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  Understanding PGO in GoLang 1.20

Background The Go 1.20 version was officially released in February 2023, it introduced the PGO(Profile Guided Optimization) mechanism. The basic principle of PGO can be divided into the following two steps: First, profiling is performed on the program to collect data about the program's runtime and generate a profiling file. When compiling the program, enable the PGO option, and the compiler will optimize the program's performance based on the content in the .pgo file. When compiling a program...

   GO 1.20,PGO,GOLANG     2023-02-28 04:27:46

  A serious security vulnerability found in MySQL/MariaDB

Recently a serious security vulnerability was found in MySQL/MariaDB. It relates to the access to the database. The issue is described below.When a user connects to MariaDB/MySQL, a token (SHA over a password and a random scramble string) is calculated and compared with the expected value. Because of incorrect casting, it might've happened that the token and the expected value were considered equal, even if the memcmp() returned a non-zero value. In this case MySQL/MariaDB would think that the p...

   MySQL,MariaDB,bug,fix,password,memcmp()     2012-06-11 10:28:09

  About JavaScript source map

Last week jQuery 1.9 was released. This is the last release before jQuery 2.0. It adds many new functions, one of them is the source map. By accessing http://ajax.googleapis.com/ajax/libs/jquery/1.9.0/jquery.min.js , you can scroll to the last line and you will see below line : 　//@ sourceMappingURL=jquery.min.map This is source map, it is a separate file and it is put at the same directory as the source file. You can click here and see what it looks like. It's an very useful functio...

   Source map, JavaScript, jQuery     2013-02-01 07:06:44

  Motorola : A Google company

According to Sina Tech, Motorola Mobility has changed its company logo this week. The new logo comes with new graphic design and new font design. The new logo still has the 'M' badge and "MOTOROLA". However, the color of the 'M' badge changes from the old white to the new gray and the outer ring color also changes from red to multi-color. It is more like the Google logo's color scheme. At the same time, the "MOTOROLA" string on the logo also changes from upper case letters to lower case letters...

   Motorola Mobility,Logo,Google     2013-06-26 11:40:02

  Using MemoryMappedBuffer to handle large file in Java

When handling large files, it will largely affect the process speed while using traditional FileInputStream, FileOutputStream or RandomAccessFile since they trigger lots of read and write operations. In Java NIO, a new way of handling large file is introduced which is to use MmeoryMappedBuffer to create memory mapped file. Memory-mapped I/O uses the filesystem to establish a virtual memory mapping from user space directly to the applicable filesystem pages. With a memory-mapped file, you can pre...

   JAVA,IO,NIO     2015-11-13 01:58:08

  When and Where to Use Pointers in Go

When declaring variables in Go, we usually have two syntax options: In some scenarios, pointers; in others, reference; sometimes, either. It’s great to have choices, but it is also confusing sometimes as to which one in which scenario. To be more reasonable in choice-making, I started from pointers, walked through their natures, and summarized some rules in using them in Go. from unsplash, Jordan Ladikos Pointers Go has pointers. A pointer holds the memory address of a ...

   POINTER,GOLANG     2022-05-01 02:24:43

  A plugin to update last_error in Delayed Job

delayed_job is a process based asynchronous task processing gem which can be ran at background. It will fork the specified number of processes to execute the tasks asynchronously. The task status is usually stored in the database so that it can be easily integrated into a Rails application where asynchronous job execution is desired. Normally when a job fails to execute or error occurs, it would save the error into the database with the column last_error. Ideally all these will be handled b...

   RUBY,RUBY ON RAILS,DELAYED JOB,LAST_ERROR     2017-11-18 13:05:49

  Check mobile device using JavaScript

Sometimes developers want to know whether the user is using a mobile browser or a desktop browser so that they can build corresponding user experience. Although in many cases responsive web design would help solve component alignment issues, there are performance related considerations in some cases where some code should not be ran or some feature should not be available if user is on mobile browser. or vice versa This post will summarize a few ways which are commonly used to check whether a us...

   CHECK,MOBILE BROWSER,MOBILE DEVICE,JAVASCRIPT     2021-10-02 01:36:16

  Facebook open sources its C++ library named Folly

Recently, Facebook open sourced its low level C++ function library for its internal use named Folly. Folly is an open sourced C++11 component library, it provides functions similar to what boost and std libraries provide, including string, vector and memory allocation, bit operation etc, to fulfill large scale high performance requirements.Currently Folly is tested with gcc4.6 on some 64 bit systems such as Fedora 17, Ubuntu 12.04 and Debian wheezy, it may also be OK on other 64 bit platforms wi...

   Facebook,Folly,C++,open source     2012-06-05 08:31:12

  Generate certificate in Java -- Certificate chain

In previous post, we have introduced the use of Certificate and how to generate self signed certificate using Java. In this post, we will show you how to generate a certificate chain. Sometimes we may only have a certificate request or we don't have a trusted certificate which can be used for business. Now we need to have a trusted CA to sign our certificate so that it can be used on SSL communications. To generate a certificate chain, we may first have our own certificate(A), then we may use ot...

   Java,Certificate chain,Creation, Pure Java     2014-07-30 08:24:52

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