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https://issues.apache.org/jira/browse/ZOOKEEPER-2770?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16085171#comment-16085171
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ASF GitHub Bot commented on ZOOKEEPER-2770:
-------------------------------------------
Github user karanmehta93 commented on a diff in the pull request:
https://github.com/apache/zookeeper/pull/307#discussion_r127127351
--- Diff:
src/java/main/org/apache/zookeeper/server/FinalRequestProcessor.java ---
@@ -430,6 +432,7 @@ public void processRequest(Request request) {
// the client and leader disagree on where the client is most
// recently attached (and therefore invalid SESSION MOVED
generated)
cnxn.sendCloseSession();
+ request.checkLatency();
--- End diff --
@eribeiro
That is exactly the reason that I created my own function after the
`cnxn.sendCloseSession()` since I was interested in end to end latency, and
didn't use the `zks.serverStats().updateLatency(request.createTime);` method. I
would also like to know opinion from others on this.
Should we scope this JIRA for adding threshold as a general and create a
new JIRA for extending the scope to include percentiles with new data-structure
inside the `ServerStats` class?
> ZooKeeper slow operation log
> ----------------------------
>
> Key: ZOOKEEPER-2770
> URL: https://issues.apache.org/jira/browse/ZOOKEEPER-2770
> Project: ZooKeeper
> Issue Type: Improvement
> Reporter: Karan Mehta
> Attachments: ZOOKEEPER-2770.001.patch, ZOOKEEPER-2770.002.patch,
> ZOOKEEPER-2770.003.patch
>
>
> ZooKeeper is a complex distributed application. There are many reasons why
> any given read or write operation may become slow: a software bug, a protocol
> problem, a hardware issue with the commit log(s), a network issue. If the
> problem is constant it is trivial to come to an understanding of the cause.
> However in order to diagnose intermittent problems we often don't know where,
> or when, to begin looking. We need some sort of timestamped indication of the
> problem. Although ZooKeeper is not a datastore, it does persist data, and can
> suffer intermittent performance degradation, and should consider implementing
> a 'slow query' log, a feature very common to services which persist
> information on behalf of clients which may be sensitive to latency while
> waiting for confirmation of successful persistence.
> Log the client and request details if the server discovers, when finally
> processing the request, that the current time minus arrival time of the
> request is beyond a configured threshold.
> Look at the HBase {{responseTooSlow}} feature for inspiration.
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