More compactions meaning "actual number of compaction tasks". A compaction
task generally operates on many SSTables (how many depends on the chosen
compaction strategy). The number of pending tasks does not line up with the
number of SSTables that will be compacted. 1 task may compact many SSTable
I have a single node cassandra installation on my dev laptop, which is used
just for dev / testing.
Recently, whenever I restart my laptop, Cassandra fails to start when I run
it via 'sudo service cassandra start'.
Doing a tail on /var/log/cassandra/system.log gives this log:
*INFO [main] 2016-
More compactions meaning "rows to be compacted" or actual number of pending
compactions? I assumed when I run nodetool compactionstats the number of
pending tasks would line up with number of sstables that will be compacted.
Most of the time this is idle, then we hit spots when it could jump into
t
On 22 October 2016 at 03:37, Seth Edwards wrote:
> We're using TWCS and we notice that if we make changes to the options to
> the window unit or size, it seems to implicitly start recompacting all
> sstables.
If you increase the window unit or size you potentially increase the number
of SSTable
Definitely sounds to me like something is not working as expected but I
don’t really have any idea what would cause that (other than the fairly
extreme failure scenario). A couple of things I can think of to try to
narrow it down:
1) Run nodetool flush on all nodes after step 2 - that will make sur
You have to manually do "nodetool flush && nodetool flush system" before
shutdown, otherwise Cassandra might break. With that it is working nicely.
On Sun, Oct 23, 2016 at 3:40 PM, Ali Akhtar wrote:
> I'm using https://github.com/jsevellec/cassandra-unit and haven't come
> across any race issues
That helps! thanks! I assume you meant "updating one the columns in the
PRIMARY KEY would require DELETE + INSERT".
since we don't do updates or deletes on this table I believe could leverage
this!
On Sun, Oct 23, 2016 at 12:44 PM, DuyHai Doan wrote:
> There is nothing wrong with your schema,
There is nothing wrong with your schema, but just remember that because to
set everything except one as clustering columns, updating them is no longer
possible. To "update" the value of one of those columns you'll need to do a
DELETE + INSERT.
Example:
with normal schema: UPDATE hello SET e = WH
Hi All,
Is there any problem having too many clustering columns? My goal is to
store data by columns in order and for any given partition (primary key)
each of its non-clustering column (columns that are not part of primary
key) can lead to a new column underneath or the CQL equivalent would be a
I'm using https://github.com/jsevellec/cassandra-unit and haven't come
across any race issues or problems. Cassandra-unit takes care of creating
the schema before it runs the tests.
On Sun, Oct 23, 2016 at 6:17 PM, DuyHai Doan wrote:
> Ok I have added -Dcassandra.unsafesystem=true and my tests a
Ok I have added -Dcassandra.unsafesystem=true and my tests are broken.
The reason is that I create some schemas before executing tests.
When unable unsafesystem, Cassandra does not block for schema flush so you
man run into race conditions where the test start using the created schema
but it has
please see CASSANDRA-12654
On Sat, Oct 22, 2016 at 3:12 AM, DuyHai Doan wrote:
> So the commit on this restriction dates back to 2.2.0 (CASSANDRA-7981).
>
> Maybe Benjamin Lerer can shed some light on it.
>
> On Fri, Oct 21, 2016 at 11:05 PM, Jeff Carpenter <
> jeff.carpen...@choicehotels.com> w
Another thing is,
Let's say that we already have a structure data, the way we load that to
HDFS is to turn that one into a files ?
Cheers
On Sun, Oct 23, 2016 at 6:18 PM, Welly Tambunan wrote:
> So basically you will store that files to HDFS and use Spark to process it
> ?
>
> On Sun, Oct 23,
So basically you will store that files to HDFS and use Spark to process it
?
On Sun, Oct 23, 2016 at 6:03 PM, Joaquin Alzola
wrote:
>
>
> I think what Ali mentions is correct:
>
> If you need a lot of queries that require joins, or complex analytics of
> the kind that Cassandra isn't suited for,
I think what Ali mentions is correct:
If you need a lot of queries that require joins, or complex analytics of the
kind that Cassandra isn't suited for, then HDFS / HBase may be better.
We have files in which one line contains 500 fields (separated by pipe) and
each of this fields is particular
"from a particular query" should be " from a particular country"
On Sun, Oct 23, 2016 at 2:36 PM, Ali Akhtar wrote:
> They can be, but I would assume that if your Cassandra data model is
> inefficient for the kind of queries you want to do, Spark won't magically
> take that way.
>
> For example,
They can be, but I would assume that if your Cassandra data model is
inefficient for the kind of queries you want to do, Spark won't magically
take that way.
For example, say you have a users table. Each user has a country, which
isn't a partitioning key or clustering key.
If you wanted to calcul
I like muti data centre resillience in cassandra.
I think thats plus one for cassandra.
Ali, complex analytics can be done in spark right?
On 23 Oct 2016 4:08 p.m., "Ali Akhtar" wrote:
>
> I would say it depends on your use case.
>
> If you need a lot of queries that require joins, or complex
I would say it depends on your use case.
If you need a lot of queries that require joins, or complex analytics of
the kind that Cassandra isn't suited for, then HDFS / HBase may be better.
If you can work with the cassandra way of doing things (creating new tables
for each query you'll need to do
It’s reasonably common to use Cassandra to cover both online and analytics
requirements, particularly using it in conjunction with Spark. You can use
Cassandra’s multi-DC functionality to have online and analytics DCs for a
reasonable degree of workload separation without having to build ETL (or
so
I mean. HDFS and HBase.
On Sun, Oct 23, 2016 at 4:00 PM, Ali Akhtar wrote:
> By Hadoop do you mean HDFS?
>
>
>
> On Sun, Oct 23, 2016 at 1:56 PM, Welly Tambunan wrote:
>
>> Hi All,
>>
>> I read the following comparison between hadoop and cassandra. Seems the
>> conclusion that we use hadoop for
By Hadoop do you mean HDFS?
On Sun, Oct 23, 2016 at 1:56 PM, Welly Tambunan wrote:
> Hi All,
>
> I read the following comparison between hadoop and cassandra. Seems the
> conclusion that we use hadoop for data lake ( cold data ) and Cassandra for
> hot data (real time data).
>
> http://www.dat
Hi All,
I read the following comparison between hadoop and cassandra. Seems the
conclusion that we use hadoop for data lake ( cold data ) and Cassandra for
hot data (real time data).
http://www.datastax.com/nosql-databases/nosql-cassandra-and-hadoop
My question is, can we just use cassandra to r
https://github.com/apache/cassandra/blob/trunk/src/java/org/apache/cassandra/serializers/CounterSerializer.java
public class CounterSerializer extends LongSerializer
On Sun, Oct 23, 2016 at 10:16 AM, Ben Slater
wrote:
> http://cassandra.apache.org/doc/latest/cql/types.html?
> highlight=counter#
http://cassandra.apache.org/doc/latest/cql/types.html?highlight=counter#counters
On Sun, 23 Oct 2016 at 19:15 Kant Kodali wrote:
> where does it say counter is implemented as long?
>
> On Sun, Oct 23, 2016 at 1:13 AM, Ali Akhtar wrote:
>
> Probably:
> https://docs.oracle.com/javase/8/docs/api/j
It seems obvious.
On Sun, Oct 23, 2016 at 1:15 PM, Kant Kodali wrote:
> where does it say counter is implemented as long?
>
> On Sun, Oct 23, 2016 at 1:13 AM, Ali Akhtar wrote:
>
>> Probably: https://docs.oracle.com/javase/8/docs/api/java/lan
>> g/Long.html#MAX_VALUE
>>
>> On Sun, Oct 23, 2016
where does it say counter is implemented as long?
On Sun, Oct 23, 2016 at 1:13 AM, Ali Akhtar wrote:
> Probably: https://docs.oracle.com/javase/8/docs/api/java/
> lang/Long.html#MAX_VALUE
>
> On Sun, Oct 23, 2016 at 1:12 PM, Kant Kodali wrote:
>
>> What is the maximum value of Cassandra Counter
Probably:
https://docs.oracle.com/javase/8/docs/api/java/lang/Long.html#MAX_VALUE
On Sun, Oct 23, 2016 at 1:12 PM, Kant Kodali wrote:
> What is the maximum value of Cassandra Counter Column?
>
What is the maximum value of Cassandra Counter Column?
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