[jboss-jira] [JBoss JIRA] (JGRP-2120) Headers.resize() called unnecessarily

[Bela Ban (JIRA)]

     [ https://issues.jboss.org/browse/JGRP-2120?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Bela Ban updated JGRP-2120:
---------------------------
    Fix Version/s: 3.6.12


> Headers.resize() called unnecessarily
> -------------------------------------
>
>                 Key: JGRP-2120
>                 URL: https://issues.jboss.org/browse/JGRP-2120
>             Project: JGroups
>          Issue Type: Bug
>            Reporter: Bela Ban
>            Assignee: Bela Ban
>            Priority: Minor
>             Fix For: 3.6.12, 4.0
>
>
> Each message has space for 4 headers. When a 5th header needs to be added, the array needs to be resized. This is something we want to avoid as much as possible.
> However, the following scenario can lead to resizing:
> * A bundler writes a message list with (say) 3 headers
> * A message list always ignores the transport header, as it is only used to carry the cluster name, but that name is available in the batch header, too.
> * Therefore, the size of the headers written is 2 and the transport header is not written
> * On the receiver side, when reading the batch, we create and read 2 headers
> ** This is OK, as message batches are matched against the receiver's cluster name using the cluster name shipped in the batch itself and not in the message
> ** Message batches are therefore passed up without the individual messages carrying a transport header
> * However, single messages need to carry a transport header as it will be used to do the cluster name matching
> * Now, if a batch contains messages tagged as {{OOB|DONT_BUNDLE}}, they will be removed from the batch and sent up the stack as separate messages, each in a separate thread.
> * To do this, each of these messages is added a transport header (created using the batch's cluster name).
> * However, this necessitates a resizing as the headers array has a length of only 2, but we now need 3 headers
> Note that we don't run into this in 4.0, as Infinispan 9 (which uses 4) doesn't use {{DONT_BUNDLE}} any longer. It is still an unnecessary memory allocation and needs to be optimized.
> However, we should fix it in 3.6 as we still use {{DONT_BUNDLE}} in Infinispan 8.



--
This message was sent by Atlassian JIRA
(v7.2.3#72005)