Sorry, there is a mistake in the question. An explanation has been made in the answer the scenario is that there is a script task, that starts multiple processes these processes operate on multiple tables at the same time (only insert, for these t...
under the premise that the created_at column is indexed. the data volume of the table is tens of millions of levels. explain shows that the number of rows scanned is 2 million select count (*) from users where created_at < 2018-08-28 0000lv 00l...
I recently did a raffle everyone can only draw once I want to insert a record for each lucky draw request, and then read the first record for comparison to determine whether he is drawing the lottery for the first time, delete the useless record if n...
Note that our current isolation level is read uncommitted, that is, the lowest isolation level. Dirty reading occurs at this level, and A transaction modifies a row of data, but in the case of uncommitted, this row of data is read by a behavior other th...
What is the automatic locking strategy for InnoDB and Myisam in RT,MySQL, respectively? When do we need to explicitly add read-write locks? ...
what is the locking mechanism of mysql transaction serialization isolation level Open transactions in both An and B clients, if 1 if A transaction deletes a record (), B transaction cannot read deleted and uncommitted transactions in A transaction not...
as shown in the question, is there only data or indexes on the hard disk and in a data page in innodb_pool_buffer? is it impossible for a data page to have both data and indexes? ...
such as the title. see that MySQL generates a tree for the primary key, and the leaf node holds the row data corresponding to the primary key. The secondary index leaf node holds the value of the primary key. excuse me: does the leaf node of th...
I use only one primary key on the innodb, table and a clustered index (the default is a clustered index). In my query statement, the where condition is this primary key, but the query column is arbitrary. I found that the extra of the execution plan is ...
there are several kinds of solid circle symbols: this is 25cf this is 2022 the following is the solid circle of the authentic list-style-type: disc list items list items list items it can be seen that its size is between 25cf and 2022. Wh...
searched the use of php iterator on the Internet for a day, several books are copy and paste, I hope php can answer, it is best to give the use of the scene, thank you very much! ...
problem description use the vue-awesome-swiper page to report Maximum call stack size exceeded main.js Home.vue Swiper.vue package.json Maximum call stack size exceeded I hope you bosses can help ...
problem description Node script filters and deletes redundant CSS files in WeChat Mini Programs s project wrote a script himself, but the dynamically bound class cannot accurately get ...
watchmixinswatchloadingaxioshttploading 1. Can you go to this.store.actions ( getList ) as soon as you enter through the vuex, page? I tried to write const actions = { getGradeList ({commit}) {. this.$request(this.$api.home_list).then(res => { ...