client side socket limit : 64K client side maximum connection per host : 8 read consistency level : Quorum
On Thu, Apr 3, 2014 at 12:59 PM, Shrikar archak <shrika...@gmail.com> wrote: > How about the client side socket limits? Cassandra client side maximum > connection per host and read consistency level? > > ~Shrikar > > > On Thu, Apr 3, 2014 at 12:20 AM, Apoorva Gaurav <apoorva.gau...@myntra.com > > wrote: > >> At the client side we are getting a latency of ~350ms, we are using >> datastax driver 2.0.0 and have kept the fetch size as 500. And these are >> coming while reading rows having ~200 columns. >> >> >> On Thu, Apr 3, 2014 at 12:45 PM, Shrikar archak <shrika...@gmail.com>wrote: >> >>> Hi Apoorva, >>> As per the cfhistogram there are some rows which have more than 75k >>> columns and around 150k reads hit 2 SStables. >>> >>> Are you sure that you are seeing more than 500ms latency? The >>> cfhistogram should the worst read performance was around 51ms >>> which looks reasonable with many reads hitting 2 sstables. >>> >>> Thanks, >>> Shrikar >>> >>> >>> On Wed, Apr 2, 2014 at 11:30 PM, Apoorva Gaurav < >>> apoorva.gau...@myntra.com> wrote: >>> >>>> Hello Shrikar, >>>> >>>> We are still facing read latency issue, here is the histogram >>>> http://pastebin.com/yEvMuHYh >>>> >>>> >>>> On Sat, Mar 29, 2014 at 8:11 AM, Apoorva Gaurav < >>>> apoorva.gau...@myntra.com> wrote: >>>> >>>>> Hello Shrikar, >>>>> >>>>> Yes primary key is (studentID, subjectID). I had dropped the test >>>>> table, recreating and populating it post which will share the cfhistogram. >>>>> In such case is there any practical limit on the rows I should fetch, for >>>>> e.g. >>>>> should I do >>>>> select * form marks_table where studentID = ? limit 500; >>>>> instead of doing >>>>> select * form marks_table where studentID = ?; >>>>> >>>>> >>>>> On Sat, Mar 29, 2014 at 5:20 AM, Shrikar archak >>>>> <shrika...@gmail.com>wrote: >>>>> >>>>>> Hi Apoorva, >>>>>> >>>>>> I assume this is the table with studentId and subjectId as primary >>>>>> keys and not other like like marks in that. >>>>>> >>>>>> create table marks_table(studentId int, subjectId int, marks int, >>>>>> PRIMARY KEY(studentId,subjectId)); >>>>>> >>>>>> Also could you give the cfhistogram stats? >>>>>> >>>>>> nodetool cfhistograms <your keyspace> marks_table; >>>>>> >>>>>> >>>>>> >>>>>> Thanks, >>>>>> Shrikar >>>>>> >>>>>> >>>>>> On Fri, Mar 28, 2014 at 3:53 PM, Apoorva Gaurav < >>>>>> apoorva.gau...@myntra.com> wrote: >>>>>> >>>>>>> Hello All, >>>>>>> >>>>>>> We've a schema which can be modeled as (studentID, subjectID, marks) >>>>>>> where combination of studentID and subjectID is unique. Number of >>>>>>> studentID >>>>>>> can go up to 100 million and for each studentID we can have up to 10k >>>>>>> subjectIDs. >>>>>>> >>>>>>> We are using apahce cassandra 2.0.4 and datastax java driver >>>>>>> 1.0.4. We are using a four node cluster, each having 24 cores and 32GB >>>>>>> memory. I'm sure that the machines are not underperformant as on same >>>>>>> test >>>>>>> bed we've consistently received <5ms response times for ~1b documents >>>>>>> when >>>>>>> queried via primary key. >>>>>>> >>>>>>> I've tried three approaches, all of which result in significant >>>>>>> deterioration (>500 ms response time) in read query performance once >>>>>>> number >>>>>>> of subjectIDs goes past ~100 for a studentID. Approaches are :- >>>>>>> >>>>>>> 1. model as (studentID int PRIMARY KEY, subjectID_marks_map map<int, >>>>>>> int>) and query by subjectID >>>>>>> >>>>>>> 2. model as (studentID int, subjectID int, marks int, PRIMARY >>>>>>> KEY(studentID, subjectID) and query as select * from marks_table where >>>>>>> studentID = ? >>>>>>> >>>>>>> 3. model as (studentID int, subjectID int, marks int, PRIMARY >>>>>>> KEY(studentID, subjectID) and query as select * from marks_table where >>>>>>> studentID = ? and subjectID in (?, ?, ?....?) number of subjectIDs in >>>>>>> query being ~1K. >>>>>>> >>>>>>> What can be the bottlenecks. Is it better if we model as (studentID >>>>>>> int, subjct_marks_json text) and query by studentID. >>>>>>> >>>>>>> -- >>>>>>> Thanks & Regards, >>>>>>> Apoorva >>>>>>> >>>>>> >>>>>> >>>>> >>>>> >>>>> -- >>>>> Thanks & Regards, >>>>> Apoorva >>>>> >>>> >>>> >>>> >>>> -- >>>> Thanks & Regards, >>>> Apoorva >>>> >>> >>> >> >> >> -- >> Thanks & Regards, >> Apoorva >> > > -- Thanks & Regards, Apoorva
