Oh, I finally understand. As I read records one by one they aren't necessarily read from a single node, so if I got 965 records out of 1000, some of them could be read from other nodes which have all of 1000 records.
And about range scan - as far as I understand, range scan could be done only with Order Preserving Partitioner, but not with Random Partitioner... It would be cool to have consistency level of LOCAL to examine content of a local node for test purposes. 2013/5/17 aaron morton <aa...@thelastpickle.com> > Are you using a multi get or a range slice ? > > Read Repair does not run for range slice queries. > > Cheers > > ----------------- > Aaron Morton > Freelance Cassandra Consultant > New Zealand > > @aaronmorton > http://www.thelastpickle.com > > On 15/05/2013, at 6:51 PM, Sergey Naumov <sknau...@gmail.com> wrote: > > see that RR works, but sometimes number of records have been read > degrades. > > RR is enabled on a random 10% of requests, see the read_repair_chance > setting for the CF. > > OK, but I forgot to mention the main thing - each node in my config is a > standalone datacenter and distribution is DC1:1, DC2:1, DC3:1. So when I > try to read 1000 records with consistency ONE multiple times while > connected to node that just have been turned on, I got the following count > of records read (approximately): 120 220 310 390 .... 950 960 965 !! 955 !! > 970 ... If all other nodes contain 1000 records and read repair already > delivered 965 records to local DC (and so - local node), why sometimes I > see degradation of total records read? > > > > 2013/5/15 aaron morton <aa...@thelastpickle.com> > >> see that RR works, but sometimes number of records have been read >> degrades. >> >> RR is enabled on a random 10% of requests, see the read_repair_chance >> setting for the CF. >> >> If so, then the question is: how to perform local reads to examine >> content of specific node? >> >> You can check which nodes are replicas for a key using >> nodetool getendpoints >> >> If you want to read all the rows for a particular row you need to use a >> range scan and limit it by the token ranges assigned to the node. >> >> Cheers >> >> ----------------- >> Aaron Morton >> Freelance Cassandra Consultant >> New Zealand >> >> @aaronmorton >> http://www.thelastpickle.com >> >> On 14/05/2013, at 10:29 PM, Sergey Naumov <sknau...@gmail.com> wrote: >> >> Hello. >> >> I'am playing with demo cassandra cluster and decided to test read repair >> + hinted handoff. >> >> One node of a cluster was put down deliberately, and on the other nodes I >> inserted some records (say 1000). HH is off on all nodes. >> Then I turned on the node, connected to it with cql (locally, so to >> localhost) and performed 1000 reads by row key (with consistency ONE). I >> see that RR works, but sometimes number of records have been read degrades. >> Is it because consistency ONE and local reads is not the same thing? If so, >> then the question is: how to perform local reads to examine content of >> specific node? >> >> Thanks in advance, >> Sergey Naumov. >> >> >> > >
