Re: question on maximum disk seeks

with different disk offsets pointing to different SSTables? On Tue, Mar 21, 2017 at 10:09 AM, Jonathan Haddad <j...@jonhaddad.com> wrote: > The partition index is never updated, as sstables are immutable. > > On Tue, Mar 21, 2017 at 9:40 AM preetika tyagi <preetikaty...@gmail.com>

Re: question on maximum disk seeks

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

question on maximum disk seeks

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: https://docs.datastax.com/en/cassandra/3.0/cassandra/dml/dmlAboutReads.html As per my understanding, two disk seeks are required in the

how to recover a dead node using commit log when memtable is lost

Hi, I read in Cassandra architecture documentation that if a node dies and there is some data in memtable which hasn't been written to the sstable, the commit log replay happens (assuming the commit log had been flushed to disk) when the node restarts and hence the data can be recovered.

Re: how to recover a dead node using commit log when memtable is lost

ure. Each >> write is acknowledged only when data has been written to the commit log AND >> memtable. That solves the issues of node failures and data consistency. >> When the node boots back up it replays commit log files and you don't loose >> data that was already

Re: how to recover a dead node using commit log when memtable is lost

Assuming we are using periodic mode for commit log sync. On Wed, Apr 5, 2017 at 3:29 PM, preetika tyagi <preetikaty...@gmail.com> wrote: > Very good explanation. > One follow-up question. If CL is set to 1 and RF to 3, then there are > chances of the data being lost if the machine

Row cache tuning

Hi, I'm new to Cassandra and trying to get a better understanding on how the row cache can be tuned to optimize the performance. I came across think this article: https://docs.datastax.com/en/cassandra/3.0/cassandra/operations/opsConfiguringCaches.html And it suggests not to even touch row

Re: Row cache tuning

your use case. Maybe > explain what are you trying to solve with row cache and people can get into > discussion with more context. > > Regards, > Matija > > On Sat, Mar 11, 2017 at 9:15 PM, preetika tyagi <preetikaty...@gmail.com> > wrote: > >> Hi, >&

Re: Row cache tuning

a JMX or nodetool (nodetool > setcachecapacity > <https://docs.datastax.com/en/cassandra/2.1/cassandra/tools/toolsSetCacheCapacity.html> > ). > > Arvydas > > On Sun, Mar 12, 2017 at 9:46 AM, preetika tyagi <preetikaty...@gmail.com> > wrote: > >> T

Re: question on maximum disk seeks

agmentation on disk which leads to seeks during > sequential reads. > > > > Jan > > > > Gesendet von meinem Windows 10 Phone > > > > *Von: *preetika tyagi <preetikaty...@gmail.com> > *Gesendet: *Montag, 20. März 2017 21:18 > *An: *user@cassandra

Cassandra table definition with no clustering key

Hi all, I'm trying to understand the scenario when no clustering key is specified in a table definition. If a table has only a partition key and no clustering key, what order the rows under the same partition are stored in? Is it even allowed to have multiple rows under the same partition when

Re: Cassandra table definition with no clustering key

)." > > http://cassandra.apache.org/doc/latest/cql/ddl.html#the-partition-key > > -- > Kind regards, > Michael > > On 07/14/2017 06:59 PM, preetika tyagi wrote: > > Hi all, > > > > I'm trying to understand the scenario when no clustering key i

Impact on latency with larger memtable

Hi, I'm experimenting with memtable/heap size on my Cassandra server to understand how it impacts the latency/throughput for read requests. I vary heap size (Xms and -Xmx) in jvm.options so memtable will be 1/4 of this. When I increase the heap size and hence memtable, I notice the drop in

Re: Impact on latency with larger memtable

ible.” — T.E. Lawrence > > sent from my mobile > Daemeon Reiydelle > skype daemeon.c.m.reiydelle > USA 415.501.0198 <(415)%20501-0198> > > On May 24, 2017 9:32 AM, "preetika tyagi" <preetikaty...@gmail.com> wrote: > >> Hi, >> >> I'm e

How to avoid flush if the data can fit into memtable

Hi, I'm running Cassandra with a very small dataset so that the data can exist on memtable only. Below are my configurations: In jvm.options: -Xms4G -Xmx4G In cassandra.yaml, memtable_cleanup_threshold: 0.50 memtable_allocation_type: heap_buffers As per the documentation in cassandra.yaml,

Re: How to avoid flush if the data can fit into memtable

What if the commit log is disabled? On May 25, 2017 4:31 AM, "Avi Kivity" <a...@scylladb.com> wrote: > Cassandra has to flush the memtable occasionally, or the commit log grows > without bounds. > > On 05/25/2017 03:42 AM, preetika tyagi wrote: > > Hi, > >

Re: How to avoid flush if the data can fit into memtable

for your responses! Preetika On Fri, Jun 2, 2017 at 10:56 AM, Jeff Jirsa <jji...@apache.org> wrote: > > > On 2017-05-24 17:42 (-0700), preetika tyagi <preetikaty...@gmail.com> > wrote: > > Hi, > > > > I'm running Cassandra with a very small dataset so that

Re: How to avoid flush if the data can fit into memtable

overwrites, larger memtables result in less >> compaction). >> >> On 05/25/2017 05:59 PM, Jonathan Haddad wrote: >> >> Why do you think keeping your data in the memtable is a what you need to >> do? >> On Thu, May 25, 2017 at 7:16 AM Avi Kivity <a.

question on the code formatter

Hi all, I was trying to configure the Cassandra code formatter and downloaded IntelliJ-codestyle.jar from this link: https://wiki.apache.org/cassandra/CodeStyle After extracting this JAR, I was able to import codestyle/Default_1_.xml into my project and formatting seemed to work. However, I'm