Unlock issues

If a process adds a lock to the table, and later the process does not unlock it normally for some reason. . So how to deal with it? For example, there is a power outage. . .

东东 2021-07-12 17:48:56 0  2  1246

Why can't the Linux file be unlocked if it is locked? ?

The files in the apache2 folder under etc are all locked. Last night, someone said that executing this command would unlock sudo chmod 777 /etc/apache2, but it still didn’t work after trying it. I am using the ubuntu16.04 version.

怪我咯 2017-06-10 09:48:58 0  1  927

linux - How to understand mutex locks and condition variables?

The following code is from "Unix/Linux Programming Practice Tutorial". Its function is to use two threads to count the number of words in two files respectively, and calculate the total number in the main thread. The following is a running screenshot: But after watching it for a long time,...

仅有的幸福 2017-06-12 09:24:46 0  1  1236

mysql optimization - mysql innodb table lock, beg the DBA expert for answers

Questions: 1. When transactions are not enabled in innodb and autocommit=1, will update and delete cause table locks? I opened two mysql sessions in the terminal, and table t has a total of 3.5 million rows of data. Execute separately: {code...} Execute at the same time, my understanding: {code...} ...

PHP中文网 2017-05-25 15:08:06 0  1  776

java - How to understand spin lock and mutex lock?

I’ve read a lot of articles online and I’m still confused. Can anyone explain these two concepts to me in an easy-to-understand way? In Python multi-thread coding, I usually use a while True infinite loop in the run method of the thread, and then call queue.task_done at the end of the loop body of t...

给我你的怀抱 2017-06-14 10:51:20 0  3  906

java - Write lock degradation problem in read-write lock

When the write lock is downgraded, the thread that has currently acquired the write lock is required to hold the write lock, then acquire the read lock, and then release the write lock. So why is it required to hold the write lock? ? In the above picture, it is mentioned that "then the current ...

大家讲道理 2017-06-12 09:24:17 0  3  1226

mysql - Why does myisAm not support row locks?

The leaf nodes of myisAm B+ tree index store row identifiers of row data, which can be located to the physical location. Is there any problem with this understanding? If there is no problem, then why does myisAm not support row locks? It should be possible to lock row identifiers, right?

某草草 2017-06-16 09:19:35 0  1  1165

Use redis to design a mechanism to mark a certain data in a locked state

The program goes to the database to read 10 data with run_status=0 every time. When a task is executed, the database updates the field run_status=-1 to indicate that the task is locked. Of course, after the task execution is completed, run_status=0, indicating that the lock has been unlocked. Now co...

迷茫 2017-06-26 10:49:39 0  1  1260

How to split paragraphs composed of multiple user information by different users in python?

Name: a002ID: ffd7eb90-3705-4248-8c21-f3d579ccc54dDisplay Name: Email: .com.cnFirst Name: a002Last Name: liDepartment: Title: Description: Account Disabled: falseAccount Unlocked At: 2017-04-24 07:...

世界只因有你 2017-05-18 10:51:32 0  4  704

MySQL: Permanent solution to "Waiting for table metadata lock" issue

My MySQL database serves three web applications as a storage backend. However, I recently encountered the error "Waiting for table metadata lock" permanently. This happens almost all the time and I don't understand why. mysql>showprocesslist->;+------+-----------+------------------+-...

P粉076987386 2023-10-18 21:53:32 0  1  764

Ways to fix issue 2003 (HY000): Unable to connect to MySQL server 'db_mysql:3306' (111)

I recently tried to containerize my FastAPIPython server (also for replication/doubling purposes). Before, I had just a MySQL server in a Docker container and everything was fine, but when I also made my web server a service, it couldn't connect to the MySQL server, so now the application doesn't wo...

P粉178132828 2023-09-05 11:18:47 0  1  851

Experiment with sorting after query limit

So this is my first question here, please forgive me if something is wrong. I'm trying to make a sort query based on constraints. So there is a Customers table with 90 records. I want to first perform a query limited to 3 records, and then sort the results of this query by a column called ContactNam...

P粉237125700 2023-09-05 14:46:42 0  1  738

CSS Grid: Create new row when child content overflows column width

I have a two column layout based on CSS grid. When the content of the second column exceeds 1fr I want to create a new row. As it currently stands, the content simply overflows the column. One requirement of this layout is that the items in the right menu column are in one row. I achieve this with: ...

P粉212114661 2023-09-05 15:18:28 0  1  631

PHP full text search functionality using AND, OR and NOT operators

Newbie question: I'm trying to implement a full text search on a search string using php and eloquent. $searchstring="+(victimsuspect)+crime-covid";$searchresult=RssItem::whereRaw("MATCH(description)AGAINST('$searchstring'INBOOLEANMODE)")->ge

P粉076987386 2023-09-05 15:06:32 0  1  601

Shortest way to convert all PHP types to string

I'm writing a general system that I hope can one day be applied to fields like medicine (i.e. it's "scientific"). I think the best way is to represent all the data in php with strings (true will be "true", false will be "false" and so on). The reason for this is that in...

P粉369196603 2023-09-05 15:34:44 0  1  1018

How to get average of DATETIME column in MySQL while grouping by other columns

I'm creating and populating a MySQL table using the following query: SETtime_zone='+00:00';CREATETABLEtimestamp_n_datetime(idINT,timeDATETIME,avg_timeDATETIME);INSERTINTOtimestamp_n_datetime(id,time,avg_time)VALUES("1","2023-01-0310:

P粉460377540 2023-09-05 11:46:21 0  1  521

Multi-device (mobile phone) synchronization - React Native

I'm trying to create a Lightshow that will launch on all users' mobile devices at the same time (can have up to 2000-3000 users). All users will use the Internet (Wi-Fi or mobile data). In our FE we use Apollo for subscriptions and it works like a charm. But the problem is, user A can get subscribed...

P粉151466081 2023-09-05 11:58:38 0  1  715

Spades, Diamonds, Hearts, Clubs => styles do not change font color in Chrome for Android

In Google Chrome on Windows, the card suit symbols (spades, hearts, diamonds, clubs) are colored correctly using the "style" attribute. Unfortunately, the same page displayed in Google Chrome on Android does not display the colors I defined but uses the default black and red. (See the atta...

P粉896751037 2023-09-05 15:25:13 0  1  768