Table of Contents 1. Experiment purpose: use crash to solve the spinlock deadlock problem 2. Experimental steps 3. Brief description of soft lockup mechanism 4. Spinlock deadlock problem analysis 4.1. Find deadlock threads from the threads being executed by the CPU 4.2. Soft lookup mechanism determines deadlock threads 4.3. ps | grep RU to find […]
Tag: deadlock
kdump+crash solves the sleep lock (mutex) deadlock problem
Table of Contents 1. Experiment purpose: Use crash to solve the dormant lock (mutex) deadlock problem 2. Experimental steps 3. Brief description of hung task mechanism 4. Analysis of mutex deadlock problem 4.1. Confirm deadlock thread 4.1.1. Use the ps | grep UN command to determine the D state thread in the crash, and use […]
Oracle deadlock problems and solutions
Deadlock is usually a mutual waiting deadlock caused by two or more threads competing for the same resource. Let’s look at the scenario shown in the figure below: The transaction executed by thread 1 first updates resource 1, and then updates resource 2; while the transaction involved in thread 2 first updates resource 2, and […]
java deadlock (Java-level deadlock)
java-level deadlock The following code can simulate java deadlock. Note: When a deadlock occurs, the application is unresponsive. error message: Found one Java-level deadlock:=============================“Thread-1”: waiting to lock monitor 0x000000001c773158 (object 0x000000076bbc06b8, a java.util.concurrent.ConcurrentHashMap), which is held by “Thread-0”“Thread-0”: waiting to lock monitor 0x000000001c774548 (object 0x000000076bbc06f8, a java.lang.Object), which is held by “Thread-1” deadlock demo and […]
Multi-threading deadlock problem
Reentrancy and non-reentrancy If a thread locks the same object twice in a row, will there be any problem? ~~ If there is no problem, it is called reentrant. If there is a problem, it is called non-reentrant. Code sample: synchronized public void add(){<!– –> synchronized (this){<!– –> count + + ; } } Analysis: […]
Causes of deadlock and countermeasures in Java
Deadlock is a common problem in multi-threaded programming. It occurs when two or more threads are waiting for resources held by each other and cannot continue to execute. When a deadlock occurs, the program will be unable to continue executing, resulting in a waste of system resources and performance degradation. In Java, we can take […]
Database lock and batch update deadlock processing
Database lock Lock Gap lock locks a gap range but does not lock a specific record. Shared lock is a read lock, Exclusive lock is a write lock, which can be understood as read-write lock, read-read is not mutually exclusive, read-write is mutually exclusive, write-write is mutually exclusive, and shared Locks (S locks) and exclusive […]
Linux thread synchronization, mutex locks, deadlock avoidance, condition variables
1. Overview of thread synchronization Thread synchronization definition Thread synchronization refers to controlling the relative execution order between multiple threads so that data can be shared correctly and orderly between threads. The following are common usage scenarios for thread synchronization. Tasks executed by multi-threads have sequential dependencies Data shared between threads can only be used […]
Analyzing optimizer characteristics from a deadlock problem
The author uses a deadlock case combined with OPTIMIZER TRACE to analyze the index cost calculation, index selection and ICP features of MySQL 5.7. Author: Li Xichao, a database engineer at Jiangsu Suning Bank who loves to laugh, is mainly responsible for daily database operation and maintenance, automation construction, and DMP platform operation and maintenance. […]
Android deadlock and reentrancy lock
Definition of deadlock: 1. General deadlock A general deadlock means that the execution of multiple threads must have multiple resources at the same time. Since the resources required by different threads are occupied by different threads, it eventually leads to a stalemate. This is the definition of a general deadlock. package com.cxt.thread; public class TestDeadLock […]