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https://issues.apache.org/jira/browse/YARN-6768?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16093803#comment-16093803
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Jason Lowe commented on YARN-6768:
----------------------------------
Thanks for updating the patch! Nice to see the state fall away and things get
simpler as a result.
The toString paths look great, just a few nits on the conversion back from a
String.
Nit: It is less work to do indexOf('_') than indexOf("_")
Rather than searching for the first underscore, creating a substring starting
at 0 to that position, and then comparing that substring to a known prefix we
can avoid some object creation and a redundant prefix scan by leveraging
startsWith and the length of the known prefix. Similarly we can use
String#regionMatches to avoid a substring creation for the epoch string. For
example:
{code}
int pos1 = CONTAINER_PREFIX.length();
if (!containerIdStr.startsWith(CONTAINER_PREFIX) ||
containerIdStr.charAt(pos1) != '_') {
throw new IllegalArgumentException("Invalid ContainerId prefix: "
+ containerIdStr.substring(0, pos1 + 1));
}
int pos2 = containerIdStr.indexOf('_', pos1 + 1);
String clusterTimestamp;
if (containerIdStr.regionMatches(pos1 + 1, EPOCH_PREFIX, 0,
EPOCH_PREFIX.length()) {
String epochStr = containerId.substring(pos1 + 1 + EPOCH_PREFIX.length(),
pos2);
epoch = Integer.parseInt(epochStr);
....
{code}
The use of startsWith to avoid the initial substring applies to app attempt and
app ID parsing as well. The test gets even cheaper if we bother to precompute
a String that is the prefix with the underscore already attached because we
wouldn't need to do the extra check for the '_' character.
This patch also causes some of the TestConverterUtils tests to fail in
hadoop-yarn-common. Arguably some of these conversion tests should be
moved/adapted to hadoop-yarn-api so they are closer to the code in question.
> Improve performance of yarn api record toString and fromString
> --------------------------------------------------------------
>
> Key: YARN-6768
> URL: https://issues.apache.org/jira/browse/YARN-6768
> Project: Hadoop YARN
> Issue Type: Improvement
> Reporter: Jonathan Eagles
> Assignee: Jonathan Eagles
> Attachments: YARN-6768.1.patch, YARN-6768.2.patch, YARN-6768.3.patch,
> YARN-6768.4.patch
>
>
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