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https://issues.apache.org/jira/browse/HBASE-13686?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14550398#comment-14550398
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Ashish Singhi commented on HBASE-13686:
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[~zghaobac], [~mbertozzi] and others can you please review the patch.
Regarding the implementation.
1. I could not find a way to combine the refill logic implemented by
AverageIntervalRefillStrategy and FixedIntervalRefillStrategy so I have added a
interface RefillStrategy which defines how the RateLimiter will refill the
resources availability.
2. Added a new configuration property {{hbase.quota.refill.strategy}}, where in
user can configure the refill strategy he/she wants to use. With default being
AverageIntervalRefillStrategy.
3. Created a conf object in TimeBasedLimiter, could not a find a better way to
pass this object. If you know any other way then please suggest.
4. With this implementation the timestamps in not in client control, instead
will be controlled by the refill strategy.
5. I have commented the test for Minutes, Hours, Days in TestRateLimiter, as to
verify these test cases will involve high time sleep to refill as timestamps
are not in client control.
If you feel the class or methods can be better documented then please suggest,
I am happy to do that.
> Fail to limit rate in RateLimiter
> ---------------------------------
>
> Key: HBASE-13686
> URL: https://issues.apache.org/jira/browse/HBASE-13686
> Project: HBase
> Issue Type: Bug
> Affects Versions: 2.0.0, 1.1.0
> Reporter: Guanghao Zhang
> Assignee: Ashish Singhi
> Priority: Minor
> Fix For: 2.0.0, 1.2.0, 1.1.1
>
> Attachments: HBASE-13686.patch
>
>
> While using the patch in HBASE-11598 , I found that RateLimiter can't to
> limit the rate right.
> {code}
> /**
> * given the time interval, are there enough available resources to allow
> execution?
> * @param now the current timestamp
> * @param lastTs the timestamp of the last update
> * @param amount the number of required resources
> * @return true if there are enough available resources, otherwise false
> */
> public synchronized boolean canExecute(final long now, final long lastTs,
> final long amount) {
> return avail >= amount ? true : refill(now, lastTs) >= amount;
> }
> {code}
> When avail >= amount, avail can't be refill. But in the next time to call
> canExecute, lastTs maybe update. So avail will waste some time to refill.
> Even we use smaller rate than the limit, the canExecute will return false.
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