Hi All,
Making transaction is my actual preoccupation of the moment.
My need is :
- update data in column family #1
- insert data in column family #2
My need is to see thes opérations in a single transaction because the
data is tightly coupled.
I use zookeeper/cage to make distributed lock to
On Wed, Jul 27, 2011 at 11:01:17PM -0500, Jonathan Ellis wrote:
On Wed, Jul 27, 2011 at 10:53 PM, Edward Capriolo edlinuxg...@gmail.com
wrote:
You can not even put two statements on the same line. So the ';' is semi
useless syntax.
Nobody ever asked for that, but lots of people asked to
This is part of a much bigger problem, one which has many parts, among them:
1. Cassandra is complex. Getting a gestalt understanding of it makes me
think I understand how Alzheimer's patients must feel.
2. There is no official documentation. Perhaps everything is out there
somewhere, who knows?
Created https://issues.apache.org/jira/browse/CASSANDRA-2964
-Ursprüngliche Nachricht-
Von: Jonathan Ellis [mailto:jbel...@gmail.com]
Gesendet: Mittwoch, 27. Juli 2011 17:35
An: user@cassandra.apache.org
Betreff: Re: results of index slice query
Sounds like a Cassandra bug to me.
On
Unfortunately, the perception that I have as a business consumer and
night-time hack, is that more importance and effort is placed on
ensuring information is up to date and correct on the
http://www.datastax.com/docs/0.8/index website and less on keeping the
wiki up to date or relevant... which
If I try to retrieve a column that is not present, using get(), then I'll
get a NotFoundException.
If (for efficiency's sake) I try to retrieve several named columns using
get_slice, with a column_names predicate (i.e. a list of columns) then I
won't get the exception if one of those columns is
On Thursday, July 28, 2011, Sasha Dolgy sdo...@gmail.com wrote:
Unfortunately, the perception that I have as a business consumer and
night-time hack, is that more importance and effort is placed on
ensuring information is up to date and correct on the
http://www.datastax.com/docs/0.8/index
Thank you. For 0.7 are the steps similar?
On Jul 27, 2011, at 19:56, Jonathan Ellis jbel...@gmail.com wrote:
As you know, with 0.6 adding a datacenter is not as easy as 0.7 with
NetworkTopologyStrategy. With 0.6 there is a right way that will work
with some manual effort, and a wrong way
No, the slice semantics are give me whatever happens to exist between
start and end. It's valid for the answer to be nothing.
On Thu, Jul 28, 2011 at 6:55 AM, David Allsopp dnalls...@gmail.com wrote:
If I try to retrieve a column that is not present, using get(), then I'll
get a
It defaults to hex because that is how bytestype is represented. The
default remains bytestype to provide the kind of backwards
compatibility you are complaining about. :)
On Thu, Jul 28, 2011 at 6:56 AM, Edward Capriolo edlinuxg...@gmail.com wrote:
On Thursday, July 28, 2011, Sasha Dolgy
This is not advisable in general, since non-mmap'd I/O is substantially slower.
The OP is correct that it is best to disable swap entirely, and
second-best to enable JNA for mlockall.
On Thu, Jul 28, 2011 at 7:05 AM, Adi adi.pan...@gmail.com wrote:
Hi,
We’ve started having problems with
I don't think there's ever been a memory_locking_policy variable.
Cassandra will call mlockall if JNA is present, no further steps
required.
On Thu, Jul 28, 2011 at 5:17 AM, Stephen Henderson
stephen.hender...@cognitivematch.com wrote:
Hi,
We’ve started having problems with cassandra and
You can quote CQL column names to allow any column name that Thrift
would allow (suitably encoded for ascii).
For instance, CQL knows that UUIDs are represented as strings like
12345678-1234-5678-1234-567812345678 and will parse them correctly.
If you mean the official CompositeType, that should
On 07/28/2011 05:29 AM, Aleksandrs Saveljevs wrote:
essentially a rewrite of the first part of the C++ example given at
http://wiki.apache.org/cassandra/ThriftExamples#C.2B-.2B- . If we run
it under strace, we see that it hangs on the call to recv() when
setting keyspace:
$ strace -s 64
Okay. So what happens when I try to add a third DC? Since we would be
using RAS any new node would get the entire dataset.
On Jul 28, 2011, at 5:49, Jonathan Ellis jbel...@gmail.com wrote:
The steps are the same for RUS - RAS no matter what version of
Cassandra you are on, but 0.7 introduced
On Thu, Jul 28, 2011 at 8:46 AM, Jonathan Ellis jbel...@gmail.com wrote:
It defaults to hex because that is how bytestype is represented. The
default remains bytestype to provide the kind of backwards
compatibility you are complaining about. :)
On Thu, Jul 28, 2011 at 6:56 AM, Edward
I'm talking about data compatibility, which is more important than cli
statement compatibility.
Consider someone with a python program that creates a CF with the
default settings and inserts some (say) uuid columns and long data.
If we changed CF creation to default to ascii we would break this
On Thu, Jul 28, 2011 at 9:35 AM, Jonathan Ellis jbel...@gmail.com wrote:
I'm talking about data compatibility, which is more important than cli
statement compatibility.
Consider someone with a python program that creates a CF with the
default settings and inserts some (say) uuid columns and
I had a few questions that I couldn't easily answer by looking through many
JIRA tickets and the wiki. We are currently developing an application based
on Cassandra 0.8.x with the CQL driver.
Does the CQL driver currently support cursor / resultsets?
I'd like to implement a pagination feature.
On Jul 28, 2011, at 9:52 PM, Jonathan Ellis wrote:
This is not advisable in general, since non-mmap'd I/O is substantially
slower.
I see this again and again as a claim here, but it is actually close to 10
years since I saw mmap'd I/O have any substantial performance benefits on any
real
On Jul 28, 2011, at 6:35, Jonathan Ellis jbel...@gmail.com wrote:
I'm talking about data compatibility, which is more important than cli
statement compatibility.
Consider someone with a python program that creates a CF with the
default settings and inserts some (say) uuid columns and long
Hi!
I am considering to use cassandra for clustered transaction logging in a
project.
What I need are in principal 3 functions:
1 - Log transaction with a unique (but possibly non-sequential) id
2 - Fetch transaction with a specific id
3 - Fetch X new transactions after a specific
Hi,
We have an old production Cassandra 0.6.8 instance without replica, i.e.,
the replication factor is 1. Recently, we noticed that
the snapshot data we took from this instance are inconsistent with the
running instance data. For example, we took snapshot
in early July 2011. From the running
Thanks Jonathan,
I just had one of our devs playing around with it and he said he had problems
with some of the column names of which we delimit using a dash (-) using the
JDBC drivers e.g.
SELECT m-UUID-hash(value) FROM column_family…..
If this is not a problem then I have my questions
I understand and agree for the case where the slice predicate is a range,
but I'd expect the semantics to be different where the predicate is a list
of column names (even if it's implemented using a range operation under the
hood?)
If I ask for columns foo and bar, then usually I'm not trying to
On Thu, Jul 28, 2011 at 4:00 PM, Edward Capriolo edlinuxg...@gmail.com wrote:
On Thu, Jul 28, 2011 at 9:35 AM, Jonathan Ellis jbel...@gmail.com wrote:
I'm talking about data compatibility, which is more important than cli
statement compatibility.
Consider someone with a python program that
To be honest, collecting the names that were missing in the first name
query and doing a new name query for those (if there is any) is so simple
that I think it is a bit dishonest to say that it pushes work to the clients.
It seems simple enough at least that it does not sound like a good idea to
On Thu, Jul 28, 2011 at 10:59 AM, Sylvain Lebresne sylv...@datastax.comwrote:
On Thu, Jul 28, 2011 at 4:00 PM, Edward Capriolo edlinuxg...@gmail.com
wrote:
On Thu, Jul 28, 2011 at 9:35 AM, Jonathan Ellis jbel...@gmail.com
wrote:
I'm talking about data compatibility, which is more
Hi,
I run Cassandra 0.8.2 and hadoop 0.20.2 on three nodes, each node includes a
Cassandra instance and a hadoop data node.
I created a simple hadoop job to scan a Cassandra column value in a column
family and write it to a file system if it meets some conditions.
I keep getting the following
See http://wiki.apache.org/cassandra/HadoopSupport#Troubleshooting - I would
probably start with setting your rpc_timeout_in_ms to something like 3.
On Jul 28, 2011, at 11:09 AM, Jian Fang wrote:
Hi,
I run Cassandra 0.8.2 and hadoop 0.20.2 on three nodes, each node includes a
My current setting is 1. I will try 3.
Thanks,
John
On Thu, Jul 28, 2011 at 12:39 PM, Jeremy Hanna
jeremy.hanna1...@gmail.comwrote:
See http://wiki.apache.org/cassandra/HadoopSupport#Troubleshooting - I
would probably start with setting your rpc_timeout_in_ms to something like
3.
I have three nodes and RF=3.here is the current ring:
Address Status State Load Owns Token
84944475733633104818662955375549269696
node1 Up Normal 15.32 GB 81.09% 52773518586096316348543097376923124102
node2 Up Normal 22.51 GB 10.48% 70597222385644499881390884416714081360
node3 Up Normal 56.1 GB
I just finished watching the video by Eric Evans on CQL - Not just NoSQL. It's
MoSQL, and I heard mention of aggregation queries. He said there's been some
talk about it, and that you guys were calling it co-processors. Can somebody
give me the gist of what that's all about? I couldn't find any
Just wondering - what consistency level are you using for hadoop reads? Also,
do you have task trackers running on the cassandra nodes so that reads will be
local?
On Jul 28, 2011, at 2:46 PM, Jian Fang wrote:
I changed the rpc_timeout_in_ms to 3 and 4, then changed the
On Thu, Jul 28, 2011 at 12:08 PM, Stephen Pope stephen.p...@quest.com wrote:
I just finished watching the video by Eric Evans on “CQL – Not just NoSQL.
It’s MoSQL”, and I heard mention of aggregation queries. He said there’s
been some talk about it, and that you guys were calling it
There is no cursor support.
Moving away from thrift is still in the hopefully someday stage.
On Jul 28, 2011 9:03 AM, Nicholas Neuberger nneuberg...@gmail.com wrote:
I had a few questions that I couldn't easily answer by looking through
many
JIRA tickets and the wiki. We are currently
Dropped read message might be an indicator of capacity issue. We
experienced the similar issue with 0.7.6.
We ended up adding two extra nodes and physically rebooted the offending
node(s).
The entire cluster then calmed down.
On Thu, Jul 28, 2011 at 2:24 PM, Yan Chunlu springri...@gmail.com
If you're actually hitting disk for most or even many of your reads then
mmap doesn't matter since the extra copy to a Java buffer is negligible
compared to the i/o itself (even on ssds).
On Jul 28, 2011 9:04 AM, Terje Marthinussen tmarthinus...@gmail.com
wrote:
On Jul 28, 2011, at 9:52 PM,
I did not set the consistency level because I didn't find this option in the
ConfigHelper class. I guess it should use level one by default.
Actually, I only twisted the word count example a bit. Here is the code
snippet,
getConf().set(CONF_COLUMN_NAME, columnName);
Job job =
Video: Matt Dennis' Data Modeling Workshop:
http://www.datastax.com/2011/07/video-data-modeling-workshop-from-cassandra-sf-2011
A list of available videos are now available on the Cassandra SF 2011
presentation page:
http://www.datastax.com/events/cassandrasf2011/presentations
--
-Lynn Bender
I would love to understand how people got to this conclusion however and try
to find out why we seem to see differences!
I won't make any claims with Cassandra because I have never bothered
benchmarking the different in CPU usage since all my use-cases have
been more focused on I/O efficiency,
On 28 July 2011 16:23, Sylvain Lebresne sylv...@datastax.com wrote:
To be honest, collecting the names that were missing in the first name
query and doing a new name query for those (if there is any) is so simple
that I think it is a bit dishonest to say that it pushes work to the
clients.
Benchmarks was done with up to 96GB memory, much more caching than most people
will ever have.
The point anyway is that you are talking I/O in 10's or at best, a few hundred
MB/sec before cassandra will eat all your CPU (with dual CPU 6 cores in our
case).
The memcopy involved here deep
So to summarize, yes, you can do that with CQL, but it's a little more
of a pain if your comparator is BytesType since you'll need to convert
to hex.
On Thu, Jul 28, 2011 at 9:48 AM, Ikeda Anthony
anthony.ikeda@gmail.com wrote:
Thanks Jonathan,
I just had one of our devs playing around
Doesn't ring a bell. But I'd say if you upgrade and it's still a
problem, then (a) you're not _worse_ off than you are now, and (b)
it's a lot more likely to get fixed in modern version.
On Thu, Jul 28, 2011 at 9:47 AM, Jian Fang
jian.fang.subscr...@gmail.com wrote:
Hi,
We have an old
Hi,
yes I was looking for this config as well.
This is really simple to achieve:
Put the following line into /etc/security/limits.conf
cassandra- memlock 32
Then, start Cassandra as the user cassandra, not as root (note there is never a
need to run Cassandra as root,
I have a rating system where users rate items. the item is the row
key, the user is the column key. The value is the rating on a 5 point
scale. People can only have one rating per item.
I'm looking to add the ability to optionally add a text comment to the
rating record. If the text comment is
On Thu, Jul 28, 2011 at 10:47 PM, Jian Fang
jian.fang.subscr...@gmail.comwrote:
Hi,
We have an old production Cassandra 0.6.8 instance without replica, i.e.,
the replication factor is 1. Recently, we noticed that
the snapshot data we took from this instance are inconsistent with the
running
add new nodes seems added more pressure to the cluster? how about your
data size?
On Fri, Jul 29, 2011 at 4:16 AM, Frank Duan fr...@aimatch.com wrote:
Dropped read message might be an indicator of capacity issue. We
experienced the similar issue with 0.7.6.
We ended up adding two extra
and by the way, my RF=3 and the other two nodes have much more capacity, why
does they always routed the request to node3?
coud I do a rebalance now? before node repair?
On Fri, Jul 29, 2011 at 12:01 PM, Yan Chunlu springri...@gmail.com wrote:
add new nodes seems added more pressure to the
Hello,
I want to run the procedure of Handling Failure option #1 in
http://wiki.apache.org/cassandra/Operations
(i.e. the (Recommended approach) Bring up the replacement node with a
new IP address ...)
Say, I have 10 dead nodes, and I want to replace it with 10 new nodes.
My questions:
Is it
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