locking | 易学教程

Jenkins - java.lang.IllegalArgumentException: Last unit does not have enough valid bits & Gradle error: Task 'null' not found in root project

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问题 Jenkins 2.176.4-3 rolling Gradle 4.3.1 Issue area : Parallel run of a given single Gradle task (or it could be any simple action) and especially when running concurrent runs of Jenkinsfile based pipelines All the sudden I got this error in Jenkins log page, never seen this error before (found no stackoverflow posts either for this error in Jenkins). Error: java.lang.IllegalArgumentException: Last unit does not have enough valid bits For some reason the previous build failed and automatically

To implement graceful shutdown check locking on async calls, or handle exceptions?

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问题 I'm developing a Java app that for much of the time, including the point of shutdown, is having to deal with a flood of incoming asynchronous calls from a foreign framework. During normal operation these incoming calls then need to be dispatched to another framework, again asynchronously. At the moment I'm having my module be a "good" citizen and do some locking around a shutdown flag which, once set, will gracefully cease the dispatch of any further outgoing calls. The troubling thing is

To implement graceful shutdown check locking on async calls, or handle exceptions?

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Form has my table locked down tight even after docmd.close

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问题 Sorry for the wall of text guys but this one requires expliaining, way too much code to post... I'm importing fixed width files into access in methods that require data entry. I import the file using transferText into two specs (ones global, the other is special circumstance). I have a function that uses DAO to cycle through all Field objects in TableDefs to build a duplicate table including an AutoIncrement PK so I have the ability to edit these records. I push the data into that table with

转 How to Find Out Who Is Locking a Table in MySQL

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MySQL is adding more tools to monitor its internals with every new release, but one thing it still lacks is a way to find out who is locking what, and therefore which transactions block which other ones. This is such a vital feature that I’m considering writing my own patch to the source! Still, it is possible, to a limited extent, to find out who’s locking resources. In this article I’ll explain how you can do that. This article is the second in a series on how to use the innotop MySQL and InnoDB monitor. Introduction Here’s the situation: you are trying to update a table and every time you

Android Safe Mode Password Protection [closed]

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问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 4 days ago . I found MMGuardian a pretty App to Monitor Android devices. It includes a Feature called Safe Mode Lock (http://www.mmguardian.com/safe-mode-lock). Which protects Safe Mode booting with a Password. Has somebody a idea how it works, how I can implement a similar Feature? 回答1: I found a easy solution. The idea is

What is ROW EXCLUSIVE in PostgreSQL exactly?

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问题 I understand that PostgreSQL inserts use ROW EXCLUSIVE locks, does that mean that inserts can be in parallel, and that one insert won't lock up the entire table? Table in question has a primary key generated outside of DB and no additional indexes (but I'm curious what would happen if that wasn't the case). Edit 1: Per documentation, ROW EXCLUSIVE conflicts with SHARE which is acquired by CREATE INDEX. Does this mean that if the table has index, insert will lock up the entire table? Or will

Difference between Semaphore and Condition (ReentrantLock)

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问题 Does anyone know the differences between the methods acquire () and release () ( java.util.concurrent.Semaphore ) and await () and signal (new ReentrantLock().newCondition() ) . Can you expose a pseudo code for each of these methods? 回答1: Superficially the behavior of these method might look similar - acquire()/await() can make threads block in some cirsumstances and release()/signal() can unblock threads in some circumstances. However Semaphore and Condition serve different purposes: java

What's the difference between PESSIMISTIC_READ and PESSIMISTIC_WRITE in JPA?

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问题 I have read the article Locking and Concurrency in Java Persistence 2.0, and run the sample application. But i still cant realize the difference between PESSIMISTIC_READ and PESSIMISTIC_WRITE. I tried to modify the code, and where the code using PESSIMISTIC_READ and PESSIMISTIC_WRITE will have the same result that the sql will invoked with "for update". 回答1: The difference lies in locking mechanism. PESSIMISTIC_READ lock means that dirty reads and non-repeatable reads are impossible when you

What's the difference between PESSIMISTIC_READ and PESSIMISTIC_WRITE in JPA?

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