Contribution

[Salih Gedik]

Hey there,

I am Salih, a sophomore CS student. I really like Cassandra project and 
I'd love to contribute to its development. I have read the steps to get 
up and running and looking for bugs in tracker. However I need to 
understand the architecture of the system. Therefore I'd appreciate if 
you could give me some tips to run a little bit faster.


Thank you so much for your time.
Regards
--
Salih Gedik

Re: Contribution

[Pedro Gordo]

Hi!

I think that the best place to start is to see the DataStax videos. They
are really useful and explain things really well. Check them here
. Although thee DS101 doesn't contain
any deep architecture info, they tell you how Cassandra first came to be.
On DS201 they cover architecture details so I think that will be your main
focus to start.

The GettingStarted wiki 
on Planet Cassandra is also really useful and contains links to other
useful sites (including the videos on DataStax).

Best of luck with your Cassandra journey ;)

Regards

Pedro Gordo

On 28 March 2016 at 13:48, Salih Gedik  wrote:

> Hey there,
>
> I am Salih, a sophomore CS student. I really like Cassandra project and
> I'd love to contribute to its development. I have read the steps to get up
> and running and looking for bugs in tracker. However I need to understand
> the architecture of the system. Therefore I'd appreciate if you could give
> me some tips to run a little bit faster.
>
> Thank you so much for your time.
> Regards
> --
> Salih Gedik
>

Re: Contribution

[Chris Lohfink]

I would second the suggestion of going over
https://academy.datastax.com/ then can
check out http://www.datastax.com/dev/blog/deep-into-cassandra-internals

Chris

On Mon, Mar 28, 2016 at 8:04 AM, Pedro Gordo 
wrote:

> Hi!
>
> I think that the best place to start is to see the DataStax videos. They
> are really useful and explain things really well. Check them here
> . Although thee DS101 doesn't
> contain
> any deep architecture info, they tell you how Cassandra first came to be.
> On DS201 they cover architecture details so I think that will be your main
> focus to start.
>
> The GettingStarted wiki 
> on Planet Cassandra is also really useful and contains links to other
> useful sites (including the videos on DataStax).
>
> Best of luck with your Cassandra journey ;)
>
> Regards
>
> Pedro Gordo
>
> On 28 March 2016 at 13:48, Salih Gedik  wrote:
>
> > Hey there,
> >
> > I am Salih, a sophomore CS student. I really like Cassandra project and
> > I'd love to contribute to its development. I have read the steps to get
> up
> > and running and looking for bugs in tracker. However I need to understand
> > the architecture of the system. Therefore I'd appreciate if you could
> give
> > me some tips to run a little bit faster.
> >
> > Thank you so much for your time.
> > Regards
> > --
> > Salih Gedik
> >
>

What is the best way to model this JSON ??

[Lokesh Ceeba - Vendor]

Hello Team,
   How to design/develop the best data model for this ?


var json=[{ "id":"9a55fdf6-eeab-4c83-9c6f-04c7df1b3225",
"user":"ssatish",
"event":"business",
"occurredOn":"09 Mar 2016 17:55:15.292-0600",
"eventObject":
{
"objectType":"LOAD",
"id":"12345",
"state":"ARRIVAL",
"associatedAttrs":
[
{

"type":"location_id",
"value":"100"
},
{

"type":"location_type",
"value":"STORE"
},
{

"type":"arrival_ts",

"value":"2015-12-12T10:10:10"
}
]
} }]


I've taken this approach :

create type event_object_0328
(
Object_Type text,
Object_ID   Int,
Object_State text
)
;


create table Events
(
event_id   timeuuid,
event_type text,
triggered_by   text,
triggered_ts   timestamp,
Appl_IDtext,
eventObjectfrozen,
primary key(event_id)
)
;

Now I need to build the Associated Attributes (Highlighted above in JSON text). 
The Associated Attributes can be very dynamic and shall come in any (Key,Value) 
pair combination.




--
Lokesh

This email and any files transmitted with it are confidential and intended 
solely for the individual or entity to whom they are addressed. If you have 
received this email in error destroy it immediately. *** Walmart Confidential 
***

Re: What is the best way to model this JSON ??

[Ryan Svihla]

Lokesh,

The modeling will change a bit depending on your queries, the rate of update 
and your tooling (Spring-data-cassandra makes a mess of updating collections 
for example).  I suggest asking the Cassandra users mailing list for help since 
this list is for development OF Cassandra.

> On Mar 28, 2016, at 11:09 AM, Lokesh Ceeba - Vendor 
>  wrote:
> 
> Hello Team,
>   How to design/develop the best data model for this ?
> 
> 
> var json=[{ "id":"9a55fdf6-eeab-4c83-9c6f-04c7df1b3225",
>"user":"ssatish",
>"event":"business",
>"occurredOn":"09 Mar 2016 17:55:15.292-0600",
>"eventObject":
>{
>"objectType":"LOAD",
>"id":"12345",
>"state":"ARRIVAL",
>"associatedAttrs":
>[
>{
>
> "type":"location_id",
>"value":"100"
>},
>{
>
> "type":"location_type",
>"value":"STORE"
>},
>{
>
> "type":"arrival_ts",
>
> "value":"2015-12-12T10:10:10"
>}
>]
> } }]
> 
> 
> I've taken this approach :
> 
> create type event_object_0328
> (
> Object_Type text,
> Object_ID   Int,
> Object_State text
> )
> ;
> 
> 
> create table Events
> (
> event_id   timeuuid,
> event_type text,
> triggered_by   text,
> triggered_ts   timestamp,
> Appl_IDtext,
> eventObjectfrozen,
> primary key(event_id)
> )
> ;
> 
> Now I need to build the Associated Attributes (Highlighted above in JSON 
> text). The Associated Attributes can be very dynamic and shall come in any 
> (Key,Value) pair combination.
> 
> 
> 
> 
> --
> Lokesh
> 
> This email and any files transmitted with it are confidential and intended 
> solely for the individual or entity to whom they are addressed. If you have 
> received this email in error destroy it immediately. *** Walmart Confidential 
> ***

Re: Contribution

[Salih Gedik]

Chris and Pedro,

Thank you so much for the tips. I will check these out!

Regards


I would second the suggestion of going over
https://academy.datastax.com/ then can
check out http://www.datastax.com/dev/blog/deep-into-cassandra-internals

Chris

On Mon, Mar 28, 2016 at 8:04 AM, Pedro Gordo 
wrote:


Hi!

I think that the best place to start is to see the DataStax videos. They
are really useful and explain things really well. Check them here
. Although thee DS101 doesn't
contain
any deep architecture info, they tell you how Cassandra first came to be.
On DS201 they cover architecture details so I think that will be your main
focus to start.

The GettingStarted wiki 
on Planet Cassandra is also really useful and contains links to other
useful sites (including the videos on DataStax).

Best of luck with your Cassandra journey ;)

Regards

Pedro Gordo

On 28 March 2016 at 13:48, Salih Gedik  wrote:


Hey there,

I am Salih, a sophomore CS student. I really like Cassandra project and
I'd love to contribute to its development. I have read the steps to get

up

and running and looking for bugs in tracker. However I need to understand
the architecture of the system. Therefore I'd appreciate if you could

give

me some tips to run a little bit faster.

Thank you so much for your time.
Regards
--
Salih Gedik







--
Salih Gedik

Plans to support OR?

[Henry M]

Is there a plan for supporting OR in Cassandra queries?

The following page points out there will be future changes to add OR
support but I could not find a Jira ticket.

   - https://github.com/apache/cassandra/blob/trunk/doc/SASI.md
   *"Not Equals and OR support have been removed in this release while
   changes are made to Cassandra itself to support them."*

Thank you,
Henry

Re: Plans to support OR?

[Pavel Yaskevich]

Hi Henry,

   Yes, I'm currently working toward that (
https://issues.apache.org/jira/browse/CASSANDRA-0),
   such would require some major changes to the way select statements are
executed but we are going to get there soon.

Best Regards, Pavel.

On Mon, Mar 28, 2016 at 12:35 PM, Henry M  wrote:

> Is there a plan for supporting OR in Cassandra queries?
>
> The following page points out there will be future changes to add OR
> support but I could not find a Jira ticket.
>
>- https://github.com/apache/cassandra/blob/trunk/doc/SASI.md
>*"Not Equals and OR support have been removed in this release while
>changes are made to Cassandra itself to support them."*
>
> Thank you,
> Henry
>

Re: Counter values become under-counted when running repair.

[Dikang Gu]

Hi Aleksey, do you get a chance to take a look?

Thanks
Dikang.

On Thu, Mar 24, 2016 at 10:30 PM, Dikang Gu  wrote:

> @Aleksey, sure, here is the jira:
> https://issues.apache.org/jira/browse/CASSANDRA-11432
>
> Thanks!
>
> On Thu, Mar 24, 2016 at 5:32 PM, Aleksey Yeschenko 
> wrote:
>
>> Best open a JIRA ticket and I’ll have a look at what could be the reason.
>>
>> --
>> AY
>>
>> On 24 March 2016 at 23:20:55, Dikang Gu (dikan...@gmail.com) wrote:
>>
>> @Aleksey, we are writing to cluster with CL = 2, and reading with CL = 1.
>> And overall we have 6 copies across 3 different regions. Do you have
>> comments about our setup?
>>
>> During the repair, the counter value become inaccurate, we are still
>> playing with the repair, will keep you update with more experiments. But
>> do
>> you have any theory around that?
>>
>> Thanks a lot!
>> Dikang.
>>
>> On Thu, Mar 24, 2016 at 11:02 AM, Aleksey Yeschenko 
>> wrote:
>>
>> > After repair is over, does the value settle? What CLs do you write to
>> your
>> > counters with? What CLs are you reading with?
>> >
>> > --
>> > AY
>> >
>> > On 24 March 2016 at 06:17:27, Dikang Gu (dikan...@gmail.com) wrote:
>> >
>> > Hello there,
>> >
>> > We are experimenting Counters in Cassandra 2.2.5. Our setup is that we
>> > have
>> > 6 nodes, across three different regions, and in each region, the
>> > replication factor is 2. Basically, each nodes holds a full copy of the
>> > data.
>> >
>> > When are doing 30k/s counter increment/decrement per node, and at the
>> > meanwhile, we are double writing to our mysql tier, so that we can
>> measure
>> > the accuracy of C* counter, compared to mysql.
>> >
>> > The experiment result was great at the beginning, the counter value in
>> C*
>> > and mysql are very close. The difference is less than 0.1%.
>> >
>> > But when we start to run the repair on one node, the counter value in
>> C*
>> > become much less than the value in mysql, the difference becomes larger
>> > than 1%.
>> >
>> > My question is that is it a known problem that the counter value will
>> > become under-counted if repair is running? Should we avoid running
>> repair
>> > for counter tables?
>> >
>> > Thanks.
>> >
>> > --
>> > Dikang
>> >
>> >
>>
>>
>> --
>> Dikang
>>
>>
>
>
> --
> Dikang
>
>


-- 
Dikang