English, asked by ranjan6108, 3 months ago

Find all the partitions of the set A={ a , b , c , d }.​

Answers

Answered by Nathalie14
4

Answer:

You have a big problem here. Indeed, you really can't find the rows without actually scanning all of your partitions. The problem real problem is that C* will allow you to restrict your queries with a partition key, and then by your cluster keys in the order in which they appear in your PRIMARY KEY table declaration. So if your PK is like this:

PRIMARY KEY (A, B, C, D)

then you'd need to filter by A first, then by B, C, and only at the end by D.

That being said, for the part of finding your rows, if this is something you have to run only once, you

Could scan all your table and do comparisons of D in your App logic.

If you know the values of A you could query every partition in parallel and then compare D in your application

You could attach a secondary index and try to exploit speed from there.

Please note that depending on how many nodes do you have 3 is really not an option, secondary indexes don't scale)

If you need to perform such tasks multiple times, I'd suggest you to create another table that would satisfy this query, something like PRIMARY KEY (D), you'd then just scan three partitions and that would be very fast.

About deleting your rows, I think there's no way to do it without triggering compactions, they are part of C* and you have to live with them. If you really can't tolerate tombstone creation and/or compactions, the only alternative is to not delete rows from a C* cluster, and that often means thinking about a new data model that won't need deletes.

Answered by iamashwin31
2

Answer:

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