On Jul 10, 2009, at 1:27 PM, gsterndale wrote:
> > Thanks Philip, > > The Postgres gem rdoc hasn't been much help. All of the PGresult > instance methods that retrieve values require a tuple number. My > PGresult has a number of fields, but not tuples (rows). > > This query (when run in psql) returns a large block of text. For > example: > email,fname,lname,created_at > [email protected],Foo,Fooster,2009-07-07 17:00:41.929865 > [email protected],Bar,Barbie,2009-07-01 20:31:08.659965 > [email protected],User,User,2009-07-07 20:33:53.293606 > [email protected],Admin,Admin,2009-07-07 20:33:53.760538 > > I agree 100% that using FasterCSV and ActiveRecord to pull the data is > much more portable (and elegant). In fact, that's how I'm doing it > now. However, this is a huge dataset that is causing server timeouts > and hogs memory. I'm investigating csv generation in Postgres as it > takes a fraction of the time and resources because each object isn't > getting instantiated. > > Any thoughts? > Skip AR and use the select_values() call perhaps. That will skip any object instantiation at least. > On Jul 10, 4:07 pm, Philip Hallstrom <[email protected]> wrote: >>> I'm using ActiveRecord's connection to execute a custom query (which >>> runs fine in psql) like this: >> >>>>> result = ActiveRecord::Base.connection.execute("COPY (select * >>>>> from users) TO STDOUT WITH CSV;") >>> SQL (0.8ms) COPY (select * from users) TO STDOUT WITH CSV; >>> => #<PGresult:0x2589ad8> >>>>> result.nfields >>> => 39 >>>>> result.ntuples >>> => 0 >> >>> An instance of PGresult is returned. How can I get data out of it? >> >> Load up the rdocs for the postgres gem... it will tell you.... but >> why >> do it this way? Why not use AR to get your records and fastercsv to >> convert it to CSV? Much more portable... > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
