1. Function to obtain MySQL version number, number of connections and database name
version() returns a string indicating the MySQL server version, which uses the utf8 character set.
[example] check the current MySQL version number. The SQL statement is as follows:
mysql> select version();
| version() |
Posted by galvin on Sat, 21 May 2022 07:51:54 +0300
SVD and CUR self summary
reference resources: https://www.cnblogs.com/endlesscoding/p/10033527.html https://blog.csdn.net/WangWeb1998/article/details/114376298
1. SVD (singular value decomposition)
definition: There is one
Posted by shruti on Sat, 21 May 2022 02:38:13 +0300
Spring Boot provides an excellent exception handling mechanism. The default implementation of ErrorController is good at catching and handling exceptions. In addition, you can also implement @ExceptionHandler yourself to catch and handle specific exceptions. However, there is room for improvement here:
Even if a custom @Exceptio ...
Posted by MattWeet on Fri, 20 May 2022 18:31:37 +0300
After submitting a flink task, I went to WebUi to check the offset indicator, and found that the value turned out to be a negative number (as shown below):
The definition given on the official website of this indicator is: For each partition, the offset of the last successful submission to Kafka; so this value is not normal anyway. ...
Posted by jefrat72 on Wed, 18 May 2022 15:44:05 +0300
1, Definition of SOA and DDD
SOA and DDD are common system architectures, but the core of them is different.
SOA (service-Oriented Architecture) was proposed by Gartner in 1996. It is a distributed software architecture. It can deploy, combine and use loosely coupled coarse-grained application components through the network according to requi ...
Posted by marcela1637 on Wed, 18 May 2022 13:32:18 +0300
Recently, the project needs to use Debezium to specify the binlog location to read data. When FileDatabaseHistory is configured to save offset, an unrecognized schema exception will appear.
14:52:18.237 [blc-22.214.171.124:3307] ERROR io.debezium.connector.mysql.MySqlStreamingChangeEventSource - Encountered change event ' ...
Posted by jasonscherer on Wed, 18 May 2022 01:40:00 +0300
Docker is great to use, especially when it comes to DevOps practices. However, when you pull mirrors in China or locally, you often encounter various "constipation" - either the mirror pull is slow, or the connection is intermittent, or the connection times out!
When our images are large (like someone dropped a Warcr ...
Posted by genom on Tue, 17 May 2022 13:01:00 +0300
Personal official account:
Implementation principle of Flink Client
Before we interpret the source code of Flink Client, we must first understand its implementation principle.
Main functions of Flink Client
We can see that the FLink Client mainly has three tasks. The first is to run the Application, the second is to operate and ma ...
Posted by statrat on Tue, 17 May 2022 00:17:30 +0300
Here is the second lesson in Financial Computing and Programming What I'm learning today is matplotlib - the most basic drawing library in python.
import matplotlib.pyplot as plt
import numpy as np
1. We first generate a one-dimensional y (to draw a line chart)
Just draw a picture
y = np.random.standard_normal(20)
Posted by gfmitchell on Mon, 16 May 2022 09:22:37 +0300
This is HTTP 2 0 series, the author recommends reading in the following order:
HTTP request in Go -- http1 1 request process analysis
Go launched http2 0 request process analysis (previous)
Go launched http2 0 request flow analysis (Part 2) -- data frame & flow control
In the previous article (* http2clientco ...
Posted by brandone on Mon, 16 May 2022 09:17:40 +0300