dirty mature

the xact_abort mechanism to ensure the atomicity of transactions) Lists common problems and causes in transactions: dirty reads, uncommitted reads, non-repeatable reads, Phantom reads , etc. The isolation level of transactions in SQL Server and how they do avoid dirty reads, uncommitted reads, non-repeatable reads, and Phantom reads (which describe these issues in code and use the chronological ord

The dirty word Dictionary of our website contains more than 600 words, which may change. Therefore, it is not enough to simply filter dirty words when adding/modifying data. When the website was revised from. NET 1.1 to 2.0, the new version of the test found that the old dirty word Filtering Algorithm It takes a long time and requires some optimization. The

We know that InnoDB uses the write Ahead log policy to prevent the loss of downtime data, that is, when a transaction commits, the redo log is written, and then the memory data page is modified, resulting in dirty pages. Now that you have redo logs to ensure data persistence, you can also fetch data directly from the buffer pool page when querying, why refresh the dirty pages to disk? If the redo log can gr

1. dirty read first distinguishes dirty pages from dirty data dirty pages. dirty pages are modified in the memory buffer pool. they are not flushed to the hard disk in time, but have been written to redolog. It is normal to read and modify the page of the buffer pool, which

1.redo LogIn order to ensure data security and improve system performance when the server crashes, the InnoDB storage engine first logs the contents of the submissions to the redo log, while the actual data file changes are placed in the future, batch mode brush disk. Redo logs are like logical storage sites, and it loops through multiple files. (Ib_logfile0, Ib_logfile1, Ib_logfile2)Innodb_log_file_size #各日志文件大小Innodb_log_files_in_group #日志文件的个数, InnoDB the final usable log size is innodb_log_f

We know that InnoDB uses the write Ahead log policy to prevent the loss of downtime data, that is, when a transaction commits, the redo log is written, and then the memory data page is modified, resulting in dirty pages. Now that you have redo logs to ensure data persistence, you can also fetch data directly from the buffer pool page when querying, why refresh the dirty pages to disk? If the redo log can gr

Old Algorithm It is simple to call String. Replace for every dirty word, of course, stringbuilder is used. Http://www.jb51.net/article/20575.htm. During my tests, RegEx is about twice faster. However, I am still not satisfied. I should use a lot of dirty word filtering on our website. after some thought, I made an algorithm myself. I tested it on my machine and used the

In the previous article, I spoke a little about my self-built ttmp algorithm ideas. It seems very good and powerful-it is estimated that it is not the strongest, but at least I think it is satisfactory, at least it reaches the available level. So what else can be written? I haven't written any technical articles of this type for a long time. I am full of ideas:1. What is the loss of efficiency besides the algorithm itself?2. The ttmp algorithm is just a rough description. It is far from detailed

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-repeated reads, and lost updates were a bit vague, so I re-reviewed them again, now I will summarize some of my understandings as follow

See note:https://www.zybuluo.com/sailorxiao/note/136014Case sceneThe line found a machine memory load is heavy, top found a redis process accounted for a large amount of memory, top content is as follows:27190 root 20 0 18.6g 18g 600 S 0.3 59.2 926:17.83 Discover that Redis accounts for 18.6G of physical memory. Since Redis is just used to cache some program data, it feels amazing to perform Redis's info command, found that the actual data occupy only 112M, as follows: #

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-repeated reads in some materials ).Loss of ModificationNext, let's take an example to illustrate the data inconsistency caused by concurrent operations.Consider an activity sequence

In order to relieve the stress of memory usage, there are mechanisms to trigger dirty page writeback in addition to the user manually writing back the dirty pages.Let's say set a timer and write back regularly to pages that have been dirty for a long time.The following writeback mechanism is described in detail, as this mechanism is not as passive as the mechanis

I. DATABASE TRANSACTION ISOLATION LEVELThere are 4 isolation levels for database transactions, from low to high, READ UNCOMMITTED,Read Committed,Repeatable read, andSerializable, which can be resolved individually by each of the four levels Problems such as dirty reading, non-repetition reading, and Phantom reading. √: May appear x: does not appear Dirty Read Non-REPEATABLE READ

Explanation of AngularJS dirty check mechanism and the usage of $ timeout, angularjstimeout | Browser event loop and Angular MVW "Dirty checking" is one of the core mechanisms in Angular. It is an important basis for implementing bidirectional binding and MVVM mode. Angular converts two-way binding to a bunch of watch expressions, and recursively checks whether the results of these watch expressions have ch

The different transaction isolation levels in 5 are defined in spring.1. Isolation_default (This configuration is normally used in both cases)This is a Platfromtransactionmanager default isolation level that uses the default transaction isolation level of the database.2. isolation_read_uncommittedThis is the lowest isolation level for transactions, and it allows a transaction to see uncommitted data for that transaction. This isolation level produces dirty