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https://issues.apache.org/jira/browse/HBASE-13888?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Guanghao Zhang updated HBASE-13888:
-----------------------------------
    Description: 
As I report the RateLimiter fail to limit in HBASE-13686, then [~ashish singhi] 
fix that problem by support two kinds of RateLimiter:  
AverageIntervalRateLimiter and FixedIntervalRateLimiter. But in my use of the 
code, I found a new bug about refill() in AverageIntervalRateLimiter.
{code}
    long delta = (limit * (now - nextRefillTime)) / super.getTimeUnitInMillis();
    if (delta > 0) {
      this.nextRefillTime = now;
      return Math.min(limit, available + delta);
    }   
{code}
When delta > 0, refill maybe return available + delta. Then in the 
canExecute(), avail will add refillAmount again. So the new avail maybe 2 * 
avail + delta.
{code}
    long refillAmount = refill(limit, avail);
    if (refillAmount == 0 && avail < amount) {
      return false;
    }   
    // check for positive overflow
    if (avail <= Long.MAX_VALUE - refillAmount) {
      avail = Math.max(0, Math.min(avail + refillAmount, limit));
    } else {
      avail = Math.max(0, limit);
    } 
{code}
I will add more unit tests for RateLimiter in the next days.

Review Board: https://reviews.apache.org/r/35384/

  was:
As I report the RateLimiter fail to limit in HBASE-13686, then [~ashish singhi] 
fix that problem by support two kinds of RateLimiter:  
AverageIntervalRateLimiter and FixedIntervalRateLimiter. But in my use of the 
code, I found a new bug about refill() in AverageIntervalRateLimiter.
{code}
    long delta = (limit * (now - nextRefillTime)) / super.getTimeUnitInMillis();
    if (delta > 0) {
      this.nextRefillTime = now;
      return Math.min(limit, available + delta);
    }   
{code}
When delta > 0, refill maybe return available + delta. Then in the 
canExecute(), avail will add refillAmount again. So the new avail maybe 2 * 
avail + delta.
{code}
    long refillAmount = refill(limit, avail);
    if (refillAmount == 0 && avail < amount) {
      return false;
    }   
    // check for positive overflow
    if (avail <= Long.MAX_VALUE - refillAmount) {
      avail = Math.max(0, Math.min(avail + refillAmount, limit));
    } else {
      avail = Math.max(0, limit);
    } 
{code}
I will add more unit tests for RateLimiter in the next days.



> refill bug from HBASE-13686
> ---------------------------
>
>                 Key: HBASE-13888
>                 URL: https://issues.apache.org/jira/browse/HBASE-13888
>             Project: HBase
>          Issue Type: Bug
>    Affects Versions: 2.0.0
>            Reporter: Guanghao Zhang
>            Assignee: Guanghao Zhang
>         Attachments: HBASE-13888-v1.patch, HBASE-13888-v2.patch
>
>
> As I report the RateLimiter fail to limit in HBASE-13686, then [~ashish 
> singhi] fix that problem by support two kinds of RateLimiter:  
> AverageIntervalRateLimiter and FixedIntervalRateLimiter. But in my use of the 
> code, I found a new bug about refill() in AverageIntervalRateLimiter.
> {code}
>     long delta = (limit * (now - nextRefillTime)) / 
> super.getTimeUnitInMillis();
>     if (delta > 0) {
>       this.nextRefillTime = now;
>       return Math.min(limit, available + delta);
>     }   
> {code}
> When delta > 0, refill maybe return available + delta. Then in the 
> canExecute(), avail will add refillAmount again. So the new avail maybe 2 * 
> avail + delta.
> {code}
>     long refillAmount = refill(limit, avail);
>     if (refillAmount == 0 && avail < amount) {
>       return false;
>     }   
>     // check for positive overflow
>     if (avail <= Long.MAX_VALUE - refillAmount) {
>       avail = Math.max(0, Math.min(avail + refillAmount, limit));
>     } else {
>       avail = Math.max(0, limit);
>     } 
> {code}
> I will add more unit tests for RateLimiter in the next days.
> Review Board: https://reviews.apache.org/r/35384/



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