• Type of MySQL lock


    Lock based attribute classification: shared lock and exclusive lock.Lock based granularity classification: row level lock (InnoDB), table level lock (InnoDB, MyISAM), page level lock (BDB engine), record lock and inter lockGap lock, temporary key lock.Lock based state classification: intentional shared lock and intentional exclusive lock. Share lock Shared lock, also known as read lock, is […]

  • InnoDB of MySQL lock


    It’s easy to feel it on paper, but you have to practice it. InnoDB row lock High cost and slow locking; There will be deadlock; Lock granularity is the smallest, the probability of lock conflict is the lowest, and the concurrency is the highest. InnoDB implements the following two types of row locks. Shared lock […]

  • You can use it: redisson distributed read-write lock component, with webfilter to release your hands


    scene Previously on: https://segmentfault.com/a/11… In order to solve the problem of transaction visibility caused by Max (ID), the gap lock is used initially, but the gap lock locks the table, which has a great impact on concurrency, so we consider using distributed read-write lock with finer granularity. Read write lock Read write lock principle, read […]

  • InnoDB lock mechanism — checking a slow insert query


    In the slow query log, an insert statement is issued, and the probability of slow query is relatively high. A simple insert takes 4-10s, which is very unusual. Insert statement is attached and some fields are omitted INSERT INTO `fc_pay_out_trade_log` (`out_trade_no`,`dateline`) VALUES (‘191120093724940457’,1574185044) [ RunTime:4.176669s ] fc_ pay_ out_ trade_ Log table except primary key, […]

  • Layout of cascade flow in CSS


    1、 Effect picture 2、 Code <!DOCTYPE html> <html> <head> <style> /* https://www.cnblogs.com/bbc66/p/9434217.html */ html,body{ padding: 0;margin: 0; } .box { padding: 10px; /* display: flex; flex-flow:column wrap; */ /* height: 100vh; */ column-count:2; /*Specify column width*/ /* column-width:500px; */ /*Specifies the spacing between columns*/ column-gap: 10px; /*Specifies the style of column to column gap*/ /*column-rule:2px […]

  • Lock and lock mechanism of MySQL


    According to the scope of locking, the locks in MySQL can be roughly divided into three categories: Global locks, table level locks and row locks. Global lock Global lock refers to locking the entire database instance. MySQL provides flush table with read lock to lock the entire database instance. After this command is executed, the […]

  • Table and table layout


    15 years ago, it was very popular. Why was table eliminated Poor performance Not good for SEO The entire table will not be displayed until it is loaded Composition of table elements characteristic:dispaly:table The default is the block element, and the wrapping property (content unfolding width)display:inline-table Inner block element, outer inner element Components of table […]

  • MySQL transaction and lock


    MySQL transaction Why the transaction exists The purpose of transaction existence is to ensure that the user is safe for data operation. (for example, bank card balance) The characteristic of transaction — acid Atomicity: a transaction is either fully executed or not executed Consistency: data is consistent at the beginning and end of a transaction […]

  • Understanding the row level lock of MySQL


    1、 Definition One row of data is locked each time, and the locking mechanism is row level locking. Row level locking is not implemented by MySQL itself, but by other storage engines 2、 Advantages and disadvantages advantage Because of small lock granularity, low contention rate and high concurrency. shortcoming The implementation is complex and expensive. […]

  • Quickly solve the problem of white gap when CSS uses @ keyframes to load pictures for the first time (flash screen)


    Problem explanation: When using the animations attribute of CSS, there will be a white gap in the first loading cycle. It looks like the page has a refresh feeling. This problem will not occur again in each subsequent cycle Question presentation   //html <div class=”container”> <div class=”first”> </div> </div> //less .container { width: 100vw; height: […]

  • A method to solve the problem of gap between elements in front-end development


    Preface Generally, when we write styles, there will be a gap between the parent and child elements when there is no special style added, which often occurs when the height attribute of the two elements uses the singular. If it is a mobile terminal, due to the diversity of devices, it is uncertain where the […]