[LOG4J2-1162] Memory-mapped file appender creates null-padded files.

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.4.1
• Fix Version/s: 2.5
• Component/s: Appenders

Environment

Apache Maven 3.3.3 (7994120775791599e205a5524ec3e0dfe41d4a06; 2015-04-22T04:57:37-07:00)
Maven home: C:\Java\apache-maven-3.3.3\bin\..
Java version: 1.7.0_79, vendor: Oracle Corporation
Java home: C:\Program Files\Java\jdk1.7.0_79\jre
Default locale: en_US, platform encoding: Cp1252
OS name: "windows 7", version: "6.1", arch: "amd64", family: "windows"

• Assignee: Unassigned
• Reporter: Gary D. Gregory
• Created: 15/Oct/15 22:19
• Updated: 24/Oct/15 06:44
• Resolved: 23/Oct/15 23:49

Description

Memory-mapped file appender creates null-padded files.

If configured my app like this:

<?xml version="1.0" encoding="UTF-8"?>
<!-- Copyright 2014-2015 Rocket Software, Inc. All rights reserved. -->
<Configuration status="WARN" monitorInterval="5">
  <Appenders>
    <Console name="Console" target="SYSTEM_OUT">
      <PatternLayout noConsoleNoAnsi="true"
        pattern="%style{%d}{white} %highlight{%-5level}{TRACE=white} %style{[%t][%logger]}{white} %highlight{%msg%n%throwable}{TRACE=white}" />
    </Console>
    <RollingRandomAccessFile name="RollingFile" append="false" fileName="/test/dv/logs/dv.log-OFF"
      filePattern="/test/dv/logs/$${date:yyyy-MM}/dv-%d{yyyy-MM-dd}-%i.log.gz">
      <PatternLayout>
        <Pattern>%d %-5level [%t][%logger] %msg%n%throwable</Pattern>
      </PatternLayout>
      <Policies>
        <SizeBasedTriggeringPolicy size="100 MB" />
      </Policies>
    </RollingRandomAccessFile>
    <MemoryMappedFile name="MemMapFile" append="false" fileName="/test/dv/logs/dv.log">
      <PatternLayout>
        <Pattern>%d %-5level [%t][%logger] %msg%n%throwable</Pattern>
      </PatternLayout>
    </MemoryMappedFile>
  </Appenders>
  <Loggers>
    <Root level="trace">
<!--       <AppenderRef ref="Console" /> -->
<!--       <AppenderRef ref="RollingFile" /> -->
      <AppenderRef ref="MemMapFile" />
    </Root>
    <Logger name="javax.management" level="INFO" />
    <Logger name="sun.rmi" level="INFO" />
    <Logger name="com.rs.dv.util.LoggerEnvironmentReporter" level="OFF" />
  </Loggers>
  <!-- Filters -->
  <Filters>
    <!-- SQL only -->
    <!-- <MarkerFilter marker="DV.SQL" onMatch="ACCEPT" onMismatch="DENY" /> <MarkerFilter marker="DV.SQL.QUERY" onMatch="ACCEPT" 
      onMismatch="DENY" /> <MarkerFilter marker="DV.SQL.UPDATE" onMatch="ACCEPT" onMismatch="DENY" /> -->
    <!-- No buffer hex dumps -->
    <!-- <MarkerFilter marker="DV.BUFFER" onMatch="DENY" onMismatch="NEUTRAL" /> -->
  </Filters>
</Configuration>

After the app runs, I have a 32 MB log file, with the later 2/3 of the file, all null bytes.

Clearly, we need to limit what we write out.