On Tue, Jul 22, 2014 at 1:26 AM, Robert Coli wrote:
> I'm pretty sure reversed comparator timestamps are a common type of schema,
> given that there are blog posts recommending their use, so I struggle to
> understand how this was not detected by unit tests.
As Karl has suggested, client driver m
hi all,
I trying add a node to a cassandra ring with only one seed-node. I have the
seed in EC2 and I have this error when I start cassandra in the other node
ERROR [Thrift:389] 2014-07-22 08:25:39,838 CassandraDaemon.java (line 191)
Exception in thread Thread[Thrift:389,5,main]
java.l
Hey, this is cool.
I didn't know this project.
As far as I see, it doesn't support Python, but it's quite interesting, as
it seems to store intermediate results in Cassandra:
- *(optional) write the computation results out to Cassandra*: we
provide a way to efficiently save the result of yo
Hi all,
In the user guide of Cassandra i got the information about the batch for
atomic DML operations.
I want either all the DML statements within the batch succeed or rollback
all.
is it possible?
another question in my can i use joins in Cassandra or any other way to
achieve it.
Regards
Ta
Verified all clocks are in sync.
On Mon, Jul 21, 2014 at 10:03 PM, Rahul Menon wrote:
> I could you perhaps check your ntp?
>
>
> On Tue, Jul 22, 2014 at 3:35 AM, Jeremy Jongsma
> wrote:
>
>> I routinely get this exception from cqlsh on one of my clusters:
>>
>> cql.cassandra.ttypes.Authentica
Hi guys, I know this topic as already been spoken many times, and I read a
lot of these discussions.
Yet, I have not been able to find a good way to do what I want.
We are receiving messages from our app that is a complex, dynamic, nested
JSON (can be a few or thousands of attributes). JSON is va
Sounds like user-defined types (UDF) in Cassandra 2.1:
https://issues.apache.org/jira/browse/CASSANDRA-5590
But... be careful to make sure that you aren’t using this powerful (and
dangerous) feature as a crutch merely to avoid disciplined data modeling.
-- Jack Krupansky
From: Alain RODRIGUEZ
Hi,
This seems to fit, even if I would need to have to look on how these fields
can be queried and indexed. Also, I would need to see if those UDF can be
modified once created and how they behave in this use case.
Yet, 2.1 is currently in beta, and we won't switch to this version
immediately (eve
No joins in Cassandra. But... with DataStax Enterprise (DSE) which integrates
Solr with Cassandra, limited Join support is available. In particular, an outer
join between two tables provided that they share identical partition key
values, so that the joined data is guaranteed to be on the same n
DSE, with Solr integration, does provide “field input transformers” so that you
can parse a column in JSON or any other format and then split it into any
number of Solr fields, including dynamic fields, which would then let you query
elements of that JSON.
-- Jack Krupansky
From: Alain RODRIGU
Does it have an annotation scheme or arrangement so I don't have to put
proprietary stuff in my Java?
Jim C.
On 07/20/2014 06:24 PM, Kevin Burton wrote:
>
>
> I just finished reading "Cassandra: The Definitive Guide" which seems
> pretty out of date and while very informative as to the te
Correction, I mean vendor specific. Proprietary is OK so long as there
aren't any lock-in tricks or they can be dodged easy.
Jim C.
On 07/22/2014 12:12 PM, jcllings wrote:
> Does it have an annotation scheme or arrangement so I don't have to
> put proprietary stuff in my Java?
>
> Jim C.
>
> On 0
So It seems that:
1. There are indeed a few (3-4) mapping schemes.
2. CQL isn't very hard and represents a subset of (ANSI?) SQ92.
Both of these are validated based on further research and list guidance.
It appears that learning Cassandra from an application developers
perspective essentially m
"What kinds of things would it be good to know for an interview?"
The underlying storage engine and how CQL3 maps to it. It's more than
important, it's crucial. Knowing what you do and what you can't with CQL3
is not sufficient.
On Tue, Jul 22, 2014 at 9:20 PM, jcllings wrote:
> So It seems
Hello -
I have a use case where I need to run the Cassandra Server as an OSGi bundle. I
have been able to embed all of the Cassandra dependencies in an OSGi bundle and
run it on Karaf container, but I am not happy with the approach I have thus far.
Since CassandraDaemon has System.exit() calls
You can also try http://caffinitas.org - Open Source Java object mapper for C*
using Datastax's Java Driver licensed using APL2. It is intended to be a bit
close to what JPA does.
Although, it cannot support JPA features 1:1 since there are fundamental
differences between RDBMS and NoSQL/C*.
But
OK to clarify, I don't mean as an Administrator but an application
developer. If you use an ORM how important is CQL3? The object being
to eliminate any *QL from Java code.
Perhaps this technology isn't as mature as I thought.
Jim C.
On 07/22/2014 12:42 PM, DuyHai Doan wrote:
> "What kinds of t
Having an ORM says nothing about the maturity of a database, it says more about
the community and their willingness to create one. The database itself has
nothing to do with the creation of the ORM. Atop everything else, as was
stated, knowing how to model your queries is the most important th
Let me respond with another question: How important is SQL for a JPA developer?
Mappers eliminate the boring and error-prone stuff like "execute SELECT", "read
fields", "call setters" etc. They can automatically perform conversions, apply
optimizations, etc etc etc.
Mappers do not remove the nee
What's your intention to do this?
There are unit test integrations using C* daemon. A related bug that prevented
proper shutdown has been closed for C* 2.1-rc1:
https://issues.apache.org/jira/browse/CASSANDRA-5635
It's perfectly fine to embed C* for unit tests.
But I'd definitely not recommend
On 07/22/2014 01:11 PM, Robert Stupp wrote:
> Let me respond with another question: How important is SQL for a JPA
> developer?
> ...
> IMO mappers help and make life easier. Period.
> Means: you should always know what the "thing" does to read/write your
> data. Practically not down to the detai
"I surmise if you are using a mapper, it should be more a matter of knowing
how the annotations map to the back-end rather than the CQL"
It would be too easy. You should also know how the CQL3 maps to underlying
data storage.
On Tue, Jul 22, 2014 at 10:33 PM, jcllings wrote:
>
> On 07/22/20
Yep - too easy. It does not matter what you use (CQL3, Pojo Mapper ;) or
whatever). And I guess it's easier for a "pure Java coder knowing nothing about
C*" to start with a mapper. But in the end you should know what's going on -
since you will be in the position to fix bugs and performance issu
On 07/22/2014 01:37 PM, DuyHai Doan wrote:
> "I surmise if you are using a mapper, it should be more a matter of
> knowing how the annotations map to the back-end rather than the CQL"
>
> It would be too easy. You should also know how the CQL3 maps to
> underlying data storage.
It would be if I
Checkout datastax devcenter which is a GUI datamodelling tool for cql3
http://www.datastax.com/what-we-offer/products-services/devcenter
On Sun, Jul 20, 2014 at 7:17 PM, jcllings wrote:
> So I'm a Java application developer and I'm trying to find entry points
> for learning to work with Cassan
Removing *QL from application code is not really an indicator of the
maturity of a technology. ORMs and automatic type mapping in general
tend to be very easy things for a developer to work with allowing for
rapid prototypes, but those applications are often ill-suited to being
deployed is high-vol
I can give you some tips.
Figure out what Cassandra does when it starts up. Best way to do that is
to read the startup script. Then all you have to do is convince the
OSGI container to do what ever prep is done by the script. Trick to
that is usually figuring out where to do it. For example if t
BTW, I agree with other posters that it seems like an awfully weird
thing to do. Perhaps you just want to run a client in an OSGI environment?
Jim C.
On 07/22/2014 02:39 PM, jcllings wrote:
> I can give you some tips.
>
> Figure out what Cassandra does when it starts up. Best way to do that
> is
We have been going through and setting up alerts on our Cassandra clusters.
We have catastrophic alerts setup to let us know when things are super
broken, but we are now looking at setting up alerts for letting us know
when we need to start scaling vertically or horizontally.
We have alerts on our
True - Hibernate, Eclipselink and others add plenty of "synchronization"
overhead owed the fact that an entity instance does not need to be explicitly
persisted to get persisted (just change the loaded instance and flush the
session). That's very expensive (CPU and heap). Even though transaction
I would look at load (disk space used) and system.compactions_in_progress.
On Tue, Jul 22, 2014 at 3:49 PM, Arup Chakrabarti
wrote:
> We have been going through and setting up alerts on our Cassandra
> clusters. We have catastrophic alerts setup to let us know when things are
> super broken, b
The problem with Hibernate and the kind is that they try to do many thing
at once. And support for JOINS bring a damned lots of complexity. You need
to manage object graphs and circular references -> statefull session ->
not thread-safe -> not good fit for async & multi threaded envs
On Tue, Jul
also pending read / write operations (nodetool tpstats) and I/O
On Tue, Jul 22, 2014 at 11:59 PM, Shane Hansen
wrote:
> I would look at load (disk space used) and system.compactions_in_progress.
>
>
>
> On Tue, Jul 22, 2014 at 3:49 PM, Arup Chakrabarti
> wrote:
>
>> We have been going through
What got our team on the path of trying to embed C* was the wiki page
http://wiki.apache.org/cassandra/Embedding which implies this can be done. Also
WSO2 Carbon and Achilles have both embedded C* (not in an OSGi container
though, and Carbon is with an older C* version).
We are wanting an "unzi
On Tue, Jul 22, 2014 at 1:10 PM, Russell Bradberry
wrote:
> Having an ORM says nothing about the maturity of a database, it says more
> about the community and their willingness to create one. The database
> itself has nothing to do with the creation of the ORM.
>
Except, as in this case, when
On Tue, Jul 22, 2014 at 1:53 AM, Ben Hood <0x6e6...@gmail.com> wrote:
> As Karl has suggested, client driver maintainers have opted to
> workaround the issue.
Indeed, reading up on the issue (and discussing it with folks) there are a
number of mitigating factors, most significantly driver workar
Hi,
Does anybody has the case study for Migrating from RDBMS to Cassandra ?
Thanks
This document:
https://wiki.apache.org/cassandra/Operations
… for example. Is extremely out dated… does NOT reflect 2.x releases
certainly. Mentions commands that are long since removed/deprecated.
Instead of giving bad documentation, maybe remove this and mark it as
obsolete.
The datastax do
So , shouldn't it be easy to rebalance a cluster?
I'm not super excited to type out 200 commands to move around individual
tokens.
I realize that this isn't a super easy solution, and that there are
probably 2-3 different algorithms to pick here… but having this be the only
option doesn't seem sc
You don't need to specify tokens. The new node gets them automatically.
> On Jul 22, 2014, at 7:03 PM, Kevin Burton wrote:
>
> So , shouldn't it be easy to rebalance a cluster?
>
> I'm not super excited to type out 200 commands to move around individual
> tokens.
>
> I realize that this isn'
Perhaps it's me but it seems this exception is wrong:
"Cassandra timeout during write query at consistency ONE (2 replica were
required but only 1 acknowledged the write)"
.. but the documentation for ONE says:
" A write must be written to the commit log and memory table of at least
one replica
ok.. I think I get what's happening. This node is still joining the
cluster.
It wasn't totally clear that it was still joining as the only indicator is
the little "J" ...
On Tue, Jul 22, 2014 at 7:09 PM, Jonathan Haddad
wrote:
> You don't need to specify tokens. The new node gets them automat
I'm super confused by this.. and disturbed that this was my failure
scenario :-(
I had one cassandra node for the alpha of my app… and now we're moving into
beta… which means three replicas.
So I added the second node… but my app immediately broke with:
""Cassandra timeout during write query at
ONE means write to one replica (in addition to the original). If you want to
write to any of them, use ANY. Is that the right understanding?
http://www.datastax.com/docs/1.0/dml/data_consistency
Andrew
On July 22, 2014 at 7:43:43 PM, Kevin Burton (bur...@spinn3r.com) wrote:
I'm super confuse
Incorrect, ONE does not refer to the number of “other" nodes, it just refers to
the number of nodes. so ONE under normal circumstances would only require one
node to acknowledge the write.
The confusing error message you are getting is related to
https://issues.apache.org/jira/browse/CASSANDRA-
There's lots of info on migrating from a relational database to Cassandra
here:
http://www.datastax.com/relational-database-to-nosql
On Tue, Jul 22, 2014 at 7:45 PM, Surbhi Gupta
wrote:
> Hi,
>
> Does anybody has the case study for Migrating from RDBMS to Cassandra ?
>
> Thanks
>
WEIRD that it was working before… with one node. Granted that this is a
rare config (one cassandra node) but it shouldn't work then.
If you attempt to write ONE to a single cassandra node, there is no (in
addition to) additional node to write to…
So this should have failed.
Bug?
… and I know w
Yeah.. that's fascinating … so now I get something that's even worse:
"Cassandra timeout during write query at consistency ANY (2 replica were
required but only 1 acknowledged the write)"
… the issue is that the new cassandra node has all its ports closed.
Only the storage port is open.
So obvi
and there are literally zero google hits on the query: "Cassandra timeout
during write query at consistency ANY (2 replica were required but only 1
acknowledged the write)"
.. so I imagine I'm the first to find this bug! Aren't I lucky!
On Tue, Jul 22, 2014 at 8:46 PM, Kevin Burton wrote:
> Y
I assumed you must have now switched to ANY which you probably didn’t want to
do, and likely won’t help (and very few people use ANY which may explain the
lack of google hits, plus this particular “Cassandra timeout during write query
at consistency” error message comes from the datastax CQL jav
Thanks of the feedback…
In hindsight.. I think what happened was that the new node started up… and
the driver wanted to write records to it… but the ports weren't up.
so I wonder if this is a bug in the datastax driver.
On bootstrap, and when joining, does cassandra always keep the ports
offline
Thansk Shane, Howover i am looking for any Proof of Concepts kind of
document .
Does anybody has complete end to end document which contains the
application overview,
How they have migrated from RDBMS to Cassandra?
What are the things to consider?
How they have converted data model and after the n
I looked into this; ONE means it must be written to one replica—i.e., a node
the data is supposed to be written to. ANY means a hinted handoff will
“count”. So as long as it writes to any node on the cluster—even one that it’s
not supposed to be on—it will be a success. Good to know.
Andrew
PlanetCassandra has a collection of migration use cases:
http://planetcassandra.org/mysql-to-cassandra-migration/
http://planetcassandra.org/oracle-to-cassandra-migration/
If they don't contain the information you need I'm sure you could reach out
to the companies involved or DataStax itself to g
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