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https://issues.apache.org/jira/browse/TRAFODION-2636?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16041089#comment-16041089
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ASF GitHub Bot commented on TRAFODION-2636:
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GitHub user zellerh opened a pull request:
https://github.com/apache/incubator-trafodion/pull/1113
[TRAFODION-2636] Memory leak in metadata context
Fixing a memory leak found by Selva. See
[[TRAFODION-2636]](https://issues.apache.org/jira/browse/TRAFODION-2636) for
details. Also adding a method that helped me in debugging this issue.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/zellerh/incubator-trafodion bug/cses_jan-17
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/incubator-trafodion/pull/1113.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 #1113
----
commit 9dd45d251fda6a103c5d90b6706babbea55f32fa
Author: Hans Zeller <[email protected]>
Date: 2017-06-07T15:43:23Z
[TRAFODION-2636] Memory leak in metadata context
Fixing a memory leak found by Selva.
----
> Modest memory leak in metadata context and with CQS
> ---------------------------------------------------
>
> Key: TRAFODION-2636
> URL: https://issues.apache.org/jira/browse/TRAFODION-2636
> Project: Apache Trafodion
> Issue Type: Bug
> Components: sql-cmp
> Affects Versions: 1.3-incubating
> Reporter: Hans Zeller
> Assignee: Hans Zeller
> Fix For: 2.2-incubating
>
>
> Selva pointed me to this leak. He found that we leak GroupAttributes objects
> in the metadata context.
> It turns out that the ControlDB object makes copies of CQD and CQS RelExpr
> trees and stores them in the context heap. This is not a good idea, since
> RelExpr and the associate GroupAttributes classes are not designed for heaps
> other than the statement heap. GroupAttributes, for example, hard-codes the
> statement heap in its constructor calls to ValueIdSets. That probably isn't a
> visible problem in ControlDB, however.
> For CQDs, the allocations and deallocations seem to match. For CQS, we
> allocate ControlQueryShape objects and also the actual shapes. However, we
> deallocate only the ControlQueryShape objects, not the shapes themselves.
> A simple, conservative fix is therefore to deallocate the shapes as well. In
> the longer term, it would be good to avoid storing RelExprs in the context
> heap.
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