Yudong Li retweeted
Some good points here
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Yudong Li retweeted
I didn't realize how terrible my posture was until an MRI showed it was slowly killing my brain.
A ticking time bomb of a problem that I've now dramatically improved with these five habits. 🧵
Yudong Li retweeted
A lady was just pushed onto the train tracks at Richmond station by someone who then ran off. Good samaritans then got onto the tracks lifted her up before she received medical attention & @metrotrains was on scene. I’ve reported what I saw to police. Thank goodness she’s ok.
Yudong Li retweeted
𝗦𝘁𝗮𝗰𝗸 𝗢𝘃𝗲𝗿𝗳𝗹𝗼𝘄 𝗔𝗿𝗰𝗵𝗶𝘁𝗲𝗰𝘁𝘂𝗿𝗲 𝗜𝘀 𝗡𝗼𝘁 𝗪𝗵𝗮𝘁 𝗬𝗼𝘂 𝗠𝗲𝗮𝗻 𝗜𝘁 𝗜𝘀
In the recent interview with Scott Hanselman, 𝗥𝗼𝗯𝗲𝗿𝘁𝗮 𝗔𝗿𝗰𝗼𝘃𝗲𝗿𝗱𝗲, 𝗛𝗲𝗮𝗱 𝗢𝗳 𝗘𝗻𝗴𝗶𝗻𝗲𝗲𝗿𝗶𝗻𝗴 𝗮𝘁 𝗦𝘁𝗮𝗰𝗸 𝗢𝘃𝗲𝗿𝗳𝗹𝗼𝘄, revealed the story about the architecture of Stack Overflow. They handle more than 6000 requests per second, 2 billion page views per month, and they manage to render a page in about 12 milliseconds. If we think about it a bit, we could imagine they use some kind of 𝗺𝗶𝗰𝗿𝗼𝘀𝗲𝗿𝘃𝗶𝗰𝗲 𝘀𝗼𝗹𝘂𝘁𝗶𝗼𝗻 𝘁𝗵𝗮𝘁 𝗿𝘂𝗻𝘀 𝗶𝗻 𝘁𝗵𝗲 𝗖𝗹𝗼𝘂𝗱 𝘄𝗶𝘁𝗵 𝗞𝘂𝗯𝗲𝗿𝗻𝗲𝘁𝗲𝘀.
But the story is a bit different. Their solution is 15 years old, and it is a 𝗯𝗶𝗴 𝗺𝗼𝗻𝗼𝗹𝗶𝘁𝗵𝗶𝗰 𝗮𝗽𝗽𝗹𝗶𝗰𝗮𝘁𝗶𝗼𝗻 𝗿𝘂𝗻𝗻𝗶𝗻𝗴 𝗼𝗻-𝗽𝗿𝗲𝗺𝗶𝘀𝗲𝘀. It is actually 𝗮 𝘀𝗶𝗻𝗴𝗹𝗲 𝗮𝗽𝗽 on IIS, which runs 200 sites. This single app is running on nine web servers and a single SQL Server (with the addition of one hot standby).
They also use 𝘁𝘄𝗼 𝗹𝗲𝘃𝗲𝗹𝘀 𝗼𝗳 𝗰𝗮𝗰𝗵𝗲, one on SQL Server with large RAM (1.5TB), where they have 30% of DB access in RAM and also they use two Redis servers (master and replica). Besides this, they have 3 tag engine servers and 3 Elastic search servers, which are used for 34 million daily searches.
All this is handled by a 𝘁𝗲𝗮𝗺 𝗼𝗳 𝟱𝟬 𝗲𝗻𝗴𝗶𝗻𝗲𝗲𝗿𝘀, who manage to 𝗱𝗲𝗽𝗹𝗼𝘆 𝘁𝗼 𝗽𝗿𝗼𝗱𝘂𝗰𝘁𝗶𝗼𝗻 𝗶𝗻 𝟰 𝗺𝗶𝗻𝘀 several times daily.
Their 𝗳𝘂𝗹𝗹 𝘁𝗲𝗰𝗵 𝘀𝘁𝗮𝗰𝗸 is:
🔹 C# + ASP. NET MVC
🔹 Dapper ORM
🔹 StaeckExchange Redis
🔹 MiniProfiler
🔹 Jil JSON Deseliazier
🔹 Exceptional logger for SQL
🔹 Sigil, a .Net CIL generation helper (for when C# isn’t fast enough)
🔹 NetGain, a high-performance web socket server
🔹 Opserver, monitoring dashboard polling most systems and feeding from Orion, Bosun, or WMI.
🔹 Bosun, backend monitoring system, written in Go
Check more links in the comments.
#technology #softwareengineering #programming #techworldwithmilan #softwarearchitecture
Yudong Li retweeted
1. Barrels and ammunition
I didn’t overlap with @KeithRabois at @Square, but when I joined, his precepts were (and still are) all over the company. One of the most powerful metaphors - not least because of the vivid imagery - was that of barrels and ammunition.
Yudong Li retweeted
Most people assume I became a startup CFO by staying up late to study balance sheets and build DCFs.
False.
I just copied what these CFOs said on FinTwit:
Yudong Li retweeted
PREDICTION: There's a mass extinction event coming for early & mid-stage companies. Late '23 & '24 will make the '08 financial crisis look quaint for startups. Below I explain when, why & how it will start & offer *detailed advice to founders* on surviving the looming die-off. /1
Yudong Li retweeted
I've watched 1000+ Conferences Talks over the last 20 years in Tech. I used to watch one every night after dinner for years.
Below are The 22 Talks that Impacted my Career the most ➕ my main highlights from each one.
🧵🧵🧵
Yudong Li retweeted
Please wear masks😊
Physical distancing helps, but aerosol spread is big part of it too.
Aerosols waft, "floating" in the air.
That’s why ventilation and filters help.
Masks reduce spreading diseased aerosol in shared spaces – indoors or close to others outdoors.
More⬇️
Yudong Li retweeted
April is the cruelest month. 四月之声: voices of frustrations, outcries, lies, moments of truth, and love, and despair.
Crying as I’m watching this.
To download: mdl.ink/L3qI6n
To watch: app.mediatrack.cn/reviews/15…
Yudong Li retweeted
Regional led bid for the 2026 Commonwealth Games. @10NewsFirstMelb #springst
Yudong Li retweeted
SCMP reports the US granted 33,896 student visas to Chinese nationals in June this year. Border restrictions mean Australian unis can only dream of figures like this. scmp.com/news/china/diplomac…
Yudong Li retweeted
Scannable QR code ads formed by drones in sky.
Shanghai.
📸 @Pathfinder
Yudong Li retweeted
Replying to @CPtraveller @AusBT
This has a lot to do with the population size as well as human density in big cities. Fortunately, Australia is lucky in both ways.
Yudong Li retweeted
1/ I thought I'd write about my experience re-entering South Korea, where I reside, during this global pandemic. It wasn't a 5 minute job like in London Heathrow where I was out in no time. Instead, it took 24 hours. Here's what happened:
Yudong Li retweeted
Fifth of countries at risk of ecosystem collapse, analysis finds theguardian.com/environment/… – at Sydney, New South Wales
Yudong Li retweeted
My parents deliberately spoke no English to me as a toddler. I went to kindy with little Eng, but they knew I would catch up. I topped the state in Eng in the HSC. And I still speak Chinese. Eng should not be a barrier to entry. Helping kids learn foreign langs shd be the focus.
Yudong Li retweeted
Australians have watched with growing anger at what the Murdoch media monopoly is doing to our country. A cancer on democracy.
Today I am launching a national petition to establish a #MurdochRoyalCommission.
If you value our democracy, please sign here: aph.gov.au/petition_list?id=…
































