tejasiyer-dev commented on code in PR #40543:
URL: https://github.com/apache/beam/pull/40543#discussion_r4569331543
##########
sdks/java/core/src/main/java/org/apache/beam/sdk/io/WriteFiles.java:
##########
@@ -1114,6 +1202,318 @@ public PCollection<FileResult<DestinationT>>
expand(PCollection<UserT> input) {
}
}
+ /**
+ * Streaming write that sends large bundles straight to temporary files.
+ *
+ * <p>Small bundles, and records that would exceed the per-bundle writer
limit, take the usual
+ * grouped path ({@link WriteShardedBundlesToTempFiles} when a shard count
is set, or the {@link
+ * GroupIntoBatches} auto-sharded path otherwise). All files then drop their
shard number and are
+ * grouped per destination, so finalization assigns shard numbers across
both paths.
+ */
+ private class WriteShardedBundlesWithDirectWrite
+ extends PTransform<PCollection<UserT>,
PCollection<List<FileResult<DestinationT>>>> {
+ private final Coder<DestinationT> destinationCoder;
+ private final Coder<FileResult<DestinationT>> fileResultCoder;
+ private final @Nullable PCollectionView<Integer> numShardsView;
+ private final long thresholdBytes;
+
+ private WriteShardedBundlesWithDirectWrite(
+ Coder<DestinationT> destinationCoder,
+ Coder<FileResult<DestinationT>> fileResultCoder,
+ @Nullable PCollectionView<Integer> numShardsView,
+ long thresholdBytes) {
+ this.destinationCoder = destinationCoder;
+ this.fileResultCoder = fileResultCoder;
+ this.numShardsView = numShardsView;
+ this.thresholdBytes = thresholdBytes;
+ }
+
+ @Override
+ public PCollection<List<FileResult<DestinationT>>>
expand(PCollection<UserT> input) {
+ TupleTag<UserT> smallBundlesTag = new TupleTag<>("smallBundles");
+ TupleTag<UserT> largeBundlesTag = new TupleTag<>("largeBundles");
+ TupleTag<FileResult<DestinationT>> directFilesTag = new
TupleTag<>("directFiles");
+ TupleTag<UserT> spilledRecordsTag = new TupleTag<>("spilledRecords");
+
+ // Evaluate the threshold per window, pane and destination, i.e. per
output file.
+ PCollectionTuple lifted =
+ input.apply(
+ "LiftLargeBundles",
+ BundleLifter.of(smallBundlesTag, largeBundlesTag,
thresholdBytes, input.getCoder())
+ .withKeyFn(new
DestinationKeyFn<>(getDynamicDestinations())));
+
+ PCollectionTuple routed =
+ lifted
+ .get(largeBundlesTag)
+ .setCoder(input.getCoder())
+ .apply(
+ "DirectWriteLargeBundles",
+ ParDo.of(new DirectWriteRecordsFn(spilledRecordsTag,
input.getCoder()))
+ .withSideInputs(getSideInputs())
+ .withOutputTags(
+ directFilesTag,
+ TupleTagList.of(ImmutableList.of(spilledRecordsTag,
BAD_RECORD_TAG))));
+ addErrorCollection(routed);
+
+ PCollection<UserT> smallBundles =
+
PCollectionList.of(lifted.get(smallBundlesTag).setCoder(input.getCoder()))
+ .and(routed.get(spilledRecordsTag).setCoder(input.getCoder()))
+ .apply("FlattenSmallBundles", Flatten.pCollections())
+ .apply("CountGroupedBundles", ParDo.of(new
CountGroupedBundlesFn<>()))
+ .setCoder(input.getCoder());
+ PCollection<FileResult<DestinationT>> groupedFiles;
+ if (getComputeNumShards() != null || getNumShardsProvider() != null) {
+ groupedFiles =
+ smallBundles
+ .apply(
+ "WriteShardedBundlesToTempFiles",
+ new WriteShardedBundlesToTempFiles(
+ destinationCoder, fileResultCoder, numShardsView))
+ .apply(
+ "DropShardNum",
+ ParDo.of(
+ new DoFn<FileResult<DestinationT>,
FileResult<DestinationT>>() {
+ @ProcessElement
+ public void process(ProcessContext c) {
+ c.output(c.element().withShard(UNKNOWN_SHARDNUM));
+ }
+ }))
+ .setCoder(fileResultCoder);
+ } else {
+ groupedFiles =
+ writeAutoShardedRecordsToTempFiles(
+ smallBundles,
+ destinationCoder,
+ fileResultCoder,
+ getBatchSizeOrDefault(),
+ getBatchSizeBytesOrDefault(),
+ getBatchMaxBufferingDurationOrDefault());
+ }
+
+ // When the small path goes through GroupIntoShards (GBK), its trigger
transitions to the
+ // continuation trigger. Set the direct path to the same windowing
strategy so
+ // FlattenTempFiles does not reject mismatched triggers when user
pipelines use non-default
+ // triggers.
+ PCollection<FileResult<DestinationT>> directFiles =
+ routed
+ .get(directFilesTag)
+ .setCoder(fileResultCoder)
+
.setWindowingStrategyInternal(groupedFiles.getWindowingStrategy());
+
+ // Group all temp files per destination so each window/pane firing is
finalized together
+ // and shard numbers are assigned once across both paths. Every file is
stamped with this
+ // firing's pane so files from different firings of the same window get
distinct names.
+ PCollection<FileResult<DestinationT>> allTempFiles =
+ PCollectionList.of(directFiles)
+ .and(groupedFiles)
+ .apply("FlattenTempFiles", Flatten.pCollections())
+ .setCoder(fileResultCoder);
+ return groupTempFilesByDestination(
+ allTempFiles,
+ destinationCoder,
+ fileResultCoder,
+ "GroupTempFilesByDestination",
+ /* stampFiringPane= */ true);
+ }
+ }
+
+ /**
+ * Key function for {@link BundleLifter}: the record's destination, so that
together with the
+ * window and pane the threshold is evaluated per output file. Returns
{@code null} if the
+ * destination cannot be computed, which sends the record to the grouped
path where the usual
+ * error handling applies.
+ */
+ private static class DestinationKeyFn<UserT, DestinationT>
+ implements SerializableFunction<UserT, @Nullable Object> {
+ private final DynamicDestinations<UserT, DestinationT, ?>
dynamicDestinations;
+
+ DestinationKeyFn(DynamicDestinations<UserT, DestinationT, ?>
dynamicDestinations) {
+ this.dynamicDestinations = dynamicDestinations;
+ }
+
+ @Override
+ public @Nullable Object apply(UserT record) {
+ try {
+ // Wrapped so that a null destination (e.g. Void) is still a valid key.
+ return
java.util.Optional.ofNullable(dynamicDestinations.getDestination(record));
+ } catch (Exception e) {
+ return null;
+ }
+ }
+ }
+
+ /** Passes records through, counting the bundles that take the grouped path.
*/
+ private static class CountGroupedBundlesFn<T> extends DoFn<T, T> {
+ private final Counter groupedBundles = Metrics.counter(WriteFiles.class,
"groupedWriteBundles");
Review Comment:
You're right. Record counts are already visible through existing pcollection
metrics. I removed groupedWriteBundles along with the extra
CountGroupedBundlesFn step.
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