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https://issues.apache.org/jira/browse/TS-1457?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13457849#comment-13457849
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Alan M. Carroll commented on TS-1457:
-------------------------------------
None of the memory is freed in the OS sense in any case. When an IOBufferBlock
is no longer in use it is put on a free list. The problem exhibited here is
that the amount of memory per operation is so large that significant numbers of
simultaneous connections drive memory usage beyond the capabilities of the host
system. This problem exists for all transforms, but becomes acute when there
are both large numbers of simultaneous clients and large files, both of which
drive the memory consumption. In practice this doesn't seem to be a major issue
for smaller files (< 1M) although our observational data is rather thin.
> transforms during video requests cause massive memory growth
> ------------------------------------------------------------
>
> Key: TS-1457
> URL: https://issues.apache.org/jira/browse/TS-1457
> Project: Traffic Server
> Issue Type: Bug
> Components: Core
> Affects Versions: 3.2.0
> Environment: Linux RHEL6.2
> Reporter: Aidan McGurn
> Assignee: Alan M. Carroll
> Priority: Critical
> Fix For: 3.3.1
>
> Attachments: 3.0.3-null-massif.txt, 3.0.5-null-massif.txt,
> alan-chunk-fix-3.2.0-null.txt, alan-nofix-3.2.0-null.txt,
> no-null-3.2.0-massif.txt, null-3.0.2-massif.txt, null-3.2.0-massif.txt,
> ts-1457-patch-1.diff
>
>
> Running the null-transform example object over 3.2.0, shows massive memory
> growth -
> This could be seen on our system since using 3.2.0 with custom plugin which
> invokes transforms - under load ~6K and with video content (only Video -
> small files are ok), a huge growth was seen (GB's) such that it crashes the
> load test machine.
> heap profiles are attached for comparison:
> -null transform example so over 3.2.0
> -NO null transform over 3.2.0
> -null transform example so over 3.0.2
> As can be seen no issue in 3.0.2 -
> The profiles show clearly the call chain is different for both releases
>
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