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  • Sean McGivern's avatar
    Fix pagination on sorts with lots of ties · 8f667bd25b23
    Sean McGivern authored
    Postgres and MySQL don't guarantee that pagination with `LIMIT` and
    `OFFSET` will work if the ordering isn't unique. From the Postgres docs:
    
    > When using `LIMIT`, it is important to use an `ORDER BY` clause that
    > constrains the result rows into a unique order. Otherwise you will get
    > an unpredictable subset of the query's rows
    
    Before:
    
        [1] pry(main)> issues = 1.upto(Issue.count).map { |i| Issue.sort('priority').page(i).per(1).map(&:id) }.flatten
        [2] pry(main)> issues.count
        => 81
        [3] pry(main)> issues.uniq.count
        => 42
    
    After:
    
        [1] pry(main)> issues = 1.upto(Issue.count).map { |i| Issue.sort('priority').page(i).per(1).map(&:id) }.flatten
        [2] pry(main)> issues.count
        => 81
        [3] pry(main)> issues.uniq.count
        => 81
    8f667bd25b23