[jira] [Commented] (IGNITE-2643) ODBC: Potential memory leak during client disconnect.

["ASF GitHub Bot (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/IGNITE-2643?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15272413#comment-15272413 ] 

ASF GitHub Bot commented on IGNITE-2643:
----------------------------------------

Github user asfgit closed the pull request at:

    https://github.com/apache/ignite/pull/487


> ODBC: Potential memory leak during client disconnect.
> -----------------------------------------------------
>
>                 Key: IGNITE-2643
>                 URL: https://issues.apache.org/jira/browse/IGNITE-2643
>             Project: Ignite
>          Issue Type: Sub-task
>          Components: odbc
>    Affects Versions: 1.5.0.final
>            Reporter: Vladimir Ozerov
>            Assignee: Vladimir Ozerov
>            Priority: Critical
>             Fix For: 1.6
>
>
> *Problem*
> When client executes a query, we preserve the cursor in concurrent collection. This could lead to two potential problems:
> 1) If problem disconnected abruptly, cursor gets stuck forever => memory leak.
> 2) Malicious client could flood us with requests which are never closed until node is out-of-memory.
> *Proposed solution*
> 1) When onDisconnect() callback is triggered, all pending client queries must be released. To achieve this it is better to move "OdbcNioListener.qryCurs" to session meta.
> 2) When new request is to be created, we must ensure that concurrent disconnect is not in progress. Otherwise, we might end up in a leak again. To achieve this, lets guard "add" logic with read-write lock.
> 3) Lets think about "max-concurrent-cursors-per-connection" property. It could be available from OdbcConfiguration. Once number of opened cursors is exceeded, we must throw an error to the client.



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