@7:36 you mentioned btree databases write it to disk first. However with WAL in combination of btress, do DBs still writes go to disk ? I was under impression that with WAL they first write to WAL and then asynchronously they flush from memory to btress on disk. Please correct me if i am wrong.
Hey Jordan, let's say we have 5 partitions of Cassandra each storing some data. Is there a way to find out the oldest entry from those partitions , considering there are multiple keys for partition(like senderid, receiver I'd)
Cassandra's data integrity can be made better by configuring quorums. However, due to hinted handoff-> it still cannot provide any transactional/strong consistency guarantees
Nice video. I have a question. I read somewhere that "While transactions in MongoDB can span multiple documents within a shard, they cannot span multiple shards within a sharded cluster.". This limits us in comparing this to traditional SQL isn't it ?
Cassandra only used for chat application? or is there any other benefits? Because if read throughput is poor, then historical chat data retrieval would take a hit on overall latency isn't it ?
Amazing summary. 1. Can you do a similar video on dynamo db and compare it to Cassandra or other No sql db . Separately what’s the notepad software you are using .
@2:20 Your information is wrong there. I think you wanted to say that there are Partition keys (at least one) and Cluster keys (0 or more). Together they form the Primary key. Please review the video as it is misinforming thousands of people.
Oops, typo on my part. If this were a bigger deal I'd revise the video, but I don't think anyone is losing their job due to using the wrong terminology on cassandra key names.
Unrelated to the video, but I'm surprised that you're still able to consistently make content for youtube. Figured you would actually have no life with the new job.
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@7:36 you mentioned btree databases write it to disk first. However with WAL in combination of btress, do DBs still writes go to disk ? I was under impression that with WAL they first write to WAL and then asynchronously they flush from memory to btress on disk. Please correct me if i am wrong.
I imagine this one is implementation specific but I do think that some B-tree pages get cached in memory so in this case it's certainly possible!
Hey Jordan, let's say we have 5 partitions of Cassandra each storing some data. Is there a way to find out the oldest entry from those partitions , considering there are multiple keys for partition(like senderid, receiver I'd)
Unless you want to use something like a version vector, your easiest bet is probably just a timestamp lol
Cassandra's data integrity can be made better by configuring quorums.
However, due to hinted handoff-> it still cannot provide any transactional/strong consistency guarantees
True, thanks!
Nice video.
I have a question. I read somewhere that "While transactions in MongoDB can span multiple documents within a shard, they cannot span multiple shards within a sharded cluster.". This limits us in comparing this to traditional SQL isn't it ?
Interesting - if that's the case then I'd agree, I suppose you could always build two phase commit on top of it yourself though
Cassandra only used for chat application? or is there any other benefits? Because if read throughput is poor, then historical chat data retrieval would take a hit on overall latency isn't it ?
Read throughput is still good if you only read from one partition and take advantage of the sort key
Amazing summary.
1. Can you do a similar video on dynamo db and compare it to Cassandra or other No sql db .
Separately what’s the notepad software you are using .
Microsoft one note - to be honest DynamoDB is closed source so I don't know the exact design lol
@2:20 Your information is wrong there. I think you wanted to say that there are Partition keys (at least one) and Cluster keys (0 or more). Together they form the Primary key. Please review the video as it is misinforming thousands of people.
Oops, typo on my part. If this were a bigger deal I'd revise the video, but I don't think anyone is losing their job due to using the wrong terminology on cassandra key names.
If Mongodb is providing facilities as MySQL, then why everyone is not using it?
Because everyone is used to the relational data model and there's not really any reason to switch.
Unrelated to the video, but I'm surprised that you're still able to consistently make content for youtube. Figured you would actually have no life with the new job.
Ah I basically do lol, to be honest if I was lifting less I'd have a decent amount of free time
Web scale
Cluster key and sort key are the same thing. You meant to say partition key and clustering key.
Derp, nice catch