jackye1995 commented on code in PR #9731:
URL: https://github.com/apache/iceberg/pull/9731#discussion_r1498195593
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api/src/main/java/org/apache/iceberg/actions/RewriteManifests.java:
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@@ -44,6 +45,16 @@ public interface RewriteManifests
*/
RewriteManifests rewriteIf(Predicate<ManifestFile> predicate);
+ /**
+ * Rewrite manifests in a given order, based on partition columns
+ *
+ * <p>If not set, manifests will be rewritten in the order of the table's
spec.
+ *
+ * @param partitionSortOrder a list of partition field names
Review Comment:
I see the question in the description about
> I would next like to have a more capable functional interface sort(row ->
{... return groupingString}), but was struggling to express a Java Functionlike
input that could be used on a DataSet<Row>'s data_file struct - any pointers on
how to parse a Row's struct into a native Pojo and supply a function that can
be used like in a UDF here would be apprecaited!
I think it aligns with my main comment, which is that we discussed the
potential to expose it as a generic function but seems like this PR directly
skipped it. Seems like there are some pieces missing, let me see if I can fill
it up.
At API level, we could express it as a function using `PartitionData` as the
transformation source:
```
default RewriteManifests sort(List<String> partitionFieldNames) {
return sort(...) // see partitionSpec.partitionToPath for an example of
how to convert the partition fields to string
}
RewriteManifests sort(Function<PartitionData, String>
partitionFieldsSortStrategy) {
throw new UnsupportedOperationException();
}
```
and when implementing in Spark, the biggest question is now how do we
convert the Row `data_file.partition` to `PartititionData` so we can apply this
transform and create the new string column in the data frame that is used for
sorting.
I think this is achievable by creating a UDF that transforms the
`data_file.partition` Row to `SparkStructLike` using
`SparkStructLike.wrap(row)`, and then create a new `PartitionData` based on
that, and finally apply the input function to create its string value. You can
see an example of that in `PartitionsTable.toPartitionData`.
@RussellSpitzer @nastra let me know if you agree with this general
direction, or if it is becoming too convoluted.
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