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To understand ThreadLocal, first find out what ThreadLocal is. What problems are they used to solve? ThreadLocal is a local variable of a thread, which is held by each thread separately, and cannot be accessed by other threads. It is usually a private static field in the class, which is a copy of the initial value of the field ...

1. sql_mode mode modeThere is an environment variable sql_mode in mysql database, which defines SQL grammar, data validation and so on that mysql should support. We can view the sql_mode used by the current database in the following ways: mysql> select @@sql_mode;   +----------------------------------------------------------------+   ...

background Connect with above https://my.oschina.net/tuxpy/blog/1631953 Previously, a two-way flow was implemented through grpc. All stream s exist in a sync.Map. If the pressure of chat room is high at this time, how to expand? To put it simply, how to do load balancing. Prior to https://segmentfault.com/a/1190000008672912 Having seen an artic ...

MySQL is currently released to MySQL version 8.0. In the new version, you can see that MySQL has been criticized before the optimizer part made a lot of changes. Because the author's previous working environment is 5.6, recently switched to the latest version 8.0, this article covers some of the optimizer-related parts that I am interested in, ...

1. Familiar with window structure diagram: 2. Understanding PhoneWindow, DecorView, Windows Manager, ViewRootImpl and other keywords. 2.1 PhoneWindow Every Activity has an instance of a Windows object, which is actually PhoneWindow type, so it can be seen that PhoneWindow is a subclass of Windows. Knowledge: Every Activit ...

Common application scenarios for form duplicate submission1. When the network is delayed, the user clicks the submit button several times, which leads to the delay.2. After submitting the form, the user clicks the refresh button to cause the form to be submitted repeatedly.3. After submitting the user's form, click the browser Back button to re ...

Article directory 1. Error log 2. General Query Log: 3. Slow Query Log 4. Binary Logging Three modes of 4.1 bin-log 4.2 Configuration Method 1. Error log Record errors encountered by mysql service process mysqld during start/close or run [root@mysql ~]# vi /data/3306/my.conf [mysqld_safe] log-error=/data/3306/mysql_q ...

My SQL tuning column: https://blog.csdn.net/u014427391/article/category/8679315 For local, such as a page list sql, we can use Oracle's execution plan for SQL tuning, but for the whole system, you can know which SQLs are time consuming?Of course, you can get it by checking Oracle's shared pool, but Oracle system itself provides sev ...

Catalog 1. Method arrival service 1.1 ProceRequest Method 1.2 Parent service Method 2.doDispatch method 2.1 Check Upload Request - Check Multipart Method 2.2 Find Processor-getHandler Method 2.2.1 Implementation of getHandler International Method for RequestMapping Handler Mapping 2.2.2 getHandler Execution Chain Method ...

Supplement: select * from mysql.user #Show chaos select * from mysql.user\G #Added\G The next line shows Data Type: Store different types of data in different categories The storage engine determines the type of table, and there are different types of data stored in the table. U.S. and Chinese data types have their own widths, but the ...