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Question

How to order features and schemas for a FeatureWriter

  • August 14, 2026
  • 1 reply
  • 25 views

chau
Contributor
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I have various FeatureReaders I use for reading both schemas and features. I also create new features and use the SchemaScanner to create the corresponding schemas.

When using a FeatureWriter I need the schema to arrive before the features. This can be done using a Sorter but it also fill up my RAM very fast because it is blocking.

I am ideally looking for a FeatureHolder with Group By (by fme_feature_type?) which supports release features when the corresponding schema has passed.

Alternatively if someone has an idea for a similar functionality combining a set of transformers?

1 reply

daveatsafe
Safer
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  • Safer
  • August 14, 2026

Hi ​@chau,

The SchemaScanner has an option to output Schema features before Data features. Set this to Yes, then route the Schema output directly to the FeatureWriter. The Schema features rarely need to be modified after scanning, so this should get them to the FeatureWriter before any of the data features.