Adeyemi Glory

software engineer

[Adeyemi Glory @AdeyemiGlory4]

You open the same website twice.
The second time, it loads much faster.
Where did the speed come from?
Browser cache?
DNS cache?
CDN?
Server cache?
Something else?
How many different caches might your request pass through?

[Adeyemi Glory @AdeyemiGlory4]

Google Maps says:
Traffic: 18 minutes slower than usual
How does Google actually know that there is traffic?
Millions of people aren't manually reporting it.

[Adeyemi Glory @AdeyemiGlory4]

You pause a movie on your phone.
Later, you open Netflix on your TV. The movie is sitting exactly where you stopped.
How does Netflix know? And what happens if your phone goes offline immediately after you pause it?

[Adeyemi Glory @AdeyemiGlory4]

You send someone a message on WhatsApp. They're offline. Three hours later, they come online. Your message appears. Where was your message sitting for those three hours? And how does WhatsApp know when to deliver it?

[Adeyemi Glory @AdeyemiGlory4]

A user clicks Submit twice.
Your backend receives both requests.
Both requests succeed. The user gets charged twice.

Whose fault is it?
Frontend?
Backend?
Database?
Payment provider?
Or all of them?

[Adeyemi Glory @AdeyemiGlory4]

A production system works perfectly during the day.

Every night around 2:00 AM, requests start becoming slower.
At 3:00 AM, everything returns to normal.
No deployment happens at 2:00 AM.

Where would you start looking?

[Adeyemi Glory @AdeyemiGlory4]

You click Pay.
Your bank account gets debited.
The merchant doesn't get the money immediately.
You refresh and it says: Payment processing... Then your internet dies.

What should happen if you open the app tomorrow? And how does the system know whether the payment succeeded?

[Adeyemi Glory @AdeyemiGlory4]

The “just add Redis” question
Your application is slow.
A developer says: “Let's add Redis.”

What problem are they actually trying to solve? And more importantly, when would Redis make the system worse instead of better?

[Adeyemi Glory @AdeyemiGlory4]

You type: https://t.co/ZMG6pw3wlH and press Enter.
What actually happens between that moment and the webpage appearing on your screen?
Not the simplified “DNS to server to response” explanation. What actually happens?

[Adeyemi Glory @AdeyemiGlory4]

Your database is at 95% CPU.
You look at the application.
Nothing looks particularly wrong.
There are no obviously terrible queries.

What's the first thing you'd investigate before touching the database architecture?

[Adeyemi Glory @AdeyemiGlory4]

@real_mno Yo

[Adeyemi Glory @AdeyemiGlory4]

Your API is handling 10,000 requests per second.
Things start getting slow, so you double your servers.
Nothing gets faster.
You double them again.
Still nothing.

What is probably happening?

[MLSA Club EKSU | #MicrosoftLearnStudentAmbassadors @mlsa_eksu]

It’s GPPB’24 day.

We are ready for you🫶🏼

#GPPB’24

[MLSA Club EKSU | #MicrosoftLearnStudentAmbassadors @mlsa_eksu]

In celebration of international women’s day yesterday we spoke about “Challenges women face in the tech space, how to overcome it and how to be motivated in a space dominated by men”

Women should be celebrated always.

#GPPB24

[MLSA Club EKSU | #MicrosoftLearnStudentAmbassadors @mlsa_eksu]

Less talks, more swags🥳🥳🥳

#GPPB24

[MLSA Club EKSU | #MicrosoftLearnStudentAmbassadors @mlsa_eksu]

CALL FOR VOLUNTEERS.🔊

We are on the lookout for passionate and skilled volunteers to join the GPBB team of Volunteers and advance the course of its success.

Join our team and let's make impact together!
We can't wait to have you on board!🥳

https://t.co/6o0LPn88kA

[Adeyemi Glory @AdeyemiGlory4]

@mlsa_eksu Can’t wait 😁

[Adeyemi Glory @AdeyemiGlory4]

Check out my Gig on Fiverr: I will help fix bugs in your website https://t.co/zGC0bwRBwO