Re: questions about consistency

Hi Paul, Thank you for your answer, about the first question, I wondered if it is possible to workaround this issue but relaxing some consistency, as I understand you it should be possible to implement this compareAndSet operation with the presence of vector clocks, then the client is going to

Will cassandra block client ?

Hi all, I made too many requests to cassandra , and then after a while, I can not connect to it. But I can still connect it from another machine ? So does it mean cassandra will block client in some situation ? -- Best Regards Jeff Zhang

Does anybody work about transaction on cassandra ?

Hi all, I need transaction support on cassandra, so wondering is anybody work on it ? -- Best Regards Jeff Zhang

Re: Will cassandra block client ?

are you reusing your connections? If not, you may be running out of tcp ports on the bombing client. check netstat -na | grep TIME_WAIT On Thu, Apr 22, 2010 at 10:52 AM, Jeff Zhang wrote: > Hi all, > > I made too many requests to cassandra , and then after a while, I can > not connect to it. But

Re: PHP client crashed if a column value > 8192 bytes

Maybe you have to send this message also to thrift user mail list? On Thu, Apr 22, 2010 at 6:34 AM, Ken Sandney wrote: > After many attempts I found this error only occurred when using PHP > thrift_protocol extension. I don't know if there are some parameters that I > could adjust for this issu

Periodically hiccups

Hello, We recently deployed a cluster of 5 Cassandra nodes into production, and ran into big problems with periodically hiccups (individual node goes down, high CPU, client connection timeout). It was terrible with 0.5 (one hiccups every 5-10 minutes), today we upgraded to 0.6.1, it happens l

RE: Periodically hiccups

Hello Alex, unfortunately I can not help with your problem, just one hint: > - RecentReadLatencyMicros and RecentWriteLatencyMicros are super high > for StorageProxy, as well as every column family in JMX: up > to 43 s and > 9s (see screenshot). However, in cfstats, they are quite small. Rem

Re: Will cassandra block client ?

I use the hector java client, I think it reuse the connection, or maybe I should check the source code. On Thu, Apr 22, 2010 at 4:10 PM, Ran Tavory wrote: > are you reusing your connections? If not, you may be running out of tcp > ports on the bombing client. check netstat -na | grep TIME_WAIT >

Re: Will cassandra block client ?

it reuses connections, yes. but wouldn't hurt to check as well ;) you may want to check the haproxy connections as well. On Thu, Apr 22, 2010 at 11:26 AM, Jeff Zhang wrote: > I use the hector java client, I think it reuse the connection, or > maybe I should check the source code. > > > On Thu, A

(sin asunto)

Hi David. I think your arquitecture is right. I'm also new in cassandra, and I ve designed my database similar than yours. I also think that division than data and indexes is more efficient in the queries. I had not raised your question about put them in a separated keyspaces, but I also app

Re: New user asking for advice on database design

Hi David, I think your arquitecture is right. I'm also new in cassandra, and I ve designed my database similar than yours. I also think that division than data and indexes is more efficient in the queries. I had not raised your question about put them in a separated keyspaces, but I also app

Re: Cassandra tuning for running test on a desktop

Yes I think. I have read this wiki entry and the JIRA. I will use different row key until it will be fixed Thanks, Nicolas On Thu, Apr 22, 2010 at 4:47 AM, Stu Hood wrote: > Nicolas, > > Were all of those super column writes going to the same row? > http://wiki.apache.org/cassandra/CassandraL

Is that normal to have some percent of reads/writes time out?

Hi I am doing some load test with 4 nodes cluster. My client is PHP. I found some reads/writes were time out no matter how I tuned the parameters. These time-outs could be caught by client code. My question is: are these time-outs normal even in production environment? Should they be treated as no

Re: New user asking for advice on database design

do you have read the article " WTF is a SuperColumn? An Intro to the Cassandra Data Model"? link: http://arin.me/blog/wtf-is-a-supercolumn-cassandra-data-model it is a good article for data model. On Thu, Apr 22, 2010 at 10:38 AM, Y

Re: Does anybody work about transaction on cassandra ?

No, as far as I know no one is working on transaction support in Cassandra. Transactions are orthogonal to the design of Cassandra[1][2], although a system could be designed incorporating Cassandra and other elements a la Google's MegaStore[3] to support transactions. Google uses Paxos, one might

Re: Is that normal to have some percent of reads/writes time out?

I see that you are aware of https://issues.apache.org/jira/browse/THRIFT-347 Have you applied the patch there? It worked for the Digg guys (probably the largest PHP user of Cassandra) and others in that JIRA issue. Timeouts are typical with unusually heavy load, node failure, and/or un-tuned param

Re: Is that normal to have some percent of reads/writes time out?

timeouts are usually a signal that you need to add capacity to handle the load you are giving the cluster. On Thu, Apr 22, 2010 at 8:22 AM, Ken Sandney wrote: > Hi > > I am doing some load test with 4 nodes cluster. My client is PHP. I found > some reads/writes were time out no matter how I tuned

Re: Does anybody work about transaction on cassandra ?

You might also consider using a Software Transactional Memory[1] approach. I haven't personally tried it, but there is a Scala/Java framework named Akka that provides both STM features and Cassandra support. Should be worth a look. Here's a nice write-up from someone who has already done some explo

Re: questions about consistency

2010/4/22 Даниел Симеонов : > Hi Paul, >     Thank you for your answer, about the first question, I wondered if it is > possible to workaround this issue but relaxing some consistency, as I > understand you it should be possible to implement this compareAndSet > operation with the presence of vecto

Re: cassandra instability

If digg uses PHP with cassandra, can the library really be that old? Or they are using their own custom php cassandra client? (probably, but just making sure). On Fri, Apr 16, 2010 at 2:13 PM, Jonathan Ellis wrote: > On Fri, Apr 16, 2010 at 12:50 PM, Lee Parker wrote: > > Each time I start it

Re: At what point does the cluster get faster than the individual nodes?

On Wed, Apr 21, 2010 at 9:50 AM, Mark Greene wrote: > Right it's a similar concept to DB sharding where you spread the write load > around to different DB servers but won't necessarily increase the throughput > of an one DB server but rather collectively. Except with Cassandra, read-repair caus

Concurrent SuperColumn update question

Suppose I have a SuperColumn CF where one of the SuperColumns in each row is being treated as a list (e.g. keys only, values are just empty). In this list, values will only ever be added; deletion never occurs. If I have two processes simultaneously add values to this list (on different nodes, wh

Implementing Tags

If I wanted to store tags in Cassandra, on a per user basis, what would be the best way to do that? ColumnFamily:Tags Key:UserID SuperColumn: Tag names Columns: keys to records using this Tag And in each of the items, have a comma separated list of its tags? Or some other way?

Re: At what point does the cluster get faster than the individual nodes?

fyi, https://issues.apache.org/jira/browse/CASSANDRA-930 https://issues.apache.org/jira/browse/CASSANDRA-982 On Thu, Apr 22, 2010 at 11:11 AM, Mike Malone wrote: > On Wed, Apr 21, 2010 at 9:50 AM, Mark Greene wrote: >> >> Right it's a similar concept to DB sharding where you spread the write >>

Re: cassandra instability

We don't use PHP to talk to Cassandra directly. But we do have the front-end communicate to our backend services which are over Thrift. We've used Framed and Buffered, both required some tweaks. We use the PHP C-extension from the Thrift repo. I have to admit, it's pretty crappy, we had to make

Cassandra Ruby Library's batch method example?

Hi, I would like to see example code about the batch() method, I searched for it on Google, but I couldn't find any. Reading the inline comments, this operation could be useful for example to insert some record and update the indexes all at once, am I right? Best regards -- Lucas Di Pentima -

Row deletion and get_range_slices (cassandra 0.6.1)

I have a curious question.. I am doing some testing where I insert 500 rows to a super column family and then delete one row, I make sure the row was indeed deleted (NotFoundException in the get call) and then I ran a get_range_slices and the row indeed returned. The shutdown Cassandra and rest

Re: Row deletion and get_range_slices (cassandra 0.6.1)

http://wiki.apache.org/cassandra/FAQ#range_ghosts On Thu, Apr 22, 2010 at 5:29 PM, Carlos Sanchez wrote: > I have a curious question.. > > I am doing some testing where I insert 500 rows to a super column family and > then delete one row, I make sure the row was indeed deleted > (NotFoundExcept

Re: Cassandra Ruby Library's batch method example?

On Thu, Apr 22, 2010 at 1:06 PM, Lucas Di Pentima wrote: > Hi, > > I would like to see example code about the batch() method, I searched for it > on Google, but I couldn't find any. Reading the inline comments, this > operation could be useful for example to insert some record and update the >

Re: Cassandra Ruby Library's batch method example?

El 22/04/2010, a las 19:57, Ryan King escribió: > The batch method in the cassandra gem is still a little crippled (it > doesn't actually batch together everything it can), but you can use it > like this: > > http://github.com/fauna/cassandra/blob/master/test/cassandra_test.rb#L299 Thanks Ryan!

Re: Cassandra Ruby Library's batch method example?

nope, there is no guarantee of that. if the server fails mid-operation you have to retry it. On Thu, Apr 22, 2010 at 7:23 PM, Lucas Di Pentima wrote: > > El 22/04/2010, a las 19:57, Ryan King escribió: > >> The batch method in the cassandra gem is still a little crippled (it >> doesn't actually

Re: Is that normal to have some percent of reads/writes time out?

yes, I've tried the patch on https://issues.apache.org/jira/browse/THRIFT-347, but seems not work for me. I doubt I am involving another issue with Thrift. If my column value size is more than 8KB(with thrift php extension enabled), my client has more chances to get "timed out error". I am still wo

Re: Is that normal to have some percent of reads/writes time out?

By the way, my testing cluster are 4 normal PCs with 2GB RAM assigned to JVM, Intel(R) Celeron(R) CPU E3200 2.40GHz. How many concurrent reads/writes should be reasonable? Or how much memory/CPU usage would be healthy for this kind of test cluster?

MapReduce, Timeouts and Range Batch Size

I was getting client timeouts in ColumnFamilyRecordReader.maybeInit() when MapReducing. So I've reduced the Range Batch Size to 256 (from 4096) and this seems to have fixed my problem, although it has slowed things down a bit -- presumably because there are 16x more calls to get_range_slices. Whil

getting cassandra setup on windows 7

So I uncompressed the .tar, in the readme it says: * tar -zxvf cassandra-$VERSION.tgz * cd cassandra-$VERSION * sudo mkdir -p /var/log/cassandra * sudo chown -R `whoami` /var/log/cassandra * sudo mkdir -p /var/lib/cassandra * sudo chown -R `whoami` /var/lib/cassandra My cassandra is at

Re: getting cassandra setup on windows 7

Hi, You should do at least these: 1.open conf/storage-conf.xml and set commitlog/data directory settings 2.open conf/log4j.properties and set log directory whichever you want 3.I recommend to set c:\java\cassandra\apache-cassandra-0.6.1/ as %CASSANDRA_HOME% to your class path. 4.Also I recommend t

Re: getting cassandra setup on windows 7

Ok so I found the config section: E:\java\cassandra\apache-cassandra-0.6.1-bin\apache-cassandra-0.6.1\commitlog E:\java\cassandra\apache-cassandra-0.6.1-bin\apache-cassandra-0.6.1\data Now when I run: bin/cassandra I get: Starting cassandra server listening for transport dt_socket at

Re: getting cassandra setup on windows 7

https://issues.apache.org/jira/browse/CASSANDRA-948 On Thu, Apr 22, 2010 at 10:03 PM, S Ahmed wrote: > Ok so I found the config section: > E:\java\cassandra\apache-cassandra-0.6.1-bin\apache-cassandra-0.6.1\commitlog >    > >  E:\java\cassandra\apache-cassandra-0.6.1-bin\apache-cassandra-0.6.1\da

Re: MapReduce, Timeouts and Range Batch Size

That would be an easy win, sure. On Thu, Apr 22, 2010 at 9:27 PM, Joost Ouwerkerk wrote: > I was getting client timeouts in ColumnFamilyRecordReader.maybeInit() when > MapReducing.  So I've reduced the Range Batch Size to 256 (from 4096) and > this seems to have fixed my problem, although it has

Re: getting cassandra setup on windows 7

I was just reading that thanks. What does he mean when he says: "This appears to be related to data storage paths I set, because if I switch the paths back to the default UNIX paths. Everything runs fine" On Thu, Apr 22, 2010 at 11:07 PM, Jonathan Ellis wrote: > https://issues.apache.org/jira/

Re: Row deletion and get_range_slices (cassandra 0.6.1)

Do those tombstone-d keys ever get purged completely ? I've tried shortening the GCGraceSeconds right down but they still don't get cleaned up. On 23 April 2010 08:57, Jonathan Ellis wrote: > http://wiki.apache.org/cassandra/FAQ#range_ghosts > > On Thu, Apr 22, 2010 at 5:29 PM, Carlos Sanchez >

ORM in Cassandra?

Hi, all: I know many people regard O/R Mapping as rubbish. However it is undeniable that ORM is quite easy to use in most simple cases, Meanwhile Cassandra is well known as No-SQL solution, a.k.a. No-Relational solution. So maybe it's weird to combine ORM and Cassandra, right? Is there anything we

Re: ORM in Cassandra?

See what you think of tragedy: http://github.com/enki/tragedy On Fri, Apr 23, 2010 at 12:12 AM, aXqd wrote: > Hi, all: > > I know many people regard O/R Mapping as rubbish. However it is > undeniable that ORM is quite easy to use in most simple cases, > Meanwhile Cassandra is well known as No-SQ

Re: ORM in Cassandra?

For PHP there's Pandra http://github.com/mjpearson/Pandra . As much as I dislike PHP and ORM's generally (ironic, yes) PHP's array/iterator interfaces make building a domain model ontop of Cassandra a fairly intuitive process. -michael On Fri, Apr 23, 2010 at 3:12 PM, aXqd wrote: > Hi, all: > >

Re: ORM in Cassandra?

>So maybe it's weird to combine ORM and Cassandra, right? Is there >anything we can take from ORM? Honestly I do not understand what is your question. It is clear that you can not combine ORM such as Hibernate or iBATIS with Cassandra. Cassandra it self is not a RDBMS, so you will not map the tabl