the smartest thing to do would be to avoid orderby when there are less records than paginate. However, it's unusual to have a query misbehaving for a couple hundreds records, and I really don't see the point on using grid with paginate=10000. Given that pagination is 99% of the time required, we need to orderby on something.... What we should orderby to then? The only assured field that has an implicit index is the id (being a PK). Orderby(ing) a PK should definitely not require a full scan. I don't see any particular case other than exceptional misbehaving tables to turn off the ordering.
On Tuesday, October 8, 2013 1:53:50 PM UTC+2, Anthony wrote: > > > db.table(id=3) is for returning the sole matching record, so you don't >>> have to worry about the database's arbitrary ordering of results. But when >>> using limitby to return a particular subset of records (e.g., when doing >>> pagination), don't you need to specify an orderby to guarantee that the >>> results on each query will remain in the same order? >>> >>> Yes you need to do it, and you need to do it in a proper way. That is >> why i think that forcing orderby when limitby is used is not a good idea. >> Seems just a hack for the grid, not a generic approach. IMHO it's better >> to be explicit. >> Consider that on datasets of size comparable to the window imposed by the >> limitby, the result is that if one uses limitby then he goes slower than >> without it, because of the implicit orderby. Maybe he wonders why (and all >> sorts of bad things about web2py ;- ) >> > > I suppose we could default orderby_on_limitby to False in the general case > and leave it to the developer to explicitly orderby when using limitby, but > what do you propose for the grid? > > Anthony > >> -- Resources: - http://web2py.com - http://web2py.com/book (Documentation) - http://github.com/web2py/web2py (Source code) - https://code.google.com/p/web2py/issues/list (Report Issues) --- You received this message because you are subscribed to the Google Groups "web2py-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to web2py+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
