max columns number

HI What is the max columns number in a key that cassandra supports. Thanks -Mark Zitnik

Re: Cassandra performance

Kamil Gorlo gmail.com> writes: > > So I've got more reads from single MySQL with 400GB of data than from > 8 machines storing about 266GB. This doesn't look good. What am I > doing wrong? :) The worst case for cassandra is random reads. You should ask youself a question, do you really have this

Re: Cassandra performance

Hello, On Wed, Sep 15, 2010 at 3:53 AM, Jonathan Ellis wrote: > The key is that while Cassandra may read less rows per second than > MySQL when you are i/o bound (as you are here) because of SSTable > merging (see http://wiki.apache.org/cassandra/MemtableSSTable), you > should be using your Cassa

Re: Cassandra performance

Hello, On Wed, Sep 15, 2010 at 3:45 AM, Chen Xinli wrote: [cut] >> > Disable row cache is ok, but key cache should be enabled. It use little > memory, but reading peformance will improve a lot. Hmm, I've tested with key cache enabled (100%) and I am pretty sure that this really doesn't help si

Re: Memtable adjusting impact expectations?

On Tue, Sep 14, 2010 at 10:52 PM, Dathan Pattishall wrote: > Yea this was a bit of a read, so > > I think what I need really is this > > http://www.slideshare.net/driftx/cassandra-summit-2010-performance-tuning > > http://riptano.blip.tv/file/4011985/ is even better. :) -Brandon

Re: Memtable adjusting impact expectations?

Yea this was a bit of a read, so I think what I need really is this http://www.slideshare.net/driftx/cassandra-summit-2010-performance-tuning On Tue, Sep 14, 2010 at 6:55 PM, Jonathan Ellis wrote: > If your question is, "should I optimize for faster compaction or less > impact on my cluster

Re: Memtable adjusting impact expectations?

If your question is, "should I optimize for faster compaction or less impact on my cluster," the answer is almost always "less impact." On Tue, Sep 14, 2010 at 8:33 PM, Dathan Pattishall wrote: > Okay from what I gather. When data is written its always written to memory. > The flow for our concer

Re: Cassandra performance

The key is that while Cassandra may read less rows per second than MySQL when you are i/o bound (as you are here) because of SSTable merging (see http://wiki.apache.org/cassandra/MemtableSSTable), you should be using your Cassandra rows as materialized views so that each query is a single row looku

Re: Cassandra performance

2010/9/15 Kamil Gorlo > Hey, > > we are considering using Cassandra for quite large project and because > of that I made some tests with Cassandra. I was testing performance > and stability mainly. > > My main tool was stress.py for benchmarks (or equivalent written in > C++ to deal with python2.

Memtable adjusting impact expectations?

Okay from what I gather. When data is written its always written to memory. The flow for our concerns is the data is written to the commitLog then to the memtable. If any of memtable's 3 tunable thresholds are hit a flush occurs writing the data sorted by key to the SSTABLE still enabling sequenti

Cassandra performance

Hey, we are considering using Cassandra for quite large project and because of that I made some tests with Cassandra. I was testing performance and stability mainly. My main tool was stress.py for benchmarks (or equivalent written in C++ to deal with python2.5 lack of multiprocessing). I will foc

jconsole uname/password

Hi, I'm trying to use Jconsole to tune our instance. jconsole is connecting to the JMX port, as verified by netstat on both machines, but I get the following error: The connection to : did not succeed. Would you like to try again? Could this be due to unset user/password are incorrect? What are

Re: Minor question on index design

I've been doing option 1 under 0.6. As usual in cassandra though a lot depends on how you access the data. - If you often want to get the user and all of the objects they have, use option 2. It's easier to have one read from one CF to answer your query. - If the user has potentially >10k objects go

Re: RE: UnavailableException with 3 nodes and RF=2

For background have a read of http://wiki.apache.org/cassandra/HintedHandoffAs the doc (the one above and Martin :) ) says, CL ONE, QUORUM and ALL only count writes to nodes that are responsible for the key. Then HH is used to eventually deliver that write to any nodes that were not available. CL.A

Re: Bootstrapping stays stuck

Hi Vineet, I have tracked the nodetool streams to completion each time. Below are the logs on the source and destination node. There are 3 sstables being transferred, and the transfer seems to be successful. However, after the streams finish, the source prints out messages about the dropped message

Re: Bootstrapping stays stuck

Hi Gurpreet What is the output of nodetool -h streams -->( to see what is going on between the nodes) . If you dont see anything happening try switching off firewall or iptables. Regards Vineet Daniel Cell : +918106217121 Websites : Blog | Linkedi

Re: Bootstrapping stays stuck

I tried this again, it happenned yet again. This time while the transfer messages seemed tobe in order, i also noticed that the source logs talk about having 9 dropped messages in the last 1000 ms. The only activity on the whole cluster is this bootstrapping, there is no read/write traffic going on

Re: Couple of cache related questions

Thanks a lot Jonathan !!! Kannan From: Jonathan Ellis To: user@cassandra.apache.org Sent: Mon, September 13, 2010 4:47:05 PM Subject: Re: Couple of cache related questions On Sun, Sep 12, 2010 at 6:10 PM, kannan chandrasekaran wrote: >> 1) What determines th

Re: Bootstrapping stays stuck

I am using cassandra 0.6.5. On Tue, Sep 14, 2010 at 9:16 AM, Gurpreet Singh wrote: > Hi, > I have a cassandra cluster of 4 machines, and I am trying to bootstrap 2 > more machines, one at a time. > For both these machines, the bootstrapping stays stuck after the streaming > is done. > > When the

Bootstrapping stays stuck

Hi, I have a cassandra cluster of 4 machines, and I am trying to bootstrap 2 more machines, one at a time. For both these machines, the bootstrapping stays stuck after the streaming is done. When the nodes come up for bootstrapping, I see all the relevant messages about getting a new token, assumi

Re: Removing Data

On Tue, Sep 14, 2010 at 9:51 AM, Jeremiah Jordan wrote: > Is setting a value to ‘’ the same as deleting it in terms of disk space > being free’d? no, you're saying "preserve that column X has an empty value, forever." >  Will it still take gc_grace_seconds for the old data to be > removed from d

Removing Data

Is setting a value to '' the same as deleting it in terms of disk space being free'd? Will it still take gc_grace_seconds for the old data to be removed from disk? -Jeremiah Jeremiah Jordan Application Developer Morningstar, Inc. Morningstar. Illuminating investi

Minor question on index design

Hi all! I'm pondering between a couple of alternatives here: I've got two CFs, one which contains Objects, and one which contains Users. Now, each Object has an owner associated to it, so obviously I need some sort of an index to point from Users to Objects. This would be of course the perfect

RE: UnavailableException with 3 nodes and RF=2

Thank you Martin, this has cleared things up for me. I thought that a replica would always be stored on the node I was connecting to, which makes sense as to why the load on each node is equally balanced. So I could sustain quorum with two node failures if I have a RF=5 or greater. Thanks

Re: column limit on multiget_slice or get_slice

Ahhh, excellent. thank you From: Chen Xinli Sent: Tuesday, September 14, 2010 10:51 AM To: user@cassandra.apache.org Subject: Re: column limit on multiget_slice or get_slice you can use get_slice: public List get_slice(String keyspace, String key, ColumnParent column_parent, SlicePredicate

Re: column limit on multiget_slice or get_slice

you can use get_slice: public List get_slice(String keyspace, String key, ColumnParent column_parent, SlicePredicate predicate, ConsistencyLevel consistency_level) throws InvalidRequestException, UnavailableException, TimedOutException, TException; In the SlicePredicate.SliceRange, set start and f

column limit on multiget_slice or get_slice

Is it possible to get the first x columns from a row without knowing the column names? So far i've been working with just grabbing all the columns in a row or just getting a specific column that i know the name of. If it is possible, can anyone point me in the right direction of how to do this?

Re: UnavailableException with 3 nodes and RF=2

On Tue, Sep 14, 2010 at 10:43 AM, Chris Jansen wrote: > Hi All, > > > > I’m a newbie to Cassandra so I could have a configuration issue here, I am > using the latest stable release 0.6.0. > > > > I have created a cluster of 3 nodes, a keyspace with RF=2 and a rack unaware > replication strategy. W

RE: UnavailableException with 3 nodes and RF=2

When you write with QUORUM, RF/2+1 of the nodes cassandra *wants to write* to have to be up. In your case, RF/2+1 = 2, that means, the two nodes responsible for the write have to be up, not any two nodes. Each write which tries to the node with token 78502309573904554351249603414557542595 and

UnavailableException with 3 nodes and RF=2

Hi All, I'm a newbie to Cassandra so I could have a configuration issue here, I am using the latest stable release 0.6.0. I have created a cluster of 3 nodes, a keyspace with RF=2 and a rack unaware replication strategy. When I write with CL=QUORUM with all 3 nodes commit the data fine, but