[Backend #8] How to avoid deadlock in DB transaction? Queries order matters!

[@sea-entertainment2159]

2:00 I really appreciate that you not only explain concepts in theory, but then show us in a very practical way by literally running two concurrent psql terminals. Sometimes concurrency can feel very abstract, and yet you show us very clearly how this problem can arise.

[@TECHSCHOOLGURU]

Thanks a lot!

[@worrapongable]

Yes i think so too.

[@lacascadaobregon]

Every sentence is literally great information. I watch these slowly and learn so much. So many golden nuggets of knowledge every video

[@TECHSCHOOLGURU]

Great to hear!

[@dangbey4822]

Best course I have ever took

[@pshaddel]

Nice video Man! Keep it up!

[@thestacksdev]

Truly thankful for the content, I can't imagine how long I would have taken figuring out the deadlock issue🥳

[@oduber.vasquez]

Excellent contribution, every day I learn more with your videos, thank you very much!

[@TECHSCHOOLGURU]

Glad to hear that!

[@orkhanrustamli2039]

Dude, I have took a lot of bootcamps, courses on Udemy, KZbin and others, but honestly, none has explained stuff you are doing. Keep it going! Moreover I would like to see a series about create microserviced app containing graphql/rest/grpc together! thanks!

[@TECHSCHOOLGURU]

Great to hear!

[@StyleTrick]

Great video explaining this, truly awesome content by the way!

[@TECHSCHOOLGURU]

Thank you! Much appreciated!

[@jounger]

mind blowing, thanks for sharing amazing knowledge

[@worrapongable]

More than how to debug that problem, But solution so minimal and powerful.

[@TECHSCHOOLGURU]

Thanks!

[@dilshataliev]

Awesome course, thanks a lot, keep up the good work!

[@TECHSCHOOLGURU]

Thanks, will do!

[@mcgam3r_tv809]

Very helpful video. for some reason my fmt.Println() is not printing.

[@昆仑弈客]

for now, i can not understand why the condiction is arg.FromAccountID > arg.ToAccountID, i think the accountid is unorderly.

[@shalsteven]

it is used just to make a consistent order. let's say arg.FromAccountID=2 and arg.ToAccountID=10. therefore by using this checking condition if arg.FromAccountID < arg.ToAccountID: both Tx1 and Tx2 will update the account with account_id=FromAccountID first then account with account_id=ToAccountID, not Tx1 update the the account with account_id=FromAccountID first then account with account_id=ToAccountID and Tx2 update the account with account_id=ToAccountIDfirst then account with account_id=FromAccountID let's say arg.FromAccountID=100 and arg.ToAccountID=20. therefore by using this checking condition if arg.FromAccountID < arg.ToAccountID: both Tx1 and Tx2 will update the account with account_id=ToAccountIDfirst then account with account_id=FromAccountID you can see that both Tx1 and Tx2 will update the account in the same order, so there isn't any deadlock

[@kertkukk]

The comparison will consistently determine which one to process first, regardless of how they're stored in the database or which one is the sender or receiver of a given transaction.

[@alexandervasilenko7773]

Cool! Thanx a lot man!! Good series!!!

[@TECHSCHOOLGURU]

Thanks, Alex!

[@sarthakmaster6797]

Awesome, got to learn a lot today👌🏻nice work, please keep up with your work.

[@TECHSCHOOLGURU]

Happy to hear that!

[@yannrolland543]

Thanks, very clear!

[@TECHSCHOOLGURU]

Great to hear!

[@danielniels22]

what if the account ID is not in sequential number? like UUID, or like random numbers?

[@bergeter5101]

excellent explanation! how do you clean data that made from unit test? is it not conflict / make another test failed when the record already exist? im studying how to make test with real database interaction (not with mock). I had looked into datadog go-txdb, seems promising

[@TECHSCHOOLGURU]

I don't need to clean test data because they are generated randomly, so they won't conflict with each other. You can checkout this video about writing unit tests: kzbin.info/www/bejne/ppmrdZmFfadlhrc

[@dangbey4822]

If update has no correlation with foreign keys it will not block other channels yes? is not there something also like "NO KEY" for update?

[@jarriabidi1438]

Great content. If you could make a larger go http service and show some design patterns that would be great

[@TECHSCHOOLGURU]

Thanks, Jarri. That's in the plan!

[@innovafrique]

Thanks a lot. How to make transaction with go for Mongodb ???

[@TECHSCHOOLGURU]

Good suggestion, Shukuru! But it might be out of scope for this course. I will consider making a video about it in another series.

[@luisweck5285]

how to avoid this deadlock is the ID is a uuid, for example?

[@TECHSCHOOLGURU]

It's the same, you can compare UUIDs as well.

[@luisweck5285]

@@TECHSCHOOLGURU i guess one can sort them lexicographically. That makes sense. I was thinking that because UUID v4 don't have an inherent ordering, I would not be able to compare them with anything other than the equals operator

[@danielniels22]

@@luisweck5285 i still don't understand. how do we solve it?

[@ajf]

nice I like your channel

[@TECHSCHOOLGURU]

Thanks!

[@Aleksei-n6h]

Why do you show us the rest of the screen