Intro to Replication - Systems Design "Need to Knows" | Systems Design 0 to 1 with Ex-Google SWE

Replication applies in real life too - I used to completely rely emotionally on one girlfriend, but I've since learned my lesson that now I need 5.
Thanks for one year Gigachads. A lot of you are working hard and I can see it paying off.

[@2sourcerer]

Systems Design 2.0 is so much better than the first attempt! Thank you so much!

[@rakeshvarma8091]

Thanks for the video. In the video, for WAL you were saying that we will store the disk address & and the content (0x0aff : "Jordan"). How will it be useful for replication on other DB replica server ? What's the difference between WAL & Replication log ? Do they represent same statements ?

[@jordanhasnolife5163]

I believe in either this video or the next I cover that lol

[@hazemabdelalim5432]

I have a question related to replication, How replication will work in case if the data is in memory? If you have a server that has a data structure like TRIE for example and you want some other servers to run and server with the same version of this TRIE ? What is the best way of doing that ? I am assuming that it might be the case they serialize the data in memory to a file and then replicate it ? I didn't find many sources about how this is actually done .

[@jordanhasnolife5163]

Should be the same honestly, just take the memory addresses you wrote to and transport it. This maintains a log which is ideal, unless you wanted the batch the final states of the write and transport them every once in a while

[@shobhitarya1637]

Does nosql databases use same mechanism i.e using WAL or Logical replication log to replicate data to other nodes OR it is just applicable to sql databases?

[@jordanhasnolife5163]

I imagine this would be database specific but I don't see why they wouldn't

[@ovsepavakian6109]

Never heard of replication between different types of database management software. Is it a Postgres feature,or you can replicate any db to any other db?

[@jordanhasnolife5163]

If nothing else you can build your own solution via change data capture

[@Anonymous-ym6st]

Thanks for the structured videos, they are super helpful! I have a n00b question about WAL. Kind of irrelevant to replication, but the mentioning of WAL here reminds me of my question. I learnt from your video WAL could be used to help with durability, as if something crash, it can help with rebuild. But what happen if the crash happened when I write into the WAL? I need a WAL of WAL?

[@jordanhasnolife5163]

If it's not completely in the WAL, it's not considered a valid write. We'd just drop that one.

[@xiaoborao982]

hi bro, i have a question about the database , there are some different types databases, and have some features like consistency or high availability, how these databases are used for the replication , thanks

[@jordanhasnolife5163]

This is a very loaded question! The short answer is that different replication patterns have their own pros and cons, and a database claiming to be "high availability" is mostly just marketing. Stick around for the next few videos, I think you'll get a better sense soon.

[@xiaoborao982]

@@jordanhasnolife5163 thanks bro, expect your coming video, keep up good working

[@zalooooo]

@@jordanhasnolife5163 Not sure I agree with this take. HA from my experience usually refers to "always on" a backup (passive) that becomes active if the leader goes down. This is generally most useful when there's some state / data structures that needs to be reconstructed on startup, and you save the downtime of your system by having a warm backup readily available

[@jordanhasnolife5163]

@@zalooooo Interesting - if that's the usage then that's fair enough though I could have sworn I've seen it used in different contexts

[@zalooooo]

@@jordanhasnolife5163 lemme find an example / fact check myself rq

[@datvithanh8192]

not the buttplug strong consistency

[@pratikkumar939]

Its The tech lead

[@jordanhasnolife5163]

His channel is literally called tech lead lol