kfaraz commented on code in PR #14642:
URL: https://github.com/apache/druid/pull/14642#discussion_r1278228358
##########
indexing-service/src/main/java/org/apache/druid/indexing/common/task/KillUnusedSegmentsTask.java:
##########
@@ -114,23 +119,37 @@ public TaskStatus runTask(TaskToolbox toolbox) throws
Exception
}
// List unused segments
- final List<DataSegment> unusedSegments = toolbox
+ final List<DataSegment> allUnusedSegments = toolbox
.getTaskActionClient()
.submit(new RetrieveUnusedSegmentsAction(getDataSource(),
getInterval()));
- if (!TaskLocks.isLockCoversSegments(taskLockMap, unusedSegments)) {
- throw new ISE(
- "Locks[%s] for task[%s] can't cover segments[%s]",
-
taskLockMap.values().stream().flatMap(List::stream).collect(Collectors.toList()),
- getId(),
- unusedSegments
- );
+ final List<List<DataSegment>> unusedSegmentBatches =
Lists.partition(allUnusedSegments, SEGMENT_NUKE_BATCH_SIZE);
+
+ // The individual activities here on the toolbox have possibility to run
for a longer period of time,
+ // since they involve calls to metadata storage and archival object
storage. And, the tasks take hold of the
+ // task lockbox to run. By splitting the segment list into smaller
batches, we have an opportunity to yield the
+ // lock to other activity that might need to happen using the overlord
tasklockbox.
+
+ for (final List<DataSegment> unusedSegments : unusedSegmentBatches) {
+ if (!TaskLocks.isLockCoversSegments(taskLockMap, unusedSegments)) {
+ throw new ISE(
+ "Locks[%s] for task[%s] can't cover segments[%s]",
+
taskLockMap.values().stream().flatMap(List::stream).collect(Collectors.toList()),
+ getId(),
+ unusedSegments
+ );
+ }
+
+ // Kill segments:
+ // Order is important here: we want the nuke action to clean up the
metadata records _before_ the
+ // segments are removed from storage, this helps maintain that we will
always have a storage segment if
Review Comment:
Yeah, I think it makes sense. As long as all the DELETEs happen inside a
single transaction, we can be sure that the whole batch either succeeded or
failed (if an exception was thrown). Thanks for the explanation!
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