Re: finding Cassandra servers
+1 on erics comments We could create a branch or git fork where you guys could develop it, and if it reaches a usable state and others find it interesting it could get integrated in then On 3/3/10, Eric Evans eev...@rackspace.com wrote: On Wed, 2010-03-03 at 10:05 -0600, Ted Zlatanov wrote: I can do a patch+ticket for this in the core, making it optional and off by default, or do the same for a contrib/ service as you suggested. So I'd appreciate a +1/-1 quick vote on whether this can go in the core to save me from rewriting the patch later. I don't think voting is going to help. Voting doesn't do anything to develop consensus and it seems pretty clear that no consensus exists here. It's entirely possible that you've identified a problem that others can't see, or haven't yet encountered. I don't see it, but then maybe I'm just thick. Either way, if you think this is important, the onus is on you to demonstrate the merit of your idea and contrib/ or a github project is one way to do that (the latter has the advantage of not needing to rely on anyone else). -- Eric Evans eev...@rackspace.com -- Sent from my mobile device
Re: Cassandra News Page
Hi Sal. we'll be moving off the incubator site shortly. we'll address that when we go to cassandra.apache.org regards Ian On Feb 18, 2010, at 4:06 PM, Sal Fuentes wrote: This is just a thought, but I think some type of *latest news* page would be nice to have on the main site (http://incubator.apache.org/cassandra/) even if its a bit outdated. Not sure if this has been previously considered. -- Salvador Fuentes Jr. -- Ian Holsman i...@holsman.net
Re: Cassandra versus HBase performance study
Hi Brian.
was there any performance changes on the other tests with v0.5 ?
the graphs on the other pages looks remarkably identical.
On Feb 4, 2010, at 11:45 AM, Brian Frank Cooper wrote:
0.5 does seem to be significantly faster - the latency is better and it
provides significantly more throughput. I'm updating my charts with new
values now.
One thing that is puzzling is the scan performance. The scan experiment is to
scan between 1-100 records on each request. My 6 node Cassandra cluster is
only getting up to about 230 operations/sec, compared to 1400 ops/sec for
other systems. The latency is quite a bit higher. A chart with these results
is here:
http://www.brianfrankcooper.net/pubs/scans.png
Is this the expected performance? I'm using the OrderPreservingPartitioner
with InitialToken values that should evenly partition the data (and the
amount of data in /var/cassandra/data is about the same on all servers). I'm
using get_range_slice() from Java (code snippet below).
At the max throughput (230 ops/sec), when latency is over 1.2 sec, CPU usage
varies from ~5% to ~72% on different boxes. Disk busy varies from 60% to 90%
(and the machine with the busiest disk is not the one with highest CPU
usage.) Network utilization (eth0 %util both in and out) varies from 15%-40%
on different boxes. So clearly there is some imbalance (and the workload
itself is skewed via a Zipfian distribution) but I'm surprised that the
latencies are so high even in this case.
Code snippet - fields is a SetString listing the columns I want;
recordcount is the number of records to return.
SlicePredicate predicate;
if (fields==null)
{
predicate = new SlicePredicate(null,new SliceRange(new byte[0], new
byte[0],false,100));
}
else
{
Vectorbyte[] fieldlist=new Vectorbyte[]();
for (String s : fields)
{
fieldlist.add(s.getBytes(UTF-8));
}
predicate = new SlicePredicate(fieldlist,null);
}
ColumnParent parent = new ColumnParent(data, null);
ListKeySlice results =
client.get_range_slice(table,parent,predicate,startkey,,recordcount,ConsistencyLevel.ONE);
Thanks!
Brian
From: Brian Frank Cooper
Sent: Saturday, January 30, 2010 7:56 AM
To: cassandra-user@incubator.apache.org
Subject: RE: Cassandra versus HBase performance study
Good idea, we'll benchmark 0.5 next.
brian
-Original Message-
From: Jonathan Ellis [mailto:jbel...@gmail.com]
Sent: Friday, January 29, 2010 1:13 PM
To: cassandra-user@incubator.apache.org
Subject: Re: Cassandra versus HBase performance study
Thanks for posting your results; it is an interesting read and we are
pleased to beat HBase in most workloads. :)
Since you originally benchmarked 0.4.2, you might be interested in the
speed gains in 0.5. A couple graphs here:
http://spyced.blogspot.com/2010/01/cassandra-05.html
0.6 (beta in a few weeks?) is looking even better. :)
-Jonathan
--
Ian Holsman
i...@holsman.net
Re: [VOTE] Graduation
+1. On Jan 26, 2010, at 8:11 AM, Eric Evans wrote: There was some additional discussion[1] concerning Cassandra's graduation on the incubator list, and as a result we've altered the initial resolution to expand the size of the PMC by three to include our active mentors (new draft attached). I propose a vote for Cassandra's graduation to a top-level project. We'll leave this open for 72 hours, and assuming it passes, we can then take it to a vote with the Incubator PMC. +1 from me! [1] http://thread.gmane.org/gmane.comp.apache.incubator.general/24427 -- Eric Evans eev...@rackspace.com cassandra-resolution.txt -- Ian Holsman i...@holsman.net
Re: Advise for choice
things positive for solr. - mature and stable - lots of documentation - a swiss army knife and can be used for a LOT of things, especially if you are manipulating a lot of text. - the query language is easier to use (imho.. but i've been using solr for years, so I am biased) - lots of people know it - fast caching - faceting cons for solr. - hard to update a single field (you need to fetch re-insert the entire row) - commits/optimizes can slow things down to a crawl - can't store structured data easily. (for example a blog post has tags which have both a key and a value). - scalability isn't as easy as cassandra. sharding works, but it requires a lot of manual effort - it's easy to get started and get something running, but if you need to do something out of the ordinary, it gets hard fast. I think cassandra is more flexible to do ordinary things that don't involve text-matching. - replication isn't instant. (this is changing.. also look at zoie which may help). of course, if you tell us what your trying to do, I can be more specific. FWIW.. we use SOLR for some of our news-content (see love.com and newsrunner.com) and it works fast enough for us. We have a incoming doc rate of about 8-10 news articles/second. On Jan 8, 2010, at 5:43 AM, Nathan McCall wrote: Agreed that there is not much to go on here in the original question. I will say that we very recently found a good fit with Solr and Cassandra in how we deal with a very heavy write volume of news article data. Cassandra is excellent with write throughput and high availability, but our search use cases are with time-dependent news content, so we need lots of term proximity, faceting and ordering functionality. We probably could store everything in Solr, but the above approach will allow us to make articles immediately available in a fault-tolerant manner while being able to efficiently send batches at regular intervals to Solr and therefore scale out our ingestion of news articles a little smoother. Full disclosure: I am still getting my head around the innards of Solr replication and clustering, but so far I feel like we made a good choice. Hopefully the above will be helpful to folks during their evaluations. Cheers, -Nate On Thu, Jan 7, 2010 at 10:02 AM, Joseph Bowman bowman.jos...@gmail.com wrote: I have to agree with Tatu. If you're struggling to find reasons to validate that Cassandra is the better choice for your task than Solr, then perhaps Solr is the correct choice. I kind of went through the same thing recently, struggled to make Cassandra fit what I was doing, then realized I was doing it wrong and moved to MongoDB. Cassandra is great at what it tries to accomplish, which is managing gigantic datasets in a distributed way. The question is, is that really what you need? On Thu, Jan 7, 2010 at 12:58 PM, Tatu Saloranta tsalora...@gmail.com wrote: On Thu, Jan 7, 2010 at 3:16 AM, Richard Grossman richie...@gmail.com wrote: Hi, This message is little different than support. I'm confronted to problem where people want to change Cassandra with Solr server. I really think that our problem is a great case for cassandra but I need more arguments. So please if you've some time just put some idea why to use cassandra instead solr. Solution is generally applicable to a problem... so what is the (main) use case? That would make it easier to find arguments for or against proposed solution. -+ Tatu +- -- Ian Holsman i...@holsman.net
Re: Is Cassandra suitable for multi criteria search engine
Hi David. 3 million is a good size. I would say it is a 'medium' but it really depends on a lot of factors, and what exactly you are indexing. as a rule of thumb if you can fit the index in memory you'll be fine. It also depends on how much of a long tail you have, how often you update the index (each commit clears the caches) and how complex your queries are. I've found the number of commits plays a bigger part than the physical size. You should get a full size index up and benchmark it, in normal operation to be sure. you can also install Solr in 'distributed' mode, which lets you scale it out further. On Dec 19, 2009, at 12:30 AM, David MARTIN wrote: Is a 3 million records set not a big deal for Solr? If I consider about 30 properties per item, I have to give Solr 90 millions properties to consider. Is that volume still correct for such a solution? And regarding lucene on top of Cassandra, can people share their feed back, if any, about such a solution. Pros cons vs Solr for instance. Thank you. 2009/12/17, Jake Luciani jak...@gmail.com: True replication and scale. On Dec 17, 2009, at 4:56 PM, Josh j...@schulzone.org wrote: I've used solr a bunch (And I'd cosign gabriel: Solr's fantastic) and I'm trying to work my head around Cassandra, but I'm really hazy on what the Cassandra+Lucene combo gives you. What are you trying to accomplish? (Meant earnestly: I'm really curious) josh @schulz http://schulzone.org On Thu, Dec 17, 2009 at 2:52 PM, Jake Luciani jak...@gmail.com wrote: You can also put lucene on top of Cassandra by using. http://github.com/tjake/Lucandra On Dec 17, 2009, at 4:43 PM, gabriele renzi rff@gmail.com wrote: On Thu, Dec 17, 2009 at 7:48 PM, David MARTIN dmartin@gmail.com wrote: Hi, That's what I was thinking. And I'm glad to read Apache solr in your answer as it is one of my main leads. as a happy solr user, I second the suggestion, lucene (the technology behind solr) handles a number of documents like that without a sweat, and solr gives your replication and a few other good things. -- Ian Holsman i...@holsman.net
Re: read latency creaping up
can you make it so that the client restarts the connection every 30m or so ? It could be an issue in thrift or something with long-lived connections. On Dec 15, 2009, at 10:16 AM, Brian Burruss wrote: i agree. i don't know anything about thrift, and i don't know how it keeps connections open or manages resources from a client or server perspective, but this situation suggests that maybe killing the clients is forcing the server to free something. how's that sound :) From: Jonathan Ellis [jbel...@gmail.com] Sent: Monday, December 14, 2009 3:12 PM To: cassandra-user@incubator.apache.org Subject: Re: read latency creaping up hmm, me neither but, I can't think how restarting the client would, either :) On Mon, Dec 14, 2009 at 4:59 PM, Brian Burruss bburr...@real.com wrote: Well not sure how that would affect he latency as reported by the Cassandra server using nodeprobe cfstats Jonathan Ellis jbel...@gmail.com wrote: possibly the clients are running into memory pressure? On Mon, Dec 14, 2009 at 4:27 PM, Brian Burruss bburr...@real.com wrote: thx, i'm actually the B. Todd Burruss in that thread .. we changed our email system and well now, i'm just Brian .. long story. anyway, in this case it isn't compaction pendings as i can kill the clients and immediately restart and the latency is back to a reasonable number. i'm still investigating. thx! From: Eric Evans [eev...@rackspace.com] Sent: Monday, December 14, 2009 8:23 AM To: cassandra-user@incubator.apache.org Subject: RE: read latency creaping up On Sun, 2009-12-13 at 13:18 -0800, Brian Burruss wrote: if this isn't a known issue, lemme do some more investigating. my test client becomes more random with reads as time progresses, so possibly this is what causes the latency issue. however, all that being said, the performance really becomes bad after a while. Have a look at the following thread: http://thread.gmane.org/gmane.comp.db.cassandra.user/1402 -- Eric Evans eev...@rackspace.com -- Ian Holsman i...@holsman.net
Re: Persistently increasing read latency
hmm. doesn't that leave the trunk in a bad position in terms of new development? you may go through times when a major feature lands and trunk is broken/buggy. or are you planning on building new features on a branch and then merging into trunk when it's stable? On Dec 3, 2009, at 5:32 AM, Jonathan Ellis wrote: We are using trunk. 0.5 beta / trunk is better than 0.4 at the 0.4 functionality and IMO is production ready (although you should always test first), but I would not yet rely on the new stuff (bootstrap, loadbalance, and moving nodes around in general). -Jonathan On Wed, Dec 2, 2009 at 12:26 PM, Adam Fisk a...@littleshoot.org wrote: Helpful thread guys. In general, Jonathan, would you recommend building from trunk for new deployments at our current snapshot in time? Are you using trunk at Rackspace? Thanks. -Adam On Tue, Dec 1, 2009 at 6:18 PM, Jonathan Ellis jbel...@gmail.com wrote: On Tue, Dec 1, 2009 at 7:31 PM, Freeman, Tim tim.free...@hp.com wrote: Looking at the Cassandra mbean's, the attributes of ROW-MUTATION-STAGE and ROW-READ-STAGE and RESPONSE-STAGE are all less than 10. MINOR-COMPACTION-POOL reports 1218 pending tasks. That's probably the culprit right there. Something is wrong if you have 1200 pending compactions. This is something that upgrading to trunk will help with right away since we parallelize compactions there. Another thing you can do is increase the memtable limits so you are not flushing + compacting so often with your insert traffic. -Jonathan -- Adam Fisk http://www.littleshoot.org | http://adamfisk.wordpress.com | http://twitter.com/adamfisk -- Ian Holsman i...@holsman.net
Re: Wish list [from users survey thread]
well. I'd like to see how many times a specific user hits the site, without having to add them up every time. On Nov 24, 2009, at 9:47 AM, Ted Zlatanov wrote: On Mon, 23 Nov 2009 13:45:09 -0600 Jonathan Ellis jbel...@gmail.com wrote: JE 1. Increment/decrement: atomic is a dirty word in a system JE emphasizing availability, but incr/decr can be provided in an JE eventually consistent manner with vector clocks. There are other JE possible approaches but this is probably the best fit for us. We'd JE want to allow ColumnFamilies with either traditional (for Cassandra) JE long timestamps, or vector clocks, but not mixed. The bad news is, JE this is a very substantial change and will probably not be in 0.9 JE unless someone steps up to do the work. (This would also cover JE flexible conflict resolution, which came up as well.) Just for my benefit, can someone explain the reasons why atomic inc/dec are needed inside Cassandra if 64-bit time stamps and UUIDs are available? I have not needed them in my usage but am curious about other schemas that do. Thanks Ted -- Ian Holsman i...@holsman.net
Re: Social network feed/wall question
One of the problems you may face is that the common operation is 'get last X'. You might want to look at redis as an alternative as it supports this operation natively. I'm sure the Cassandra experts can help with your schema to optimize it as well --- Sent from my phone Ian Holsman - 703 879-3128 On 23/11/2009, at 9:55 AM, Kristian Lunde kr.lu...@gmail.com wrote: I am currently building a social network application where one of the important features is a feed / wall (Something similar to the Facebook wall). We will have several feeds, one for each profile and one for each group and so on. I have looked into using Cassandra for storing this, but I am not sure I am on the right track regarding my schema. My thoughs was that the schema would be similar to this Feed [SuperColumn] - Row [user id as identifier] [Columns] - type - timestamp - message - url Each user would have his own feed super column and store all feed items related to him in this super column. I am not sure this is the best idea, since it creates an insane amount of writes whenever someone writes to their wall (this will have to write the feed of all his friends). Also I read in this thread http://www.mail-archive.com/cassandra-user@incubator.apache.org/msg00360.html that super columns are not suited for 60k rows in a super column. What would be the optimal way of storing a set of feeds in cassandra? Thanks Kristian
Re: Cassandra users survey
We're looking at it to be part of a near real time Web analytics engine, which sounds similar to Ooyala. at the moment I'm pushing to get the thing open sourced if possible. we're looking at combining Cassandra + Esper, but we are still in the very early stages. On Nov 21, 2009, at 8:17 AM, Jonathan Ellis wrote: Hi all, I'd love to get a better feel for who is using Cassandra and what kind of applications it is seeing. If you are using Cassandra, could you share what you're using it for and what stage you are at with it (evaluation / testing / production)? Also, what alternatives you evaluated/are evaluating would be useful. Finally, feel free to throw in I'd love to use Cassandra if only it did X wishes. :) I can start: Rackspace is using Cassandra for stats collection (testing, almost production) and as a backend for the Mail Apps division (early testing). We evaluated HBase, Hypertable, dynomite, and Voldemort as well. Thanks, -Jonathan (If you're in stealth mode or don't want to say anything in public, feel free to reply to me privately and I will keep it off the record.) -- Ian Holsman i...@holsman.net
Re: Cassandra users survey
--- Sent from my phone Ian Holsman - 703 879-3128 On 21/11/2009, at 12:38 PM, Dan Di Spaltro dan.dispal...@gmail.com wrote: At Cloudkick we are using Cassandra to store monitoring statistics and running analytics over the data. I would love to share some ideas about how we set up our data-model, if anyone is interested. This isn't the right thread to do it in, but I think it would be useful to show how we store billions of points of data in Cassandra (and maybe get some feedback). Wishlist -remove_slice_range -auto loadbalancing -inc/dev On Fri, Nov 20, 2009 at 1:17 PM, Jonathan Ellis jbel...@gmail.com wrote: Hi all, I'd love to get a better feel for who is using Cassandra and what kind of applications it is seeing. If you are using Cassandra, could you share what you're using it for and what stage you are at with it (evaluation / testing / production)? Also, what alternatives you evaluated/are evaluating would be useful. Finally, feel free to throw in I'd love to use Cassandra if only it did X wishes. :) I can start: Rackspace is using Cassandra for stats collection (testing, almost production) and as a backend for the Mail Apps division (early testing). We evaluated HBase, Hypertable, dynomite, and Voldemort as well. Thanks, -Jonathan (If you're in stealth mode or don't want to say anything in public, feel free to reply to me privately and I will keep it off the record.) -- Dan Di Spaltro
Re: Meetup?
I'm in Melbourne, and frequently in DC and NY as well. On Nov 13, 2009, at 11:18 AM, Nick Lothian wrote: Where in Australia are you from? (Adelaide here) I might be interested in one down here. From: Chris Were [mailto:chris.w...@gmail.com] Sent: Friday, 13 November 2009 9:09 AM To: cassandra-user@incubator.apache.org Subject: OT: Meetup? Hi, I'm from Australia, but currently in SF for the next 2 weeks working on a startup. If any cassandra users want to meet up to discuss cassandra or any other tech, shoot me an email. Cheers, Chris IMPORTANT: This e-mail, including any attachments, may contain private or confidential information. If you think you may not be the intended recipient, or if you have received this e-mail in error, please contact the sender immediately and delete all copies of this e-mail. If you are not the intended recipient, you must not reproduce any part of this e-mail or disclose its contents to any other party. This email represents the views of the individual sender, which do not necessarily reflect those of Education.au except where the sender expressly states otherwise. It is your responsibility to scan this email and any files transmitted with it for viruses or any other defects. education.au limited will not be liable for any loss, damage or consequence caused directly or indirectly by this email. -- Ian Holsman i...@holsman.net
Re: bandwidth limiting Cassandra's replication and access control
going to suffice. What this snippet could do, though, and may be the rationale for the request, is to ensure that unauthorized users cannot instantiate a new Cassandra server. However, if a user has physical access to the machine on which Cassandra is installed, they could easily bypass that layer of security. What if Cassandra IS the application you're exposing? Imagine a large company that creates one large internal Cassandra deployment, and has multiple departments it wants to create separate keyspaces for. You can do that now, but there's nothing except a gentlemen's agreement to prevent one department from trashing another department's keyspace, and accidents do happen. You can front the service with some kind of application layer, but then you have another API to maintain, and you'll lose some performance this way. -Brandon -- Ian Holsman i...@holsman.net
Re: Newbe´s question
would it be worthwhile to start including these clients in the core codebase? in some kind of 'client' or 'contrib' directory? maybe even mentioning the 'popular' clients that people use in the readme (with links to them) would be good. On Aug 27, 2009, at 9:18 AM, Sal Fuentes wrote: Just would like to say great job so far. On Wed, Aug 26, 2009 at 4:01 PM, Ian Eure i...@digg.com wrote: On Aug 25, 2009, at 2:46 PM, Drew Schleck wrote: For anyone using my branch of Lazyboy, Ian Eure pulled my work, improved it, and more. You ought to switch back to his version. I'm doing some heavy refactoring all this week, to bring it up to Cassandra trunk and simplify/genericize it wherever possible. I should have something to show in a day or two. Feel free to contact me if you have questions or requests. - Ian -- Salvador Fuentes Jr. 323-540-4SAL -- Ian Holsman i...@holsman.net
Re: Newbe´s question
isn't there a way to use svn:external or svn:link to pull them in from their own repos? (not sure how legal it would be). On Aug 27, 2009, at 10:03 AM, Jonathan Ellis wrote: I thought about that, but I really don't want Cassandra committers to have to be in the business of updating them all when we make changes, and having them in the repo creates that expectation even in contrib. On Wed, Aug 26, 2009 at 6:57 PM, Ian Holsmani...@holsman.net wrote: would it be worthwhile to start including these clients in the core codebase? in some kind of 'client' or 'contrib' directory? maybe even mentioning the 'popular' clients that people use in the readme (with links to them) would be good. On Aug 27, 2009, at 9:18 AM, Sal Fuentes wrote: Just would like to say great job so far. On Wed, Aug 26, 2009 at 4:01 PM, Ian Eure i...@digg.com wrote: On Aug 25, 2009, at 2:46 PM, Drew Schleck wrote: For anyone using my branch of Lazyboy, Ian Eure pulled my work, improved it, and more. You ought to switch back to his version. I'm doing some heavy refactoring all this week, to bring it up to Cassandra trunk and simplify/genericize it wherever possible. I should have something to show in a day or two. Feel free to contact me if you have questions or requests. - Ian -- Salvador Fuentes Jr. 323-540-4SAL -- Ian Holsman i...@holsman.net -- Ian Holsman i...@holsman.net
Re: Announcing 0.3.0
you need to give a tiny bit of time (say 24 hours) for the mirrors to catch up. On 21/07/2009, at 10:09 AM, Daniel Hengeveld wrote: I clicked on the link in my browser (Safari) - even copied the url and pasted it into the location bar of a new window, and was absolutely *not* greeted with a page of mirrors. Upon your reply, I tried an alternate browser (Firefox) and did get the links. Still doesn't work in Safari. Thanks for the help! ~d On Mon, Jul 20, 2009 at 17:05, Jeff Hodgesj...@somethingsimilar.com wrote: Click through. It takes you to a page of mirror links. In the future, much debugging can be done by pointing your browser to the page. -- Jeff On Mon, Jul 20, 2009 at 4:56 PM, Daniel Hengevelddanie...@gmail.com wrote: When I download this file, I get a 5KB file rather than the actual release. Is anyone else having this problem? On Mon, Jul 20, 2009 at 12:57, Eric Evanseev...@rackspace.com wrote: It is with great pleasure that I announce the very first release of Apache Cassandra, 0.3.0[1] A projects first release is a significant milestone and one that our burgeoning community should be proud of. Many thanks to everyone that submitted patches and bug reports, helped with testing, documented, organized, or just asked the important questions. Without further ado: The official download: http://www.apache.org/dyn/closer.cgi/incubator/cassandra/0.3.0/apache-cassandra-incubating-0.3.0-bin.tar.gz SVN Tag: https://svn.apache.org/repos/asf/incubator/cassandra/tags/cassandra-0.3.0-final/ [1] DISCLAIMER: Apache Cassandra is an effort undergoing incubation at The ASF, sponsored by the Apache Incubator Project Management Committee (PMC). Incubation is required of all newly accepted projects until a further review indicates that the infrastructure, communications, and decision making process have stabilized in a manner consistent with other successful ASF projects. While incubation status is not necessarily a reflection of the completeness or stability of the code, it does indicate that the project has yet to be fully endorsed by the ASF. -- Eric Evans eev...@rackspace.com -- ..[daniel hengeveld].. neoglam.com -- ..[daniel hengeveld].. neoglam.com -- Ian Holsman i...@holsman.net
