Concurrent Requests and Unique Keys on Web Applications

In this video I explain how primary key cannot be duplicated even if concurrent transactions are executed in the same time.
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Stay Awesome,
Hussein

[@anonymous.youtuber]

As usual, a superb explanation!

[@anthonyfarias321]

This is very good stuff man.

[@dominicwong5647]

Great stuff Hussein, love your videos

[@javedutube10]

As Always, love your explanation.

[@IBITZEE]

nice thinking... nice tests... CCC thx !

[@arunsatyarth9097]

Thanks for your videos Hussein. Really beneficial and love your presentation style...

[@hnasr]

arun satyarth thanks Arun!! ❤️ glad you like the content

[@sachinkalkur]

These short videos are extremely informative.

[@hnasr]

Glad to hear that!

[@ahmedkhudhair8035]

Very nice ❤️

[@AAZinvicto]

Thank you bro for such informative videos. Love from India. Ma-as-salama

[@hnasr]

AAZinvicto much love to all my subs from India 🇮🇳❤️

[@arpitpandey8797]

You reminded of me Dora the explorer 😅... Great video

[@6Sambora]

Was about to ask you to do the same with MongoDB until the end of the video, when you mention NoSQL does not have isolation level haha

[@hnasr]

Kid Amador we can do some of things of not all of it. 😊 MongoDB is a different beast with different set of features

[@simon66668]

At the document level, MongoDB already supports ACID transactions

[@ramonberrutti]

Nice explain, you just forgot the deadlock case, inserting in a different order in each transaction

[@hnasr]

Nice idea for another video forgot to mention it! Thanks 🙏

[@8Trails50]

Sorry can you expand, what do you mean by this?

[@adarshupadhyay8265]

But how you were able to see the insert result without Commit operation in the beginning?

[@MrDecorative]

If the database is replicated, and the leader is processing a write with id 1 , and then crashes for some reason before those changes has been yet replicated to the follower which is elected to be the new leader , this new leader wouldn’t be aware of the key 1 which already exists , and after a while when the system gets eventual consistency, boom 💥 a problem in the system. This bug happened at github in 2011 with auto incrementing key 🔐

[@AShahabov]

But what about when two transactions insert duplicate values in a NON-INDEX column? One of the transaction also will be blocked?

[@hnasr]

Hey Adam, if the column doesn't have a unique index, it is absolutely fine to duplicate values between transactions.

[@ankitraj9684]

A video on log structured merge tree?

[@hnasr]

Ankit Raj soon! Not yet, 👍

[@NivekMoto59]

it not ACID the word you search??