AdventCalendar

Performance impact of MySQL performance-schema-instruments

Hi, there! I’m Otsuka (tom__bo), mainly responsible for MySQL operations and development of various DB administration and verification tools. In this post, I am going to write about my experiment on MySQL performance when its performance consumers, namely the performance_schema database and the innodb_metrics table of the information_schema database, are up and running.  I got to learn about the performance_schema and the INFORMATION_SCHEMA.INNODB_METRICS from a book […]

Troubleshooting Data Engineering Software

Hello, I’m Keiji Yoshida. I currently work as a data engineer at LINE Data Labs. In this posting, I’d like to share a few cases on data engineering software troubleshooting: Apache Hadoop YARN ResourceManager failover Apache Hadoop HDFS NameNode failover Apache Zeppelin Notebook scheduler issue Apache Zeppelin deadlock issue Apache Spark SQL performance issue Troubleshooting failover issue in Apache Hadoop […]

TensorFlow.js

Greetings! This is Jun and I’m a front-end developer at LINE. Recently the front-end development scene is booming with new technologies and it’s becoming difficult to catch up with all those new things. Personally I’m onto machine learning (ML). As part of today’s topic as “implementing machine learning in front-end web development”, let me share […]

LIFF + TIC-80

Hello, this is Seisuke. I work at LINE Fukuoka as an engineer for LINE app for Android. Our office held a hackathon for LINERs in November 2018, at which I had a chance to try out TIC-80, a fantasy console, with LIFF. I wanted to share some of the lessons I learned through the event. […]

LTOドライブを使ってみた

こんにちは、LINEメッセージングアプリの Android Client の開発を担当している玉木(@r_ralph_h)です。
この記事では、あまりコンシューマー向けには馴染みのない「LTOドライブ」について、実際に使ってみて紹介する記事になります。

Redis Lua script for atomic operations and cache stampede

Hello, this is Kagaya, a member of the LINE GAME Platform development team. It’s nice to be back after writing a post on Lazybones (Japanese post), in 2016. Redis and LINE GAME Platform The LINE GAME Platform uses Redis — in-memory no SQL database — for its main database, mainly for cache. For instance, we are using […]

V8 Hidden class

As a frontend engineer, I feel I still need to know more about the structure of JavaScript and web browsers, in order to provide quality UX to our users. Thankfully, we are given an access to peak through JavaScript’s thoughts, thanks to Google and Mozilla for making their engine code available to public, along with nicely prepared documentation. The availability of various means for tracing and profiling code surely helps too.

LINE Animation Sticker Checker on Web browser

Great to meet you all. This is ha1f from LINE Fukuoka, I develop iOS apps at LINE. Back when I was as a part timer at LINE, I was involved in making in-house tools for LINE. To share a little bit of my background, I was hired as a part timer with a confirmed offer to a full time position. Anyway, today, I’d like to show you a tool I developed during my time as a part timer, the Animation Sticker Checker.

What is APNG?

Before we get into the details of the tool, let’s discover what APNG is. APNG (Animated Portable Network Graphics) is a specification for animated image, consisting of images each numbered with a sequence number. LINE animation stickers use APNG. Unlike GIF, APNG supports full color, alpha channel and has a high compression rate. APNG is compatible with PNG, and is displayed as a still image for image viewers that do not support APNG. If you have the right tool, you can convert a sequence of PNG files into an APNG file.

apng

Floor map management system on web, with Leaflet

LINE Japan’s office relocated in April, 2017 to JR Shinjuku Miraina Tower to accommodate its growing number of staff. At the time of relocation, the IT support department introduced a number of new systems into the company. One of those is the LINE Floor Map system which I am going to share with you in this post.

Background story

Before we moved to Shinjuku, we used to manage our floor map with Microsoft Excel. Here is a part of the excel file. (We’ve erased names off from the screenshot.)

The structure of the LINE LIVE’s encoder layer

On December 10th of 2017, we celebrated our second anniversary for LINE LIVE, our live streaming service. The service has been up and running ever since the launch with no trouble, thanks to the efforts put in by countless engineers at LINE. On this blog post, as a member of ITSC, a team at LINE running a global infrastructure system, I’d like to share with you some of decisions we had to make in the initial phase of designing and implementing the system. Back then, I had absolutely no experience in building or running a live media service.