Re: question on maximum disk seeks

2017-03-21 Thread preetika tyagi
Oh I see. I understand it now. Thank you for the clarification! Preetika On Tue, Mar 21, 2017 at 11:07 AM, Jonathan Haddad wrote: > Each sstable has it's own partition index, therefore it's never updated. > > On Tue, Mar 21, 2017 at 11:04 AM preetika tyagi

Re: question on maximum disk seeks

2017-03-21 Thread Jonathan Haddad
Each sstable has it's own partition index, therefore it's never updated. On Tue, Mar 21, 2017 at 11:04 AM preetika tyagi wrote: > Yes, I understand that. However, what I'm trying to understand is the > internal structure of partition index. When a record associate with

Re: question on maximum disk seeks

2017-03-21 Thread preetika tyagi
Yes, I understand that. However, what I'm trying to understand is the internal structure of partition index. When a record associate with the same partition key is updated, we have two different records with different timestamps. There are chances of these two records being split across two

Re: question on maximum disk seeks

2017-03-21 Thread Jonathan Haddad
The partition index is never updated, as sstables are immutable. On Tue, Mar 21, 2017 at 9:40 AM preetika tyagi wrote: > Thank you Jan & Jeff for the responses. That was really useful. > > Jan - I have one follow-up question. When the data is spread over more > than one

Re: question on maximum disk seeks

2017-03-21 Thread preetika tyagi
Thank you Jan & Jeff for the responses. That was really useful. Jan - I have one follow-up question. When the data is spread over more than one SSTable in case of updates as you mentioned, we will need two seeks per SSTable (one for partition index and another for SSTable itself). I'm curious to

Re: question on maximum disk seeks

2017-03-20 Thread Jeff Jirsa
On 2017-03-20 13:17 (-0700), preetika tyagi wrote: > I'm trying to understand the maximum number of disk seeks required in a > read operation in Cassandra. I looked at several online articles including > this one: >