Tag:Memory size

  • Interviewer: redis memory data is full, will it go down?


    background Redis database memory full, will it go down? The answer is: it will not be full. When using redis, we need to configure the maximum memory size that redis can use. When the storage reaches a certain capacity, there are redis’s memory elimination strategies, LRU algorithm elimination, and so on. Redis’s memory elimination strategy […]

  • The growth factor of vector in C + +


    We all know what C + + doesvectorThe capacity of will increase automatically with the added elements, but how much does it increase each time? Twice the original? triple? Or how much? Next, let’s study how the growth factor is determined. First of all, I want to elaborate a problemvectorRealization related facts:vectoruseallocatorInstead ofreallocSo, no matter […]

  • test2


    Test2 new to fwq 1. Setting – XMS = – Xmx goes without saying 2. The initial heap memory allocated by the JVM is specified by – XMS, which is 1 / 64 of the physical memory by default; the maximum heap memory allocated by the JVM is specified by – Xmx, which is 1 […]

  • Shell one click configuration of single instance Oracle basic environment variables (linux7)


    #!/bin/bash Echo “modify host name” hostnamectl set-hostname wangxfa hostname sleep 1 Echo “view and close firewall” systemctl status firewalld systemctl stop firewalld systemctl disable firewalld systemctl status firewalld sleep 1 Echo “disable SELinux” sed -i “s/SELINUX=enforcing/SELINUX=disabled/g” /etc/selinux/config #add user and group Echo “create users and groups needed to install oracle” groupadd -g 1030 oinstall groupadd […]

  • The difference and usage of calloc, malloc and realloc functions


    /*The memory size needs to be calculated manually and is not initialized*/ int *p = (int *)malloc(20 * sizeof(int)); /*There is no need to calculate the memory size manually, and it is initialized to 0*/ int *q = (int *)calloc(20, sizeof(int)); /*Dynamic memory expansion / reduction * 1. Successful allocation: *1.1 if the return address […]

  • PHP preload


    PHP preload php.ini #Only after setting to 0, restart PHP to clear the preload file opcache.enable = 1 #Configure the PHP script for preload. When PHP FPM starts, it will preload according to this file opcache.preload=/home/www/test/preload.php #For preload users, root is not recommended opcache.preload_user = www Using opcache_ compile_ File for file cache, once the […]

  • On the handling of error report in ora-00603 ora-27504 ora-27300 ora-27301 ora-27302


    Description of phenomena Environmental Science:Oracle RAC+Redhat 7.6 Abnormal found Exception view The background log is shown below solve Reference MOS:Oracle Linux: ORA-27301:OS Failure Message: No Buffer Space Available (Doc ID 2041723.1) 1、 Modify network configuration Modify configuration [email protected]:/root #vi /etc/sysconfig/network-scripts/ifcfg-lo 1 | #Additional 2 | MTU=16436 service network restart # systemctl stop network # […]

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


    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 […]

  • Metadata decryption of JVM source code analysis


    This article is from the perfma technology community Official website of perfma summary Metaspace, as the name suggests, metadata space is specially used to store metadata. It is a unique data structure in jdk8 to replace perm. This space has its own characteristics. Some time ago, there were too many problems in the company, mainly […]

  • How to plan rocksdb memory capacity in Flink?


    By Stefan RichterTranslation: Mao JiaqiProofread by: Hu Zheng This article describes some configuration options that will help you effectively manage the memory size of the rocksdb state backend in Apache Flink. In the previous article [1], we described the optional state backend options supported in Flink. This article will introduce some rocksdb operations related to […]

  • Performance comparison between recv peek and memory copy


    Performance comparison between recv peek and memory copy scene Compare the program pairs per secondUnix Socketimplementpeek recvThe number of operations and the program per secondcopyMemory times. Copy memory withcopy 256KBFor example, the code is as follows: #include <stdlib.h> #include <string.h> #include <sys/time.h> #include <stdint.h> #include <iostream> #define BUFFER_SIZE 256 * 1024 uint64_t get_current_ms() { struct […]

  • Multipass installation


    Multipass official website https://multipass.run/ Download the installation package from the official website. The process is not shown After installation, check the version: $ multipass version multipass 1.3.0+mac multipassd 1.3.0+mac Create virtual machine $ multipass launch -n vm01 -c 4 -m 4G -d 40G Creating vm01 Starting vm01 Waiting for initialization to complete Launched: vm01 -n. […]