SELECT
*
FROM
performance_schema.threads
WHERE
PROCESSLIST_host = "10.40.96.26"
and processlist_db like '%gem_staking%'
;
SELECT
*
FROM
performance_schema.threads
WHERE
PROCESSLIST_host = "10.40.96.26"
and processlist_db like '%gem_staking%'
The query you provided is correct. It selects all the columns from the performance_schema.threads table where the PROCESSLIST_host is "10.40.96.26" and the processlist_db contains the substring "gem_staking". This query will return the threads information for connections from host "10.40.96.26" that are related to the "gem_staking" database.
这个语句是什么作用
这个SQL语句的作用是从performance_schema.threads表中检索出与主机"10.40.96.26"相关并且数据库名称中包含"gem_staking"的所有线程信息。这个查询可以用于了解在指定主机上与特定数据库相关的线程信息,有助于监控和优化数据库性能。
2024-07-16 14:29:27.070 ERROR [Curator-TreeCache-0] o.a.c.f.recipes.cache.TreeCache [GEM-STAKING-ADMIN,gem-staking-admin-6d7c6f6969-crwm4,172.24.169.229,,,]
java.lang.NullPointerException: null
at com.dangdang.ddframe.job.lite.internal.failover.FailoverListenerManager$JobCrashedJobListener.dataChanged(FailoverListenerManager.java:80)
at com.dangdang.ddframe.job.lite.internal.listener.AbstractJobListener.childEvent(AbstractJobListener.java:44)
at org.apache.curator.framework.recipes.cache.TreeCache$2.apply(TreeCache.java:741)
at org.apache.curator.framework.recipes.cache.TreeCache$2.apply(TreeCache.java:735)
at org.apache.curator.framework.listen.ListenerContainerSameThreadExecutorService.execute(MoreExecutors.java:297)
at org.apache.curator.framework.listen.ListenerContainer.forEach(ListenerContainer.java:85)
at org.apache.curator.framework.recipes.cache.TreeCache.callListeners(TreeCache.java:734)
at org.apache.curator.framework.recipes.cache.TreeCache.access$1700(TreeCache.java:71)
at org.apache.curator.framework.recipes.cache.TreeCacheRunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
根据你提供的日志信息,这段日志显示在一个Java应用程序中发生了NullPointerException
异常。以下是对日志的详细解释和可能的解决方案:
时间戳: 2024-07-16 14:29:27.070
线程: [Curator-TreeCache-0]
日志级别: ERROR
类和方法: o.a.c.f.recipes.cache.TreeCache
org.apache.curator.framework.recipes.cache.TreeCache
类中。上下文信息: [GEM-STAKING-ADMIN,gem-staking-admin-6d7c6f6969-crwm4,172.24.169.229,,,]
异常类型和信息: java.lang.NullPointerException: null
堆栈追踪:
at com.dangdang.ddframe.job.lite.internal.failover.FailoverListenerManager$JobCrashedJobListener.dataChanged(FailoverListenerManager.java:80)
FailoverListenerManager
类的dataChanged
方法的第80行。at com.dangdang.ddframe.job.lite.internal.listener.AbstractJobListener.childEvent(AbstractJobListener.java:44)
AbstractJobListener
类的childEvent
方法的第44行。检查NullPointerException的来源:
FailoverListenerManager.java
文件的第80行,看看是什么对象可能为null
。添加空值检查:
null
检查,以防止空指针异常。例如:if (someObject != null) {
someObject.someMethod();
}
调试和日志记录:
null
。查看配置和依赖:
升级库:
通过以上步骤,你应该能够更好地理解和解决这个NullPointerException
问题。
//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by FernFlower decompiler)
//
package com.dangdang.ddframe.job.lite.internal.failover;
import com.dangdang.ddframe.job.lite.config.LiteJobConfiguration;
import com.dangdang.ddframe.job.lite.internal.config.ConfigurationNode;
import com.dangdang.ddframe.job.lite.internal.config.ConfigurationService;
import com.dangdang.ddframe.job.lite.internal.config.LiteJobConfigurationGsonFactory;
import com.dangdang.ddframe.job.lite.internal.instance.InstanceNode;
import com.dangdang.ddframe.job.lite.internal.listener.AbstractJobListener;
import com.dangdang.ddframe.job.lite.internal.listener.AbstractListenerManager;
import com.dangdang.ddframe.job.lite.internal.schedule.JobRegistry;
import com.dangdang.ddframe.job.lite.internal.sharding.ShardingService;
import com.dangdang.ddframe.job.reg.base.CoordinatorRegistryCenter;
import java.util.Iterator;
import java.util.List;
import org.apache.curator.framework.recipes.cache.TreeCacheEvent;
import org.apache.curator.framework.recipes.cache.TreeCacheEvent.Type;
public final class FailoverListenerManager extends AbstractListenerManager {
private final String jobName;
private final ConfigurationService configService;
private final ShardingService shardingService;
private final FailoverService failoverService;
private final ConfigurationNode configNode;
private final InstanceNode instanceNode;
public FailoverListenerManager(CoordinatorRegistryCenter regCenter, String jobName) {
super(regCenter, jobName);
this.jobName = jobName;
this.configService = new ConfigurationService(regCenter, jobName);
this.shardingService = new ShardingService(regCenter, jobName);
this.failoverService = new FailoverService(regCenter, jobName);
this.configNode = new ConfigurationNode(jobName);
this.instanceNode = new InstanceNode(jobName);
}
public void start() {
this.addDataListener(new JobCrashedJobListener());
this.addDataListener(new FailoverSettingsChangedJobListener());
}
private boolean isFailoverEnabled() {
LiteJobConfiguration jobConfig = this.configService.load(true);
return null != jobConfig && jobConfig.isFailover();
}
class FailoverSettingsChangedJobListener extends AbstractJobListener {
FailoverSettingsChangedJobListener() {
}
protected void dataChanged(String path, TreeCacheEvent.Type eventType, String data) {
if (FailoverListenerManager.this.configNode.isConfigPath(path) && Type.NODE_UPDATED == eventType && !LiteJobConfigurationGsonFactory.fromJson(data).isFailover()) {
FailoverListenerManager.this.failoverService.removeFailoverInfo();
}
}
}
class JobCrashedJobListener extends AbstractJobListener {
JobCrashedJobListener() {
}
protected void dataChanged(String path, TreeCacheEvent.Type eventType, String data) {
if (FailoverListenerManager.this.isFailoverEnabled() && Type.NODE_REMOVED == eventType && FailoverListenerManager.this.instanceNode.isInstancePath(path)) {
String jobInstanceId = path.substring(FailoverListenerManager.this.instanceNode.getInstanceFullPath().length() + 1);
if (jobInstanceId.equals(JobRegistry.getInstance().getJobInstance(FailoverListenerManager.this.jobName).getJobInstanceId())) {
return;
}
List<Integer> failoverItems = FailoverListenerManager.this.failoverService.getFailoverItems(jobInstanceId);
Iterator i$;
int each;
if (!failoverItems.isEmpty()) {
i$ = failoverItems.iterator();
while(i$.hasNext()) {
each = (Integer)i$.next();
FailoverListenerManager.this.failoverService.setCrashedFailoverFlag(each);
FailoverListenerManager.this.failoverService.failoverIfNecessary();
}
} else {
i$ = FailoverListenerManager.this.shardingService.getShardingItems(jobInstanceId).iterator();
while(i$.hasNext()) {
each = (Integer)i$.next();
FailoverListenerManager.this.failoverService.setCrashedFailoverFlag(each);
FailoverListenerManager.this.failoverService.failoverIfNecessary();
}
}
}
}
}
}
从你提供的代码中可以看出,NullPointerException
异常是发生在FailoverListenerManager
类的JobCrashedJobListener
内部类的dataChanged
方法中。以下是详细分析和可能的解决方案。
JobCrashedJobListener
类的dataChanged
方法class JobCrashedJobListener extends AbstractJobListener {
JobCrashedJobListener() {
}
protected void dataChanged(String path, TreeCacheEvent.Type eventType, String data) {
if (FailoverListenerManager.this.isFailoverEnabled() && Type.NODE_REMOVED == eventType && FailoverListenerManager.this.instanceNode.isInstancePath(path)) {
String jobInstanceId = path.substring(FailoverListenerManager.this.instanceNode.getInstanceFullPath().length() + 1);
if (jobInstanceId.equals(JobRegistry.getInstance().getJobInstance(FailoverListenerManager.this.jobName).getJobInstanceId())) {
return;
}
List<Integer> failoverItems = FailoverListenerManager.this.failoverService.getFailoverItems(jobInstanceId);
Iterator i$;
int each;
if (!failoverItems.isEmpty()) {
i$ = failoverItems.iterator();
while(i$.hasNext()) {
each = (Integer)i$.next();
FailoverListenerManager.this.failoverService.setCrashedFailoverFlag(each);
FailoverListenerManager.this.failoverService.failoverIfNecessary();
}
} else {
i$ = FailoverListenerManager.this.shardingService.getShardingItems(jobInstanceId).iterator();
while(i$.hasNext()) {
each = (Integer)i$.next();
FailoverListenerManager.this.failoverService.setCrashedFailoverFlag(each);
FailoverListenerManager.this.failoverService.failoverIfNecessary();
}
}
}
}
}
NullPointerException
来源FailoverListenerManager.this.isFailoverEnabled()
:
this.configService.load(true)
可能返回 null
,导致 jobConfig.isFailover()
抛出 NullPointerException
。FailoverListenerManager.this.instanceNode.getInstanceFullPath()
:
getInstanceFullPath()
返回 null
,那么 path.substring
会抛出 NullPointerException
。JobRegistry.getInstance().getJobInstance(FailoverListenerManager.this.jobName)
:
getJobInstance
返回 null
,则后续的 getJobInstanceId()
会抛出 NullPointerException
。FailoverListenerManager.this.failoverService.getFailoverItems(jobInstanceId)
:
getFailoverItems
返回 null
,那么 failoverItems.isEmpty()
会抛出 NullPointerException
。FailoverListenerManager.this.shardingService.getShardingItems(jobInstanceId)
:
getShardingItems
返回 null
,那么 FailoverListenerManager.this.shardingService.getShardingItems(jobInstanceId).iterator()
会抛出 NullPointerException
。添加空值检查:
protected void dataChanged(String path, TreeCacheEvent.Type eventType, String data) {
if (FailoverListenerManager.this.isFailoverEnabled() && Type.NODE_REMOVED == eventType && FailoverListenerManager.this.instanceNode.isInstancePath(path)) {
String instanceFullPath = FailoverListenerManager.this.instanceNode.getInstanceFullPath();
if (instanceFullPath == null) {
// Log and handle the null case
return;
}
String jobInstanceId = path.substring(instanceFullPath.length() + 1);
JobInstance jobInstance = JobRegistry.getInstance().getJobInstance(FailoverListenerManager.this.jobName);
if (jobInstance == null || jobInstanceId.equals(jobInstance.getJobInstanceId())) {
// Log and handle the null case
return;
}
List<Integer> failoverItems = FailoverListenerManager.this.failoverService.getFailoverItems(jobInstanceId);
if (failoverItems != null && !failoverItems.isEmpty()) {
for (Integer each : failoverItems) {
FailoverListenerManager.this.failoverService.setCrashedFailoverFlag(each);
FailoverListenerManager.this.failoverService.failoverIfNecessary();
}
} else {
List<Integer> shardingItems = FailoverListenerManager.this.shardingService.getShardingItems(jobInstanceId);
if (shardingItems != null) {
for (Integer each : shardingItems) {
FailoverListenerManager.this.failoverService.setCrashedFailoverFlag(each);
FailoverListenerManager.this.failoverService.failoverIfNecessary();
}
}
}
}
}
日志记录:
null
的地方添加日志记录,方便调试和定位问题。确保对象初始化:
通过这些措施,你应该能够解决NullPointerException
的问题,并提高代码的健壮性。