What is Redis and What Does It Do?
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- เผยแพร่เมื่อ 13 เม.ย. 2021
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Trevor Sullivan covers the Redis cache service: what it is, what it does, and how it helps. It's an open source tool that runs as a service in the background that allows you to store data in memory for high-performance data retrieval and storage. That's the technical explanation, but watch on to hear about how useful it is for all manner of use cases.
Imagine you have a web application that's running inside a Docker container or directly on a server. If that web application needs to retrieve some data from a database like MySQL, PostgreSQL or MS SQL, that query could take anywhere between 15 and 60 seconds.
If you have a user waiting up to a minute for the performance of that report data or whatever data the user is trying to receive, you're going to have an unhappy user. A redis cache speeds all that up.
It's possible to store data inside of a Redis cache instance and make the retrieval of that data occur directly from memory (RAM) from a server that's running the Redis service - rather than making the application go all the way back to the database. Instead, the web server can check with Redis if it has the data it wants.
Redis isn't particularly valuable when it's standing in-between one web server and a database. But, what if you're running a large scale fleet of hundreds of webservers? One Redis cache can pool the requests and answers for all those webservers so that they don't have to individually go all the way to the database each time.
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#redis #docker #mysql #ittraining #cbtnuggets
My man looks like he's putting tutorials straight from Antarctica
He looks like the CEO of a certain fortune 500 company. And that can't be a bad thing.
I mean, minus the nose ring.
I think he looks pretty similar to Twitter's CEO Jack Dorsey...
I started a LinkedIn course on Redis, just to see what is it about. After 20 minutes I started to search on TH-cam for a summary of Redis and get the meaning of it in short time. This explanation is short, understandable, just great. Thanks!
Awesome explanation Trevor. Breaking down problems into dummy understanding is an art.
Awesome elaboration. He hit the nail straight to the point
I thought u were Jack Dorsey at firsts lol
😂 me too
🤣🤣🤣🤣
Me too
lol, me too.
Lmfaooooooooo 😂😂😂
This is a really good video. I’m a network engineer playing with docker and I’ve seen this a few times. Always wondered what it is.
FINALLY! a clear explanation as to what it actually does. thank you for this.
Couldn't have put it better, great work!
real quick and awesomely covered in less time.
Thanks for starting from User experience, so we can understand the use-case clearly.
Thank you so much. Heard Vercel recently implemented a Key-Value system, and it’s a Redis-like data system. This video gave me a good overview of Redis.
Very good in explaining Redis serving as a cache system; would be nice to expand to all important features of Redis ...
the beard is an indicator of experience
awesome explanation and greatly clear english speaking. I can fully listen to you without looking at the sub. Well done!
Simple and precise, it made me recall how my fried explained me about Redis and Guava caching but unfortunately i dont recall the difference btw them.
That's a nice explanation Trevor, i like the way you explained bit by bit to understanding level
Excellent video! Thanks a lot.
simple and clear, to the point.......really like the way you explain.
i agree with your thinking！🥤cheers🥤
Awesome dude... simple and crispy explanation. Keep it up appreciate.
Just what I needed.
Wonderful Video! Thank you for the clear explanation!
Good for start. Thanks 😊
Best video on Redis ❤️
thank you for such a quick useful explanation
Great explanation! wonder what will happen to traffic if the redis goes down? will the web goes down as well as it cant retrieve data from cache? or will the web traffic will go directly to the database. Thanks
Thank you for your great explanation! 💥
thank you, it was so helpful
Clean and clear. Thank you very much!
awesome. simple and explained with diagrams !
Wonderful tutorial, thank you.
Fantastic! concise. clear
Awesome explanation in easy way ❤
excellent explanation!
very clear explanation. make us impressed a lot.
Excellent explanation, thanks a lot 🤗
Great explanation thanks.
Excellent explanation!!!
Thank you for this content. very helpful
Very informative. Thank you.
That was a great breakdown thanks!!!
This was very helpful. Thanks sir!
We're so glad it's helpful for you! Thank you for learning with us.
What if the user has updated he is info, Would the user get an old data or new data?
That was really helpful...Thank You!!
awesome explanation jack dorsey
great explanation , thank you
Very informative.
thanks, very well explained and clear
I have to admit, I was initially distracted by your glorious beard! :D
I have a few questions I hope you can clarify -
1) Why is querying Redis faster than directly querying a database - is it because there is less amount of data to search from? Also, at what point does the cache start removing data? Is the oldest data removed first or is it the data that is accessed least often?
2) If we are using a cache worker to update the Redis cache every time there is a change to the database, why is this any faster than just directly querying the database? It seems that in this case, the Redis cache contains the same amount of information as the database and that the database would be updated before the Redis cache anyways.
Thank you. It cleared all my doubts😀
Greatly explained
Very good explanation.
Nice video Sir ,please carry on ,nice voice clarity and representation
excellent explanation
thanks for creating this video,
Liking for the adorable outro. It HAS been informative for me!
Thanks, that was very helpful.
Well i had a query how long does the redis store a cache for is it for days or hours as if the cache does not clear then the redis cache size would get full right
awesome loved it!!!!
Aha, so basically an in memory cache. Very well structured video; shows the problem and how Redis attempts to solve it, making it intuitive to grasp its purpose.
@Alek Wolf I'm a complete beginner at Redis, but this seems to be a general software problem. Since Redis is an in-memory app that strives to use cache, to decrease the wait time for common data queries, it is based on RAM usage. Since it is based on RAM usage, it's limited by the RAM provided with the machine. I don't think BigData ever was a viable target for usage of Redis. BigData can return huge responses to queries and it's not really feasible to hold it all in limited RAM, a few bigger reports and OOM is achieved. I suppose at that point a better approach would be putting in resources to speed up the access to BigData resources and optimizing queries.
This isn't what redis is, this is just an explanation of how a cache works. Caching is just one use case for redis. This video will make beginners think that redis is a cache, which is false. Redis is an in-memory key-value store with pub-sub model with many use cases such as creating event streams in architecture beyond mere caching.
Great video!
Thanks for the great explanation. So in order words, without a cache workers, redis won't be aware of new data and there is always the risk to fetching stale data?
good explanation. thakns a bunch
Well explained
Truly a great beard, so wow! much wisdom!
Thanks! Helped me alott!!
Amazing content, tkss
Well understood 😎. Thanks
thank you ,Sir
Thank you!
So does this mean that the redis caching service will only be a hit if there has already been an existing query on the DB?
Also, will the cache itself ever get too full, then what?
Thank you for this
super explained
Thank you
greeeaaat video
Can you please let us know how the Redis implementation in Openstack Controller works?
I’m not totally clear how the amount of RAM allocated to a docker instance would be able to hold any substantial amount of data from a database. I understand how this is useful for commonly queried data, but wouldn’t the service have to be very selective in what it chooses to cache? And don’t we have to worry about available RAM for the web server? Does Redis ever battle the server for resources?
That easy, thank you
Sounds interesting
1. What are the memory requirements in the case of a large-scale database to keep this solution effective?
2. How effective this solution for a system that generates random access to a large-scale database?
in which case Redis cache would require a lot of memory to stay effective
I think that these topics should be referred to by the video.
Hi Shuky, thank you for your questions.
It will really depend on the load and amount of data, but there are some profiles in AWS and Azure that will be for enterprise requirements up to 14TB of memory. docs.microsoft.com/en-us/azure/azure-cache-for-redis/cache-planning-faq#azure-cache-for-redis-performance This is a good break down of some performance recommendations.
We hope this is helpful! Thank you for learning with us.
Store data in a redis cache instance and retrieve that data from the RAM of the server that’s running the service.
Initially the instance doesn’t have any data instead of it’s config data.
insightful
Thank u!
Good video
Wish we all Had Guys like this before College.
Redis, which stands for Remote Dictionary Server cements it
is there a follow up on this, or is this part of some series that is available elsewhere? Thanks in advance!
You can check out the course here: www.cbtnuggets.com/it-training/devops/redis-essentials
If you're not a current subscriber, you can sign up for a FREE 7-day trial to watch: training.cbt.gg/sbp
@@cbtnuggets Thank you very much!
Thankyou
So is the preferred pattern to have your webserver do all reads from redis, and all its writes to the database? Then run a cache worker so that the cache gets updated automatically?
This video isn't what redis is, this is just an explanation of how a cache works. Caching is just one use case for redis. This video will make beginners think that redis is a cache, which is false. Redis is an in-memory key-value store with pub-sub model with many use cases such as creating event streams in architecture beyond mere caching. Redis is a tool, like a nail, your preferred pattern in how to use it depends on your architecture which you need to create.
where is the next video ? i cant find it
Thanks
Very good, great accent
SQL server already has buffer cache where it stores frequently used data from database. This helps in fast data retrieval.
How is redis different from SQL Buffer cache ?
If using sql then i think no need to use redis
Cache hit on the explanation
I used to hit the cache pretty hard in college.
thanks
Thank you for the explanation, you made it simple to understand.
thanks, ..
save your self the trouble and just use redis as a database, it is amazing
One question: Suppose we have a web application in which we upload data. Web application also performs some analysis on that data based on the options we give. In the end, application gives prepared and analyzed output data back to user. Will in this case can the redis cache makes things faster?
Hi, Vikas! To simply answer your question, yes it will make it faster. Most of the data even when a web app is processing the information will have a cache and that will be purged or exceed the limits. The Redis cache will be able to have the information ready and be able to transmit the data without having to do a full retrieval every time.
Hope that helps! Thank you for learning with us.
How it is different than Riverbed’s technology?
Hi, can you please do a video on Ncache?
Request here! www.cbtnuggets.com/request-training
well, another thing to learn about