[
https://issues.apache.org/jira/browse/HDFS-3456?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13286192#comment-13286192
]
Colin Patrick McCabe commented on HDFS-3456:
--------------------------------------------
Well, I was going by
http://docs.oracle.com/javase/1.4.2/docs/api/java/util/Random.html#nextDouble%28%29,
which includes this text:
bq. The general contract of nextDouble is that one double value, chosen
(approximately) uniformly from the range 0.0d (inclusive) to 1.0d (exclusive),
is pseudorandomly generated and returned. All 2^53 possible float values of the
form m x 2^53 , where m is a positive integer less than 2^53, are produced with
(approximately) equal probability.
I haven't done the analysis myself so I don't know how they came to this
number. If you think you've found a bug in Oracle's docs, you should
definitely let them know.
We have a lot of other time periods that are given as longs. I just don't like
mixing and matching types, because the potential for mistakes is too high. At
the same time, it's silly to make something a long and then throw an exception
if it's greater than 31 bits. Just my 2 cents.
> blockReportInterval is long value but when we take the random value it uses
> getRandom().nextInt,it is causing frequently BR
> ---------------------------------------------------------------------------------------------------------------------------
>
> Key: HDFS-3456
> URL: https://issues.apache.org/jira/browse/HDFS-3456
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: data-node
> Affects Versions: 2.0.0-alpha
> Reporter: Brahma Reddy Battula
> Assignee: Colin Patrick McCabe
> Priority: Minor
> Attachments: HDFS-3456.001.patch, HDFS-3456.002.patch,
> HDFS-3456.003.patch, HDFS-3456.004.patch
>
>
> blockReportInterval is long value but when we take the random value it uses
> getRandom().nextInt.
> Due to this, offerService can throw exception as long may get rotated to
> negative value.
> So, block report may send very frequently.
> {code}
> if (resetBlockReportTime) {
> lastBlockReport = startTime -
> DFSUtil.getRandom().nextInt((int)(dnConf.blockReportInterval));
> resetBlockReportTime = false;
> {code}
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators:
https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira
