• JVM — memory leak and memory overflow


    Series articles: JVM — memory leak and memory overflow JVM — garbage collector and memory allocation 1. Memory overflow 1.1 what is Java’s memory overflow? In the process of running Java programs, we often encounter the following errors:java.lang.OutOfMemoryError。Generally speaking,Memory overflow refers to the outofmemoryerror when a program does not have enough memory space for it […]

  • Capacity understanding and example explanation of coroutine channel in droole


    First go to the official websitehttps://wiki.swoole.com/#/coroutine/channel。 About channel: channel, used for communication between coroutines, supporting multi producer and multi consumer collaborations. The lower layer automatically realizes the switch and scheduling of coprocess. Its construction method: swote / coroutine / Channel – >__ Construct (int $capacity = 1) has a capacity parameter. At first, I didn’t […]

  • What is SRE? A detailed explanation of SRE operation and maintenance system


    Observability system In any enterprise with a certain scale, once the operation and maintenance mode of SRE is implemented, the construction of observability system will become particularly important. In the whole observability system, we usually divide it into the following three aspects: Indicator monitoring: various indicators monitoring, such as basic resource indicators, service performance indicators, […]

  • Getting started with Amazon dynamodb 6: query and scan


    In the last section, we introduced the creation and management of dynamodb indexes. In this section, we will introduce the use of query and scan. Query SQL can use select statements to query key, non critical, or any combination. The where clause determines the rows returned. Dynamodb query operations provide fast and efficient access to […]

  • Record some problems of normal development (2)


    1. In order to improve the user experience, click the text next to the radio box circle to select the click box The first way: <label for=”radiobutton”> < input type = “radio” name = “RadioButton” id = RadioButton “value =” RadioButton “/ > test? </label> The second way: <div> <input type=”radio” id=”modeltype5″ name=”” v-model=”” value=”” […]

  • How to estimate capacity


    With the growth of business, the daily traffic increases from 10W level to 100W level. At this time, capacity estimation is required. What kind of scenario needs capacity estimation? Qualitative growth of capacity Temporary operation activities New system launched Scene 1: When PM was going to do the double 11 event, the technical boss came […]

  • Getting started with Amazon dynamodb 8: deleting projects


    The last article introduced the dynamodb update, this one will introduce the project deletion operation and dynamoab py Delete data from table In SQL, the delete statement removes one or more rows from the table.Dynamodb uses the delete item operation to delete items one at a time. SQL In SQL, you can use the delete […]

  • Go language slice detailed explanation (combined with source code)


    1、 Definition of slice in go language Slice is a structure type, which is defined in the source code as: src/runtime/slice.go type slice struct { array unsafe.Pointer len int cap int } As can be seen from the definition, slice is a value type with three elements. Array is an array pointer, which points to […]

  • 1. Learn the data structure array in PHP


    Note: the code uses the automatic loading of composer class, and adopts the psr4 naming standard. If it is not used, the definition of namespace can be required 1. Implementation logic <?php /** *Content: implementation of array * create: 2020-10-20 */ namespace ArrayBundle; class BaseArray { /** *Array current length * @var int */ protected […]

  • Detailed explanation of the source code principle of redis (13) HashMap


    Why learn HashMap source code? As a java developer, basically the most commonly used data structures are HashMap and list. The HashMap design of JDK is worth learning. Whether in the interview or in the work, knowing the principle will help us a lot. The content of this article is long. It is suggested to […]

  • AT24C02 – introduction.md


    1. Introduction to AT24C02 1.1. Main specifications Capacity: 256byte Maximum speed: 100kHz (1.8V) or 400kHz (2.7V, 5V) Support random read-write and sequential read-write Page write delay 5ms 1.2. Main precautions 1.2.1. I2C address The at24 series supports limited modification of the I2C address of the chip by pulling up and down some pins, which is […]

  • Basic use of channel


    1. Pipeline classification Read write pipeline Read only pipeline Pipe only Buffer channel: specify the size when creating (if not specified, the default is non buffered channel) 2. Proper use of pipes After the pipeline is closed, it can be read and cannot be written The write pipe cannot exceed the capacity of the pipecapIf […]