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https://issues.apache.org/jira/browse/HTTPASYNC-116?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15840861#comment-15840861
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Rob Griffin commented on HTTPASYNC-116:
---------------------------------------
[~olegk]
Oleg,
I have finally got around to building the library a few days ago and since then
I have had another out of memory problem. An analysis of the memory dump shows
that all nested future tasks are now correctly flagged as cancelled however the
CPool object in
org.apache.http.impl.nio.conn.PoolingNHttpClientConnectionManager has 209,487
item org.apache.http.nio.pool.LeaseRequest objects in it's linked list. It
seems to me that cancellation does not remove the LeaseRequest from the
connection manager.
I've attached a couple of screen dumps to show what I saw. I have a memory dump
(.hprof file) if you want to examine it. It's a bit over 4GB in size.
> Cancelling the Future returned by CloseableHttpAsyncClient should release all
> resources allocated to the request that created it.
> ---------------------------------------------------------------------------------------------------------------------------------
>
> Key: HTTPASYNC-116
> URL: https://issues.apache.org/jira/browse/HTTPASYNC-116
> Project: HttpComponents HttpAsyncClient
> Issue Type: Improvement
> Affects Versions: 4.1.1
> Reporter: Rob Griffin
> Assignee: Oleg Kalnichevski
> Fix For: 4.1.2
>
> Attachments: ScreenShot001.jpg, ScreenShot026.jpg
>
>
> We call CloseableHttpAsyncClient.execute() to execute HTTP PUTs at the rate
> of several hundred per minute. Sometimes our web site slows down and does not
> respond quickly enough and when this occurs the requests back up. We have
> code that detects this and cancels the Future returned from the execute
> method when the request has waited too long. If this happens too often the
> application crashes with an out of memory error.
>
> Analysis of a dump showed that there were more 108,000 instances of
> org.apache.http.nio.pool.LeaseRequest along with a similar number of
> instances of other HTTP Client classes. Inspecting one of these objects
> showed that its future variable is not cancelled but that by tracing though
> the callback variables there is a cancelled Future further up the chain. That
> cancelled Future object is one returned by execute because its callback is
> one of our classes. So it appears that the library is unaware that cancel has
> been called on the Future returned by execute() and keeps a reference to all
> resources allocated to the request.
> Instead cancelling the Future should release any resources allocated to the
> request and should also cancel execution if it has started.
> We regard this as a very urgent issue because it causes our application to
> crash. We realise that improving the responsiveness of our web site will
> alleviate the problem somewhat but the library shouldn't leak memory.
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