Performance Test Terms

• throughput

the amount of material or items passing through a system. In general, throughput is the below.

• tps transaction per sec. definition of transaction is different with the projects.
• PV/s  page view per sec

• elapsed time

time that elapses before all the response returns after request

• latency

time that elapses before the first response returns after request

How to make SPA stronger against SEO

Brief

Considering regarding how to make SPA stronger against SEO

Issues

If introduced SAP, the below issues could be considered.

• It's not obvious if web contents updated dynamically is evaluated or not in accurate.
• Google web crawler does not evaluate JS

How to solve

• SSR(Server Side Rendering):  Using node.js or etc.., and execute front end process in server side.
• Prerendering: Using cui browser, and return contents rendered in server side in advance.

kubernetes begining

Brief

By spread of container technology like Docker, it was easy to solve dependencies  of libraries, applications and files among servers. Also, container technology makes it easy to migrate resources.
Next problem is management of containers. If there are just only several containers, managing is not so difficult. But increasing the number of containers, it makes managing more complex.

What's Kubernetes?

Kubernetes is one of the operation tools of container clustering and called as container orchestration tool. It is developed to solve the above container management problems. Google is developing.
It has functions of container operation like auto deploy, storage mount, health check and getting logs or etc...

Numa Architecture and innodb_buffer_pool_size

Event
e.g.
The machine spec
the number of processors: 2
RAM: 32GB

MySQL configuration
innodb_buffer_pool_size = 24GB

If these configurations, Numa architecture divide RAM each16GB. But innodb_buffer_pool_size is over 16GB, so there is possibility that swap occurs.
This event is called as "Swap Insanity".

How to solve

• Deactivate Numa
• Decrease innodb_buffer_pool_size

etc...

Reference
http://d.hatena.ne.jp/fat47/20121121/1353495937

Numa Architecture

What's Numa Architecture
Numa is the abbreviation of "non-uniform memory access".
The objective of Numa is parallelization of *bus.
Numa is an alternative approach that links several small *nodes.

*bus to connect between cpu and RAM.
*node means a pair of processor and RAM.

Features
If Numa architecture is adopted, RAM is divided by the number of bus and accessed.

e.g.
If there are 2 buses on the machine which has 32GB RAM, RAM is divided per 16GB and accessed.

ReactJS Features

Brief
Consideration regarding ReactJS merit and demerit

ReactJS Features

• JSX is essential

ReactJS Merit

• Rendering speed is faster than ordinary template engine.
• Writing logic per a html part is reused.

ReactJS Demerit

• Not good at Ajax
• It's not suitable for the pages which do not have many dynamic contents.
• Rendering speed is slower than JQuery optimized.

Multi process and memory segment

Brief
Explain memory condition in multi process

There are a parent process and several child processes in multi process.
All the process share parent process text segment and refer same memory domain.
On the other hand, data segment is copied by each child processes.

Global variables are not shared in each data segments.


Basic memory segment explanation is below.
https://cocoamaemae-tec-diary.blogspot.jp/search?q=memory


Reference
http://moro-archive.hatenablog.com/entry/2014/09/11/013520
https://teratail.com/questions/15389
http://ts0818.hatenablog.com/entry/2015/09/23/191335