Tag:free

  • Talk about Mongo driver’s connection pool

    Time:2021-1-18

    preface For the server, before a single link reaches the maximum throughput, less links means less context switching and less memory consumption (TCP stack memory consumption, application layer buffer). Therefore, in addition to the conventional indexing, fragmentation, read-write separation, the design of connection pool also has a very important impact on the database performanceThe language […]

  • HTTP request in go — Analysis of HTTP 1.1 request process

    Time:2021-1-11

    From the official account: New World grocery store preface HTTP is one of the most widely used protocols, and it is also one of the most frequently contacted protocols by programmers. Today, the author makes a comprehensive analysis of the request process of HTTP1.1 from the perspective of gopher. I hope that readers can have […]

  • Notes: CPLD communicates with MCU through SPI

    Time:2021-1-9

    1、 Requirement description MCU needs to receive firmware data from CPLD CPLD only sends data to MCU and does not receive data from MCU CPLD can’t tell the beginning and end of data transmission, which needs MCU to judge by itself (CPLD only transmits data through, and doesn’t judge data) The data communication rate is […]

  • Regions and segments of InnoDB’s internal analysis (3)

    Time:2020-12-28

    A series of articles: Row of InnoDB’s internal analysis (1) InnoDB’s internal analysis page (2) Regions and segments of InnoDB’s internal analysis (3) Analysis of inode structure binary page Analysis of inode structure file of table’t ‘ Analysis of xdes entry structure file of table’t ‘ Analyze a picture from theory preface Let’s look at […]

  • Analysis of a graph from theory

    Time:2020-12-21

    Series articles: Row (1) from inside analysis of InnoDB InnoDB internal analysis page (2) Areas and segments of InnoDB’s internal analysis (3) Binary page analysis of inode structure Analysis of inode structure file of table’t ‘ Analysis of xdes entry structure file of table’t ‘ Analysis of a graph from theory preface A lot of […]

  • STM32 receives indefinite length data based on Hal serial port idle interrupt

    Time:2020-12-9

    1、 Preface Recently, when using the Hal Library of STM32, I found that there was no integration of idle interrupt processing. The Hal library processing logic written by itself is very cumbersome, and the efficiency is not high, and there are still lack of arms and legs. Usually, the data received by the serial port […]

  • In depth analysis of buffer pool mechanism of Kafka producer [diagram + source code analysis]

    Time:2020-11-17

    Last time I shared with you “Is Kafka producer blocking when sending messages asynchronously?After reading the source code, I found that the design of the buffer pool is very good and elegant by its design ideas. So I can’t help but share a wave with you. In the new version of Kafka producer, a message […]

  • JDBC pool in Tomcat

    Time:2020-11-10

    What is connection pool What is?Connection pool — connection poolWhat about it? I won’t explain. Take a closer look at this article [production level nodejs development practice – using connection pool](the first half of this article describes what connection pooling is) JDBC connection pool in Tomcat Its English documents are in: [the Tomcat JDBC connection […]

  • RT thread linked list heap manager of practical algorithm series

    Time:2020-10-31

    [guide] the previous article described the basic concept of stack. This article is to talk about how heap works. RT thread is very popular in the community. After reading its kernel code and realizing heap management, the code design is very clear and readable. Therefore, on the one hand, we can understand the implementation of […]

  • Oracle operation and maintenance — 08 memory usage analysis and view

    Time:2020-10-20

    1. Query the usage of SGA and PGA; select name,total,round(total-free,2) used, round(free,2) free,round((total-free)/total*100,2) pctused from (select ‘SGA’ name,(select sum(value/1024/1024) from v$sga) total, (select sum(bytes/1024/1024) from v$sgastat where name=’free memory’)free from dual) union select name,total,round(used,2)used,round(total-used,2)free,round(used/total*100,2)pctused from ( select ‘PGA’ name,(select value/1024/1024 total from v$pgastat where name=’aggregate PGA target parameter’)total, (select value/1024/1024 used from v$pgastat where name=’total […]

  • [problem analysis] there are too many connections on redis clients, and a large number of idle connections and readonly connections

    Time:2020-10-16

    problem There are too many connections of redis clients during operation and maintenance, which exceeds the default maximum limit of 1W.Execute the order ./redis-cli –h host –p port info clients Check the connection number of redis clients. There are 6 nodes in total, and each node is 2000+ analysis Execute the order ./redis-cli –h host […]

  • Overview of partner system

    Time:2020-10-8

    One of the most important tasks of Linux kernel memory management is how to avoid the generation of fragments in the case of frequent applications for releasing memory. In this case, we use the external fragmentation to solve the problem of external fragmentation. There are two ways to avoid external fragmentation: one is to use […]