RE: Read latency issue

by ~20ms, compared to using QUORUM. It would only have read from the local node. (I think, may be confusing secondary index reads here). Cheers - Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 3/10/2012, at 2:17 AM, Roshni Rajagopal

RE: Data Modeling: Comments with Voting

two users vote on the same comment simultaneously? How do you update the entries in #d column family to prevent duplicates? Also #a and #c can be combined together using TimeUUID as comment ids. - Drew On Sep 27, 2012, at 2:13 AM, Roshni Rajagopal roshni_rajago...@hotmail.com wrote: Hi

RE: Data Modeling: Comments with Voting

Hi Drew, I think you have 4 requirements. Here are my suggestions. a) store comments : have a static column family for comments with master data like created date, created by , length etcb) when a person votes for a comment, increment a vote counter : have a counter column family for

RE: 1.1.5 Missing Insert! Strange Problem

By any chance is a TTL (time to live ) set on the columns... Date: Tue, 25 Sep 2012 19:56:19 -0700 Subject: 1.1.5 Missing Insert! Strange Problem From: gouda...@gmail.com To: user@cassandra.apache.org Hi All, I have a 4 node cluster setup in 2 zones with NetworkTopology strategy and strategy

RE: Cassandra Counters

, you know), so I may be wrong in any given statement.Cheers On Tue, Sep 25, 2012 at 6:53 AM, Roshni Rajagopal roshni_rajago...@hotmail.com wrote: Thanks Milind, Has anyone implemented counting in a standard col family in cassandra, when you can have increments and decrements to the count

RE: Cassandra Counters

Hi folks, I looked at my mail below, and Im rambling a bit, so Ill try to re-state my queries pointwise. a) what are the performance tradeoffs on reads writes between creating a standard column family and manually doing the counts by a lookup on a key, versus using counters. b) whats the

RE: Cassandra Counters

, the CAP theorem comes into life. in Cassandra, Availability and Network Partitioning trumps over Consistency. So yes, you sacrifice strong consistency for availability and partion tolerance; for eventual consistency. On Sep 24, 2012 10:28 AM, Roshni Rajagopal roshni_rajago...@hotmail.com wrote

Data Model - Consistency question

Hi Folks, In the relational world, if I needed to model students, courses relationship, I may have donea students -master tablea course - master tablea bridge table students-course which gives me the ids to students and the courses they are taking. This can answer both 'which students take

Solr Use Cases

Hi, Im new to Solr, and I hear that Solr is a great tool for improving search performanceIm unsure whether Solr or DSE Search is a must for all cassandra deployments 1. For performance - I thought cassandra had great read write performance. When should solr be used ?Taking the following use

Data Model

I want to learn how we can model a mix of static and dynamic columns in a family. Consider a course_students col family which gives a list of students for a coursewith row key- Course IdColumns - Name, Teach_Nm, StudID1, StudID2, StudID3Values - Maths, Prof. Abc, 20,21,25 where 20,21,25 are

Re: Data Modelling Suggestions

other query strategies without messing with how you store the item information. Maybe you can solve it with a secondary index by timestamp too. Guille On Thu, Aug 23, 2012 at 7:26 AM, Roshni Rajagopal roshni.rajago...@wal-mart.commailto:roshni.rajago...@wal-mart.com wrote: Hi, Need some help

Data Modeling- another question

Hi, Suppose I have a column family to associate a user to a dynamic list of items. I want to store 5-10 key information about the item, no specific sorting requirements are there. I have two options A) use composite columns UserId1 : { itemid1:Name = Betty Crocker, itemid1:Descr = Cake

Re: Secondary index partially created

What does List my_column_family in CLI show on all the nodes? Perhaps the syntax u're using isn't correct? You should be getting the same data on all the nodes irrespective of which node's CLI you use. The replication factor is for redundancy to have copies of the data on different nodes to help

Data Modelling Suggestions

Hi, Need some help on a data modelling question. We're using Hector Datastax Enterprise 2.1. I want to associate a list of items for a user. It should be sorted on the time added. And items can be updated (quantity of the item can be changed), and items can be deleted. I can model it like

Re: Decision Making- YCSB

and change the read patterns from latest/random/etc does a decent job of stressing normal and worst-case scenarios on the read path. Still I would try to build my own real world use case as a tool to evaluate a solution before making a choice. Edward On Thu, Aug 9, 2012 at 8:58 PM, Roshni Rajagopal

Decision Making- YCSB

Hi Folks, I'm coming up with a set of decision criteria on when to chose traditional RDBMS vs various NoSQL options. So one aspect is the application requirements around Consistency, Availability, Partition Tolerance, Scalability, Data Modeling etc. These can be decided at a theoretical

Re: Project Management

Hi Baskar, The key aspect here is, you have to think of your queries , and denormalize. Here are my suggestions based on my understanding so far. You seem to have 2 queries A) what all users do I have B) what organizations do the users belong to The first can be a static column family- these

Re: Changing comparator

the encoding. It would be just simpler to let the CQL driver take care of it...) Regards, Christof On 8/3/2012 11:31 AM, Roshni Rajagopal wrote: Christof , can't you just use ASSUME for the CQL session? http://www.datastax.com/docs/1.0/references/cql/ASSUME Regards, Roshni On 03/08/12

Re: Unsuccessful attempt to add a second node to a ring.

that the communication is somehow established? -- regards, Jakub Glapa On Wed, Aug 1, 2012 at 11:36 AM, Jakub Glapa jakub.gl...@gmail.commailto:jakub.gl...@gmail.com wrote: yes it's the same -- regards, pozdrawiam, Jakub Glapa On Wed, Aug 1, 2012 at 11:24 AM, Roshni Rajagopal roshni.rajago...@wal

Re: Changing comparator

Christof , can't you just use ASSUME for the CQL session? http://www.datastax.com/docs/1.0/references/cql/ASSUME Regards, Roshni On 03/08/12 2:26 PM, Christof Roduner chris...@scandit.com wrote: Hi, I know that changing a CF's comparator is not officially supported. However, there is a

Re: Unsuccessful attempt to add a second node to a ring.

Jakub, Have you set the Data, commitlog, saved cache directories to different ones in each yaml file for each node? Regards, Roshni From: Jakub Glapa jakub.gl...@gmail.commailto:jakub.gl...@gmail.com Reply-To: user@cassandra.apache.orgmailto:user@cassandra.apache.org

Re: Unsuccessful attempt to add a second node to a ring.

: cassandra -- regards, pozdrawiam, Jakub Glapa On Wed, Aug 1, 2012 at 10:29 AM, Roshni Rajagopal roshni.rajago...@wal-mart.commailto:roshni.rajago...@wal-mart.com wrote: Jakub, Have you set the Data, commitlog, saved cache directories to different ones in each yaml file for each node

Re: Does Cassandra support operations in a transaction?

Hi Ivan, Cassandra supports 'tunable consistency' . If you always read and write at a quorum (or local quorum for multi data center) from one , you can guarantee that the results will be consistent as in all the data will be compared and the latest will be returned, and no data will be out of

Re: Schema question : Query to support Find which all of these 500 email ids have been registered

In general I believe wide rows (many cols ) are preferable to skinny rows (many rows) so that you can get all the information in 1 go, One can store 2 billion cols in a row. However, on what basis would you store the 500 email ids in 1 row? What can be the row key? For e.g. If the query you want

Re: Cassandra and Tableau

Hi Robin, Im from an analytics background, was working in the traditional BI tools like OBIEE and Business Objects, so I am very interested in your evaluations of a good analytics toolset combination. Do share your learnings, At a high level as I understand, cassandra can be used as the

Starting cassandra with -D option

Hi Folks, We wanted to have a single cassandra installation, and use it to start cassandra in other nodes by passing it the cassandra configuration directories as a parameter. Idea is to avoid having the copies of cassandra code in each node, and starting each node by getting into

Re: Setting column to null

to prepared statement executed multiple times? If I need to execute those specialized statements, should I still use prepared statement or should I just generate a string with everything in ascii format? -Original Message- From: Roshni Rajagopal [mailto:roshni.rajago...@wal-mart.com] Sent

Re: Setting column to null

Would you want to view data like this there was a key, which had this column , but now it does not have any value as of this time. Unless you specifically want this information, I believe you should just delete the column, rather than have an alternate value for NULL or create a composite

Re: Problem in getting data from a 2 node cluster of Cassandra

Hi Prakrati, In an ideal situation, no data should be lost when a node is added. How are you getting the statistics below. The output below looks like its from some code using Hector or Thrift..is the code to get statistics from a 1 node cluster or 2 exactly the same- with the only change

Re: How to include two nodes in Java code using Hector

In Hector when you create a cluster using the API, you specify an IP address cluster name. Thereafter internally which node serves the request or how many nodes need to be contacted to read/write data depends on the cluster configuration i.e. Whats your replication strategy, factor,

Re: Can not find auto bootstrap property in cassandra.yaml for Cassandra 1.1.0

Hi Prakrati, In 1.1.0 you don't need to set this, its by default. Im also on 1.1.0 and I didn't need to set this. Regards, Roshni From: Prakrati Agrawal prakrati.agra...@mu-sigma.commailto:prakrati.agra...@mu-sigma.com Reply-To: user@cassandra.apache.orgmailto:user@cassandra.apache.org

Re: Adding a new node to Cassandra cluster

Prakrati, I believe even though you would specify one node in your code, internally the request would be going to any – perhaps more than 1 node based on your replication factors consistency level settings. You can try this by connecting to one node and writing to it and then reading the

Replication factor via hector

Hi , I'm trying to see the effect of different replication factors and consistency levels for a keyspace on a 4 node cassandra cluster. I'm doing this using hector client. I could not find an api to set replication factor for a keyspace though I could find ways to modify consistency level.

Re: no snappyjava in java.library.path (JDK 1.7 issue?)

Hi Stephen, Cassandra's wiki says Cassandra requires the most stable version of Java 1.6 you can deploy. http://wiki.apache.org/cassandra/GettingStarted Regards, Roshni From: Stephen McKamey step...@mckamey.commailto:step...@mckamey.com Reply-To: