NLog causes memory leak

[karlovnv]

Bug

NLog version: 5.0.0-beta05
Platform: .NET Core, aspnet.core (hosted in IIS)

Current NLog config (xml or C#, if relevant)

<?xml version="1.0" encoding="utf-8"?>
<nlog autoReload="true" internalLogLevel="Error" internalLogFile="c:\logs\internal-log.txt" xmlns="http://www.nlog-project.org/schemas/NLog.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <variable name="logDirectory" value="c:/logs/xxxx" />
    <extensions>
        <add assembly="NLog.Extended" />
    </extensions>
    <targets >
        <!-- comment out buffering wrapper to solve memory leak issue partialy; 
               also async="true" has been removed -->

        <!--default-wrapper xsi:type="BufferingWrapper" bufferSize="10" FlushTimeout="1000" /-->

        <target name="fileinfo" xsi:type="File" fileName="${logDirectory}\info.log" layout="${newline}${longdate}:
${newline}${message}" archiveFileName="${logDirectory}\info{#####}.log" archiveAboveSize="1024000" archiveNumbering="Sequence" concurrentWrites="true" keepFileOpen="false" />

        <target name="fileexception" xsi:type="File" fileName="${logDirectory}\err.log" layout="${newline}${longdate}:&gt;&gt; 
${newline}MESSAGE 
${newline}${message}
${newline}${exception:format=Message,Type,Method,ToString,StackTrace:maxInnerExceptionLevel=5:innerFormat=ToString}" archiveFileName="${logDirectory}\err{#####}.log" archiveAboveSize="1024000" archiveNumbering="Sequence" concurrentWrites="true" keepFileOpen="false" />
    </targets>

    <rules>
        <logger name="*" level="Fatal" writeTo="fileexception" />

        <logger name="*" level="Error" writeTo="fileexception" />
    </rules>
</nlog>

In case of a BUG:

• What is the current result?

There are too much internal objects (such as Nlog.Common.LogEventInfoBuffer, Nlog.Layouts.*, Nlog.Internal.LoggingRule, AppDomainWrapper, and so on) in process dump, that leads to memory leak.

When async mode (async="true"), buffering and autoreload features are enabled process grows rapidly (up to 100 mb/min ).

We disabled async mode and buffering wrapper and as a result of the speed of growing was decreased.

Memory dump:

The size of all Nlog objects is about 300 MB:

• What is the expected result?
• Did you checked the Internal log?
  It is empty, but in case of internal log level=warn log is full of messages like 'unused target fileinfo'
• Please post full exception details (message, stacktrace, inner exceptions)
  No exceptions
• Are there any work arrounds? yes/no
  no
• Is there a version in which it did worked?
  version for .net worked fine
• Can you help us by writing an unit test?

I think that the issue is related to #1846, #2220, #316 and #1846

[snakefoot]

@karlovnv I think that the issue is related to #1846, #2220, #2343

Great research on finding similar issues, and I guess you have followed the advice presented in those issues:

• Upgrade to latest NLog (Ex https://www.nuget.org/packages/NLog/5.0.0-beta11 )
  • Requires all your dependencies to have been build with the same latest NLog (Because of major improvements)
• Configure the async-wrapper for optimal performance (avoid async="true" until AsyncTargetWrapper - Change default overflow action to blocking #1757), instead use timeToSleepBetweenBatches="0" and overflowAction="Block" (Ex https://github.com/NLog/NLog/wiki/Performance#file-logging-performance)
• Double-checking the file-target configuration, and setting keepFileOpen="true" (Ex https://github.com/nlog/NLog/wiki/File-target#performance-tuning-options)

And what are your results after following this advice?

[snakefoot]

Also maybe consider removing target name="fileinfo" since no logging-rule is pointing to this target.

[karlovnv]

Thank you for reply, I'll keep you informed.

[snakefoot]

@karlovnv Have your memory issues been resolved?

[304NotModified]

Closing this due to inactivity. Please let us know if this still an issue and please provide the requested info.

[karlovnv]

We downgraded to 4.x and then the issue was resolved

[304NotModified]

4.5?

[karlovnv]

Now we use 4.4.12 and 5.0.0-beta11 for full framework and .net core projects correspondingly. It seems that memory leak is disappeared.

Thank you for the instructions!

[saboorahmed]

I am using NLogv4.9.7 along with NLog.Extension.Loggingv1.7.1 and facing memory leakages.

Config file:

Memory Dump using PerfView:

[snakefoot]

@saboorahmed Please create new issue, instead of awaking old issues (Please also include steps to re-produce the problem. Maybe an issue with continous autoload of NLog LoggingConfiguration? Also there seems to a disconnect between you NLog.config and use of DatabaseParameterInfo and NLogLoggingConfiguration).