Thanks Tyler. I was unaware of counters.
The use case for column counts is really from a operational perspective,
to allow a sysadmin to do adhoc checks on columns to see if something
has gone wrong in software outside of cassandra.
I think running a cassandra-cli command such as count, which mak
You want to store every value twice? That would be a pain to maintain, and
possibly lead to inconsistent data.
On Fri, Dec 10, 2010 at 3:50 AM, Nick Bailey wrote:
> I would also recommend two column families. Storing the key as NxN would
> require you to hit multiple machines to query for an ent
Hi cassandra experts -
We're planning a cassandra cluster across 2 datacenters
(datacenter-aware, random partitioning) with QUORUM consistency.
It seems to me that with 2 datacenters, if one datacenter is lost,
the reads/writes to cassandra will fail in the surviving datacenter
because of the N
> Is my logic wrong here? Is there a way to ensure the nodes in the
> alive datacenter respond successfully if the second datacenter is
> lost? Anyone have experience with this kind of problem?
It's impossible to achieve the consistency and availability at the
same time. See:
http://en.wikip
>> Is my logic wrong here? Is there a way to ensure the nodes in the
>> alive datacenter respond successfully if the second datacenter is
>> lost? Anyone have experience with this kind of problem?
>
> It's impossible to achieve the consistency and availability at the
> same time. See:
(Assuming
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On Dec 12, 2010, at 1:26 AM, Dave Martin wrote:
> Hi there,
>
> I see the following:
>
> 1) Add 8,000,000 columns to a single row. Each column name is a UUID.
> 2) Use cassandra-cli to run count keyspace.cf['myGUID']
>
> The following is reported in the
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/ Peter Schuller
Thanks a lot Peter. So basically we would need to choose a
consistency other than QUORUM.I think in our case consistency is
not necessarily an issue since our data is write-once, read-many
(immutable data). I suppose having a replication factor of 4 would
result in two nodes in each datacen
On Dec 10, 2010, at 19:37, Peter Schuller wrote:
> To cargo cult it: Are you running a modern JVM? (Not e.g. openjdk b17
> in lenny or some such.) If it is a JVM issue, ensuring you're using a
> reasonably recent JVM is probably much easier than to start tracking
> it down...
I had OOM problems
http://www.riptano.com/docs/0.6/troubleshooting/index#nodes-are-dying-with-oom-errors
On Sun, Dec 12, 2010 at 9:52 AM, Timo Nentwig wrote:
>
> On Dec 10, 2010, at 19:37, Peter Schuller wrote:
>
> > To cargo cult it: Are you running a modern JVM? (Not e.g. openjdk b17
> > in lenny or some such.) I
Hi again.
It would be great if someone could comment whether the following is true
or not.
I tried to understand the consequences of using
|-Dcassandra.dynamic_snitch=true for the read path |and that's what I
came up with:
1) If using CL > 1 than using the dynamic snitch will result in a dat
> Thanks a lot Peter. So basically we would need to choose a
> consistency other than QUORUM. I think in our case consistency is
> not necessarily an issue since our data is write-once, read-many
> (immutable data). I suppose having a replication factor of 4 would
> result in two nodes in ea
Is the same connection is required when iterating over all the rows with
Random Paritioner or is it possible to use a different connection for each
iteration?
Shimi
> Is the same connection is required when iterating over all the rows with
> Random Paritioner or is it possible to use a different connection for each
> iteration?
In general, the choice of RPC connection (I assume you mean the
underlying thrift connection) does not affect the semantics of the RP
So if I will use a different connection (thrift via Hector), will I get the
same results? It's make sense when you use OPP and I assume it is the same
with RP. I just wanted to make sure this is the case and there is no state
which is kept.
Shimi
On Sun, Dec 12, 2010 at 8:14 PM, Peter Schuller w
On Sun, Dec 12, 2010 at 3:20 AM, David Boxenhorn wrote:
> You want to store every value twice? That would be a pain to maintain, and
> possibly lead to inconsistent data.
>
> On Fri, Dec 10, 2010 at 3:50 AM, Nick Bailey wrote:
>>
>> I would also recommend two column families. Storing the key as N
Well, in this case I would say you probably need about 300MB of space in the
heap, since that's what you've calculated.
The APIs are designed to let you do what you think is best and they
definitely won't stop you from shooting yourself in the foot. Counting a
huge row, or trying to grab every ro
This should be the case, yes, semantics isn't affected by the
connection and state isn't kept. What might happen if you read/write
with low consistency levels then when you hit a different host on the
ring it might have an inconsistent state in case of partition.
On Sunday, December 12, 2010, shim
Nice email Dan.
I would also add if you are still in the initial stages take a look at
Hadoop+Pig. If your source data is write once read many it may be a better fit,
but then you would also need to calculate the aggregates and store them
somewhere.
So Cassandra *may* be just what you want. T
RE: storing every value twice. Cassandra is not a RDBMS, the goal is not to
achieve fifth normal form. The goal is to design your storage schema to support
the queries you wish to run.
Storage is cheap. And it's really not a pain to store the values more than
once. Use the batch_mutate() funct
I think there's a flaw in your logic. Take the following scenario:
- you use QUORUM for reads and QUROUM for writes
- you have 2 datacenters (DC1, DC2), with 3 servers in each (so 6 nodes
total).
- you set replication factor to 3
- you use RackAwareStrategy
So, you have DC1-S1, DC1-S2, DC1-S3, DC
I am trying to run cassandra-0.7r2 in eclipse by following
http://wiki.apache.org/cassandra/RunningCassandraInEclipse. there is
not compiling errors however, got error message: Bad configuration; unable
to start server. Any idea?
Liangzhao
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