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https://issues.apache.org/jira/browse/KAFKA-3892?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15345095#comment-15345095
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ASF GitHub Bot commented on KAFKA-3892:
---------------------------------------

GitHub user iamnoah opened a pull request:

    https://github.com/apache/kafka/pull/1541

    KAFKA-3892 prune metadata response to subscribed topics

    I believe this will cause clients to defensively prune their cluster 
metadata in all cases. It doesn't address why a client without a Pattern 
subscription would receive a response containing all topics and partitions for 
the cluster (which is still undesirable, but I am guessing would require a fix 
for the broker.)
    
    In my own testing, this restored the amount of heap required to 0.8 
consumer levels.
    
    I am concerned that I do not 100% understand all the uses of this class. My 
assumption is that only topics that have been added are expected in the 
response and that the two unit test modifications I needed to make were 
oversights.
    
    I am also assuming that this behavior was only applied to the pattern 
matching case to avoid a small amount of (presumed) unnecessary work and not 
for correctness reasons.

You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/spredfast/kafka-1 remove-extra-metadata

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/kafka/pull/1541.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

    This closes #1541
    
----
commit cb19feac9c1473e8406fd10a895a41468373ddae
Author: Noah Sloan <nsl...@spredfast.com>
Date:   2016-06-22T20:10:35Z

    KAFKA-3892 prune metadata response to subscribed topics

----


> Clients retain metadata for non-subscribed topics
> -------------------------------------------------
>
>                 Key: KAFKA-3892
>                 URL: https://issues.apache.org/jira/browse/KAFKA-3892
>             Project: Kafka
>          Issue Type: Bug
>          Components: clients
>    Affects Versions: 0.9.0.1
>            Reporter: Noah Sloan
>
> After upgrading to 0.9.0.1 from 0.8.2 (and adopting the new consumer and 
> producer classes,) we noticed services with small heap crashing due to 
> OutOfMemoryErrors. These services contained many producers and consumers (~20 
> total) and were connected to brokers with >2000 topics and over 10k 
> partitions. Heap dumps revealed that each client had 3.3MB of Metadata 
> retained in their Cluster, with references to topics that were not being 
> produced or subscribed to. While the services were running with 128MB of heap 
> prior to the upgrade, we to had increased max heap to 200MB to accommodate 
> all the extra data. 
> While this is not technically a memory leak, it does impose a significant 
> overhead on clients when connected to a large cluster.



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