned in: Page Loading...