On the problem of concurrency

php backend needs to insert records into the mysql database table. The id of this table is primary key but not self-growing, which needs to be calculated by some rules. For example, if you first check that there are N records created that day, then set the id to xxxN+1. this time. If there is a large number of visits, multiple requests may get the same number of records first, so it is possible to generate the same id, and insert it into the database, then an error will be reported. How should we deal with this situation?

Mysql php

Mar.03,2021

1, if the business requirements are very consistent, add locks, or thread blocking to ensure the strong consistency of the array
2, use non-relational databases such as redis or mongodb or mecache
3, use queues

the first way: change the rules of the primary key to self-increment or other random algorithms to generate this simpler form.
the second way: to maintain the generation and use of primary keys separately, you can generate a certain number of primary keys in advance in accordance with the original rules, get a primary key from it every time you insert a record, and then destroy it, but you need to pay attention to the appropriate time to supplement the primary key. In fact, this is to establish a dynamic data pool.

Redis's incr can solve

locking the database is not a good way, which may cause the commit to fail when concurrency.
it is recommended that you modify the database schema and change the current primary key to the unique index.

it is suggested that id do the reserved field. As you said, the rule is to make the date as a field and the record number of the day as a field to establish a joint unique index

redis to count the number of records for the day. If the concurrency is large, you can consider queue consumption

Previous: Query Application of knowledge Graph constructed by django

Next: Wechat scanned the PC to pay, and after scanning, it showed that the cashier was a dedicated SDK account.

The optimization problem of group by sentence in mysql and how to find the train of thought
I want to optimize a sentence about group by. I don t know where to start. I want to find a train of thought . SELECT adv_id, network_id, SUM(re_click) AS clk, SUM(deny_click) AS dny_clk, SUM(re_conver) AS re_ins, SUM(mat_conver) AS mat_ins, SUM(def_...

Mysql php

Feb.27,2021
Please help me convert this native SQL statement into TP5 thank you!
ask God to help me translate this native SQL statement into TP5 thank you! It is Db:: ( name )-> this kind of chained operation select a.id, a.titlerect a. Createwriting time as answer_count from fa_question a. Isometric solvepaper count (b.qid) as ...

Thinkphp5 mysql php

Feb.28,2021
Request interface Times wrong The API configuration file does not exist.
I have a vegetable chicken at the front end. Recently, there is a new demand for the company s project, which has been maintained by others before. the front end uses a framework built by pHp and uses the memcached plug-in. After the project runs, ,...

Front-end apache mysql php

Feb.28,2021
There is a problem of read repetition in LOCK TABLES auto_table WRITE;.
The basic logic of the program is as follows: execute "LOCK TABLES auto_table WRITE "; then "select ID from auto_table; then update ID+1 " UPDATE auto_table set ID=ID+1 "; finally execute " UNLOCK TABLES " but this logic occurs when two users r...

Mysql php

Feb.28,2021
The mysql stored procedure is called in PHP, and the rest of the code is executed, but the stored procedure is not executed.
php calls the stored procedure, and there is other execution code before and after the stored procedure, in the same transaction, but the code before and after the stored procedure is executed, but the code in the stored procedure is not executed. What i...

Mysql php

Feb.28,2021
Php queries all the data in table an of the mysql database, and then looks up the table B that belongs to table A with the most data.
this is a function of asking and answering questions questions asked by users in Table A questions answered by users in Table B Table An is the only question corresponding to ID, Table B PID corresponds to Table An ID users answer which question PI...

Mysql php

Feb.28,2021
Php memory problem
the code is as follows $num = M ( log )-> where ( "date_format (create_time, %Y-%m ) = $date ")-> count ( id ); for($i = 0; ($i+5000)<=20000;$i += 5000){ $datas = M( credit_log )->where("date_format(create_time, %...

Mysql php

Feb.28,2021
How to change the key name to a field comment when tp5 acquires data
for example: I have a table T1 in which there is a comment named name name field select name from T1 that gets array (). [0]=array( name => 123 ), [1]=array( name => 236 ) ) how to change the above name to name ...

Mysql php

Mar.01,2021
The browser reported an error Access denied for user 'root'@'localhost' (using password:NO
browser error: SQLSTATE [HY000] [1045] Access denied for user root @ localhost (using password: NO) I successfully connected to the database with navicat, the user name is root, password is the password set when installing mysql, and the framework...

Thinkphp thinkphp5 mysql php

Mar.01,2021
How to record likes and display likes and nos in youtube?
how do you design database fields like youtube pages that show whether you have pressed like or dislike? And go to the database to judge when the user arrives at the page? whether the design idea is like this Post table id picroute likeusers dislik...

Database laravel mysql php

Mar.02,2021
About the execution of load_file () as NULL? in mysql
when learning the knowledge of mysql penetration, the attempt to read the file on disk D with sql statement failed as follows: root@host after testing, the value of secure-file-priv is not valid even if it is empty. mysql,apache is running normal...

Windows apache mysql php

Mar.02,2021
Mysql inserts the following values. Why do you prompt for duplicate inserts?
backend PHP sends the submitted data to Filter submit data: "> < script > alert ( 1 ) < script > Filter (equivalent to conversion via htmlspecialchars): "> < script > alert ( 1 ) < script > name varchar (255) description text prom...

Mysql php

Mar.02,2021
How does PHP remove quotation marks on both sides of the array and return the array
as shown in the figure, how to get to the quotation marks on both sides of the queue and return the data in array format ...

Mysql php

Mar.02,2021
After the order exceeds a certain time, the user does not confirm the receipt of the goods, which requires the system to automatically complete the confirmation operation, that is, to change the status of the order. Do you have any good ideas?
after the order exceeds a certain time, the user does not confirm the receipt, so the system needs to automatically complete the confirmation operation, that is, to change the status of the order. Do you have any good ideas? I have seen before that so...

Redis mysql php

Mar.03,2021
Unlimited distribution, top-to-bottom settlement of distribution commission
< H2 > hierarchical relationship table (processed using baum) < H2 > when the distributor buys, the performance automatically adds up to all his superiors monthly performance the settlement method determines whether the minimum settlement ra...

Mysql php Distribution

Mar.04,2021
How to access the php file of the Wampserver server deployed by Aliyun through ip?
it is necessary to build a php integrated development environment on this machine. Whether it can be deployed in the cloud can be found directly through the public network ip! ...

Mysql php

Mar.04,2021
Mysql query statement
A a_id a_title a_key a_desc a_pid 1 A A A 1 B b_id b_title b_key b_desc b_pid 1 b 2 C c_id c_title c_key c_desc c_pid 1 $title= Ctitile || ...

Sql mysql php

Mar.04,2021
How does php store session in a database?
SessionHandler.php the contents of the file are as follows <?php namespace Dry Base; class SessionHandler{ private $pdo = null; private $lifeTime = 1440; public function __construct($pdo) { $this->pdo = $pdo; ...

Session mysql php

Mar.04,2021
Php uses curl, and the counterpart is also php. How can I get it?
I wrote an api hypothesis called sql.php myself. I am in another sql-test.php $data = array( "errno" => 1 , "errstr" => 2 , "errfile" => 3 , "errline" => 4 ); $data_string = js...

Mariadb curl mysql php7 php

Mar.04,2021
Can the counterparty access my database through php curl?
want to check the hypothesis. I want the counterparty to access my database via php curl what can I do this? Is there a template you can refer to? this is due to the fact that the host is in parallel with mysql and all the mysql data are managed cent...

Mariadb mysqli mysql php7 php

Mar.04,2021