记一次Jstack排查（jar包假死，logback死锁）


1.先查找进程的pid

jstack -l pid > jstack.log

2.排查文件

- waiting to lock <0x00000004101255e8> (a ch.qos.logback.core.util.CachingDateFormatter)

3.分析得知

logback多线程打印日志会有死锁的问题

4.解决方式

重新配置logback.xml，将ConsoleAppender注释掉，xml的内容如下

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<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <include resource="org/springframework/boot/logging/logback/defaults.xml"/>
    ?
    <springProperty scope="context" name="springAppName" source="spring.application.name"/>
    <!-- Example for logging into the build folder of your project -->
    <property name="LOG_FILE" value="logs/${springAppName}.log"/>?
    <!-- You can override this to have a custom pattern -->

    <property name="CONSOLE_LOG_PATTERN" value="%d [%X{traceId}/%X{spanId}] [%thread] %-5level %logger{36} - %msg%n"/>

    <!-- Appender to log to console -->
    <appender name="console" class="ch.qos.logback.core.ConsoleAppender">
        <filter class="ch.qos.logback.classic.filter.ThresholdFilter">
            <!-- Minimum logging level to be presented in the console logs-->
            <level>INFO</level>
        </filter>
        <encoder>
            <pattern>${CONSOLE_LOG_PATTERN}</pattern>
            <charset>utf8</charset>
        </encoder>
    </appender>

    <!-- Appender to log to file -->?
    <appender name="flatfile" class="ch.qos.logback.core.rolling.RollingFileAppender">
        <file>${LOG_FILE}</file>
        <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
            <fileNamePattern>${LOG_FILE}.%d{yyyy-MM-dd}.gz</fileNamePattern>
            <maxHistory>7</maxHistory>
        </rollingPolicy>
        <encoder>
            <pattern>${CONSOLE_LOG_PATTERN}</pattern>
            <charset>utf8</charset>
        </encoder>
    </appender>

    <!-- 异步输出 -->
    <appender name ="ASYNC" class= "ch.qos.logback.classic.AsyncAppender">
        <!-- 不丢失日志.默认的,如果队列的80%已满,则会丢弃TRACT、DEBUG、INFO级别的日志 -->
        <discardingThreshold >0</discardingThreshold>
        <!-- 更改默认的队列的深度,该值会影响性能.默认值为256 -->
        <queueSize>256</queueSize>
        <!-- 添加附加的appender,最多只能添加一个 -->
        <appender-ref ref ="flatfile"/>
    </appender>
    ?
    <root level="INFO">
<!--        <appender-ref ref="console"/>-->
<!--        <appender-ref ref="flatfile"/>-->
        <appender-ref ref="ASYNC"/>
    </root>
</configuration>