Great articles, I did not find those before !
*
SSTable Index - yes I mean column Index.
*I would like to understand, how many disk seeks might be required to find
column in single SSTable.
I am assuming positive bloom filter on row key. Now Cassandra needs to find
out whenever given SSTable cont
I would take a look at the replication: whats the RF per DC and what does
nodetool ring say. It's hard (as in no recommended) to get NTS with rack
allocation working correctly. Without know much more I would try to understand
what the topology is and if it can be simplified.
>> Additionally, t
> If you use the remove function to delete an entire row, is that an atomic
> operation?
Yes. Row level deletes are atomic.
cheers
-
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com
On 17/08/2012, at 3:39 PM, Derek Williams wrote:
> On Thu, Aug 16,
> 2) Rad from disk all row keys, in order to find one (binary search)
No.
At startup cassandra samples the -index.db component every index_interval keys.
At worst index_interval keys must be read from disk.
> As I understand, in the worst case, we can have three disk seeks (2, 4, 6)
> pro SSTa
If you specify the columns by name in the select clause the query returns them
because they should be projected in the result set.
Can you use a column slice instead ?
Cheers
-
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com
On 17/08/2012, at 11:09 A
Hi guys,
I am trying to understand what happens when an UnavailableException is
thrown.
a) Suppose we are doing a ConsistencyLevel.ALL write on a 3 node cluster.
My understanding is that if one of the nodes is down and the coordinator
node is aware of that(through gossip), then it will respond to
Hi Aaron,
Thanks for the answer. That makes sense and I can see it as a formal
reason for returning empty columns, but as a practical matter, is
there a situation in which that behavior would be useful?
Unfortunately a column slice won't do the trick -- the columns we're
looking for at any given
Hi,
I've been running a number of tests with Cassandra using a couple of
PHP drivers (namely PHPCassa (https://github.com/thobbs/phpcassa/) and
PDO-cassandra (http://code.google.com/a/apache-extras.org/p/cassandra-pdo/),
and the experience hasn't been great, mainly because I can't try out
the CQL3
On Fri, 2012-08-17 at 11:09 +0100, Andy Ballingall TF wrote:
> So my question is - if you were to build a new scalable project from
> scratch tomorrow sitting on top of Cassandra, which technologies would
> you select to serve HTTP requests to ensure you get:
>
> a) The best support from the cassa
UnavailableException is bit tricky. It means, that not all replicas
required by CL received update. Actually you do not know, whenever update
was stored or not, and actually what went wrong.
This is the case, why writing with CL.ALL might get problematic. It is
enough, that only one replica is off
I am not sure what you mean by play with the timestamp. I think this works
without playing with the timestamp(thanks for you help as it got me here).
1. On a scan I hit
2. I end up looking up the pk
3. I compare the value in the row with the indexed value "mike" but I see the
row with th
The best stack is the THC stack. :)
Tomcat Hadoop Cassandra :)
On Fri, Aug 17, 2012 at 6:09 AM, Andy Ballingall TF
wrote:
> Hi,
>
> I've been running a number of tests with Cassandra using a couple of
> PHP drivers (namely PHPCassa (https://github.com/thobbs/phpcassa/) and
> PDO-cassandra (http:
Does this mean that the coordinator sends requests to all nodes, even when
it knows that sufficient number of nodes are not available, via gossip?
On Fri, Aug 17, 2012 at 4:49 PM, Maciej Miklas wrote:
> UnavailableException is bit tricky. It means, that not all replicas
> required by CL receive
Robin,
Are you talking about total writes to the cluster, writes to a
specific column family, or something else?
There has been some changes to OpsCenters metric collection/storage
system but nothing that should cause something like that. Also its
possible the number of writes to the OpsCenter k
This blog post should help:
http://www.datastax.com/dev/blog/how-cassandra-deals-with-replica-failure
But to answer your question:
>> UnavailableException is bit tricky. It means, that not all replicas
>> required by CL received update. Actually you do not know, whenever update
>> was stored or
Thank you very much Aaron. Information you provided is very helpful.
Have a great Weekend!!!
swat.vikas
From: aaron morton
To: user@cassandra.apache.org
Sent: Thursday, August 16, 2012 6:29 PM
Subject: Re: wild card on query
> I want to retrieve all the pho
1) For now i am using sstableloader. I think, some time later i will write some
code using RPC.
2) Yes, I looked into many blogs and found information that i need to use last
index to retrieve next 100 rows. I was trying to save some time if some one has
already done this kind of streaming. I
We see similar issues with some of the repairs at Netflix.
Regarding the growth in payload… we see similar symptoms where nodes can double
or triple size. Part of this may be because the repair may deal in large
chunks for comparisons. This means that even if there is one byte of entropy,
you
My stack:
Java + JRuby + Rails + Torquebox
I'm using the Hector client (arguably the most mature out there) and
JRuby+RoR+Torquebox gives me a great development platform which really
scales (full native thread support for example) and is extremely
powerful. Honestly I expect, all my future RoR a
Thanks Nick for your answers. The blog post is very well written and was
much needed i guess.
On Fri, Aug 17, 2012 at 8:30 PM, Nick Bailey wrote:
> This blog post should help:
>
> http://www.datastax.com/dev/blog/how-cassandra-deals-with-replica-failure
>
> But to answer your question:
>
> >> Un
On Fri, Aug 17, 2012 at 8:00 AM, Nick Bailey wrote:
> This is actually incorrect. If you get an UnavailableException, the
> write was rejected by the coordinator and was not written anywhere.
Last time I checked, this was not true for batch writes. The row
mutations were started sequentially (ie,
Aaron, thanks for your answer.
I'm actually tracking a problem where mutations get dropped and cfstats
show no activity whatsoever, I have 100 threads for the mutation pool, no
running or pending tasks, but some mutations get dropped none the less.
I'm thinking about some scheduling problems but
Hi Dean,
I'm interested in this too, but I get a 404 with the link below, looks
like I can't see your nosqlORM project.
-Ben
On Thu, Aug 2, 2012 at 9:04 AM, Hiller, Dean wrote:
> For how to do it with astyanax, you can see here...
>
> Lines 310 and 335
>
> https://github.com/deanhiller/nosql
> How come a node would consume 5x its normal data size during the repair
> process?
https://issues.apache.org/jira/browse/CASSANDRA-2699
It's likely a variation based on how out of synch you happen to be,
and whether you have a neighbor that's also been repaired and bloated
up already.
> My set
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