<style>
/* Changing the layout to use less space for mobiles */
@media screen and (max-device-width: 480px), screen and (-webkit-min-device-pixel-ratio: 2) {
    #email-body { min-width: 30em !important; }
    #email-page { padding: 8px !important; }
    #email-banner { padding: 8px 8px 0 8px !important; }
    #email-avatar { margin: 1px 8px 8px 0 !important; padding: 0 !important; }
    #email-fields { padding: 0 8px 8px 8px !important; }
    #email-gutter { width: 0 !important; }
}
</style>
<div id="email-body">
<table id="email-wrap" align="center" border="0" cellpadding="0" cellspacing="0" style="background-color:#f0f0f0;color:#000000;width:100%;">
    <tr valign="top">
        <td id="email-page" style="padding:16px !important;">
            <table align="center" border="0" cellpadding="0" cellspacing="0" style="background-color:#ffffff;border:1px solid #bbbbbb;color:#000000;width:100%;">
                <tr valign="top">
                    <td bgcolor="#003366" style="background-color:#003366;color:#ffffff;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;line-height:1;"><img src="http://jira.qos.ch/s/en_USb9v8he-418945332/850/25/_/jira-logo-scaled.png" alt="" style="vertical-align:top;" /></td>
                </tr><tr valign="top">
    <td id="email-banner" style="padding:32px 32px 0 32px;">

                
        
        
            <table align="left" border="0" cellpadding="0" cellspacing="0" width="100%" style="width:100%;">
    <tr valign="top">
        <td style="color:#505050;font-family:Arial,FreeSans,Helvetica,sans-serif;padding:0;">
                                        <img id="email-avatar" src="http://jira.qos.ch/secure/useravatar?avatarId=10122" alt="" height="48" width="48" border="0" align="left" style="padding:0;margin: 0 16px 16px 0;" />
                        <div id="email-action" style="padding: 0 0 8px 0;font-size:12px;line-height:18px;">
                                    <a class="user-hover" rel="stefan" id="email_stefan" href="http://jira.qos.ch/secure/ViewProfile.jspa?name=stefan" style="color:#326ca6;">Stefan Prange</a>
     commented on <img src="http://jira.qos.ch/images/icons/issuetypes/bug.png" height="16" width="16" border="0" align="absmiddle" alt="Bug"> <a style='color:#326ca6;text-decoration:none;' href='http://jira.qos.ch/browse/LOGBACK-992'>LOGBACK-992</a>
            </div>
                        <div id="email-summary" style="font-size:16px;line-height:20px;padding:2px 0 16px 0;">
                <a style='color:#326ca6;text-decoration:none;' href='http://jira.qos.ch/browse/LOGBACK-992'><strong>Rolling File Appender creates .tmp files but never deletes them</strong></a>
            </div>
                    </td>
    </tr>
</table>
    </td>
</tr>
<tr valign="top">
    <td id="email-fields" style="padding:0 32px 32px 32px;">
        <table border="0" cellpadding="0" cellspacing="0" style="padding:0;text-align:left;width:100%;" width="100%">
            <tr valign="top">
                <td id="email-gutter" style="width:64px;white-space:nowrap;"></td>
                <td>
                    <table border="0" cellpadding="0" cellspacing="0" width="100%">
                        <tr valign="top">
    <td colspan="2" style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 0 16px 0;width:100%;">
        <div class="comment-block" style="background-color:#edf5ff;border:1px solid #dddddd;color:#000000;padding:12px;"><p>Hi,<br/>
one of our developers observed a similar behavior recently.<br/>
He found this log output after enabling the "debug" attribute in the <configuration> element in logback.xml:</p>

<div class="code panel" style="border-width: 1px;"><div class="codeContent panelContent">
<pre class="code-java">[11/5/14 0:00:05:004 CET] 0000001a SystemOut     O 00:00:05,004 |-INFO in c.q.l.core.rolling.DefaultTimeBasedFileNamingAndTriggeringPolicy - Elapsed period: Tue Nov 04 16:33:30 CET 2014
[11/5/14 0:00:05:005 CET] 0000001a SystemOut     O 00:00:05,005 |-INFO in c.q.l.co.rolling.helper.RenameUtil - Renaming file [logs/log-output-MyAppl.log] to [logs/log-output-MyAppl.log14538255624893230.tmp]
[11/5/14 0:00:05:019 CET] 0000001a SystemOut     O 00:00:05,019 |-INFO in c.q.l.core.rolling.helper.TimeBasedArchiveRemover - first clean up after appender initialization
[11/5/14 0:00:05:019 CET] 0000001a SystemOut     O 00:00:05,019 |-INFO in c.q.l.core.rolling.helper.TimeBasedArchiveRemover - periodsElapsed = 64
[11/5/14 0:00:05:019 CET] 00000092 SystemOut     O 00:00:05,019 |-INFO in ch.qos.logback.core.rolling.helper.Compressor - GZ compressing [logs/log-output-MyAppl.log14538255624893230.tmp] as [logs/log-output-MyAppl.log.2014-11-04.gz]
[11/5/14 0:00:05:019 CET] 0000001a SystemOut     O 00:00:05,019 |-INFO in c.q.l.core.rolling.helper.TimeBasedArchiveRemover - deleting logs/log-output-MyAppl.log.2014-10-04.gz
[11/5/14 0:00:30:018 CET] 0000002b SystemOut     O 00:00:30,018 |-INFO in c.q.l.core.rolling.DefaultTimeBasedFileNamingAndTriggeringPolicy - Elapsed period: Tue Nov 04 16:33:30 CET 2014
[11/5/14 0:00:30:019 CET] 0000002b SystemOut     O 00:00:30,019 |-INFO in c.q.l.co.rolling.helper.RenameUtil - Renaming file [logs/log-output-MyAppl.log] to [logs/log-output-MyAppl.log14538280639291244.tmp]
[11/5/14 0:00:30:019 CET] 0000002b SystemOut     O 00:00:30,019 |-INFO in c.q.l.core.rolling.helper.TimeBasedArchiveRemover - first clean up after appender initialization
[11/5/14 0:00:30:019 CET] 00000093 SystemOut     O 00:00:30,019 |-WARN in ch.qos.logback.core.rolling.helper.Compressor - The target compressed file named [logs/log-output-MyAppl.log.2014-11-04.gz] exist already. Aborting file compression.
[11/5/14 0:00:30:020 CET] 0000002b SystemOut     O 00:00:30,019 |-INFO in c.q.l.core.rolling.helper.TimeBasedArchiveRemover - periodsElapsed = 64
</pre>
</div></div>

<p>As you can see, logback tries to compress the log file twice. The second time it fails because the target .gz file already exists.<br/>
In my opinion, logback should remove the .tmp file by all means, also in case of compression failure.</p>

<p>The root cause of the problem (at least in our case) is that logback seems to be running twice here. We haven't tracked that down yet, our environment is sort of messed up at the moment, but I assume a JavaEE classloading problem here. Logback is encapsulated by SLF4J and both are running in a IBM WebSphere Application Server which brings its own Slf4J jar. So having not the correct classloading order configured can produce strange effects.</p>

<p>Versions used here are: Logback 1.1.2 and SLF4J 1.7.7 on IBM WebSphere Application Server 8.0.0.8</p></div>
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            </table>
        </td><!-- End #email-page -->
    </tr>
    <tr valign="top">
        <td style="color:#505050;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:10px;line-height:14px;padding: 0 16px 16px 16px;text-align:center;">
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        </td>
    </tr>
</table><!-- End #email-wrap -->
</div><!-- End #email-body -->