Guozhang Wang created KAFKA-1616:
------------------------------------
Summary: Purgatory Size and Num.Delayed.Request metrics are
incorrect
Key: KAFKA-1616
URL: https://issues.apache.org/jira/browse/KAFKA-1616
Project: Kafka
Issue Type: Bug
Reporter: Guozhang Wang
Assignee: Guozhang Wang
Fix For: 0.9.0
The request purgatory used two atomic integers "watched" and "unsatisfied" to
record the purgatory size ( = watched + unsatisfied) and number of delayed
requests ( = unsatisfied). But due to some race conditions these two atomic
integers are not updated correctly, result in incorrect metrics.
Proposed solution: to have a cleaner semantics, we can define the "purgatory
size" to be just the number of elements in the watched lists, and the "number
of delayed requests" to be just the length of the expiry queue. And instead of
using two atomic integeres we just compute the size of the lists / queue on the
fly each time the metrics are pulled. This may use some more CPU cycles for
these two metrics but should be minor, and the correctness is guaranteed.
--
This message was sent by Atlassian JIRA
(v6.2#6252)
