【Python】分析JVM的GC日志

在项目启动命令中增加JVM参数

nohup /usr/local/jdk1.8.0_361/bin/java -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+PrintGCDateStamps -XX:+PrintHeapAtGC -Xloggc:/usr/local/logs/gc.log  -jar /opt/test.jar --spring.profiles.active=prod  > /dev/null 2>&1 &
说明：
-XX:+PrintGCDetails  					打印GC的详细信息
-XX:+PrintGCTimeStamps 					打印进程启动到现在经历的时间 启用配置：
-XX:+PrintGCDateStamps					打印GC当时的时间 启用配置：
-XX:+PrintGCApplicationStoppedTime 		打印GC时，应用停顿时间 启用配置：
-XX:+PrintHeapAtGC    					每次GC前后打印堆信息启用配置：
-Xloggc:/usr/local/logs/gc.log			GC日志输出路径 启用配置：

gc.log样例

2025-01-06T17:48:27.813+0800: 1.280: [Full GC (Metadata GC Threshold) [PSYoungGen: 5093K->0K(132096K)] [ParOldGen: 2137K->6947K(51712K)] 7231K->6947K(183808K), [Metaspace: 20369K->20369K(1067008K)], 0.0365654 secs] [Times: user=0.08 sys=0.00, real=0.04 secs] 

2025-01-06T17:48:28.082+0800: 1.548: [GC (Allocation Failure) [PSYoungGen: 126976K->1728K(203776K)] 133923K->8683K(255488K), 0.0045147 secs] [Times: user=0.01 sys=0.00, real=0.00 secs] 
 

python处理日志

import re
from datetime import datetime

def parse_gc_log(log_file):
    gc_logs = []
    with open(log_file, 'r') as file:
        for line in file:
            match = re.match(r'(\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.\d{3}\+\d{4}): (\d+\.\d+): \[(GC|Full GC) \((.*?)\) \[(.*?): (\d+)K->(\d+)K\((\d+)K\)\] (\d+)K->(\d+)K\((\d+)K\),(.*?) (\d+\.\d+) secs\](.*?)\[Times: user=(\d+\.\d+) sys=(\d+\.\d+), real=(\d+\.\d+) secs\]', line)
            if match:
                gc_start_time = datetime.strptime(match.group(1), '%Y-%m-%dT%H:%M:%S.%f%z')
                gc = match.group(3)
                gc_type = match.group(4)
                gc_pause_time = match.group(13)
                gc_logs.append({
                    'gc_start_time': gc_start_time,
                    'gc': gc,
                    'gc_type': gc_type,
                    'gc_pause_time': gc_pause_time
                })
    return gc_logs

def main():
    log_file = "D:\\temp\\gc.log"
    gc_logs = parse_gc_log(log_file)
    
    # for log in gc_logs:
        # print(f"GC Start Time: {log['gc_start_time']},GC : {log['gc']}, GC Type: {log['gc_type']}, GC Pause Time: {log['gc_pause_time']} secs")
    with open('D:\\temp\\gc.txt', 'w') as file:
        for log in gc_logs:
            file.write(f"GC Start Time: {log['gc_start_time']},GC : {log['gc']}, GC Type: {log['gc_type']}, GC Pause Time: {log['gc_pause_time']} secs\n")



if __name__ == "__main__":
    main()

输出样例

GC Start Time: 2025-01-06 17:48:27.813000+08:00,GC : Full GC, GC Type: Metadata GC Threshold, GC Pause Time: 0.0365654 secs
GC Start Time: 2025-01-06 17:48:28.082000+08:00,GC : GC, GC Type: Allocation Failure, GC Pause Time: 0.0045147 secs