cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Quintero <>
Subject Re: Seeking advice on Schema and Caching
Date Tue, 15 Nov 2011 16:10:06 GMT

Aditya Narayan <> wrote:

>I need to add 'search users' functionality to my application. (The trigger
>for fetching searched items(like google instant search) is made when 3
>letters have been typed in).
>For this, I make a CF with String type keys. Each such key is made of first
>3 letters of a user's name.
>Thus all names starting with 'Mar-' are stored in single row (with
>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 ids of
>users with same name may fit as sub-columns inside a super-column) but
>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 ?
>2. Another thing, I would like to row cache this CF so that when the user
>types in the next character & the query is made consequently, then this row
>be retrieved from the cache without touching DB. It is expected while
>searching for a single username, the query(as a part of making
>instantaneous suggestions) will be made at least 2-3 times. One may also
>suggest to fetch all the columns starting with queried string to be
>retrieved & then filter out at application level but what about just
>fecthing the exact no of columns(ids/names of users) I need to show to the
>user. Thus instead of keeping all the hundreds of cols in the application
>layer what about keeping it within the DB cache.!?
>The space alloted for the cache will be very small so that row remains in
>cache for a very short time(enough to serve only for the time duration
>while user is making a single search!?) ?
View raw message