logging-log4j-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Sascha Scholz (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (LOG4J2-1235) org.apache.logging.log4j.core.appender.routing.IdlePurgePolicy not working correctly
Date Fri, 19 Feb 2016 10:02:18 GMT

    [ https://issues.apache.org/jira/browse/LOG4J2-1235?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15154019#comment-15154019
] 

Sascha Scholz commented on LOG4J2-1235:
---------------------------------------

I think I've found another race condition that is related to how appenders are purged: In
update(), appenders are put into the appendersUsage map with its current usage time. In purge(),
they are removed again if timeToLive has expired, then the appender is deleted. So, we have
three different execution orders when update() and purge() run concurrently.


{noformat}
appendersUsage.remove()
routingAppender.delete()
appendersUsage.put()
{noformat}
This is ok. Appender is removed and deleted, and then added again. Appender is only removed
after put when next timeToLive expired.


{noformat}
appendersUsage.put()
appendersUsage.remove()
routingAppender.delete()
{noformat}
This is not optimal. The just added appender is removed and deleted, althouth timeToLive is
extended. This could be solved by using remove(entry.getKey(), entry.getValue()) and then
deleting the appender only on successful removal.


{noformat}
appendersUsage.remove()
appendersUsage.put()
routingAppender.delete()
{noformat}
This is the worst case. The appender is removed from the map, but immediately added back.
Afterwards the appender is deleted. On the next run of purge() deletion will be re-attempted,
which leads to a NPE in RoutingAppender#deleteAppender because there appender.remove() returns
null for the already deleted appender.

Should I open this as a separate bug or should it be treated here?

> org.apache.logging.log4j.core.appender.routing.IdlePurgePolicy not working correctly
> ------------------------------------------------------------------------------------
>
>                 Key: LOG4J2-1235
>                 URL: https://issues.apache.org/jira/browse/LOG4J2-1235
>             Project: Log4j 2
>          Issue Type: Bug
>          Components: Appenders
>    Affects Versions: 2.5
>            Reporter: Niranjan Rao
>            Priority: Critical
>
> There is a problem in the function org.apache.logging.log4j.core.appender.routing.IdlePurgePolicy.scheduleNext().
> I got out of file handles errors despite of setting IdlePurgePolicy. I did some digging
I believe following is the cause
> If the createTime is Long.MAX_VALUE, task is never scheduled. However function org.apache.logging.log4j.core.appender.routing.IdlePurgePolicy.update(String,
LogEvent) checks if the future is not null before deciding to schedule.
> After appendersUsage becomes empty first time, appenders keep piling up.
> I believe fix will be to set future to null in the function scheduleNext in the else
part of the condition where it checks for createTime



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

---------------------------------------------------------------------
To unsubscribe, e-mail: log4j-dev-unsubscribe@logging.apache.org
For additional commands, e-mail: log4j-dev-help@logging.apache.org


Mime
View raw message