hbr ten must reads

Tags: style blog http color io ar java strong spTransferred from: http://blog.csdn.net/sunxing007/article/details/64272904 Features of database transactions:Atomicity (atomic): both succeed or fail;Consistency (consistency): After the transaction operation, the database is in the same state and the business rules, such as a, B account mutual transfer, the total amount of the same;Isolation (Isolation): transactions in the operation do not affect each other;Persistence (Durability): After a trans

Lost modifications, non-repeated reads, dirty reads, Phantom readsCommon concurrency consistency problems include: Lost modifications, non-repeated reads, dirty reads, and Phantom reads (Phantom reads are often classified as non-r

Dirty reads, Phantom reads, non-repeated reads, and loss of updates, lost The weather is rain on January 1, June 5, 2017. When I sorted out the previous learning notes two days ago, I found that the problems caused by transaction concurrency-dirty reads, Phantom reads, non-r

Dirty readDirty reads: This event occurs when the transaction reads data that has not been committed. For example, transaction 1 modifies a row of data, and then transaction 2 reads the modified row before transaction 1 submits the modification operation. If transaction 1 rolls back the modification operation, the data read by transaction 2 can be viewed as never

Transaction isolation issues in Hibernate (dirty reads, non-repeated reads, Phantom reads), hibernate transactionsTransaction isolation issues in Hibernate (dirty reads, non-repeated reads, Phantom reads)1. Features of transaction

The database has four isolation levels, namely:Solation_read_uncommitted: Allows reading of changed uncommitted data, which can result in dirty reads, non-repeatable reads, and Phantom reads.Isolation_read COMMITTED: Allows concurrent transactions to be read after committing, avoiding dirty reads, which can result in repeated

Database dirty reads, non-repeated reads, and Phantom reads are all related to the isolation of transactions. First, let's take a look at the four features of transactions.Four major features of transactions (ACID ): Atomicity: a transaction is the logical unit of work of the database. It either executes all the modifications to the database or does not execute

SQL SERVER Data Storage Format Before talking about several different reading methods, you must first understand the SQL SERVER data storage methods. the minimum unit of SQL SERVER storage is Page ). the size of each page is 8 KB. SQL SERVER performs atomic reading on the page. It either reads one page or does not read the page at all. There is no intermediate state. The data structure between pages is B tree (refer to my previous blog post). Therefo

In my previous blog post on SQL Server indexes, Yuan You asked about the concepts of logical read, pre-read, and physical read. I think I still write a blog post to explain this question clearly. In my previous blog post on SQL server indexes, Yuan You asked about the concepts of logical read, pre-read, and physical read. I think I still write a blog post to explain this question clearly. SQL SERVER Data Storage Format Before talking about several different reading methods, you must first und

SQL SERVER Data Storage Format Before talking about several different reading methods, you must first understand the SQL SERVER data storage methods. the minimum unit of SQL SERVER storage is Page ). the size of each page is 8 KB. SQL SERVER performs atomic reading on the page. It either reads one page or does not read the page at all. There is no intermediate state. The data structure between pages is B tree (refer to my previous blog post). Therefor

SERVER data storage methods. the minimum unit of SQL SERVER storage is Page ). the size of each page is 8 KB. SQL SERVER performs atomic reading on the page. It either reads one page or does not read the page at all. There is no intermediate state. The data structure between pages is B tree (refer to my previous blog post). Therefore, SQL SERVER uses the unit of logical read, pre-read, and physical read as pages. The total size of a single page

form of SQL Server data store Before you talk about several different ways of reading, the first thing to understand is how SQL Server data is stored. The smallest unit of SQL Server storage is pages (page). Each page size is 8k,sql server reads for pages are atomic, either after reading a page or not reading at all, There is no intermediate state. The data structure between pages is a B-tree (see my previous blog post). So SQL Server is a page

Forms of SQL Server data storage Before talking about several different ways to read, you first need to understand how SQL Server data is stored. The smallest unit of SQL Server storage is a page. Each page size is 8k,sql server is atomic to read a page, or read a page, or simply not read it, There is no middle state. The data between pages is organized into B-tree (please refer to my previous blog post). So SQL Server for logical read, prefetching, and physical reading units are pages .

Oracle physical reading and logical reading comprehension 2008-02-2809: 51: 23 persons classification: Learning View (3120) Comments (22) score (2311) 1. physicalread: when a data block is read for the first time, it is cached in buffercache. When the data block is read and modified for the second time, it is cached in the memory buffercache. The following is an example: Oracle physical read, logical read comprehension/09:51:23/personal classification: Learning View (3120)/comment (22)/score (23

Unique reads: There is only one match point on the reference groupMulti-mapping reads: There are multiple matching points on the reference groupHere is a result case for tophat:Reads: Input : 26140314 Mapped : 25159791 (96.2% of Input) of these: 10276914.1%) has multiple alignments (1832 has >)96.2% overall read mapping rate.The quantity of unique

There is a function that reads mysql resources at a time and reads all functions without loops! There is a function that reads mysql Resources nbsp; it is a function that reads all at a time nbsp; no loop is needed! I used nbsp; recorded nbsp; and was deleted later. nbsp; poor memory nbsp; I suddenly forgot to us

PHP reads dot matrix data of Chinese characters and php reads dot matrix data. PHP reads the dot matrix data of Chinese characters, and php reads the dot matrix data of Chinese characters: how does PHP read the dot matrix data of Chinese characters? To input a piece of text, you can get all the points of the text. PHP

Visual WebPart Basic Development--treeview control reads all folders and files in the document library (recursive method reads)1. Create a new document library named "Test Document Library" in the deployed SharePoint site and add subfolders and sub-files at all levels for testing2. Create a new blank SharePoint project in VS20103. Create a Visual Web PartAdd a TreeView control in Treeviewtestusercontrol.asc

When a file is open in text mode, an attempt to read lines of text by usingFscanfFunction may fail and onlyOne line of text is read from the file. The delimeter is set to "[^ \ n]".FscanfFunction reads up to but does not include the delimiting character. Therefore,The file stream stops at the First '\ n' in the file. SubsequentFscanfFunction CILS fail because the file pointer remains at the delimiting character andFscanfFunction cannotAdvance the func