Hi Claude Actually I did some testing with Transformer, which I'm more used to than OpVisitor, and with it I can evaluate a cost function for each node. However I would need several different trees to be evaluated in order to find the best plan, and I can't see how Transformer could help on it.
I was thinking that maybe ARQ has a default query planner that could be substituted on configuration, or by applying a custom cost function. Was your work on DERI opensourced? Can you talk about it? I'm curious about which strategies did you used on your planner. Cheers, -- diogo patrão On Wed, Aug 28, 2013 at 6:24 PM, Claude Warren <[email protected]> wrote: > This discussion reminds me that a friend and I discussed the possibility of > adding pluggable OpVisitors to allow chained rewrites of the query before > execution. > > > On Wed, Aug 28, 2013 at 10:23 PM, Claude Warren <[email protected]> wrote: > > > When I did the work on the query engine described above I used an > > OpVisitor implementation in modifyOp to rewrite the query. It should be > > possible to implement the optimization there, but I don't know that it is > > the best place. > > > > Claude > > > > > > On Wed, Aug 28, 2013 at 5:19 PM, Diogo FC Patrao <[email protected] > >wrote: > > > >> Hi Claude > >> > >> I meant the first option, optimize queries to run at federated > >> environments. Although I'm working on a query "federator" as well, and > am > >> also interested in similar projects as well. > >> > >> Thanks > >> > >> -- > >> diogo patrão > >> > >> > >> > >> > >> On Wed, Aug 28, 2013 at 12:50 PM, Claude Warren <[email protected]> > wrote: > >> > >> > I did some work on query planning for federated queries when I worked > >> for > >> > DERI. (http://deri.ie). However, that work may have been a bit more > >> > complex than you are considering as we had some sources for vocabulary > >> > equivalence and were attempting to handle that at the same time. > >> > > >> > When you say a query planner for federated queries, are you looking to > >> > optimise queries that contain federated queries, or attempting to > build > >> a > >> > federated query from a non-federated one? > >> > > >> > Claude > >> > > >> > > >> > On Wed, Aug 28, 2013 at 1:54 PM, Diogo FC Patrao < > [email protected] > >> > >wrote: > >> > > >> > > Hello > >> > > > >> > > I was thinking about writing a query planner for federated queries. > >> > AFAIK, > >> > > there's no such thing on ARQ, and couldn't find any third-party libs > >> for > >> > > that. > >> > > > >> > > So my questions are: > >> > > > >> > > 1) do you know of any open source projects out there that deals with > >> it? > >> > > I'm willing to contribute. > >> > > > >> > > 2) If there is no such project, is a Transformer the right place to > go > >> > for > >> > > it? I thought about extending TransformerCopy to reorder OpJoins to > >> solve > >> > > first those with smaller costs. > >> > > > >> > > Thanks! > >> > > > >> > > > >> > > -- > >> > > diogo patrão > >> > > > >> > > >> > > >> > > >> > -- > >> > I like: Like Like - The likeliest place on the web< > >> > http://like-like.xenei.com> > >> > Identity: https://www.identify.nu/[email protected] > >> > LinkedIn: http://www.linkedin.com/in/claudewarren > >> > > >> > > > > > > > > -- > > I like: Like Like - The likeliest place on the web< > http://like-like.xenei.com> > > Identity: https://www.identify.nu/[email protected] > > LinkedIn: http://www.linkedin.com/in/claudewarren > > > > > > -- > I like: Like Like - The likeliest place on the web< > http://like-like.xenei.com> > Identity: https://www.identify.nu/[email protected] > LinkedIn: http://www.linkedin.com/in/claudewarren >
