Understanding Phantom Reads Problem with hands on examples

[@akhil1996kc]

Now I understand why it's called "read committed". You always read the latest committed value, even if its done by a different transaction. Thanks for this Arpit.

[@meditationdanny701]

I think "Repeatable reads" isolation solves the problem for "Non repeatable" read phenomena where as to solve "Phantom reads" the appropriate isolations level should be "serializable" but we don't necessarily need to have such strong isolation level to solve "Phantom reads" where as we can have our own locking strategy on reads/writes on different txn. to solve it

[@sumitkhanna7786]

exactly. don't expect these single-digit experienced leetcode parrots to teach us what computer science is :D

[@rishiraj1616]

Awesome stuff. Just one suggestion brother - Whenever you point to a different video which has detailed info, please leave the link in the description. It will help the viewers to navigate to videos easily.

[@LeoLeo-nx5gi]

I agree

[@LeoLeo-nx5gi]

Definitely mind blowing the example that you said, response would be 5 posts but at the top we would see total posts = 4, man thanks a ton!!! This cleared and made me understand the problem so well..... Eargerly waiting for more such videos

[@JubyJ-s5g]

Thank you. Very well explained with a good example. !

[@ansitun]

This video deserves a lot more likes than it has today (76) :( Beautifully explained. Thanks, Arpit. We will keep supporting #AsliEngineering

[@rickenjus34]

Where is your "Transaction Isolation Level" video that you talked about, unable to find it ?

[@ramjonchhen5882]

kzbin.info/www/bejne/d5qzeJWMn9FmgLs

[@RameshSingh-oj7hq]

@Arpit thanks for the video. Can you please share the link for database isolation level video. I couldn't find it.

[@WebDevMatrix]

Great content! Do you use iPad in the screen share to scribble or it's a digital whiteboard?

[@architshukla8076]

Great Stuff Arpit !! Thankyou .

[@shantanutripathi]

11:18 Repeatable Read prevents non-repeatable reads, but can still allow phantom reads, where a transaction reads data that was inserted or deleted by other transactions. Is it correct?

[@shantanutripathi]

I think that Repeatable Read isolation level uses shared locks are not held on range of rows that match the query criteria, but only on the individual rows that are read by the transaction. This means that if another transaction inserts or deletes a row that matches the query criteria, the transaction executing the query can potentially see the new row or miss a row that was there previously, leading to phantom reads.

[@shantanutripathi]

So better use Serializable to totally eliminate the chance of phantom reads

[@godofall746]

I think you're correct

[@abhiksamanta3424]

should I change my isolation level from read committed to serializable or repeatable read to avoid phantom read problem

[@AsliEngineering]

repeatable read is the most preferred one if you cannot live with phantom reads.

[@shivamsoni6242]

@@AsliEngineering repeatable read will not avoid phantom read problem in most of the db engines except in Postgress (as Postgress implements repeatable reads as snapshot). Correct isolation level will be Snapshot or Serializable. Repeatable reads (except in Postgress) pessmistically locks the rows it reads so, that no changes happen to them when the transaction reads it again but, other rows might come out of nowhere (phantom rows) since it doesn't have lock on those rows.

[@aritroroy8230]

Thanks for your efforts :)

[@AsliEngineering]

Thank you for becoming a member 🙌 means a ton.

[@rajan-u6b]

content to kaafi cool h bhaiya aapka....bss sb sir ka upar se jata😅, but trying my best to learn so many things from you. thank you so much for your content.

[@ashishmaurya3113]

😮

[@gurupreetsingh8347]

sorry , but the repeatable read transaction isolation level does not prevent phantom reads at all

[@gmmkeshav]

how to design infinite scroll of Instagram? just wondered

[@mayankraj4990]

kyu maar re ho bhai concepts ka..