sunchao commented on code in PR #2276:
URL: https://github.com/apache/iceberg/pull/2276#discussion_r1018632924
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core/src/main/java/org/apache/iceberg/util/TableScanUtil.java:
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@@ -121,10 +128,66 @@ public static <T extends ScanTask>
CloseableIterable<ScanTaskGroup<T>> planTaskG
Function<T, Long> weightFunc =
task -> Math.max(task.sizeBytes(), task.filesCount() * openFileCost);
+ return toTaskGroupIterable(splitTasks, splitSize, lookback, weightFunc);
+ }
+
+ @SuppressWarnings("unchecked")
+ public static <T extends PartitionScanTask> List<ScanTaskGroup<T>>
planTaskGroups(
+ List<T> tasks,
+ long splitSize,
+ int lookback,
+ long openFileCost,
+ Types.StructType projectedPartitionType) {
+
+ Preconditions.checkArgument(splitSize > 0, "Invalid split size (negative
or 0): %s", splitSize);
+ Preconditions.checkArgument(
+ lookback > 0, "Invalid split planning lookback (negative or 0): %s",
lookback);
+ Preconditions.checkArgument(
+ openFileCost >= 0, "Invalid file open cost (negative): %s",
openFileCost);
+
+ List<T> splitTasks = Lists.newArrayList();
+ for (T task : tasks) {
+ if (task instanceof SplittableScanTask<?>) {
+ ((SplittableScanTask<? extends T>)
task).split(splitSize).forEach(splitTasks::add);
+ } else {
+ splitTasks.add(task);
+ }
+ }
+
+ Function<T, Long> weightFunc =
+ task -> Math.max(task.sizeBytes(), task.filesCount() * openFileCost);
+
+ Map<Integer, StructProjection> projectionsBySpec = Maps.newHashMap();
+
+ // Group tasks by their partition values
+ StructLikeMap<List<T>> groupedTasks =
StructLikeMap.create(projectedPartitionType);
+
+ for (T task : splitTasks) {
+ PartitionSpec spec = task.spec();
+ projectionsBySpec.computeIfAbsent(
+ spec.specId(),
+ specId -> StructProjection.create(spec.partitionType(),
projectedPartitionType));
+ StructProjection projectedStruct =
projectionsBySpec.get(spec.specId()).copy();
+ groupedTasks
+ .computeIfAbsent(projectedStruct.copy().wrap(task.partition()), k ->
Lists.newArrayList())
+ .add(task);
+ }
+
+ // Now apply task combining within each partition
+ return groupedTasks.values().stream()
+ .flatMap(
+ ts ->
+ StreamSupport.stream(
+ toTaskGroupIterable(ts, splitSize, lookback,
weightFunc).spliterator(), false))
+ .collect(Collectors.toList());
+ }
+
+ private static <T extends ScanTask> CloseableIterable<ScanTaskGroup<T>>
toTaskGroupIterable(
Review Comment:
OK, let me change it to `toTaskGroupStream`.
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