Re: the process of reading and writing

On Thu, Sep 2, 2010 at 8:19 PM, Ying Tang wrote: > Recently , i read the paper about Cassandra again . > And now i have some concepts about  the reading and writing . > We all know Cassandra uses NWR , > When read : > the request ---> a random node in Cassandra .This node acts as a proxy ,and > it

Re: question about Cassandra error

You seem to be typing 0.7 commands on a 0.6 cli. Please follow the README in the version you are using, e.g.: set Keyspace1.Standard2['jsmith']['first'] = 'John' On Thu, Sep 2, 2010 at 5:35 PM, Simon Chu wrote: > I downloaded cassendra 0.6.5 and ran it, got this error: > > bin/cassandra -f >  I

Re: the process of reading and writing

Hi Aaron Thanks for your reply. In you text , does the coordinator means the random client that user send request to ? Do you mean no matter how many W is assigned to , the data will copy on N node ? Just the client will think this write action is successful when W nodes are be written ? Ps. The

Re: the process of reading and writing

AKAIK, For read the coordinator sends the request to the number of nodes specified in the RF. RR is kicked off on the coordinator node after the read has completed. There is no key coordinator, what would you do if it as down ? The first node in the list of replication nodes is considered special,

Re: Is the secondary index maintained synchronously in 0.7

Thanks. But why does this situation happen? I mean "but not in isolation". Can we avoid it? 2010/9/2 Jonathan Ellis > yes, it is updated atomically (but not in isolation, it's possible for > a client to see changes to one but not the other temporarily) > > On Thu, Sep 2, 2010 at 1:47 PM, Alvin J

Re: 4k keyspaces... Maybe we're doing it wrong?

Create one big happy love in keyspace. Use the key structure to identify the different clients data. The is more support for multi tenancy systems but a lot of the memory configuration is per keyspace/column family, so you cannot run that many keyspaces. This page has some more information http://w

the process of reading and writing

Recently , i read the paper about Cassandra again . And now i have some concepts about the reading and writing . We all know Cassandra uses NWR , When read : the request ---> a random node in Cassandra .This node acts as a proxy ,and it routes the request. Here , 1. the proxy node route this requ

Re: question about Cassandra error

JNA is _not_ necessary to use Cassandra, but the server can perform some operations more efficiently if JNA is in place. Not sure what is causing the error you are seeing in the CLI though: those statements appear to be valid. -Original Message- From: "Mike Peters" Sent: Thursday, Sept

Re: question about Cassandra error

Simon, See this page: http://www.riptano.com/blog/whats-new-cassandra-065 "Because of licensing issues , we can't distribute JNA with Cassandra, so you must manually add it to the Cassandra lib/ directory or otherwise place it on the classpath." On 9

4k keyspaces... Maybe we're doing it wrong?

Hi, We're in the process of migrating 4,000 MySQL client databases to Cassandra. All database schemas are identical. With MySQL, we used to provision a separate 'database' per each client, to make it easier to shard and move things around. Does it make sense to migrate the 4,000 MySQL dat

question about Cassandra error

I downloaded cassendra 0.6.5 and ran it, got this error: bin/cassandra -f INFO 16:46:06,198 JNA not found. Native methods will be disabled. INFO 16:46:06,875 DiskAccessMode 'auto' determined to be mmap, indexAccessMode is mmap is this an issue? When I tried to run cassandra cli from the exampl

Re: Is the secondary index maintained synchronously in 0.7

yes, it is updated atomically (but not in isolation, it's possible for a client to see changes to one but not the other temporarily) On Thu, Sep 2, 2010 at 1:47 PM, Alvin Jin wrote: > > Hello, > > I was thinking the details of the secondary index in 0.7. > Will it be updated atomically with its b

Impact on running cassandra cluster from changing hostnames...

Folks- What is the correct process of changing the hostnames and IPs of each server in a cassandra cluster. In my use-case we're shutting it down and then changing the names and ips. No changes to hardware during the processes. Beyond config changes, what should I be concerned about? -- Virtua

Re: Data Center Move

Hi, Yes we saw that but felt that maybe moving files would be faster than rerolling a patched version of the server, so we were wondering if we could move files as described. If that fails to work for us, we may try out this patch. -Anthony On Thu, Sep 02, 2010 at 01:28:15PM -0500, Peter Fale

Is the secondary index maintained synchronously in 0.7

Hello, I was thinking the details of the secondary index in 0.7. Will it be updated atomically with its base table? Any explaination the on secondary index is appreciated. Thanks. -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Is-the-secondar

Re: Data Center Move

You will likely need to rename some of the files to avoid collisions (they are only unique per node). Otherwise, yes, this can work. On Thu, Sep 2, 2010 at 11:09 AM, Anthony Molinaro wrote: > Hi, > >  We're running cassandra 0.6.4, and need to do a data center move of > a cluster (from EC2 to ou

Re: Data Center Move

Anthony, I'm just getting my feet wet with Cassandra, so I'm far from an expert, but I'm curious whether you saw my posting a few days ago about using the EC2 "public" IP addreses with cassandra: http://www.mail-archive.com/user@cassandra.apache.org/msg05692.html *If* I understand the problem cor

Data Center Move

Hi, We're running cassandra 0.6.4, and need to do a data center move of a cluster (from EC2 to our own data center). Because of the way the networks are set up we can't actually connect these boxes directly, so the original plan of add some nodes in the new colo, let them bootstrap then decomm

Re: docs about the secondary index?

You can't, yet. There are examples in test/system/test_thrift_server.py; look for "index" (moving to user@) On Thu, Sep 2, 2010 at 8:20 AM, Changjiu Jin wrote: > Hello, > > > > Where can we find docs about the secondary index? > > > > Thanks > > > > > > > > -- Jonathan Ellis Project Chair,

Re: Cassandra on AWS across Regions

On Thu, Sep 2, 2010 at 5:52 AM, Phil Stanhope wrote: > Ben, can you elaborate on some infrastructure topology issues that would > break this approach? > As noted, the naive approach results in nodes behind the same NAT having to communicate with each other through that NAT rather than directly.

Re: Looking for something like "like" of mysql.

you can try using different CF for different result sets or inverted index. but looking at the number of inserts that you have..it will become complicated. The first thing that you need to do is stop thinking in terms of any RDBMS as cassandra is not at all like them. __

Re: Follow-up post on cassandra configuration with some experiments on GC tuning

-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Hi Carsten, > In this regard, what I personally miss in Mikios - however nice - analysis, > is what are the effects on the application stop times due to any garbage > collection runs for the cases tested. In most cases, I prefer having low > pauses

Re: Migrate data from 0.7 pre-release to 0.7 Beta

no. 1. if you delete system folder you'll blow away token information too, which is not safe on > 1 machine. just delete the schema CFs 2. yaml is ignored, you need to explicitly run import-from-yaml (see NEWS) On Thu, Sep 2, 2010 at 9:32 AM, Mike Peters wrote: >  Thanks Jonathan, > > Just to m

Re: Migrate data from 0.7 pre-release to 0.7 Beta

Thanks Jonathan, Just to make sure I understand, are you suggesting - 1. Delete system folder 2. Add the keyspace&cf definitions to cassandra.yaml 3. Restart That should do it? On 9/2/2010 12:08 PM, Jonathan Ellis wrote: probably you will have to blow away the system schema CF and re-import

Re: Looking for something like "like" of mysql.

Cassandra doesn't support adhoc queries, like what you're describing I recommend looking at Lucandra On 9/2/2010 12:27 PM, Anuj Kabra wrote: I am working with cassandra-0.6.4. I am working on mail retreival problem. We have the metadata of mail like sender, r

Looking for something like "like" of mysql.

I am working with cassandra-0.6.4. I am working on mail retreival problem. We have the metadata of mail like sender, recipient, timestamp, subject and the location of mail file stored in a cassandra DB.Everyday about 25,000 records will be entered to this DB. We have not finalised on the data mode

Re: Migrate data from 0.7 pre-release to 0.7 Beta

probably you will have to blow away the system schema CF and re-import from yaml On Thu, Sep 2, 2010 at 7:53 AM, Mike Peters wrote: >  Hi, > > Is there a way to migrate data from a 0.7 pre-release build (June 30, 2010) > to the latest 0.7 beta 1? > > Replacing the binaries and starting-up Cassand

Migrate data from 0.7 pre-release to 0.7 Beta

Hi, Is there a way to migrate data from a 0.7 pre-release build (June 30, 2010) to the latest 0.7 beta 1? Replacing the binaries and starting-up Cassandra, throws the "are you upgrading a pre-release version" error and dies. Thanks, Mike

Re: Cassandra on AWS across Regions

Ben, can you elaborate on some infrastructure topology issues that would break this approach? On Wed, Sep 1, 2010 at 6:25 PM, Benjamin Black wrote: > On Wed, Sep 1, 2010 at 4:16 PM, Andres March wrote: > > I didn't have anything specific in mind. I understand all the issues > around > > DNS and

Re: about insert benchmark

Are you running all of the inserts through one node or distributing the connections around the cluster? You are using the order preserving partioner, so the load around the cluster will be highly dependant on the keys you send. Are they evenly distributed? The JVM will tune the hot spots the lo

Re: about insert benchmark

1000 and 1 records take too short time to really benchmark anything. You will use 2 seconds just for stuff like tcp_windows sizes to adjust to the level were you get throughput. The difference between 100k and 500k is less than 10%. Could be anything. Filesystem caches, sizes of memtables (de

SV: about insert benchmark

Batchmutate insert? Can be package size that differ if not nr threads sending data to Cassandra nodes. Från: ChingShen [mailto:chingshenc...@gmail.com] Skickat: den 2 september 2010 08:59 Till: user@cassandra.apache.org Ämne: Re: about insert benchmark Hi Daniel, I have 4 nodes in my cluster

Cassandra 0.7 example

<<< Courtney Robinson [sa...@live.co.uk] Hello everyone, I'm sorry if that has been asked already, i've just joined the list. can anyone provide a quick java example of connecting to cassandra and setting up a keyspace and a column family using thrift. I know my way around 0.6 and i

Re: about insert benchmark

Sorry, my Cassandra version is 0.6.4.