Getting doublets of records while using an offset

rubyonrails-talk
1

Consider this schenario where I’m having pagination on a page

@recordings =  Recording.order(:title).page(params[:page]).per(4)
 puts params[:page]
@recordings.each do |recording|
      puts recording.id

end 

  page ----------------3------------------------
Recording Load (4.0ms) SELECT "recordings".* FROM "recordings" ORDER BY "recordings"."title" ASC LIMIT 4 OFFSET 8
1032
952
1063
1166 <<<<<<<<<<<<<<<<<<<<<<<<<< notice 

page ----------------4------------------------

Recording Load (4.3ms) SELECT "recordings".* FROM "recordings" ORDER BY "recordings"."title" ASC LIMIT 4 OFFSET 12
1166 <<<<<<<<<<<<<<<<<<<<<<<<<< notice 1168
657
756

So record 1166 is on both pages
2

Is the issue that title is not in fact unique?

If so you could order on two columns (rather than creating an extra unique column), for example

Recording.order(:title, :id).page(params[:page]).per(4)

Fred

3

Are you on Postgresql? It takes a very literal interpretation of the SQL standard when row order isn’t uniquely specified:

Sorting on something that’s reliably unique (even just id along with title) should sort this out.

–Matt Jones