rdblue commented on code in PR #7731:
URL: https://github.com/apache/iceberg/pull/7731#discussion_r1220268210
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core/src/main/java/org/apache/iceberg/util/TableScanUtil.java:
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@@ -79,6 +88,44 @@ public static CloseableIterable<FileScanTask> splitFiles(
return CloseableIterable.combine(splitTasks, tasks);
}
+ /**
+ * Produces {@link CombinedScanTask combined tasks} from an iterable of
{@link FileScanTask file
+ * tasks}, using an adaptive target split size that targets a minimum number
of tasks
+ * (parallelism).
+ *
+ * @param files incoming iterable of file tasks
+ * @param parallelism target minimum number of tasks
+ * @param splitSize target split size
+ * @param lookback bin packing lookback
+ * @param openFileCost minimum file cost
+ * @return an iterable of combined tasks
+ */
+ public static CloseableIterable<CombinedScanTask> planTasksAdaptive(
+ CloseableIterable<FileScanTask> files,
+ int parallelism,
+ long splitSize,
+ int lookback,
+ long openFileCost) {
+
+ validatePlanningArguments(splitSize, lookback, openFileCost);
+
+ Function<FileScanTask, Long> weightFunc =
+ file ->
+ Math.max(
Review Comment:
> Comparing fileSize and openCost per each file seems worth exploring.
This seems more correct to me. Otherwise, a single large file could be
combined with lots of small files and delete files that take too long. This is
for a separate PR though.
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