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From Aditya <>
Subject Re: Seeking advice on Schema and Caching
Date Wed, 16 Nov 2011 21:59:45 GMT
Thanks to samal who pointed to look at the composite columns. I am now
using composite columns names containing username+userId & valueless
column. Thus column names are now unique even for users with same name as
userId is also attached to the same composite col name. Thus the
supercolumn issue is resolved.
But I am still seeking advice some on the caching strategy for these rows.
Since while a user is doing the search, the DB will be queried multiple
times because  I 'm not keeping the retrieved columns in the application
layer. Thus I am thinking of caching this row so that the further queries
be served through the cache. However the important point here is that I am
using very fewer resources for this cache so that the rows remain in cache
for a very short time so as to serve the needs only for a single search
time interval like max 30 seconds. Is this approach correct.? That way I
wont be putting unneccessary data in cache for a long time thus saving
resources for other needs.

On Wed, Nov 16, 2011 at 11:20 AM, samal <> wrote:

> I think you can but I am not sure, I haven't tried that yet, Nothing harm
> in keeping value also it will be read in single query only.
> In 2nd case, yes 2 or more query required to get specific user details. As
> username is map to user_id's key(unique like UUID) and user_id key store
> actual details.
> On Wed, Nov 16, 2011 at 11:10 AM, Aditya Narayan <> wrote:
>> Regarding the first option that you suggested through composite columns,
>> can I store the username & id both in the column name and keep the column
>> valueless?
>> Will I be able to retrieve both the username and id from the composite
>> col name ?
>> Thanks a lot
>> On Wed, Nov 16, 2011 at 10:56 AM, Aditya Narayan <>wrote:
>>> Got the first option that you suggested.
>>> However, In the second one, are you suggested to use, for e.g,
>>> key='Marcos' & store cols, for all users of that name, containing userId
>>> inside that row. That way it would have to read multiple rows while user is
>>> doing a single search.
>>> On Wed, Nov 16, 2011 at 10:47 AM, samal <> wrote:
>>>>  > I need to add 'search users' functionality to my application. (The
>>>>>> trigger for fetching searched items(like google instant search) is
>>>>>> when 3 letters have been typed in).
>>>>>> >
>>>>>> > For this, I make a CF with String type keys. Each such key is
>>>>>> of first 3 letters of a user's name.
>>>>>> >
>>>>>> > Thus all names starting with 'Mar-' are stored in single row
>>>>>> key="Mar").
>>>>>> > The column names are framed as remaining letters of the names.
>>>>>> Thus, a name 'Marcos' will be stored within rowkey "Mar" & col
name "cos".
>>>>>> The id will be stored as column value. Since there could be many
users with
>>>>>> same name. Thus I would have multple userIds(of users named "Marcos")
to be
>>>>>> stored inside columnname "cos" under key "Mar". Thus,
>>>>>> >
>>>>>> > 1. Supercolumn seems to be a better fit for my use case(so that
>>>>>> of users with same name may fit as sub-columns inside a super-column)
>>>>>> since supercolumns are not encouraged thus I want to use an alternative
>>>>>> schema for this usecase if possible. Could you suggest some ideas
on this ?
>>>>>> >
>>>> Aditya,
>>>> Have you any given thought on Composite columns [1]. I think it can
>>>> help you solve your problem of multiple user with same name.
>>>> mar:{
>>>>   {cos,unique_user_id}:unique_user_id,
>>>>   {cos,1}:1,
>>>>   {cos,2}:2,
>>>>   {cos,3}:3,
>>>> //  {utf8,timeUUID}:timeUUID,
>>>> }
>>>> OR
>>>> you can try wide rows indexing user name to ID's
>>>> marcos{
>>>>    user1:' ',
>>>>    user2:' ',
>>>>    user3:' '
>>>> }
>>>> [1]

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