[ros-users] Storing many files in a database ROS style

[Jeremy Leibs]

Billy,

I'm sorry I'm not entirely sure what it is that you are looking for.  If you
want things to be fast, it sounds like you can load all of these files as
messages into memory and work with them there without too much trouble.
1000 files of 4000 floats is only about 30MB, even if you store them as
doubles you should be fine.

Are you just looking for a way to write the messages out to disk and load
them in again at a later point?  It sounds like you already have a way of
reading your text files and converting them to messages.  Is it that you
haven't implemented a way of writing them back out to your text format, or
are you wanting to use a different, ROS-native, format to store them?

If you could elaborate a little bit on what it is that you are looking for a
solution to I can maybe point you in the right direction.

--Jeremy


On Fri, Jun 11, 2010 at 1:38 PM, Billy Okal <b.okal at jacobs-university.de>wrote:

> Dear Ros Users,
>
> I am writting a ros package to emulate a database in which I want to store
> many(1000+) text files(each containing about 4000 float values). Originally
> I though of using bag files to store this info but now it looks like thats
> not what I want. Basically I want to store these files and be able to
> perform Addition, Deletion, and Querying(compare one text file against all
> the rest to infer some properties of grasps). Right now I have made Ros msg
> representing the text files and can move them around ros, but the problem is
> storing these messages in some lasting memory so that I just load the
> database(which I can also make a ros message) in the beginning and to stuff
> then write it back.
>
> Does anybody have experience in this or something related or just some
> ideas I could use to go about this? Also I need to querying to be really
> fast(the goal is real time control)
>
> --
> Best Regards,
>
> Billy Okal
>
> sure vi is user friendly, its just particular about who to be friends with
>
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