I agree there's value in this. The cause of BEAM-11614 is a good example of
your first instantiation. An optimization was added to the Convert
transform to make it recognize when it's unneeded and short-circuit itself.
This short-circuit was triggered (twice) within the SqlTransform used in
I just want to highlight that "just returns its inputs" has a couple of
non-useless instantiations:
- programmatically generating a transform (as in SqlTransform)
- rearranging the Java or Python data structures (like PCollectionList and
PCollectionTuple) that are noops in the protocol buffers
Thanks Robert. Docs PR is up: https://github.com/apache/beam/pull/13744
Brian
On Tue, Jan 12, 2021 at 2:04 PM Robert Bradshaw wrote:
> Yes, a PTansform can have no sub-transforms, as long as it only returns
> its inputs. Updating the docs would be a good idea.
>
> On Tue, Jan 12, 2021 at 1:04
Yes, a PTansform can have no sub-transforms, as long as it only returns its
inputs. Updating the docs would be a good idea.
On Tue, Jan 12, 2021 at 1:04 PM Brian Hulette wrote:
> A recent bug with SqlTransform on Dataflow Runner V2 [1] revealed an
> interesting ambiguity in the Beam model: it's
A recent bug with SqlTransform on Dataflow Runner V2 [1] revealed an
interesting ambiguity in the Beam model: it's not clear if a composite
transform is allowed to have zero sub-transforms [2]. This may sound like
an academic concern, but it can happen if a PTransform returns its own
input, making
