Hi Emmanuel et al., My apologies for the log radio silence. I've taken a look at the code-base on Jon Halliday's repo, and have set up a nick on freenode - #jlesinge.
On the time-series question I was wondering how you envisaged the data stored: I tend to think of a single row under an primary key with an object-instance per column. Now what we have typically done (generally the data has been immutable) is to store the data serialized as a blob (JSON or XML), but I understand you do not favour this approach. With this sort of model I imagine the collection is then all the objects stored in the row, and the challenge is to page through the objects in the row. An approach we have often taken is to create multiple copies of data in different (obviously works well only for immutable objects) or better to create a table of keys to a main table where in either approach the row-keys are effectively a foreign-key and there is column per object associated through the foreign-key. Another approach though might be to use a column with type list (or set, or map) to contain keys to the associated objects - this would be a little like the extensions Oracle have for mapping 1-* associations, though with the caveat that a column of collection type may only contain 64k elements. I wondered if some though had been given to this strategy (which I must admit I have not yet used myself). It seems very likely that different mapping strategies should be specifiable, but then I have still to understand how these might fit with treiid. Can I ask about assumptions: is it fair to assume that for Cassandra, OGM will target only CQL 3 (which means Cassandra 2 or maybe 1.2)? This would certainly make life simpler. An issue I don't see addressed is the choice of consistency-level (read or write) and I wondered if there was a plan for this? Assumptions can be made on a per table basis, but, certainly for ad hoc queries, it is important think to have the flexibility to specify on a per-query basis. Those are my thoughts so far... I'll see about doing a POC of some of what I have described above Cheers, John On Mon, Jul 21, 2014 at 4:48 PM, John Worrell <jlesi...@gmail.com> wrote: > Hi Emmanuel, > > I'll take a look at what is there, and I'll get up and running on IRC. > > I'll particularly look at the time-series issue - non-trivial I think. > > Cheers, > > John > > > On Mon, Jul 21, 2014 at 1:06 PM, Emmanuel Bernard <emman...@hibernate.org> > wrote: > >> Hi John, >> >> I thought I had replied to you on Friday but apparently the email never >> went through :/ >> >> That is good news :) >> Jonathan worked on a Cassandra prototype but had to drop due to other >> duties. He pushed everything at >> https://github.com/jhalliday/hibernate-ogm/tree/jonathan_cassandra >> >> Have a look at what he has done and come ask any question to Gunnar, >> Davide or me. There are a bunch of moving pieces. We are mostly on >> freenode’s #hibernate-dev ( you need a freenode login >> http://freenode.net/faq.shtml#nicksetup ). If you are allergic to IRC, >> let me know and we will find alternatives. >> >> The most interesting challenge will be to see how we can map time series >> into a collection and make sure we let the user decide how much he wants to >> load. >> >> Emmanuel >> >> On 16 Jul 2014, at 13:17, John Worrell <jlesi...@gmail.com> wrote: >> >> > Hi, >> > >> > I'm interested in contributing to the Cassandra module of Hibernate-OGM >> - >> > what would be the baest way to go about this? >> > >> > Thanks, >> > >> > John >> > _______________________________________________ >> > hibernate-dev mailing list >> > hibernate-dev@lists.jboss.org >> > https://lists.jboss.org/mailman/listinfo/hibernate-dev >> >> > _______________________________________________ hibernate-dev mailing list hibernate-dev@lists.jboss.org https://lists.jboss.org/mailman/listinfo/hibernate-dev
