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From: franz1981 <git@git.apache.org>
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Subject: [GitHub] activemq-artemis issue #1361: ARTEMIS-1248 Reduce garbage while Paging
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Message-Id: <20170623060308.7737ADFE8B@git1-us-west.apache.org>
Date: Fri, 23 Jun 2017 06:03:08 +0000 (UTC)
archived-at: Fri, 23 Jun 2017 06:03:10 -0000

Github user franz1981 commented on the issue:

    https://github.com/apache/activemq-artemis/pull/1361
  
    @clebertsuconic There is no need to use a ThreadLocal or a pooled buffer there because:
    1) the method (write/read) is synchronized and it is safe to reuse the same ByteBuf wrapper between different threads (note: is only a wrapper on the ByteBuffer provided by the file factory)
    2) the file factory already provides a (thread local) pooled direct ByteBuffer (on NIO)
    In the old version the most of the garbage was already avoided due to the fileFactory ByteBuffer thread local pooling, but I've measured after multiple Page writes lots of minor GCs due to many short living ActiveMQBuffer instances. This change aims reduce that instances to be only 1 per Page: it is not optimal but is a big improvement.
    With 100 bytes messages and a Page of 10 MB it avoids about 104856 instances of garbage.


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