On Mon, Mar 8, 2010 at 10:14 AM, Jonathan Ellis wrote:
> On Mon, Mar 8, 2010 at 12:07 PM, Erik Holstad
> wrote:
> > So why is it again that the value field in the Column cannot be null if
> it
> > is not the
> > value field in the map, but just a part of the value f
On Mon, Mar 8, 2010 at 9:30 AM, Jonathan Ellis wrote:
> On Mon, Mar 8, 2010 at 11:22 AM, Erik Holstad
> wrote:
> > I was probably a little bit unclear here. I'm wondering about the two
> byte[]
> > in Column.
> > One for name and one for value. I w
On Mon, Mar 8, 2010 at 9:10 AM, Jonathan Ellis wrote:
> On Mon, Mar 8, 2010 at 11:07 AM, Erik Holstad
> wrote:
> > Why is it that null column values are not allowed?
>
> It's semantically unnecessary and potentially harmful at an
> implementation level. (Many java
Hey!
Been looking at the src and have a couple of questions:
Why is it that null column values are not allowed?
What is the reason for using a ConcurrentSkipListMap for
columns_ in ColumnFamily
compared to using the set version and use the comparator to sort on the name
field in IColumn?
For the
Thanks David and Jonathan!
@David
Yes rows doesn't have a name, I'm just using the word name for anything,
like cluster name,
table name, row name etc, that is my bad.
Yes, I did change two things, that was probably stupid, but the reason for
the second change
is space efficiency.
You are totall
What are the benefits of using multiple ColumnFamilies compared to using a
composite
row name?
Example: You have messages that you want to index on sent and to.
So you can either have
ColumnFamilyFrom:userTo:{userFrom->messageid}
ColumnFamilyTo:userFrom:{userTo->messageid}
or something like
Colu
Thank you!
On Mon, Mar 1, 2010 at 2:51 PM, Jonathan Ellis wrote:
> On Mon, Mar 1, 2010 at 4:49 PM, Erik Holstad
> wrote:
> > Haha!
> > Thanks. Well I'm z little bit worried about this but since the indexes
> are
> > pretty
> > small I don't think it is going to
Haha!
Thanks. Well I'm z little bit worried about this but since the indexes are
pretty
small I don't think it is going to be too bad. But was mostly thinking about
performance and and having the index row as a bottleneck for writing, since
the
partition is per row.
--
Regards Erik
Yes, Cassandra has supercolumns and HBase versions and you are probably
correct that supercolumns
are more used than versions, but I don't really think you can compare them
since versions are not a
serialized structure.
The reason that I didn't include table and family in the mapping is as I've
u
So that is kinda of what I want to do, but I want to go from
a row with multiple columns to multiple rows with one column,
maybe I'm not hearing you here and you are trying to tell me that
the columns, not supercolumns, are not stored together in a row structure?
--
Regards Erik
On Mon, Mar 1, 2010 at 4:41 AM, Brandon Williams wrote:
> On Mon, Mar 1, 2010 at 5:34 AM, HHB wrote:
>
>>
>> What are the advantages/disadvantages of Cassandra over HBase?
>>
>
> Ease of setup: all nodes are the same.
>
> No single point of failure: all nodes are the same.
>
> Speed: http://www.
Sorry about that!
Continuing:
And in that case when using rows as indexes instead of columns we only need
to read
that specific row and might be more efficient in that case than to read a
big row every
time?
--
Regards Erik
ure first need to
be deserialized
and then we can get the columns we are looking for?
And in that case when using rows as indexes instead of columns we only need
to read
On Mon, Mar 1, 2010 at 11:24 AM, Jonathan Ellis wrote:
> On Mon, Mar 1, 2010 at 12:50 PM, Erik Holstad
> wrote:
>
I've been looking at the source, but not quite find the things I'm looking
for, so I have a few
questions.
Are columns for a row stored in a serialized data structure on disk or
stored individually and
put into a data structure when the call is being made? Because of the slice
query, does that
mean
When deleting rows from a table and then using a get_range_slice query, the
keys or the
deleted rows show up, with no name/value pairs. What is the reasoning behind
this?
I have also seen a weird issue when using a md5 generated byte[] as a column
name,
doesn't seem like it actually work. I can't
Haha!
Yeah, fortunately we are only in the testing phase so this is not that big
of a deal.
Thanks a lot!
--
Regards Erik
Thanks Jonathan!
We are thinking about moving over to the OPP to be able to be able to do
this
and to use an md5 for some of the data just to get the data written to
different nodes
for some of the cases where order is not really needed. Is there anything we
need to
think about when making the swi
If you have a system setup using the RandomPartitioner and have a couple of
indexes
setup for your data but realize that you need to add another index. How do
you get the
keys for your data, so that you can know where to point your indexes?
I guess what I'm really asking is, is there a way to get y
Hey Rusian!
Maybe you should do what Ted suggested, look at what Cassandra is good at
and then try
to change your data structure from 10 rows with 10 columns to maybe
10 rows
with 10 columns each. I think the best way to solve a problem is to look at
the tools that
you have at hand and try
Don't be silly, thanks a lot for helping me out!
--
Regards Erik
I don't understand what you mean ;)
Will see what happens when we are done with this first project, will see
if we can get some time to give back.
--
Regards Erik
s I dont have anything reporting-ish like you describe with
> SuperColumns (yet). I will defer to more experienced folks with this.
>
> Regards,
> -Nate
>
>
> On Tue, Feb 2, 2010 at 3:02 PM, Erik Holstad
> wrote:
> > @Nathan
> > So what I'm planning to do i
e number of SuperColumns for a key, but make
> > sure you understand get_slice vs. get_range_slice before you commit to
> > a design. Hopefully I understood your example correctly, if not, do
> > you have anything more concrete?
> >
> > Cheers,
> > -Nate
> >
Thanks Nate for the example.
I was thinking more a long the lines of something like:
If you have a family
Data : {
row1 : {
col1:val1,
row2 : {
col1:val2,
...
}
}
Using
Sorts : {
sort_row : {
sortKey1_datarow1: [],
sortKey2_datarow2: []
}
}
Instead of
Sorts : {
Thank you!
On Tue, Feb 2, 2010 at 9:41 AM, Jonathan Ellis wrote:
> On Tue, Feb 2, 2010 at 11:36 AM, Erik Holstad
> wrote:
> > Is there a way to use a byte[] as the key instead of a string?
>
> no.
>
> > If not what is the main reason for using strings for the key
On Tue, Feb 2, 2010 at 9:57 AM, Brandon Williams wrote:
> On Tue, Feb 2, 2010 at 11:39 AM, Erik Holstad wrote:
>
>>
>> Wow that sounds really good. So you are saying if I set it to reverse sort
>> order and count 10 for the first round I get the last 10,
>> for the
Sorry that there are a lot of questions from me this week, just trying to
better understand
the best way to use Cassandra :)
Let us say that you know the length of your key, everything is standardized,
are there people
out there that just tag the value onto the key so that you don't have to pay
t
On Tue, Feb 2, 2010 at 9:35 AM, Brandon Williams wrote:
> On Tue, Feb 2, 2010 at 11:29 AM, Erik Holstad wrote:
>
>> Thanks guys!
>> So I want to use sliceRange but thinking about using the count parameter.
>> For example give me
>> the first x columns, next call
Is there a way to use a byte[] as the key instead of a string?
If not what is the main reason for using strings for the key but
the columns and the values can be byte[]? Is it just to be able
to use it as the key in a Map etc or are there other reasons?
--
Regards Erik
?
On Tue, Feb 2, 2010 at 9:23 AM, Brandon Williams wrote:
> On Tue, Feb 2, 2010 at 11:21 AM, Erik Holstad wrote:
>
>> Hey!
>> I'm looking for a comparator that sort columns in reverse order on for
>> example bytes?
>> I saw that you can write your own comp
Hey!
I'm looking for a comparator that sort columns in reverse order on for
example bytes?
I saw that you can write your own comparator class, but just thought that
someone must have done that already.
--
Regards Erik
On Tue, Feb 2, 2010 at 7:45 AM, Brandon Williams wrote:
> On Tue, Feb 2, 2010 at 9:27 AM, Erik Holstad wrote:
>>
>> A supercolumn can still only compare subcolumns in a single way.
>>>
>> Yeah, I know that, but you can have a super column per sort order without
&g
Hi Sebastien!
I'm totally new to Cassandra, but as far as I know there is no way of
getting just the keys that are in the
database, they are not stored separately but only with the data itself.
Why do you want a list of keys, what are you going to use them for? Maybe
there is another way of solvin
On Mon, Feb 1, 2010 at 3:31 PM, Brandon Williams wrote:
> On Mon, Feb 1, 2010 at 5:20 PM, Erik Holstad wrote:
>
>> Hey!
>> Have a couple of questions about the best way to use Cassandra.
>> Using the random partitioner + the multi_get calls vs order preservatio
Hi Carlos!
I'm also really new to Cassandra but here are a couple of links that I found
useful:
http://wiki.apache.org/cassandra/ClientExamples
http://arin.me/blog/wtf-is-a-supercolumn-cassandra-data-model
and one of the presentations like:
http://www.slideshare.net/jhammerb/data-presentations-ca
Hey!
Have a couple of questions about the best way to use Cassandra.
Using the random partitioner + the multi_get calls vs order preservation +
range_slice calls?
What is the benefit of using multiple families vs super column? For example
in the case of sorting
in different orders. One good thing
Thanks a lot Brandon!
Hey guys!
I'm totally new to Cassandra and have a couple of question about the
internal structure of some of the calls.
When using the slicerange(count) for the get calls, does the actual result
being truncated on the server
or is it happening on the client ie is it more efficient than the regula
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