Re: Read consistency

Hi Arko, Never used that consistency level so far, but here is some information: http://docs.datastax.com/en/cassandra/2.0/cassandra/dml/dml_tunable_consistency_c.html Cassandra 2.0 uses the Paxos consensus protocol, which resembles 2-phase > commit, to support linearizable consistency. All

Re: Read consistency

On Tue, Mar 15, 2016 at 6:43 PM, Arko Provo Mukherjee < arkoprovomukher...@gmail.com> wrote: > I am designing a system where for a situation, I need to have SERIAL > consistency during writes. > Be sure to understand the implications of : https://issues.apache.org/jira/browse/CASSANDRA-9328

Read consistency

Hello, I am designing a system where for a situation, I need to have SERIAL consistency during writes. I understand that if the write was with QUORUM, a Read with QUORUM would have fetched me the correct (most recent) data. My question is what is the minimum consistency level required for read,

Re: Read Consistency

From:Tyler Hobbs ty...@datastax.com Date:Tue, 30 Jun, 2015 at 10:42 pm Subject:Re: Read Consistency I think these scenarios are still possible even when we are writing at QUORUM ..if we have dropped mutations in our cluster.. It was very strange in our case ...We had RF=3 and READ/WRITE CL=QUORUM..we

Re: Read Consistency

wrote: Sorry for typo in your name Owen !! Anuj Sent from Yahoo Mail on Android https://overview.mail.yahoo.com/mobile/?.src=Android -- *From*:Anuj Wadehra anujw_2...@yahoo.co.in *Date*:Sun, 28 Jun, 2015 at 11:11 pm *Subject*:Re: Read Consistency Agree Owem

Re: Read Consistency

On Tue, Jun 30, 2015 at 12:27 PM, Anuj Wadehra anujw_2...@yahoo.co.in wrote: Agree Tyler. I think its our application problem. If client returns failed write in spite of retries, application must have a rollback mechanism to make sure old state is restored. Failed write may be because of the

Re: Read Consistency

On Tue, Jun 30, 2015 at 11:16 AM, Tyler Hobbs ty...@datastax.com wrote: Correct, if you get a WriteTimeout error, you don't know if any replicas have written the data or not. It's even possible that all replicas wrote the data but didn't respond to the coordinator in time. I suspect most

Re: Read Consistency

Sorry for typo in your name Owen !! Anuj Sent from Yahoo Mail on Android From:Anuj Wadehra anujw_2...@yahoo.co.in Date:Sun, 28 Jun, 2015 at 11:11 pm Subject:Re: Read Consistency Agree Owem !! Response in both scenarios would depend on the 2 replicas chosen for meeting QUORUM. But, the intent

Re: Read Consistency

: | Thanks..So all of us agree that in scenario 1, data would be returned and that was my initial understanding.. Anuj Sent from Yahoo Mail on Android | From:Anuj Wadehra anujw_2...@yahoo.co.in Date:Wed, 24 Jun, 2015 at 12:15 am Subject:Re: Read Consistency | M more confused...Different

Re: Read Consistency

(%7B%7D,'cvml','anujw_2...@yahoo.co.in'); *Date*:Wed, 24 Jun, 2015 at 12:15 am *Subject*:Re: Read Consistency M more confused...Different responses. .Anyone who can explain with 100% surity ? Thanks Anuj Sent from Yahoo Mail on Android https://overview.mail.yahoo.com/mobile/?.src=Android

Re: Read Consistency

https://overview.mail.yahoo.com/mobile/?.src=Android -- *From*:arun sirimalla arunsi...@gmail.com *Date*:Tue, 23 Jun, 2015 at 11:39 pm *Subject*:Re: Read Consistency Scenario 1: Read query is fired for a key, data is found on one node and not found on other two

Re: Read Consistency

Scenario 1: Read query is fired for a key, data is found on one node and not found on other two nodes who are responsible for the token corresponding to key. You read query will fail, as it expects to receive data from 2 nodes with RF=3 Scenario 2: Read query is fired and all 3 replicas have

Re: Read Consistency

M more confused...Different responses. .Anyone who can explain with 100% surity ? Thanks Anuj Sent from Yahoo Mail on Android From:arun sirimalla arunsi...@gmail.com Date:Wed, 24 Jun, 2015 at 12:00 am Subject:Re: Read Consistency Thanks good to know that. On Tue, Jun 23, 2015 at 11:27

Re: Read Consistency

, 2015 at 11:39 pm *Subject*:Re: Read Consistency Scenario 1: Read query is fired for a key, data is found on one node and not found on other two nodes who are responsible for the token corresponding to key. You read query will fail, as it expects to receive data from 2 nodes with RF=3

Re: Read Consistency

sirimalla arunsi...@gmail.com *Date*:Tue, 23 Jun, 2015 at 11:39 pm *Subject*:Re: Read Consistency Scenario 1: Read query is fired for a key, data is found on one node and not found on other two nodes who are responsible for the token corresponding to key. You read query will fail, as it expects

Re: Read Consistency

Thanks..So all of us agree that in scenario 1, data would be returned and that was my initial understanding.. Anuj Sent from Yahoo Mail on Android From:Anuj Wadehra anujw_2...@yahoo.co.in Date:Wed, 24 Jun, 2015 at 12:15 am Subject:Re: Read Consistency M more confused...Different

Read Consistency

Hi, Need to validate my understanding.. RF=3 , Read CL = Quorum What would be returned to the client in following scenarios: Scenario 1: Read query is fired for a key, data is found on one node and not found on other two nodes who are responsible for the token corresponding to key.

Re: Read Consistency

Why would it fail and with what Thrift error? What if the data didnt exist on any of the nodes..query wont fail if doesnt find data.. Not convinced.. Sent from Yahoo Mail on Android From:arun sirimalla arunsi...@gmail.com Date:Tue, 23 Jun, 2015 at 11:39 pm Subject:Re: Read Consistency

Re: Read Consistency

:39 pm *Subject*:Re: Read Consistency Scenario 1: Read query is fired for a key, data is found on one node and not found on other two nodes who are responsible for the token corresponding to key. You read query will fail, as it expects to receive data from 2 nodes with RF=3 Scenario 2: Read

Re: Read Consistency

Mail on Android https://overview.mail.yahoo.com/mobile/?.src=Android -- *From*:arun sirimalla arunsi...@gmail.com *Date*:Tue, 23 Jun, 2015 at 11:39 pm *Subject*:Re: Read Consistency Scenario 1: Read query is fired for a key, data is found on one node

Re: Read Consistency

.. Sent from Yahoo Mail on Android https://overview.mail.yahoo.com/mobile/?.src=Android -- *From*:arun sirimalla arunsi...@gmail.com *Date*:Tue, 23 Jun, 2015 at 11:39 pm *Subject*:Re: Read Consistency Scenario 1: Read query is fired for a key, data is found on one

Question about read consistency level

configure server to be DC aware), and that is fine. The point being, I wonder if there is something between ONE and QUORUM read consistency level that I could specify in my situation to return as soon as any node returns a non tombstone value? Thanks, Graham P.S. If not has this been discussed

Re: read consistency and clock drift and ntp

Here some links related do C* and clock synchronization: http://www.datastax.com/dev/blog/why-cassandra-doesnt-need-vector-clocks http://ria101.wordpress.com/2011/02/08/cassandra-the-importance-of-system-clocks-avoiding-oom-and-how-to-escape-oom-meltdown/ 2013/9/11 Jimmy Lin

Immutable CFs and read consistency

We have a Column Family that is immutable (no updates after the first write). Suppose we use RF=2 and W=1. Do we still need R=2, so that R+WRF? Or is it sufficient to have R=1? My guess is yes, R=1 is sufficient since if it reads a row, the row has to be correct: it can't get stale data.

RE: Immutable CFs and read consistency

The last sentence should have been In other words, does R apply also to (possibly failed) read attempts or only to successful reads? Anthony From: peacepatr...@hotmail.com To: user@cassandra.apache.org Subject: Immutable CFs and read consistency Date: Fri, 7 Oct 2011 06:21:04 -0700 We

RE: Immutable CFs and read consistency

...@hotmail.com] Sent: October-07-11 9:33 To: user@cassandra.apache.org Subject: RE: Immutable CFs and read consistency The last sentence should have been In other words, does R apply also to (possibly failed) read attempts or only to successful reads? Anthony _ From: peacepatr

A few questions on row caching and read consistency ONE

(all assume that row-caching is enabled for the column family). Q. If we're using read consistency ONE does the read request get sent to all nodes in the replica set and the first to reply is returned (i.e. all replica nodes will then have that row in their cache), OR does the request only get

RE: A few questions on row caching and read consistency ONE

From: Edward Capriolo [mailto:edlinuxg...@gmail.com] Sent: 18 August 2011 14:14 To: user@cassandra.apache.org Subject: Re: A few questions on row caching and read consistency ONE On Thu, Aug 18, 2011 at 5:01 AM, Stephen Henderson stephen.hender...@cognitivematch.commailto:stephen.hender

Re: A few questions on row caching and read consistency ONE

we know if it can work). If anyone could help answer/clarify the following questions it would be a great help (all assume that row-caching is enabled for the column family). Q. If we're using read consistency ONE does the read request get sent to all nodes in the replica set and the first

Re: A few questions on row caching and read consistency ONE

@cassandra.apache.org Subject: Re: A few questions on row caching and read consistency ONE On Thu, Aug 18, 2011 at 5:01 AM, Stephen Henderson stephen.hender...@cognitivematch.com wrote: Hi, We're currently in the planning stage of a new project which needs a low latency, persistent key/value store