my understanding of atomicity is either not done or finished. A variable with atomic operations atomic < int > gCounter; . There are two threads that perform write operations on gCounter . If these two threads happen to perform write operations at t...
start transaction; select * from test where id = 8 for share; update test set name = grayvtouch where id = 8; select * from test where id = 8 for share; at first I thought it was a shared lock , but as a result, I did get stuck by executing the fol...
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...
in order to prevent deadlocks, I locked my program sequentially. Such as the order of oa--as-aa. But since I found that the data did not exist when I got the OA, I first new, and then lock it. The result is the new oa- lock, the oa-new as- lock, the as-...
in the following figure, while thread An executes the synchronized method of obj, thread B can execute other non-synchronized methods of obj I have read several blogs on the Internet, and most of them say yes. But as I understand it, when thread A ...
some attributes that are asynchronously assigned to the background thread during program initialization may be ready for UI before the completion of set, that is, the user can operate. If you need to get some attribute that has not yet been set in the op...
suppose that thread 1 executes wait (), thread 2 to acquire lock resources, while thread 3 starts to execute synchronized to compete for lock resources, and thread 2 uses notifyAll () to wake up thread 1 before ending, so which thread 1 or thread 3 can ...
all the spin locks I see are implemented using CAS technology, without mutexes, and are often used for lock-free programming, so spin locks should not be locks, am I right? In addition, is there any other way to implement spin lock besides using CAS? ...
After thinking about it for a long time, I really can t understand how locks are used in listing 6-9. Locks are only set with a key, and are not used at all (such as if getkey () = = true and so on). The generated locks are still random, that is, the co...
demand FooService: methodA methodB methodC An and B C are mutually exclusive, that is, they cannot operate at the same time, but B and C can operate at the same time obviously synchronized does not support it because it is mutually ex...
Table structure CREATE TABLE `table1` ( `id` int(10) unsigned NOT NULL AUTO_INCREMENT COMMENT id , `account_name` varchar(65) NOT NULL COMMENT , PRIMARY KEY (`id`), KEY `idx_an` (`account_name`,`already_login`), ) ENGINE=InnoDB AUTO_INCREMEN...
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...
A lot of code that you don t like, turn it off. ...
is CAS compare and set or compare and sweep, or are these two different things ...
problem description echarts cooperates with Amap to realize scatter plot: visual mapping components are confused after clicking related codes Please paste the code text below (do not replace the code with pictures) var series = [ { ...
php developed by Mini Program, in order to save sessionid Mini Program end like this: then what settings do you want to make on the server side? (what about $_ SERVER [ HTTP_COOKIE ]?) ...
first composer require guzzlehttp guzzle use GuzzleHttp Client; function curl_get($url) { $ch = curl_init(); curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); curl_setopt($ch, CURLOPT_URL, $url); curl_setopt($ch, CURLOPT...
js Code: var socket = new WebSocket( ws: 47.94.80.240:12345 ); socket.onopen = function (evt) { console.log("socket"); var mes = { type: 1 } socket.send(JSON.stringify(mes)); }; part of php code: publi...
Ubuntu comes with two network cards that are assigned addresses through dhcp. How to configure which card to transfer the data from the external network? I don t know the gateway ip in advance. ...