isolation | 易学教程

Deadlock on SELECT/UPDATE

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问题 I'm having a problem with deadlock on SELECT/UPDATE on SQL Server 2008. I read answers from this thread: SQL Server deadlocks between select/update or multiple selects but I still don't understand why I get deadlock. I have recreated the situation in the following testcase. I have a table: CREATE TABLE [dbo].[SessionTest]( [SessionId] UNIQUEIDENTIFIER ROWGUIDCOL NOT NULL, [ExpirationTime] DATETIME NOT NULL, CONSTRAINT [PK_SessionTest] PRIMARY KEY CLUSTERED ( [SessionId] ASC ) WITH ( PAD_INDEX

Deadlock on SELECT/UPDATE

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Spring @Transactional - isolation, propagation

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问题 Can someone explain what isolation & propagation parameters are for in the @Transactional annotation via real-world example? Basically when and why I should choose to change their default values. 回答1: Good question, although not a trivial one to answer. Propagation Defines how transactions relate to each other. Common options: Required : Code will always run in a transaction. Creates a new transaction or reuses one if available. Requires_new : Code will always run in a new transaction.

How do I specify the database isolation level to be used, at a high level?

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问题 I am using TransactionScope s at a high level to wrap some high level code that makes a number of connections to the database. One of the functions I call is a generic read that is used for read only functions where a read uncommitted isolation level is needed. But in some cases it is used as part of large update operation and a read committed would be more suitable. At the highest level where I am calling my functions inside a transaction scope, should I be able to set the Isolation Level

MySQL transactions and concurrent inserts

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问题 I've got this script made by someone and I looked over it and found something I'm not sure is safe: Inside a transaction there are 2 consecutive inserts, in 2 different tables, both with auto incremented primary keys. They are supposed to be the same (the primary key generated from the first insert = the primary key generated from the second insert). Don't ask me why, it's just how the script was made. I'm new to transactions and I can't quite figure out if there is a concurrency issue here.

Docker : find sendmail in other container

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问题 I'm learning how to use Docker with multiple containers, as opposed to a single one. I'd like to learn how to call, from container A, a program located on container B. (i.e.: I want to be able to call sendmail from my web container, while sendmail and similar programs are located on a mailhog container.) I have this: docker-compose.yml web: container_name: centosweb image: fab/centosweb ports: - "80:80" volumes: # Single files - ./config/httpd.conf:/etc/httpd/conf/httpd.conf # Directories - .

Typemock vs Moq [closed]

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问题 As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance. Closed 7 years ago . I have heard/read a little about both of these frameworks and have decided I want to use of of the two. Which is better? Why? Thanks

What's the recommended way to run plugins with dependency dll's that have different version?

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问题 I have a WCF plugin service that loads plugins via MEF and runs them. Each plugin is a directory with multiple dll's that implements a specific interface. I load all the plugins in the same AppDomain using MEF ( DirectoryCatalog ) and run them in a generic way (using reflection). Now lets assume I have two plugins with dll dependencies: Plugin1 ----> Entities 1.0.0.1 Plugin2 ----> Entities 1.0.0.2 I've added some new entities in 1.0.0.2. When I run the plugin's I get a sporadic error that the

Isolation in PHP?

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Here's something I've thought about for a while. I am creating an application where's my users will upload their own custom themes, which means that there's going to be a good opportunity for anyone with basic PHP/XSS/whatever skills to cause a lot of headache. I would like to run any uploaded files in a sort-of sandboxed, closed environment that only has access to the stuff (variables) that I want and nothing else. Would this be good practice and how would it be done? rook To allow arbitrary html/javascript safely then each user must have its own subdomain. If each user has their own

Does Linux support memory isolation for processes?

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In more detail, the question is: without root permission , is it possible for a process to read (not only write) the memory of another process? (eg. by somehow reading /proc/gcore or /proc/[PID]/mem. I'm not sure their permission requirements yet.) I do understand that virtual address is implemented and each process has its own space. I did a quick search but find neither strong guarantees nor approaches to hack. This article says: Each process in the system has its own virtual address space. These virtual address spaces are completely separate from each other and so a process running one