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https://issues.apache.org/jira/browse/MAPREDUCE-7370?focusedWorklogId=783993&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-783993
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ASF GitHub Bot logged work on MAPREDUCE-7370:
---------------------------------------------
Author: ASF GitHub Bot
Created on: 22/Jun/22 23:04
Start Date: 22/Jun/22 23:04
Worklog Time Spent: 10m
Work Description: cnauroth commented on code in PR #4248:
URL: https://github.com/apache/hadoop/pull/4248#discussion_r904363794
##########
hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/lib/output/MultipleOutputs.java:
##########
@@ -570,8 +570,14 @@ public void setStatus(String status) {
*/
@SuppressWarnings("unchecked")
public void close() throws IOException, InterruptedException {
- for (RecordWriter writer : recordWriters.values()) {
- writer.close(context);
- }
+ recordWriters.values().parallelStream().forEach(writer -> {
Review Comment:
I'm concerned that this could have unintended side effects for callers,
because it changes the error contract. Errors during `close()` that were
formerly visible as a checked `IOException` or `InterruptedException` now
become an unchecked `RuntimeException`. In the case of thread interruption, the
interrupt now occurs on the background thread with no propagation of
interrupted status back up to the coordinating thread.
Unfortunately, `parallelStream()` with a lambda puts us down this path. It
would be more code, but directly managing a `ThreadPoolExecutor` would give you
the chance to preserve the contract by unwrapping checked exceptions from the
`Future` and propagating.
Issue Time Tracking
-------------------
Worklog Id: (was: 783993)
Time Spent: 1h 10m (was: 1h)
> Parallelize MultipleOutputs#close call
> --------------------------------------
>
> Key: MAPREDUCE-7370
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-7370
> Project: Hadoop Map/Reduce
> Issue Type: Improvement
> Affects Versions: 3.3.0
> Reporter: Prabhu Joseph
> Assignee: Ashutosh Gupta
> Priority: Major
> Labels: pull-request-available
> Time Spent: 1h 10m
> Remaining Estimate: 0h
>
> This call takes more time when there are lot of files to close and there is a
> high latency to close. Parallelize MultipleOutputs#close call to improve the
> speed.
> {code}
> public void close() throws IOException {
> for (RecordWriter writer : recordWriters.values()) {
> writer.close(null);
> }
> }
> {code}
> Idea is from [~ste...@apache.org]
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