Hmm, maybe not... It seems that it always save NULL values, i’ll keep investigating and keep you posted...
Thanks, From: [email protected] [mailto:[email protected]] On Behalf Of Dominique Prunier Sent: Monday, January 16, 2012 2:37 PM To: FastBit Users Subject: Re: [FastBit-users] Convert a bundle into a partition Hey, I found a pretty easy way to create an on-disk projection. ibis::table* tbl = ibis::table::create("<partition directory>"); ibis::table* sel = tbl->select("<cols>", "<where>"); ibis::table* dev = sel->groupby("<cols> "); dev->backup("<projection directory>", "<projection name>", "<projection description>"); It seems to do pretty much what you’d expect. John, please tell us if this is a decently efficient way of doing it. More specifically, i have no idea about the memory overhead of the intermediate sel and the dev tables (does it only store a hit vector and reference the tbl table ? i see that groupby uses a bundle, but what about the dev table itself ?). Thanks, From: Jon Strabala [mailto:[email protected]] Sent: Monday, January 16, 2012 1:35 PM To: K. John Wu Cc: Dominique Prunier Subject: Re: [FastBit-users] Convert a bundle into a partition John, This might be a very usefull enhancement, e.g. imagine a system where fasbit could a created directed permenate materialized views (manged explicitly for say a DSS) or a alternatively a cache of materialized views from the most recent queries. I can image several use cases for such functionality. Best Regards, Jon Strabala On Mon, Jan 16, 2012 at 7:59 AM, K. John Wu <[email protected]<mailto:[email protected]>> wrote: Hi, Dominique, There is an in-memory data partition known as ibis::bord which can take a select clause and a data partition as input argument. This might be the closest to what you want. A little bit more work is needed to get to where you need it.. I am out of office during the day, might have time to look into this in the night.. John On 1/16/12 6:25 AM, Dominique Prunier wrote: > Hi, > > > > I was wondering if there were a way to convert a a bundle into a > partition. My goal here would be to create some projection of my > partition grouped by a subset of columns. For ex, my main partition > would be: > > > > Col1 Col2 Col3 > > 1 A B > > 2 C D > > 3 A B > > 4 A B > > > > And i’d like the following projection (Col2 and Col3), which is the > result of “SELECT Col2,Col3 GROUP BY Col2,Col3”: > > > > Col2 Col3 > > A B > > C D > > > > Thanks, > > > > */Dominique Prunier/**//* > > APG Lead Developper > > Logo-W4N-100dpi > > 4388, rue Saint-Denis > > Bureau 309 > > Montreal (Quebec) H2J 2L1 > > Tel. +1 514-842-6767 x310<tel:%2B1%20514-842-6767%20%20x310> > > Fax +1 514-842-3989<tel:%2B1%20514-842-3989> > > [email protected]<mailto:[email protected]> > <mailto:[email protected]<mailto:[email protected]>> > > www.watch4net.com<http://www.watch4net.com> <http://www.watch4net.com/> > > / / > > /This message is for the designated recipient only and may contain > privileged, proprietary, or otherwise private information. If you have > received it in error, please notify the sender immediately and delete > the original. Any other use of this electronic mail by you is prohibited. > > //Ce message est pour le récipiendaire désigné seulement et peut > contenir des informations privilégiées, propriétaires ou autrement > privées. Si vous l'avez reçu par erreur, S.V.P. avisez l'expéditeur > immédiatement et effacez l'original. Toute autre utilisation de ce > courrier électronique par vous est prohibée./// > > > > > > _______________________________________________ > FastBit-users mailing list > [email protected]<mailto:[email protected]> > https://hpcrdm.lbl.gov/cgi-bin/mailman/listinfo/fastbit-users _______________________________________________ FastBit-users mailing list [email protected]<mailto:[email protected]> https://hpcrdm.lbl.gov/cgi-bin/mailman/listinfo/fastbit-users
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