How do Transactions Work? | Get to know Cloud Firestore #8
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- Опубликовано: 16 апр 2019
- Transactions can help you avoid race conditions and strange inconsistencies in your database application. But what is a transaction, and how do they work? What is the difference between a client-side and server-side transaction in Cloud Firestore, and how are they different from batched writes? Find out the answers to all of these questions and more in this episode of Get to Know Cloud Firestore!
More episodes on Cloud Firestore → goo.gle/Cloud-Firestore
Subscribe to Firebase → goo.gle/Firebase 
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I love Todd's style. His tutorials are excellent!
Literally the most fun I've ever had watching any programming tutorial. Seriously, his sense of humor is top-notch.
Me to
He's so entertaining!! His videos have been a huge factor in making me want to look more into Firebase, and now I use it for almost every project.
I once made a game where a hundred people all started button mashing arrow keys all at the same time which were supposed to update a single shared location amongst everyone through transactions (basically twitch plays pokemon). I ran out of my free tier reads in under 30 seconds because nobody's transactions went through... :) I learned a lot that day...
And I learned from this comment, thanks!
@@LightDragooon what exactly is the learning from this comment? i am trying to learn
I love firebase please be more active in RUclips
are you kidding? firebase team's youtube content is second to none!
Protect Todd at all costs! Best teaching flow I've seen in my life
You saved me a lot of time with this video. It's like you know about my needs :D thanks a lot for this video.
I wish my teachers had your skills. This was a perfect explanation about Transactions. Thank you, Todd. Also, that you make a good attempt to be funny :)
Glad it was helpful!
I`ve been waiting for this cloud firestore videos keep going Firebase
You do a great job explaining these concepts. Loving the firebase products
These videos are well made. Very insightful, thanks!
Literally amazing tutorials!
Finally another video from this series
Exactly what I needed, thanks!
Thank you! Excellent video !
Thank you so much for explaining this so easily and beautifully. Thanks again
Very good and practical use cases !
Very well explained. Thanks.
this guy is literally the best, damn theese tutorials are greate
This is great 👍. Thank you 🤓
Love this course!
Perfect explanation, thanks!
Glad you enjoyed it!
Well, that was an awesome explanation :)
Thank you for this video.
Great video! Thank you!
I just thought about this only after implementing the logic for my app (not a lot but had to do a significant amount of work) and then remembered this problem when I wanted to update the same document from multiple users. Here we go again!
Firestore is amazing. I love it
Nice one... help a lot...
Excellent work! (The PubG one) 😉
This was so fun to watch
And I wrote this before I even saw the part with the puns with the word “fun”
Awesome!
Thank you so much
Counters Documentation:
firebase.google.com/docs/firestore/manage-data/add-data#update-data
Distributed Counters Documentation:
firebase.google.com/docs/firestore/solutions/counters
Increment operations are useful for implementing counters, but keep in mind that you can update a single document only once per second. If you need to update your counter above this rate, see the Distributed counters page.
At 10:43, He talks about a new feature that allows you to increment data with the most recent version of the data. Does anyone know if he is referring to the increment function that is a part of FieldValue, distributed counters, or something else that I did not mention?
Yes, he meant about the increment field value
awesome tutorial and funny
Oh man. You make life easy.
In Firebase V9, the special function that increments a value without needing to write a transaction is called 'increment'.
I wasn't aware of these potential bugs to my app. Fortunately this video showed up in recommendation
Fantastic! How did you create this video?
Nice video.... Could you point me to documentation regarding the new add functions to increment/decrement a counter... Thanks
@@ToddKerpelmanCorp Nice one Todd. I really like where this is going. superb work on the video
Would it be a bad idea to create a matchmaking system with transactions? I feel like it would fail more often then it would succeed and that might be a problem cost wise, i'm not really sure. For example if you had a ton of users matchmaking all at once. Some users would get lucky and find a game immediately. While most other users would need to keep retrying until a spot that was open was not stolen before the data was committed.
As always awesome video! However, transactions would not help in situation when, I checked that opponent has enough gold, I still have a pan but what if opponent have not updated database yet? What if he is playing offline and spent all gold on some upgrade? I will successfully trade with him and when he will get online/sync with database, he will get my pan for free... correct me if I am wrong
If you limit spending to only transactions, you should be able to avoid this issue all together since upgrading requires spending gold. If this isn't good enough, you could enforce an offline system for currency where when it's time to sync backup to an online state, you could run some logic on whether or not it is fair to allow the upgrade to be synced to the database.
Even though I hate firebase, gotta say this is very well presented. Good job
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Todd Kerpelman
do you have any suggestion when I caculate some math like total money of invoice in few years then I compare each year growing rate( 36 500 document invoice / year). => should I download all (36500 document * years) then do sum math on client or do it on firebase function sir? please help me, I really need your suggestion.
sanFrancisco to funfrasisco , that was in deed a greate idea
Does it affect the pricing for transaction if it fails and start to read again?
@@ToddKerpelmanCorp Thank you :)
@@ToddKerpelmanCorp maybe you should try to make videos related to firestore together with storage :)
I have a transaction setup that is calculating an average (similar to the average review example used). Since transactions don't wonk in offline mode, the average is not updated with any new data input while the app is offline. Is there a way to queue up a transaction to run when the app comes back online?
Or how can I best keep calculating the average online and offline?
@@ToddKerpelmanCorp Thanks I'll give it a try!
9:38 what does he mean by “individual document reads, not queries”?
@CharletteGHz But then later @ 13:52 he says he can create a transaction where he can perform a query. Now I am confused, can a transaction perform a query inside or not?!
Maybe it is allowed on the server, but that is not mentioned explicity.
For the last example, can't we use a batch update to update the city name of all restaurants?
hey so is it suggested to use transaction at all times? What if you app has a lot of users, is it necessary to use transactions for even trivial stuff?
Uh, no, clearly no. Almost explicitly said so around the 10:20 mark.
Just to clarify, "Batch write does not work or available for realtime database at least with the client sdk" - is this statement right???. Please clarify. By the way, great informative content.👍👍👍
Hello, good day. How could I create a hotel reservation system where users can book a room, pay with Stripe or PayPal, and assign them the corresponding room? The challenge is to prevent another user from trying to book the same room at the same time while one user is making a payment. Is this possible with transactions? What happens if I charge the user, and the transaction detects a change and doesn't commit the changes, then it retries and charges again? Or how can I work in a scenario where it's very likely that users want the same product at the same time?
so are impressive, the unique problem with firestore is the price for the big apps
Hi, Could you please help me out. How can i get the total number of documents without getting documents data, i just want total counter. I have googled a lot but no luck. For, small collection i can get total number but if large collection then it might cause problem of memory issue & documents read coast.
Language : PHP
You mention that transactions **assume** (6:19) the documents will not change. So there is no built-in locks on the documents? Will two transactions ran at the same time against the same documents changing the same fields cause inconsistencies? How is this any better than a batch write?
Ah, 12:34, documents are locked - OK, so then why the "assume"? What detail are we missing? If documents are locked as a part of the transaction process, why is it only assumed that the documents don't change?
I believe the layout that the video assumes involves three parties: client, server, and database. He speaks about locking as a typical method to solve race issues and states that the server actually does this. It's a little bit confusing the way he words it because he prefaces it with transactions being a solution to a problem with unreliable clients locking and then keeping the resource locked. Resource locking is generally an ideal solution, but you cannot resource lock when you cannot guarantee the editor's availability to unlock it. So the client should never be allowed to lock because you can't guarantee it will be around to unlock. That's the only reason for the first method, because it's not a good idea to let the client lock your data and disappear.
How does transactions and batches affect pricing?
Had to check my slack xD
If the logic is only implemented client-side, how does that protect against exploits?
Can anyone tell me if the transaction or batch write fails due to 1write per second does it throws any error
I dont get firebase recommended anywhere in the forum for large scale app to profitable at all
optimistic concurrency seems the same concept of eventual consistency
Trust me!! You should a professor in a top University..
Funfetti. Lolz :)
lol, the FED doesn't seem to have transactions... they create money like that ;)
What is the diference between this and promise.all?
Is this Transaction the same as using Facebook's dev dataloader?
Diablo 1 had a dupe bug and it was still a great game
Every video I watch from this channel makes me wanna go back to SQL
MySQL ♥
How you create those little cartoons . i like them ?? name pls ..
How much is +3 Todd?
Champing* at the bit
Ido not like bisuness group date and online payment system. Thank you
Lol! what is a plus-3 pen
The explanation is good but it’s too fast. For someone that is not good in English like me, it’s quite confusing 😅 but, thanks for making this video 😁
Pretty sure Diablo 2 Duping was exactly exploiting this.
it's not necessary to explain like this way!