nginx - Questions about server load balancing and high availability

Please answer some questions about server high availability! For example, if ngnix is ​​used as an intermediate server and the reverse proxy web server (tomcat) is used for load balancing, is this considered high availability? Then I was afraid that ngnix would hang up and I used lvs+keepalived as m...

漂亮男人 2017-06-29 10:09:13 0  2  1100

nginx high concurrency problem

nginx can support high concurrency mainly because of the network I/O model of epoll in the Linux 2.6 kernel. So I wonder, will the concurrency of nginx not work on Windows? Or on another system? So what network IO model does nginx use on Windows or other systems? Seeking heights...

怪我咯 2017-05-16 17:26:48 0  2  986

java - trade-off between sql performance and high concurrency

SELECT {code...} It is possible to simply use multi-table association. If high concurrency is encountered, performance defects will appear immediately.

PHP中文网 2017-05-17 10:09:04 0  1  620

linux - Help: php high CPU usage

Linux-deployed lnmp recently found that the server CPU usage is very high. I used strace -cp 30811 to find that one access has the most severe usage. Then I called strace -T -e access -p 30811. The result is as shown in the figure: But I can’t find it in the program. There is a place where I am look...

天蓬老师 2017-06-30 09:55:09 0  2  971

java - What are the specific business usage scenarios of high-performance classes such as ConcurrentHashMap?

Like the question, what are the specific business usage scenarios of high-performance classes like ConcurrentHashMap? Usually when we write code, we usually use HashMap the most, and we are used to it. However, there are other high-performance Maps in Java, and I feel that we don’t usually use them....

给我你的怀抱 2017-06-28 09:23:10 0  4  1229

Query causing huge CPU utilization and high latency

The following query is causing huge CPU utilization and high latency in my database environment. I tried using different types of indexes to improve query performance, but unfortunately any index did not help improve performance. Is there any suggestion to rewrite the query to get the same result. q...

P粉182218860 2024-01-10 17:21:24 0  1  459

Windows - Help with Java high-precision operation problems

The company's projects required a lot of high-precision operations. At first, we used double-type operations. Later, we found that the accuracy of some values ​​exceeded the ideal range after using double-type operations, so we used BigDecimal to calculate. The current problem is the operation effic...

typecho 2017-06-28 09:22:10 0  3  947

java - Partial thread SessionException: Session is closed! when Hibernate adds operation under high concurrency conditions.

Servlet + hibernate will cause org.hibernate.SessionException: Session is closed! in some threads under high concurrency conditions, but it will not occur under single-threaded conditions. {code...} BaseDAO.java {code...}

我想大声告诉你 2017-06-12 09:22:23 0  2  1078

javascript - How to make a high-quality picture on the front end compatible with multiple terminals

I have a high-quality picture. How can I make it compatible with multiple terminals, such as PC and mobile terminals? The mobile terminals include Android and Apple. How can I make it compatible?

淡淡烟草味 2017-05-16 13:36:58 0  3  548

May I ask what kind of high-quality screen recording software this is? Can it also be used to edit files?

May I ask what kind of high-quality screen recording software this is? Can it also be used to edit text?

Mr.lai 2020-07-20 00:18:12 0  1  1343

php - How to check the execution order of Redis commands under high concurrency?

I have a question: I use the ab tool to test the program I wrote. Redis is used in the program. I want to know in what order redis executes commands under high concurrency conditions. The picture below was posted by a netizen. It is what I want, but I don’t know where or how he got it: ...

给我你的怀抱 2017-06-20 10:06:08 0  2  1274

The employment dilemma faced by high school students who learn PHP by themselves

I only have a high school education, and as a fresh graduate I have been doing backbreaking physical labor. Later, I felt unwilling to accept it and went to a training institution to study. However, after two-thirds of the study, I couldn't persist due to financial reasons (I was really helpless at ...

..... 2018-04-28 23:55:37 5  61  8974

python - Django web project has high CPU usage. How to perform performance analysis?

First of all, I have never done performance analysis. I am a newbie. When I was maintaining the previous code, the project had a very high CPU usage, which could probably eat up the CPU. Now that the original code maintainer has resigned, it is difficult to ask people. I am helpless. Let me ask you ...

typecho 2017-06-12 09:26:40 0  2  1190

javascript - How does js handle data with low-end first and high-end last?

For example, during the interaction with the hardware device, a hexadecimal number is received from the hardware, with the low digit in front and the high digit in the back. How to elegantly parse it into the correct decimal data {code...} Currently The processing method: cut num according to length...

滿天的星座 2017-05-19 10:31:47 0  1  590

nginx - How to understand the asynchronous non-blocking high-performance web server advertised by openresty?

I understand asynchronous and synchronous, whether it is blocking or not, but I just don’t understand how openresty implements asynchronous non-blocking IO and achieves high concurrency processing capabilities? I usually write Lua interfaces, but I can see considerable QPS when doing stress tests, b...

仅有的幸福 2017-05-16 17:10:59 0  1  840

Why is the app high defense server preferred when deploying the app?

As HTML5 code matures, more and more users are building app servers. Since the app installs common materials and caches on the mobile device and then reads the content on the server, the loading speed is faster than the mobile website and the user stickiness It is also relatively powerful, so the co...

纵横数据** 2020-03-16 14:46:27 0  0  1208

The traffic between PHP+Mysql website front-end and data server is extremely high

PHP + MYsql front-end and database are separated. Now the communication traffic between the front-end and the database server is very large, and the load on the MYsql database server is too high (up to 398%). The login of front-end users is also very slow. The number of people online at the same tim...

hello 2018-10-21 20:17:20 0  3  1408

php+mysql high concurrency how to download data in a loop based on ID to avoid duplication (interface)

For example, the table content is id name1 a2 b3 c4 d. The first download id is 1. The second download id is 2. The third download id is 3. The fourth download id is 4. After the id is 4, it starts from 1 again, and it continues in an infinite loop. , must be able to support high concurrency! What I...

。。。。 2020-02-08 11:30:16 0  1  1095