[jira] [Commented] (POOL-356) deadlock if borrowObject gets called to fast and maxIdle is 0

["M Sazzadul Hoque (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/POOL-356?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16935230#comment-16935230 ] 

M Sazzadul Hoque commented on POOL-356:
---------------------------------------

IMHO, it doesn't make any sense to {{create()}} within {{destroy(p)}}.  For example, {{clear()}} uses {{destroy(p)}} {{}} and it's absurd to create same number of idle objects again. Even worse, doesn't this lead to an infinite loop?{{}}

> deadlock if borrowObject gets called to fast and maxIdle is 0
> -------------------------------------------------------------
>
>                 Key: POOL-356
>                 URL: https://issues.apache.org/jira/browse/POOL-356
>             Project: Commons Pool
>          Issue Type: Bug
>    Affects Versions: 2.6.0
>            Reporter: Mark Struberg
>            Assignee: Mark Struberg
>            Priority: Major
>             Fix For: 2.6.1
>
>
> I figured this while creating a unit test for OpenJPA. But also did see this in real production with commons-dbcp2. See DBCP-513 for more info.
> See this comment for a precise explanation what happens https://issues.apache.org/jira/browse/DBCP-513?focusedCommentId=16660545&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-16660545
> The problem is basically that the logic to immediately destroy a pool object does not notify the DeLinkedQueue:
> {code}
>         if (isClosed() || maxIdleSave > -1 && maxIdleSave <= idleObjects.size()) {
>             try {
>                 destroy(p);
> {code}
> But the borrowObject code is locking on that condition...
> {code}
>                     if (borrowMaxWaitMillis < 0) {
>                         p = idleObjects.takeFirst();
>                     } 
> {code}



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