[Backend #9] Understand isolation levels & read phenomena in MySQL & PostgreSQL via examples

When working with database transactions, one crucial thing we must do is choosing the appropriate isolation level for our application. Although there’s a well-defined standard, each database engine might choose to implement it in a different way, and thus may behave differently in each isolation level. In this video, we will explore deeply how each level of isolation work in MySQL and Postgres by running some concrete SQL queries. It also shows you how each isolation level prevents read phenomena like dirty read, non-repeatable read, phantom read, and serialization anomaly.

Official documentation about transaction isolation levels:

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TECH SCHOOL - From noob to pro

[adilkhatri]

BY FAR THE BEST VIDEO ON ISOLATION I HAVE EVER SEEN.

[ramjonchhen]

This is one of the most clearest and practical video on isolation level I have found. Kudos to you for explaining the topic is such simple and practical manner 🥰🥰

[B-Billy]

OMG, this is the perfect session, covering two major DBs, on the Isolation level. Subscribed. Loved it.

[Sensibles]

This is so far the best description of isolation levels based on real dbs. Thanks!

[AbhishekVaid]

This is one of THE BEST tech learning channels on Youtube. Period !

[nuttaphonr.]

Thanks again TECH SCHOOL !

MySQL Part
7:02 dirty read
9:04 non repeatable read
9:30 phantom read, same query but result miss 1 row
11:31 repeatble read prevent phantom read
12:55 move to highest isolation level
13:36 select is blocking, mysql convert plain select to select for share
14:42 deadlock occured

[abhilashpadmanabhan]

The way you tried every scenario in terms of Serialization anomaly coming back to MySQL. Thats the level of detail we all need, appreciate it! Thanks for the video. A suggestion would be to do the comparison on Oracle as well. :)

[TheSalrec]

this is the best video I've found explaining the isolation levels in practice!

[flatmapper]

Thank you for such a great content. It would be great if you could make another video showing how transactions with DIFFERENT isolation levels interfere with each other. That is how transactions will interfere when you set DIFFERENT isolation levels in console windows. I believe it will clearly show what really influence the occurrence of read phenomenas

[ibmspringsprings]

First of all, thank you
TECH SCHOOL had a public an excellent Explanation and Demonstrate about isolation levels & read phenomena and comparison between MySQL and Postgres of how its does it works on both MySQL and Postgres, thank you
so much.

[nadezhdaburunova]

I finally understood isolation levels! And I love clear examples you provided. Subscribed, thank you

[fserzz]

Thank you for the best isolation lecture!

[artemcodes]

Thank you so much for this tutorial. It was extremely useful!

[dmitrybunin]

Great walkthrough, simple and clear breakdown. Thanks!

[Goldenhand]

Fantastic, Priceless informations that cant find anywhere simple and exemplified like this!!!

[rainedJMTi]

luckily I found your video, I think your video is the best at explaining phenomena and isolation. Kudos.

[oduber.vasquez]

I am carrying out a project for a public institution, where several users have access to a game and from that game they transfer money to others and sometimes the balances are not correct! This gives me an idea of how to deal with these transfers or transactions. Thank you for your contribution!

[ngodinhloc]

Excellent !!! Waiting for a tutorial about retrying when an error occurred(timeout or deadlock). Thank you so much !!!!

[anassbenhalima]

bro your content is great and so helpful . i hope it was totally free

[simonpermeke]

This is one of the best courses on the interent :)